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Even after nearly 3 years of loyal service, the Hubble Area Telescope continues to run and supply spectacular pictures of the universes. As one of NASA’s Excellent Observatories, its observations of far-off galaxies, exoplanets, and the growth of deep space have actually had an innovative influence on astronomy, astrophysics and cosmology. Hubble’s most current contribution can be found in the type of a deep-sky mosaic image that was built utilizing 16 years’ worth of observations. Called the “ Hubble Tradition Field“, this mosaic is being referred to as the biggest and most thorough “history book” of galaxies. All informed, it includes approximately 265,000 galaxies that go back to simply 500 million years after the Big Bang. Almost 7,500 specific direct exposures entered into the production of the Hubble Tradition Field, supplying a broad picture of the far-off Universe that recalls to the earliest noticeable times. In so doing, the image demonstrates how galaxies have actually altered with time, growing through mergers to end up being the huge galaxies we see in deep space today. This successfully suggests that 13.3 billion years of cosmic advancement have actually been narrated in this one image. This enthusiastic undertaking makes up the cumulative work of 31 Hubble programs by various groups of astronomers. It likewise included observations taken by numerous Hubble deep-field studies. These consist of the Hubble Deep Field in 1995, the Excellent Observatories Origins Deep Study(ITEM) of 2003, the Hubble Ultra Deep Field of 2004, and the eXtreme Deep Field(XDF) of 2012, which is the inmost view of deep space to date. As Garth Illingworth, Teacher Emeritus at UCSC and head of the group that put together the ” Now that we have actually gone broader than in previous studies, we are gathering much more far-off galaxies in the biggest such dataset ever produced. No image will exceed this one till future area telescopes like James Webb are released.” In addition to revealing galaxies in the noticeable light, the wavelength variety covers from the ultraviolet to the near-infrared part of the spectrum. This is type in modern-day astronomy and cosmology, because it enables crucial functions of galaxy assembly to be made evident. A fine example is ” Such elegant high-resolution measurements of the various galaxies in this brochure allow a broad swath of extragalactic research study,” stated brochure lead scientist Katherine Whitaker of the University of Connecticut, in Storrs. “Frequently, these sort of studies have actually yielded unexpected discoveries which have actually had the best influence on our understanding of galaxy advancement.” About a century back, Edwin Hubble (for whom the HST is called) explained galaxies are the “markers of area”. At the time, he was observing far-off galaxies and kept in mind how light originating from most of them was moved towards the red end of the spectrum– aka. “redshifted”, which is a sign that huge things are moving far from us. These observations verified a forecast made by Einstein’s Theory of General Relativity— that deep space was either in a state of growth or contraction. Subsequent studies have actually utilized galaxies to determine the rate of cosmic growth (referred to as the Hubble Continuous), which has actually likewise provided hints regarding the underlying physics of the universes, when chemical aspects stemmed, and how our Planetary system and life ultimately appeared. This broader view is particularly practical in that regard given that it includes about 30 times as lots of galaxies as the previous deep fields. The Tradition Field has actually likewise exposed numerous uncommon things, a number of which are the residues of crashes and mergers that occurred throughout the early Universe– what are described as galactic “train wrecks”. As you can picture, assembling this image was no simple job. As Dan Magee, of the University of California, Santa Cruz, the group’s information processing lead, described: ” Our objective was to put together all 16 years of direct exposures into a tradition image. Formerly, the majority of these direct exposures had actually not been created in a constant manner in which can be utilized by any scientist. Astronomers can pick the information in the Tradition Field they desire and deal with it right away, instead of needing to carry out a substantial quantity of information decrease prior to performing clinical analysis.” In Spite Of being the most in-depth and extensive picture of galaxies ever taken, this brand-new image is simply the very first in a series of Hubble Tradition Field images. The group is presently dealing with another set of images, which amount to more than 5,200 Hubble direct exposures, from another location of the sky. Looking ahead, astronomers wish to expand the multiwavelength variety in the tradition images to consist of a lot more information on This will consist of longer-wavelength IR and high-energy X-ray observations from 2 other NASA Great Observatories– the Spitzer Area Telescope and the Chandra X-ray Observatory. As staff member Rychard Bouwens of Leiden University in the Netherlands stated in ESA news release: ” One interesting element of these brand-new images is the a great deal of delicate color channels now readily available to see far-off galaxies, particularly in the ultraviolet part of the spectrum. With images at a lot of frequencies, we can dissect the light from galaxies into the contributions from old and young stars, along with active stellar nuclei.” In the meantime, no picture of deep space is anticipated to exceed the Hubble Tradition Field images one till next-generation area telescopes are released. These consist of the James Webb Area Telescope(JWST) and the Wide-Field Infrared Area Telescope(WFIRST), both of which have instruments will that use enhanced resolution and level of sensitivity over Hubble and hence allow more thorough studies. The large variety of galaxies in the Tradition Field image are likewise prime targets for future telescopes. As Illingworth stated in a HubbleSite news release: ” We have actually created this mosaic as a tool to be utilized by us and by other astronomers. The expectation is that this study will cause a a lot more meaningful, thorough and higher understanding of deep space’s advancement in the coming years … This will actually set the phase for NASA’s prepared Wide-Field Infrared Study Telescope (WFIRST). The Tradition Field is a pathfinder for WFIRST, which will record an image that is 100 times bigger than a normal Hubble picture. In simply 3 weeks’ worth of observations by WFIRST, astronomers will have the ability to put together a field that is much deeper and more than two times as big as the Hubble Tradition Field.” In addition, the JWST’s imaging abilities in the IR band (which are beyond the limitations of Hubble or Spitzer) will permit astronomers to penetrate much deeper into the Tradition Field image to expose more about how infant galaxies grew. The image(together with the specific direct exposures that entered into making it) is readily available through the Mikulski Archive for Area Telescopes(MAST).

These days, consumers can take their pick from an impressive array of fabulous items of diamond jewellery. For example, they can head online to select princess cut diamond engagement rings. All they need is a little spare time and a web connection. As long as they know where to look, they should be able to find the perfect princess cut diamond rings for them, and within their budgets too. Meanwhile, it seems as though the Earth is not the only planet in the Solar System to feature diamonds. According to a BBC report, these precious stones could be raining down on Saturn and Jupiter. Scientists in the US have calculated that there is an abundance of these items within the gas giants. The researchers noted that lightning storms within the planets’ atmospheres turn methane into carbon. This soot-like substance hardens as it falls into chunks of graphite and then into diamond. Eventually, these unusual ‘hail stones’ melt into a liquid at the core of the planets. Dr Kevin Baines from the University of Wisconsin-Madison and Nasa’s Jet Propulsion Laboratory suggested that the biggest diamonds would probably be around a centimetre in diameter. Expanding on this, he noted they would be “big enough to put on a ring, although of course they would be uncut”. The expert added: “The bottom line is that 1,000 tonnes of diamonds a year are being created on Saturn. People ask me – how can you really tell? Because there’s no way you can go and observe it. It all boils down to the chemistry. And we think we’re pretty certain.” Dr Baines stated that the process of diamond creation begins in the upper atmosphere or so-called ‘thunderstorm alleys’, where the soot forms. Explaining the subsequent processes, he said: “As the soot falls, the pressure on it increases. And after about 1,000 miles it turns to graphite – the sheet-like form of carbon you find in pencils.” By a depth of 6,000 kilometres, this graphite toughens into diamond. The specialist went on to draw attention to the “hellish” temperatures on Saturn and Jupiter. About this, he remarked: “Diamonds aren’t forever on Saturn and Jupiter. But they are on Uranus and Neptune, which are colder at their cores.” He presented his findings during the recent annual meeting of the Division for Planetary Sciences of the American Astronomical Society in the US along with his co-author, Mona Delitsky, from California Speciality Engineering. When asked to comment on the predictions, fellow expert Professor Raymond Jeanloz told the BBC: “The idea that there is a depth range within the atmospheres of Jupiter and (even more so) Saturn within which carbon would be stable as diamond does seem sensible.” He added: “Given the large sizes of these planets, the amount of carbon (therefore diamond) that may be present is hardly negligible.” Of course, consumers do not have to go to the lengths of trying to source precious stones in space. When they are after a princess cut engagement ring or other similar item, they can simply turn to the web and place their orders. About the Author – Anna Longdin is a regular contributor to lifestyle blogs and loves perusing the fabulous range of jewellery products now available. Find out where she gets her inspiration by visiting Marlow’s Diamonds.

In addition to James K's answer, many gases exist in the disk of material that forms into planets. What's a gas as opposed to a liquid or solid also depends on temperature and pressure. The most abundant "gases" in our solar-system are hydrogen, helium, CO2, H2O, CH4, NH3, N2, O2, CO, Neon (and maybe some others I've overlooked), in something sort of close to that order. Many of these "gases" are also ices that form up the majority of comets. During planetary formation, the ring of debris is too warm for hydrogen, Helium and Neon to be anything but a gas, though some hydrogen is bound to heavier elements and abundant in planet formation. Helium and Neon and the other Noble Gases don't bind well with other elements. The other abundant "gases", H20, CO2, NH3, CH4, etc, can exist as ices past their respective frost lines. That's why those molecular compounds are much more common in the outer part of the solar system. Earth and Mars formed inside the frost-line so they formed mostly out of rocky material, after which, much of the lighter elements, primarily gases and liquids, were acquired by comet impacts after formation, though some probably existed prior too formation. During the late heavy bombardment there were many large impacts and one consequence of very large comet or meteor impacts is a rise in temperature, so, even in the early solar-system when the sun wasn't as luminous as it is now, the planets, Earth and Mars spent some of the time quite hot. There's two primary ways a planet can lose it's atmosphere, Jeans Escape and by the solar wind. The solar wind is made up of almost entirely charged particles, so if a planet has a magnetic field, the impact of those high speed particles is largely deflected, where as, if they impact the upper atmosphere, the planet can lose it's atmosphere like tiny billiard balls being knocked off one at a time. While the method of those two ways a planet can lose it's atmosphere are different, it comes down to basically the same thing. When gas molecules on the outer edge of a planet's atmosphere move faster than escape velocity they are likely to escape the planet into space and because lighter gas molecules move faster than heavier ones. That's the Maxwell-Boltzmann law or Root-mean-square formula, planets are more likely to retain heavier gases. Venus and Mars have both lose most of their lighter gases, H20, CH4, NH3 but CO2 is heavy enough to have been retained by both those planets, though it's worth pointing out that we don't know how much CO2 Mars had millions and billions of years ago. Mars may have lost much of it's CO2 over time as well. It just lost it more slowly than the lighter gases. Mars was able to retain some of it's water, however, in the form of ice. Venus, like Mars, lost nearly all of it's gaseous water. We know that Venus used to have much more water because it's very high D to H ratio wouldn't be possible unless it had lost a significant percentage of it's water, likely 99.9% or higher. Earth is massive enough and Earth has a strong magnetic field, so Earth is able to retain it's lighter gases like CH4, NH3 and atmospheric H20, though Earth loses Hydrogen and Helium to space. NH3 is kind of interesting because it dissolves in water quite readily, so as soon as the young Earth had oceans, those oceans were likely Ammonia/water with whatever else readily dissolved in the liquid such as Iron. The early oceans are thought to have been brown colored from the dissolved Iron. But Earth's young atmosphere was likely mostly CO2 and CH4 with most of the H20 in liquid form, (and at times, much of it was ice). As life and photosynthesis began releasing Oxygen, Oxygen readily bonded with the CH4 and dissolved Iron in the oceans, turning the oceans blue and in time, making the Atmosphere free of CH4 and more abundant with O2. It's unclear (and perhaps unlikely?) if Mars and Venus ever underwent that Oxygenation period that Earth did. Having abundant liquid oceans and having photosynthetic life made a significant difference to Earth's atmosphere. You mentioned plate tectonics and that plays a role too as does the chemistry that happens in the oceans and below the surface of a planet. The main reason Mars is 95% CO2 now is because it's small and it doesn't have a good magnetic field, only small localized ones. It lost most of it's atmosphere and nearly all of it's lighter gas molecules.

Crescent ♉ Taurus Moon phase on 3 June 2035 Sunday is Waning Crescent, 26 days old Moon is in Taurus.Share this page: twitter facebook linkedin Previous main lunar phase is the Last Quarter before 4 days on 30 May 2035 at 07:31. Moon rises after midnight to early morning and sets in the afternoon. It is visible in the early morning low to the east. Moon is passing about ∠6° of ♉ Taurus tropical zodiac sector. Lunar disc appears visually 2.5% wider than solar disc. Moon and Sun apparent angular diameters are ∠1939" and ∠1891". Next Full Moon is the Strawberry Moon of June 2035 after 17 days on 20 June 2035 at 19:37. There is low ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at big angle, so their combined tidal force is weak. The Moon is 26 days old. Earth's natural satellite is moving from the second to the final part of current synodic month. This is lunation 437 of Meeus index or 1390 from Brown series. Length of current 437 lunation is 29 days, 7 hours and 17 minutes. It is 38 minutes longer than next lunation 438 length. Length of current synodic month is 5 hours and 27 minutes shorter than the mean length of synodic month, but it is still 42 minutes longer, compared to 21st century shortest. This lunation true anomaly is ∠338.4°. At the beginning of next synodic month true anomaly will be ∠354.2°. The length of upcoming synodic months will keep decreasing since the true anomaly gets closer to the value of New Moon at point of perigee (∠0° or ∠360°). 10 days after point of apogee on 24 May 2035 at 09:19 in ♐ Sagittarius. The lunar orbit is getting closer, while the Moon is moving inward the Earth. It will keep this direction for the next 2 days, until it get to the point of next perigee on 6 June 2035 at 11:36 in ♊ Gemini. Moon is 369 741 km (229 746 mi) away from Earth on this date. Moon moves closer next 2 days until perigee, when Earth-Moon distance will reach 357 357 km (222 051 mi). 4 days after its descending node on 30 May 2035 at 10:00 in ♓ Pisces, the Moon is following the southern part of its orbit for the next 8 days, until it will cross the ecliptic from South to North in ascending node on 11 June 2035 at 20:42 in ♍ Virgo. 18 days after beginning of current draconic month in ♍ Virgo, the Moon is moving from the second to the final part of it. 9 days after previous South standstill on 25 May 2035 at 00:53 in ♑ Capricorn, when Moon has reached southern declination of ∠-18.782°. Next 3 days the lunar orbit moves northward to face North declination of ∠18.820° in the next northern standstill on 7 June 2035 at 10:40 in ♋ Cancer. After 2 days on 6 June 2035 at 03:21 in ♊ Gemini, the Moon will be in New Moon geocentric conjunction with the Sun and this alignment forms next Sun-Moon-Earth syzygy.

NASA's two Voyager spacecraft show nothing's simple at the edges of the solar system. After a three-decade journey away from Earth, the two Voyager spacecraft are approaching the outer edges of the solar system. To scientists' surprise, the satellites have revealed a region vastly different than previously modeled. The solar system's boundary is defined by a steady stream of particles known as the solar wind. The solar wind shoots out from the sun until it pushes up against the galactic medium and slows down at a line called the termination shock. Beyond this lies the heliosheath, where the solar wind's journey stops completely. Scientists thought the solar wind turned back smoothly at this point, sweeping back around the outskirts of the solar system. As seen in the video below, Voyager now shows that solar wind hits the heliosheath and piles up into a frothy layer filled with magnetic bubbles. This layer must have an affect on how intense energetic particles from the rest of the universe, called cosmic rays, make it into our solar system. But scientists have yet to figure out if the bubbles help stop the bulk of the rays, or are the prime factor that allows them to enter.

(Inside Science) -- Terrestrial animals may owe a special debt to the sun and the moon. It may have been their combined pull on ancient Earth's oceans that helped primitive air-breathing fish gain a toehold on land, new research suggests. In a new study, published in the journal Proceedings of the Royal Society A, physicist Steven Balbus argues that the gravitational forces generated by the sun and moon would have been conducive to the formation of a vast network of isolated tidal pools during the Devonian Period, between 420 to 360 million years ago, when fish-like vertebrates first clambered out of the sea. "By the end of the Devonian, there were vertebrates that were quite at home moving around on land," said Balbus, who is at the University of Oxford in the United Kingdom. According to Balbus, a rather remarkable confluence of cosmic, geological and biological events occurred during the Devonian period that helped jump-start life on land. First, when viewed from the Earth, the sun and the moon appeared to be almost the same size, as is true today. This is called having the same angular diameter. "The sun is much bigger than the moon, but it's also much farther away, so the two bodies look to be about the same size to us. This is extraordinary," Balbus said. He added that it's very unusual for an Earth-sized planet to have such a large moon. One consequence of this arrangement is that the "tidal force" of the sun and the moon on our planet are similar. The tidal force is a side effect of the force of gravity and is responsible for ocean tides. Because the Earth is a sphere, gravity doesn't act equally on all parts of it. "The part of the surface that's closer to the sun is pulled a little bit more strongly, and the part that's farther away is pulled a little less strongly," said Balbus. "The same thing happens with the moon." Because the tidal forces of the sun and moon are similar, the timing and size of Earth's ocean tides can change depending on whether the solar and lunar tidal forces are opposed to one another or acting in synchrony. The variety of ocean tide patterns generated by the sun and the moon would have been especially noticeable during the Devonian due to the arrangement of our Earth's continents, Balbus said. "The positions of Earth’s continents have changed over time because of [plate tectonics]. They had a rather special orientation in the Devonian," explained Balbus. Watery safe havens Specifically, there were only two "supercontinents," Gondwana and Euramerica, at the time, and the two land masses were separated by an expanse of water known as the Rheic Ocean. The Rheic Ocean had a unique tapered shape, so that its eastern side was narrower and shallower than its western end, which would be conducive to the formation of large tides. "This would have helped create a very extensive and very complex network of inland tidal pools," Balbus said. The final part of Balbus' proposal is biological. The Devonian period also happened to be when scientists think stubby-legged fish with primitive air-breathing lungs known as tetrapods first ventured onto land. If strong tides stranded animals in shallow pools, they could be trapped and perish if unable to scramble to larger bodies of water. If, as Balbus suggests, tidal pools were plentiful during the Devonian, early tetrapods that were mobile would have had an easier time surviving out of the water because they could have dipped back into one of the many refuges scattered across the landscape. From there, it would have been a relatively short leap to a full-time terrestrial lifestyle, Balbus said. A bold idea Per Alhberg, an evolutionary biologist at Uppsala University in Sweden, praised Balbus's original thinking. "I love the boldness of this paper ... and the way Steven has dared to link together wildly different scientific disciplines in an attempt to understand a unique evolutionary event," said Alhberg, who was not involved in the study. Alhberg also thinks the scenario envisioned by Balbus is very plausible. "There is direct evidence that many of the earliest tetrapods and their fish ancestors lived in deltaic or marginal marine environments, so one way or another they must have passed through the tidal zone on the way from water to land," Alhberg said. "It could hardly have failed to have an effect on them, and we know that there are plenty of animals today that exploit the intertidal environment and live partly in, partly out of, the water." Balbus said that developing his theory has made him skeptical of the notion that complex terrestrial life might be common in the universe. "A lot of things had to come together in a strange way on the Earth," he added. Alhberg, on the other hand, thinks alien life could still be plentiful, but that its makeup might be different from Earth's. "An Earth-like planet without a moon might have a rich diversity of life in the oceans but rather simple microorganism-dominated ecosystems on land," he said. Ker Than is a freelance writer living in the Bay Area. He tweets at @kerthan.

By Sam Wilkinson There are a couple of man-made objects in space that almost everyone will know about: the International Space Station, the Hubble Space Telescope, Mars Science Laboratory Curiosity and maybe Voyager I and/or II. However, there is so much other man-made stuff in space it’s crazy (and it’s actually starting to become a problem). This abundance of space-faring objects can make it hard for some truly awesome experiments, missions etc to get much exposure! I’d like to fix that with a recurring blog post series called “Awesome Stuff in Space”. Since this is the inaugural post, I’m going to cover two of the coolest lesser-known things currently in space (in my humble opinion), as well as an awesome example of recycling (which is no longer in space). 1. LAGEOS: The (really useful) orbital disco ball When asked what the most precise method currently available for determining the position of a place on earth was, my first response would probably be military-grade GPS, but I’d be wrong. In fact, the most precise way to determine your position on earth is by bouncing a laser beam off of what is essentially a disco ball in space. That disco ball would either be LAGEOS-1 or LAGEOS-2 (LAser GEOdynamics Satellite), two 60cm wide spheres each covered in 426 retroreflectors (a special mirror that reflects light back the way it came) currently orbiting the earth at 5,900km above us. By measuring the time taken for a laser pulse to travel to a LAGEOS satellite and back, the distance between the ground station and the satellite can be calculated to a very high degree of accuracy (~1 inch for thousands of miles). Since the orbits of the LAGEOS satellites are very stable, their positions can be determined to a high degree of accuracy. This coupled with the distance between the ground station and the satellite can be used to determine the precise location of the ground station. There are ground stations performing these measurements in many countries, and the results are used to study tectonic plate movement by groups from around the world. 2. Dawn: Exploring new frontiers in new ways One of my favourite statistics on the solar system is this: approximately 42% of the mass of the asteroid belt is made up from just two objects, the dwarf planet Ceres and the asteroid Vesta. These also happen to be the two main objectives for the spacecraft Dawn, launched in September of 2007. Dawn has already travelled to Vesta, and is currently en route to Ceres. The study of Ceres and Vesta will greatly contribute to our understanding of the formation of planets. Since Ceres and Vesta are the two largest remaining protoplanets (planetary embryos) in the solar system, the observation of these objects will give us a peek at the earliest stages in the formation of the solar system. What makes Dawn even more special, aside from it being the first craft to travel to both Vesta and Ceres (hopefully), is that it is NASA’s first purely exploratory mission to use ion thrusters as its sole mode of propulsion. 3. SuitSat-1: “A Russian Brainstorm” The concept behind SuitSat-1 is quite simple, put some simple electronics (radio communications system, telemetry) into a Russian Orlan spacesuit, then throw it out of the airlock. According to Frank Bauer of NASA’s Goddard Space Flight Center, “SuitSat is a Russian brainstorm, some of our Russian partners in the ISS program … had an idea: Maybe we can turn old spacesuits into useful satellites.” Aside from broadcasting voice messages from students around the world, and some telemetry data, SuitSat-1 also looked really eerie. Images of Suit-Sat as it was being jettisoned from the ISS are kind of haunting… -See Part II of Amazing Stuff in Space here…

The Dark Side of the Universe by Jan Smit and Renske Smit To put us, as book reviewers, in context, like many scientists, we study our surroundings in an effort to understand where we came from. Jan, the historical geologist, likes to begin with the birth of our solar system 4.56 billion years ago. Before that, in his mind, there was nothing. Renske, the astrophysicist, works on much larger time scales, beginning with the birth of the earliest galaxies 13.2 billion years ago. For her, our solar system is just a little speck in recent history. It is therefore rare to come across a publication that piques the interest of both of us. Such was the case with particle physicist Lisa Randall’s new book,/Dark Matter and the Dinosaurs./ The first thought that crossed both our minds when reading the title of this book was: “Oh, no, not again, another outlandish proposal for the extinction of dinosaurs….” However, we were relieved to find that, right from the start, Randall dismisses almost all connections between dark matter and the mass-extinction event that wiped out the dinosaurs. Instead, the book takes the reader on a journey through the cosmos, describing what we know about dark matter and what more we are poised to learn as new and better equipment becomes available. Randall starts with an outline of “The Big Questions”: Why is there something rather than nothing? What happened during the Big Bang? What came before the Big Bang? She explains that there has to be dark matter because the behavior of merged galaxy clusters like the Bullet Cluster cannot be explained otherwise. She skims through the Big Bang, cosmic inflation, and how the galaxies formed when normal matter hitchhiked along with dark matter to form the seeds of the first stars. Without dark matter, we learn, our Milky Way and Earth as we know it would not exist. Having covered the creation of stars, the book turns to our solar system. Here, Randall vividly describes the comets and asteroids that have hit or will hit Earth. She recounts how meteorites may have brought essential amino acids and perhaps some water to Earth and describes the Chicxulub asteroid/comet and its role in the mass extinction at the end of the Cretaceous. The story of the Chicxulub impact and its role in the extinction of the dinosaurs is highly entertaining and largely correct. In the last chapters of the book, Randall outlines an important new way of thinking that applies to the search for viable dark matter models. The only way to find out whether something is allowed or even preferred is to evaluate the consequences of new assumptions and determine their experimental implications. Although observations indicate that dark matter consists of a mostly noninteracting substance, no experiment can currently rule out that dark matter may have a weak interaction with its own particles or, alternatively, that a small fraction of particles of dark matter have a moderately large interaction with one another. If true, these new models would be an extension of current theories, some of which can be tested in new experiments over the next few years. One model explored in this book shows how a narrow disk of dark matter in the galactic plane could potentially explain the periodicity in the crater records on Earth and could have contributed to the impact 66 million years ago that generated the mass extinction of the dinosaurs. Randall is quick to admit that the data that favor such a model are still tenuous and that the theory requires further testing. So does that mean that dark matter and dinosaurs are connected? Likely not, although there is a chance that they could be. In the end, drawing a definitive connection between the two is not really the aim of the book. Randall has a manner of writing that is pleasant and compelling: Cliff-hangers at the end of each chapter reel you into the next. Her method of using everyday situations as metaphors for explaining complicated concepts in physics is also very effective. For example, she describes how scientists know that dark matter is present in much the same way that you may be able to infer that George Clooney is in busy downtown New York: You may not see, smell, or hear him, but you can observe that all faces on the street are directed toward him. Despite the provocative title, the scientific reasoning set out in this book is sound and interesting. Randall succeeds in guiding the reader through the history of the cosmos and the Earth from the Big Bang to the emergence of life as we know it in a fun and captivating way. The rich metaphors and personal anecdotes peppered throughout the book make this a very enjoyable read for both lay readers and scientists of various backgrounds.

I am looking for basic data regarding red-shifting that comes with reliable measure of distance of the emitting star. Red shift is usually measured for galaxies rather than individual stars. Unless a star has just gone supernova, it's usually not bright enough to be seen even w the world's most powerful telescopes at the distances where cosmological redshift comes into play. Hubble's law operates over large distances; the expansion constant being 67.8 km/sec per megaparsec (3.3 million light years) Andomeda galaxy (M31) is 2.54 million light years away, and although some individual stars are visible at that distance, the galaxy has a net blueshift of 0.001001 (303 km/sec) due to its peculiar (i.e. non-Hubble) velocity. Further out is where you start to see redshifts in excess of peculiar motion; and there you need to start using standard candles of some sort. Cepheid variables when visible, Supernova, globular cluster brightness functions, are all used, as well as some spectral methods: Cosmic distance ladder Supernova measurements go the furthest out, highest redshift, but are still a bit of a can of worms as far as interpretation goes.

Behold: Arp 273 – a great interstellar battle featuring upper galaxy UGC 1810 and its smaller collisional neighbour UGC 1813. War is hell. To wit: The overall shape of the UGC 1810 — in particular its blue outer ring — is likely a result of wild and violent gravitational interactions. The blue colour of the outer ring at the top is caused by massive stars that are blue hot and have formed only in the past few million years. The inner part of the upper galaxy — itself an older spiral galaxy — appears redder and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to colliding galaxies, while several far-distant galaxies are visible in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekicks over the next billion years and settle into a classic spiral form.

This image illustrates the four common states of matter: solid, liquid, gas, and plasma. States of Matter This figure shows the four common states of matter: solid, liquid, gas, and plasma. Consider water as an example. Solid water is ice. Liquid water is, well, water. We call water in its gaseous form "water vapor". A plasma created from water would include electrons, protons (hydrogen atom nuclei), and oxygen atom nuclei (protons and neutrons). There are special names for most transitions from one state to another. Freezing is turning from a liquid to a solid; melting is turning from a solid to a liquid. The transition from liquid to gas can happen by boiling or evaporation. Condensation is changing from a gas to a liquid. Sometimes (usually at low pressure) a solid can become a gas directly (without first melting to become a liquid); this transformation is called "sublimation". Removing electrons from atoms (usually in a gas) to produce a plasma is called "ionization". Stars are made of plasma, so plasma is the most abundant form of matter in the There are several other very exotic and unusual forms of matter that we don't encounter in daily life. A Bose-Einstein condensate can only form at temperature near absolute zero, and was first created in a lab in 1995. Degenerate matter can come into being under incredibly high pressure inside white dwarf and neutron stars. There are other very strange, very rare forms of matter as well. You might also be interested in: Solid is one of the four common states of matter. The three others are gas, liquid, and plasma. There are also some other exotic states of matter that have been discovered in recent years. Unlike liquids...more Plasma is known as the fourth state of matter (the first three states being solid, liquid and gas).Matter in ordinary conditions on Earth has electrons that orbit around the atomic nucleus. The electrons...more The cryosphere includes the parts of the Earth system where water is in its frozen (solid) form. This includes snow, sea ice, icebergs, ice shelves, glaciers, ice sheets, and permafrost soils. Approximately...more Oxygen is a chemical element with an atomic number of 8 (it has eight protons in its nucleus). Oxygen forms a chemical compound (O2) of two atoms which is a colorless gas at normal temperatures and pressures....more Any substance, called matter, can exist as a solid material, liquid, or gas. These three different forms are called states. Matter can change its state when heated. As a solid, matter has a fixed volume...more One process which transfers water from the ground back to the atmosphere is evaporation. Evaporation is when water passes from a liquid phase to a gas phase. Rates of evaporation of water depend on factors...more White Dwarfs are the remnants of stars that were massive enough to stay alive using nuclear fusion in their cores, but not massive enough to blow apart in a Type II supernova. When stars like our own sun...more

DIALLING, sometimes called gnomonics, is a branch of applied mathematics which treats of the construction of sun-dials, that is, of those instruments, either fixed or portable, which determine the divisions of the day by the motion of the shadow of some object on which the sun's rays fall. It must have been one of the earliest applications of a knowledge of the apparent motion of the sun ; though for a long time men would probably be satisfied with the division into morning and afternoon as marked by sun-rise, sun-set, and the greatest elevation. History.The earliest mention of a sun-dial is found in Isaiah xxxviii. 8 : " Behold, I will bring again the shadow of the degrees which is gone down in the sun-dial of Ahaz ten degrees backward." The date of this would be about 700 years before the Christian era, but we know nothing of the character or construction of the instrument. The earliest of all sun dials of which we have any certain knowledge was the hemicycle, or hemisphere, of the Chal-dean astronomer Berosus, who probably lived about 340 B.C. It consisted of a hollow hemisphere placed with its rim perfectly horizontal, and having a bead, or globule, fixed in any way at the centre. So long as the sun remained above the horizon the shadow of the bead would fall on the inside of the hemisphere, and the path of the shadow during the day would be approximately a circular arc. This arc, divided into twelve equal parts, deter-mined twelve equal intervals of time for that day. Now, supposing this were done at the time of the solstices and equinoxes, and on as many intermediate days as might be considered sufficient, and then curve lines drawn through the corresponding points of division of the different arcs, the shadow of the bead falling on one of these curve lines would mark a division of time for that day, and thus we should have a sun-dial which would divide each period of daylight into twelve equal parts. These equal parts were called temporary hours; and, since the duration of daylight varies from clay to day, the temporary hours of one day would differ from those of another ; but this inequality would probably be disregarded at that time, and especially in countries where the variation between the longest summer day and the shortest winter day is much less than in our climates. The dial of Berosus remained in use for centuries. The Arabians, as appears from the work of Albateguius, still followed the same construction about the year 900 A.D. Four of these dials have in modern times been found in Italy, One, discovered at Tivoli in 1746, is supposed to have belonged to Cicero, who, in one of his letters, says that he had sent a dial of this kind to his villa near Tusculum. The second and third were found in 1751 one at Castel-Nuovo, and the other at Bignauo; and a fourth was found in 1762 at Pompeii. G. H. Martini, the author of a dissertation in German on the dials of the ancients, says that this dial was made for the latitude of Memphis ; it may therefore be the work of Egyptians, per-haps constructed in the school of Alexandria. It is curious that no sun-dial has been found among the antiquities of Egypt, and their sculptures give no indication of any having existed. It has, however, been supposed that the numerous obelisks found everywhere were erected in honour of the sun and employed as gnomons. Herodotus has recorded that the Greeks derived from the Babylonians the use of the gnomon, but the great pro-gress made by the Greeks in geometry enabled them in later times to construct dials of great complexity, some of which remain to us, and are proofs, not only of extensive knowledge, but also of great ingenuity. Ptolemy's Syntaxis treats of the construction of dials by means of his analemma, an instrument which solved a variety of astronomical problems. The constructions given by him were sufficient for regular dials, that is, horizontal dials, or vertical dials facing east, west, north, or south, and these are the only ones he treats of. It is certain, however, that the ancients were able to construct declining dials, as is shown by that most interesting monument of ancient gnomonicsthe Tower of the Windswhich is still in existence at Athens. This is a regular octagon, on the faces of which the eight principal winds are represented, and over them eight different dialsfour facing the cardinal points and the other four facing the intermediate directions. The date of the dials is long subsequent to that of the tower ; for Vitruvius, who describes the tower in the sixth chapter of his first book, says nothing about the dials, and as he has described all the dials known in his time, we must believe that the dials of the tower did not then exist. The tower and its dials are described by Stuart in his Antiquities of Athens. The hours are still the temporary hours, or, as the Greeks called them, hectemoria. As already stated, the learning and ingenuity of the Greeks enabled them to construct dials of various forms among others, dials of suspension intended for travellers; but these are only spoken of and not explained; they may have been like our ring-dials. The Romans were neither geometers nor astronomers, and the science of gnomonics did not flourish among them. The first sun-dial erected at Rome was in the year 290 B.C, and this Papirius Cursor had taken from the Samnites. A dial which Valerius Messala had brought from Catania, the latitude of which is five degrees less than that of Borne, was placed in the forum in the year 261 B.C. The first dial actually constructed at Borne was in the year 164 B.C., by order of Q. Marcius Philippus, but, as no other Roman has written on gnomonics, this was perhaps the work of a foreign artist. If, too, we remember that the dial found at Pompeii was made for the latitude of Mem-phis, and consequently less adapted to its position than that of Catania to Rome, we may infer that mathematical knowledge was not cultivated in Italy. The Arabians were much more successful. They attached great importance to gnomonics, the principles of which they had learned from the Greeks, but they greatly simplified and diversified the Greek constructions. One of their writers, Abul-Hassan, who lived about the beginning of the 13th century, taught them how to trace dials on cylindrical, conical, and other surfaces. He even introduced equal or equinoctial hours, but the idea was not sup-ported, and the temporary hours alone continued in use. Where or when the great and important step already conceived by Abul-Hassan, and perhaps by others, of reckoning by equal hours was generally adopted cannot now be determined. The history of gnomonics from the 13th to the beginning of the 16th century is almost a blank, and during that time the change took place. We can see, however, that the change would necessarily follow the introduction of clocks and other mechanical methods of measuring time ; for, however imperfect these were, the hours they marked would be of the same length in summer and in winter, and the discrepancy between these equal hours and the temporary hours of the sun-dial would soon be too important to be overlooked. Now, we know that a balance clock was put up in the palace of Charles V. of France about the year 1370, and wo may reasonably sup-pose that the new sun-diafs came into general use during the 14th and 15th centuries. Among the earliest of the modern writers on gnomonics must be named Sebastian Munster, a cordelier who pub-lished his Horologiographia&t Basel in 1531. He gives a number of correct rules, but without demonstrations. Among his inventions was a moon-dial, but this does not admit of much accuracy. During the 17th century dialling was discussed at great length by all writers ou astronomy. Clavius devotes a quarto volume of 800 pages entirely to the subject. This was published in 1612, and may be considered to contain all that was known at that time. In the 18th century clocks and watches began to supersede sun-dials, and these have gradually fallen into disuse except as an additional ornament to a garden, or in remote country districts where the old dial on the church tower still serves as an occasional check on the modern clock by its side. The art of constructing dials may now be looked upon as little more than a mathematical recrea-tion. General Principles.The diurnal and the annual motions of the earth are the elementary astronomical facts on which dialling is founded. That the earth turns upon its axis uniformly from west to east in 24 hours, and that it is carried round the sun in one year at a nearly uniform rate, is, we know, the correct way of expressing these facts. But the effect will be precisely the same, and it will suit our purpose better, and make our explanations easier, if we adopt the ideas of the ancients, of which our senses furnish apparent confirmation, and assume the earth to be fixed. Then, the sun and stars revolve round the earth's axis uniformly from east to west once a day,the sun lagging a little behind the stars, making its day some 4 minutes longer, so that at the end of the year it finds itself again in the same place, having made a complete revolution of the heavens relatively to the stars from west to east. The fixed axis about which all these bodies revolve daily is a line through the earth's centre ; but the radius of the earth is so small, compared with the enormous distance of the sun, that, if we draw a parallel axis through any point of the earth's surface, we may safely look on that as being the axis of the celestial motions. The error in the case of the sun would not, at its maximum, that is, at 6 A.M. and 6 P.M., exceed half a second of time, and at noon would vanish. An axis so drawn is in the plane of the meridian, and points, as we know, to the pole,its elevation being equal to the latitude of the place. The diurnal motion of the stars is strictly uniform, and so would that of the sun be if the daily retardation of about 4 minutes, spoken of above, were always the same. But this is constantly altering, so that the time, as measured by the sun's motion, and also consequently as measured by a sun-dial, does not move on at a strictly uniform pace. This irregularity, which is slight, would be of little consequence in the ordinary affairs of life, but clocks and watches being mechanical measures of time could not, except by extreme complication, be made to follow this irregularity, even if desirable, which is not the case. The clock is constructed to mark uniform time in such wise that the length of the clock day shall be the average of all the solar days in the year. Four times a year the clock and the sun-dial agree exactly ; but the sun-dial, now going a little slower, now a little faster, will be some-times behind, sometimes before the clockthe greatest accumulated difference being about 16 minutes for a few days in November, but on the average much less. The four days on which the two agree are April 15, June 15, September 1, and December 24. Clock-time is called mean time, that marked by the sun-dial is called apparent time, and the difference between them is the equation of time. It is given in most calendars and almanacs, frequently under the heading " clock slow,'-" clock fast." When the time by the sun-dial is known, the equation of time will at once enable us to obtain the corresponding clock time, or vice versa. Atmospheric refraction introduces another error, by altering the apparent position of the sun ; but the effect is too small to need consideration in the construction of an instrument which, with the best workmanship, does not after all admit of very great accuracy. The general principles of dialling will now be readily understood. The problem before us is the following : A rod, or style, as it is called, being firmly fixed in a direction parallel to the earth's axis, we have to find how and where points or lines of reference must be traced on some fixed surface behind the style, so that when the shadow of the style falls on a certain one of these lines we may know that at that moment it is solar noon,that is, that the plane through the style and through the sun then coincides with the meridian ; again, that when the shadow reaches the next line of reference, it is 1 o'clock by solar time, or, which comes to the same thing, that the above plane through the style and through the sun has just turned through the twenty-fourth part of a complete revolution; and so on for the subsequent hours,the hours before noon being indi-cated in a similar manner. The style and the surface on which these lines are traced together constitute the dial. The position of an intended sun-dial having been selected whether on church tower, south front of farm-stead, or garden wallthe surface must be prepared, if necessary, to receive the hour-lines. The chief, and in fact the only practical difficulty will be the accurate fixing of the style, for on its accuracy the value of the instrument depends. It must be in the meridian plane, and must make an angle with the horizon equal to the latitude of the place. The latter condition will offer no difficulty, but the exact determination of the meridian plane which passes through the point where the style is fixed to the surface is not so simple. We shall, further on, show how this may be done; and, in the meantime, we shall assume that we have found the true position, and have firmly fixed the style to the dial and secured it there by cross wires, or by other means. The style itself will be usually a strong metal wire whose thickness may vary with circumstances; and when we speak of the shadow cast by the style it must always be understood that the middle line of the thin band of shade is meant. The point where the style meets the dial is called the centre of the dial. It is the centre from which all the hour-lines radiate. The position of the xii o'clock line is the most important to determine accurately, since all the others are usually made to depend on this one. We cannot trace it correctly on the dial until the style has been itself accurately fixed in its proper place, as will be explained hereafter. When that is done the xn o'clock line will be found by the inter-section of the dial surface with the vertical plane which contains the style ; and the most simple way of drawing it on the dial will be by suspending a plummet from some point of the style whence it may hang freely, and waiting until the shadows of both style and plumb line coincide on the dial. This single shadow will be the xn o'clock line. In one class of dials, namely, all the vertical ones, the xn o'clock line is simply the vertical line from the centre; it can, therefore, at once be traced on the dial face by using a fine plumb line. The xn O'CIOCK line being traced, the easiest and most accurate method of tracing the other hour lines would at the present day when good watches are common, be by marking where the shadow of the style falls when 1, 2, 3, &c, hours have elapsed since noon, and the next morning by the same means the forenoon hour lines could be traced ; and in the same manner the hours might be subdivided into halves and quarters, or even into minutes. But formerly, when watches were not, the tracing of the i, II, in, &c. o'clock lines was done by calculating the angle which each of these lines would make with the xn o'clock line. Now, except in the simple cases of a horizontal dial or of a vertical dial facing a cardinal point, this would require long and intricate calculations, or elabor-ate geometrical constructions, implying considerable mathematical knowledge, but also introducing increased chances of error. The chief source of error would lie in the uncer-tainty of the data ; for the position of the dial-plane would have to be found before the calculations began, that is, it would be necessary to know exactly by how many degrees it declined from the south towards the east or west, and by how many degrees it inclined from the vertical. The ancients, with the means at their disposal, could obtain these results only very roughly. Dials received different names according to their posi-tion : Horizontal dials, when traced on a horizontal plane ; Vertical dials, when on a vertical plane facing one of the cardinal points; Vertical declining dials, on a vertical plane not facing a cardinal point; Inclining dials, when traced on planes neithei vertical nor horizontal (these were further distinguished as reclin-ing when leaning backwards from an observer, proclining when leaning forwards); Eqidnoctial dials, when the plane is at right angles to the earth's axis, &c. &c. We shall limit ourselves to an investigation of the simplest and most usual of these cases, referring the reader, for further details, to the later works given at the end of this article. Dial Construction.A very correct view of the problem of dial construction may be obtained as follows : Conceive a transparent cylinder (fig. 1) having an axis AB parallel to the axis of the earth. On the surface of the cylinder let equidistant generating lines be traced 15° apart, one of them xn.. xn being in the meridian plane through AB, and the others I... I, n...n, &c, following in the order of the sun's motion. Then the shadow of the line AB will obviously fall on the line £11...XII at apparent noon, on the line I...I at one hour afternoon, on II...II at two hours after noon, and so on. If now the cylinder be cut by any plane MN representing the plane on which the dial is to be traced, the shadow of AB will be intercepted by this plane, and fall on the lines Axu, Ai, An, &c. The construction of the dial consists in determining the angles made by Ai, An, &c. with Axn; the line Axn itself, being in the vertical plane through AB, may be supposed known. For the purposes of actual calculation, perhaps a trans-parent sphere will, with advantage, replace the cylinder, and we shall here apply it to calculate the angles made by the hour line with the xn o'clock line in the two cases of a horizontal dial and of a vertical south dial. Horizontal Dial.Let PEy (fig. 2), the axis of the supposed transparent sphere, be directed towards the north and south poles of the heavens. Draw the two great circles, HMA, QMa, the former horizontal, the other perpendicular to the axis Vp, and therefore coinciding with the plane of the equator. Let EZ he vertical, then the circle QZP will be the meridian, and by its intersection A with the horizontal will determine the xn o'clock line EA. Next divide the equatorial circle QMa into 24 equal parts ai, be, cd, &c. ... of 15° each, beginning from the meridian Pa, and through the various points of division and the poles draw the great circles Fbp, Fcp, &c. . . . These will exactly correspond to the equidistant generating lines on the cylinder in the previous construction, and the shadow of the style will fall on these circles after successive intervals of 1, 2, 3, &c. hours from noon. If they meet the horizontal in the points B, C, D, &c, then EB, EC, ED, &c. . . . will be the i, II, in, &c., hour lines required ; and the problem of the horizontal dial consists in calculating the angles which these lines make with the xn o'clock line EA, whose position is known. The spherical triangles PAB, PAC, &c, enable us to do this readily. They are all right-angled at A, the side PA is the latitude of the place, and the angles APB, APC, &c, are respectively 15°, 30°, &c, then tan. AB = tan. 15° sin. latitude, tan. AC = tan. 30° sin. latitude, These determine the sides AB, AC, &c. that is, the angles AEB, AEC, &c, required. For examples, let us find the angles made by the I o'clock line at the following placesMadras, London, Edinburgh, and Hammer" fest (Norway). == TABLE == Thus the I o'clock hour line ET3 must make an angle on a Madras dial of only 3° 28' with the meridian EA, 11° 51' on a London dial, 12° 31'at Edinburgh, and 14° 25'at Hammerfest. In the same way may be found the angles made by the other hour lines. The calculations of these angles must extend throughout one quadrant from noon to vi o'clock, but need not be carried further, because all the other hour-lines can at once be deduced from these. _In the first place the dial is symmetrically divided by the meridian, and therefore two times equidistant from noon will have their hour lines equidistant from the meridian ; thus the XI o'clock line and the I o'clock line must make the same angles with it, the xi o'clock the came as the n o'clock, and so on. And next, the 24 great circles, which were drawn to determine these lines, are in reality only 12 ; for clearly the great circle which gives I o'clock after midnight, and that which gives I o'clock after noon, are one and the same, and so also for the other hours. Therefore the hour lines between vi in the evening and VI the next morning are the prolongations of the remaining twelve. Let us now remove the imaginary sphere with all its circles, and retain only the style EP and the plane HMA with the lines traced on it, and we shall have the horizontal dial. On the longest clay in London the sun rises a little after 4 o'clock, and sets a little before 8 o'clock; there is there-fore no necessity for extending a London dial beyond those hours. At Edinburgh the limits will be a little longer, while at Hammerfest, which is within the Arctic circle, the whole circuit will be required. Instead of a wire style it is often more convenient to use a metal plate from one quarter to half an inch in thickness. This plate, which is sometimes in the form of a right-angled triangle, must have an acute angle equal to the latitude of the place, and, when properly fixed in a vertical position on the dial, its two faces must coincide with the meridian plane, and the sloping edges formed by the thickness of the plate must point to the pole and form two parallel styles. Since there are two styles, there must be two dials, or rather two half dials, because a little consideration will show that, owing to the thickness of the plate, these styles will only one at a time cast a shadow. Thus the eastern edge will give the shadow for all hours before 0 o'clock in the morning. From C o'clock until noon the western edge will be used. At noon, it will change again to the eastern edge until 6 o'clock in the evening, and finally the western edge for the remaining hours of daylight. The centres of the two dials will be at the points where the styles meet the dial face; but, in drawing the hour-lines, we must be careful to draw only those lines for which the corresponding style is able to give a shadow as explained above. The dial will thus have the appear-ance of a single dial plate, and there will be no confusion (see %. 3). The line of demarcation between the shadow and the light will be better defined than when a wire style is used ; but the indications by this double dial will always be one minute too fast in the morning and one minute too slow in the afternoon. This is owing to the magnitude of the sun, whose angular breadth is half a degree. The well-defined shadows are given, not by the centre of the sun, as we should require them, but by the forward limb in the morning and by the backward one in the afternoon; and the sun takes just about a minute to advance through a space equal to its half-breadth. Dials of this description are frequently met with in the country. Placed on an ornamental pedestal some 4 feet high, they form a pleasing and useful addition to a lawn or to a garden terrace. The dial plate is of metal as well as the vertical piece upon it, and they may be purchased ready for placing on the pedestal,the dial with all the hour-lines traced on it, and the style-plate firmly fastened in its proper position, if not even cast in the same piece with the dial-plate. When placing it on the pedestal care must be taken that the dial be perfectly horizontal and accurately oriented. The levelling will be done with a spirit-level, and the orien-tation will be best effected either in the forenoon or in the afternoon, by turning the dial-plate till the time given by the shadow (making the one minute correction mentioned above) agrees with a good watch whose error on solar time is known. It is, however, important to bear in mind that a dial, so built up beforehand, will have the angle at the base equal to the latitude of some selected place, such as London, and the hour-lines will be drawn in directions calculated for the same latitude. Such a dial can therefore not be used near Edinburgh or Glasgow, although it would, without appreciable error, be adapted to any place whose latitude did not differ more than 20 or 30 miles from that of London, and it would be safe to employ it in Essex, Kent, or Wiltshire. == TABLE == If a series of such dials were constructed, differing by 30 miles in latitude, then an intending purchaser could select one adapted to a place whose latitude was within 15 miles of his own, and the error of time would never exceed a small fraction of a minute. The following table will enable us to check the accuracy of the hour-lines and of the angle of the style,all angles on the dial being readily measured with an ordinary protractor. It extends from 50° lat. to 59|° lat., and therefore includes the whole of Great Britain and Ireland : == TABLE == Vertical South Dial.Let us take again our imaginary trans-parent sphere QZPA (fig. 4), whose axis PEp is parallel to the earth's axis. Let Z be the zenith, and consequently, the great circle QZP the meridian. Through E, the centre of the sphere, draw a vertical plane facing south. This will cut the sphere in the great circle ZMA which, being vertical, will pass through the zenith, and, facing south, will be at right angles to the meridian. Let QMa be the equatorial circle, obtained by drawing a plane through E at right angles to the axis PEp. The lower portion Ep of the axis will be the style, the vertical line EA in the meridian plane will be the xn o'clock line, and the hori-zontal line EM1 will be the VI o'clock line. Now, as in the pre-vious problem, divide the equatorial circle into 24 equal arcs of 15° each, beginning at a, viz., ab, be, &c.,each quadrant all, MQ, &c, containing six,then through each point of division and through the axis Pp draw a plane cutting the sphere in 24 equidistant great circles. As the sun revolves round the axis the shadow of the axis will successively fall on these circles at intervals of one hour, and if these circles cross the vertical circle ZilA in the points A, B, C, &c, the shadow of the lower portion Ep of the axis will fall on the lines EA, EB, EC, &c, which will therefore be the required hour lines on the vertical dial, Ep being the style. There is no necessity for going beyond the vi o'clock hour-line on each side of noon ; for, in the winter months the sun sets earlier than 6 o'clock, and in the summer months it passes behind the plane of the dial before that time, and is no longer available. It remains to show how the angles AEB, AEC, <fec, may be calculated. The spherical triangles pAB, pAC, &c, will give us a simple rule. These triangles are all right-angled at A, the side pA, equal to ZP, is the co-latitude of the place, that is, the differ-ence between the latitude and 90°; and the successive angles ApB, ApC, &c. are 15°, 30°, &c, respectively. Then tan. AB=tan. 15° sin. co-latitude; or more simply, tan. AB = tan. 15° cos. latitude, tan. AC=tan. 38° cos. latitude, &e., &c. and the arcs AB, AC so found are the measure of the angles AEB, AEC, &e., required. London (51" 30' N. lat.) Log. tan. 15° 9-42805 Log. cos. 51° 30' 9-79415 "We shall, as examples, calculate the I o'clock hour angle AEB for each of the four places we had already taken in the horizontal dial. Madras (18' 4' N. lat.) Log. tan. 15°. 9-42805 Log. cos. 13° 4' 9-98861 Hammorfcst (73" 40' N. lat.) Log. tan. 15° 9-42805 Log. cos. 73° 40' 9-44905 Log. tan. 14° 38'.....9-41666 Log. tan. 9° 28' 9'22220 Edinburgh (55° 57' N. lat.) Log. tan. 15° 9-42S05 Log. cos. 55° 57' 974812 Log. tan. 8° 32'. 9-17617 Log. tan. 4° 19'. In this case the angles diminish as the latitudes increase, the opposite result to that of the horizontal dial. 1 EM is obviously horizontal, since M is the intersection of two great circles ZM, QM, each at right angles to the vertical plane QZP. Inclining, Reclining, &c, Dials.-We shall not enter into the calculation of these cases. Our imaginary sphere being, as before supposed, constructed with its centre at the centre of the dial, and all the hour-circles traced upon it, the intersection of these hour-circles with the plane of the dial will determine the hour-lines just as in the previous cases ; but the triangles will no longer be right-angled, and the simplicity of the calculation will be lost, the chances of error being greatly increased by the difficulty of drawing the dial-plane in its true position on the sphere, since that true position will have to be found from obser-vations which can be only roughly performed. In all these cases, and in cases where the dial surface is not a plane, and the hour-lines, consequently, are not straight lines, the only safe practical way is to mark rapidly on the dial a few points (one is sufficient when the dial face is plane) of the shadow at the moment when a good watch shows that the hour has arrived, and afterwards connect these poiuts with the centre by a continuous line. Of course the style must have been accurately fixed in its true position before we begin. Equatorial Dial.The name equatorial dial is given to one whose plane is at right angles to the style, and therefore parallel to the equator. It is the simplest of all dials. A circle (fig. 5) divided into 24 equal arcs is placed at right angles to the style, and hour divisions are marked upon it. Then if eare be taken that the style point accurately to the pole, and that the noon division coincide with the meridian plane, the shadow of the style will fall on the other divisions, each at its proper time. The divisions must be 5- marked on both sides of the dial, because the sun will shine on opposite sides in the summer and in the winter months, changing at each equinox. To find the Meridian Plane.We have, so far, assumed the meridian plane to be accurately known ; we shall pro-ceed to describe some of the methods by which it may be found. The mariner's compass may be employed as a first rough approximation. It is well known that the needle of the compass, when free to move horizontally, oscillates upon its pivot and settles in a direction termed the magnetic meridian. This does not coincide with the true north and south line, but the difference between them is generally known with tolerable accuracy, and is called the variation of the compass. The variation differs widely at different parts of the surface of the earth, being now about 20° W. in London, 7° W. in New York, and 17° E. in San Francisco. Nor is the variation at any place stationary, though the change is slow. We said that now the variation in London is about 20° W. ; in 1837 it was about 24° W.; and there is even a small daily oscillation which takes place about the mean position, but too small to need notice here. "With all these elements of uncertainty, it is obvious that the compass can only give a rough approximation to the position of the meridian, but it will serve to fix the style so that only a small further alteration will be necessary when a more perfect determination has been made. A very simple practical method is the following : Place a table (fig. 6), or other plane surface, in such a position that it may receive the sun's rays both in the morning and in the afternoon. Then carefully level the surface by means of a spirit-level. This must be done very accurately, and the table in that position made perfectly secure, so that there be no danger of its shifting during the day. Next, suspend a plummet SH from a point S, which must be rigidly fixed. The extremity H, where the plum-met just meets the surface, should be somewhere near the middle of one end of the table. With H for centre, describe any number of concentric arcs of circles, AB, CD, EF, &c. A bead P, kept in its place by friction, is threaded on the plummet line at some convenient height above H. Every thing being thus prepared, let us follow the shadow of the bead P as it moves along the surface of the table during the day. It will be found to describe a curve ACE .... FDB, approaching the point H as the sun advances towards noon, and receding from it afterwards. (The curve is aconic sectionan hyperbola in these regions.) At the moment when it crosses the arc AB, mark the point A; AP is then the direction of the sun, and, as AH is horizontal, the angle PAH is the altitude of the sun. In the afternoon mark the point B where it crosses the same arc ; then the angle PBH is the altitude. But the right-angled triangles PHA, PHB are obviously equal; and the sun has therefore the same altitudes at those two instants, the one before, the other after noon. It follows that, if the sun has not changed its declination during the interval, the two positions will be symmetrically placed one on each side of the meridian. Therefore, drawing the chord AB, i and bisecting it in M, HM will be the meridian line. Each of the other concentric arcs, CD, EF, <fcc, will furnish its meridian line. Of course these should all coincide, but if not, the mean of the positions thus found must be taken. The proviso mentioned above, that the sun has not changed its declination, is scarcely ever realized; but the change is slight, and may be neglected, except per-haps about the time of the equinoxes, at the end of March and at the end of September. Throughout the remainder of the year the change of declination is so slow that we may safely neglect it. The most favourable times are at the end of June and at the end of December, when the sun's declination is almost stationary. If the line H1I be produced both ways to the edges of the table, then the two points on the ground vertically below those on the edges may be found by a plummet, and, if permanent marks be made there, the meridian plane, which is the vertical plane passing through these two points, will have its position perfectly secured. To place the Style of a Dial in its True Position. Before giving any other method of finding the meridian plane, we shall complete the construction of the dial, by showing how the style may now be accurately placed in its true position. The angle which the style makes with a hanging plumb-line, being the co-latitude of the place, is known, and the north and south direction is also roughly given by the mariner's compass. The style may therefore be already adjusted approximatelycorrectly, indeed, as to its inclinationbut probably requiring a little horizontal motion east or west. Suspend a fine plumb-line from some point of the style, then the style will be properly adjusted if, at the very instant of noon, its shadow falls exactly on the plumb-line,or, which is the same thing, if both shadows coincide on the dial. This instant of noon will be given very simply by the meridian plane, whose position we have secured by the two permanent marks on the ground. Stretch a cord from the one mark to the other. This will not generally be horizontal, but the cord will be wholly in the meridian plane, and that is the only necessary condition. Next, suspend a plummet over the mark which is nearer to the sun, and, when the shadow of the plumb-line falls on the stretched cord, it is noon. A signal from the observer there to the observer at the dial enables the latter to adjust the style as directed above. Other Methods of finding the Meridian Plane.-We have dwelt at some length on these practical operations because they are simple and tolerably accurate, and because they want neither watch, nor sextant, nor telescopenothing more, in fact, than the careful observation of shadow lines. The polar star may also be employed for finding the meridian plane without other apparatus than plumb-lines. This star is now only about 1° 21' from the pole ; if there-fore a plumb-line be suspended at a few feet from the observer, and if he shift his position till the star is exactly hidden by the line, then the plane through his eye and the plumb-line will never be far from the meridian plane. Twice in the course of the 24 bours the planes would be strictly coincident. This would be when the star crosses the meridian above the pole, and again when it crosses it below. If we wished to employ the method of determin-ing the meridian, the times of the stars crossing would have to be calculated from the data in the Nautical Almanac, and a watch would be necessary to know when the instant arrived. The watch need not, however, be very accurate, because the motion of the star is so slow that an error of ten minutes in the time would not give an error of one-eighth of a degree in the azimuth. The following accidental circumstance enables us to dis-pense with both calculation and watch. The right ascen-sion of the star -q Ursce Majoris, that star in the tail of the Great Bear which is farthest from the " pointers," happens to differ by a little more than 12 hours from the right ascension of the polar star. The great circle which joins the two stars passes therefore close to the pole. When the polar star, at a distance of about 1|° from the pole, is crossing the meridian above the pole, the star r/ Ursce Majoris, whose polar distance is about 40°, has not yet reached the meridian below the pole. When -i) Ursce Majoris reaches the meridian, which will be within half an hour later, the polar star will have left the meridian; but its slow motion will have carried it only a very little distance away. Now at some instant between these two timesmuch nearer the latter than the former the great circle joining the two stars will be exactly vertical; and at this instant, which the observer determines by seeing that the plumb-line hides the two stars simultaneously, neither of the stars is strictly in the meridian; but the deviation from it is so small that it may be neglected, and the plane through the eye and the plumb-line taken for meridian plane. In all these cases it will be convenient, instead of fixing the plane by means of the eye and one fixed plummet, to have a second plummet at a short distance in front of the eye ; this second plummet, being suspended so as to allow of lateral shifting, must be moved so as always to be between the eye and the fixed plummet. The meridian plane will be secured by placing two permanent marks on the ground, one under each plummet. This method, by means of the two stars, is only available for the upper transit of Polaris ; for, at the lower transit, the other star r¡ Ursce Majoris would pass close to or beyond the zenith, and the observation could not be made. Also the stars will not be visible when the upper transit takes place in the day-time, so that one-half of the year is lost to this method. Neither could it be employed in lower latitudes than 40° N., for there the star would be below the horizon at its lower transit;we may even say not lower than 45° N., for the star must be at least 5° above the horizon before it becomes distinctly visible. There are other pairs of stars which could be similarly employed, but none so convenient as these two, on account of Polaris with its very slow motion being one of the pair. To place the Style in its True Position without previous determination of the Meridian Plane,The various methods given above for finding the meridian plane have for ultimate object the determination of the plane, not on its own account, but as an element for fixing the instant of noon, whereby the style may be properly placed. We shall dispense, therefore, with all this preliminary work if we determine noon by astronomical observation. For this we shall want a good watch, or pocket chronometer, and a sextant or other instrument for taking altitudes. The local time at any moment may be determined in a variety of ways by observation of the celestial bodies. The simplest and most practically useful methods will be found described and investigated in any good educational work on astronomy. For our present purpose a single altitude of the sun taken in the forenoon will be most suitable. At some time in the morning, when the sun is high enough to be free from the mists and uncertain refractions of the horizonbut to insure accuracy, while the rate of increase of the altitude is still tolerably rapid, and, therefore, not later than 10 o'clocktake an altitude of the sun, an assistant, at the same moment, marking the time shown by the watch. The altitude so observed being properly corrected for refraction, parallax, &c, will, together with the latitude of the place, and the sun's declination, taken from the Nautical Almanac, enable us to calculate the time. This will be the solar or apparent time, that is, the very time we require ; and we must carefully abstain from applying the equation of time. Comparing the time so found with the time shown by the watch, we see at once by how much the watch is fast or slow of solar time ; we know, therefore, exactly what time the watch must mark when solar noon arrives, and waiting for that instant we can fix the style in its proper position as explained before. We can dispense with the sextant and with all calcula-tion and observation if, by means of the pocket chronometer, we bring the time from some observatory where the work is done ; and, allowing for the change of longitude, and also for the equation of time, if the time we have brought is clock time, we shall have the exact instant of solar noon as in the previous case. In remote country districts a dial will always be of use to check and even to correct the village clock; and the description and directions here given will, we think, enable any ingenious artisan to construct one. In former times the fancy of dialists seems to have run riot in devising elaborate surfaces on which the dial was to be traced. Sometimes the shadow was received on a cone, sometimes on a cylinder, or on a sphere, or on a combination of these. A universal dial was constructed of a figure in the shape of a cross; another universal dial showed the hours by a globe and by several gnomons. These universal dials required adjusting before use, and for this a mariner's compass and a spirit-level were necessary. But it would be tedious and useless to enumerate the various forms designed, and, as a rule, the more complex the less accurate. Another class of useless dials consisted of those with variable centres. They were drawn on fixed horizontal planes, and each day the style had to be shifted to a new position. Instead of honr-li?ies they had hour-points ; and the style, instead of being parallel to the axis of the earth, might make any chosen angle with the horizon. There was no practical advantage in their use, but rather the reverse; and they can only be considered as furnishing material for new mathematical problems. Portable Dials.The dials so far described have been fixed dials, for even the fanciful ones to which reference was just now made were to be fixed before using. There were, however, other dials, made generally of a small size, so as to be carried in the pocket; and these, so long as the sun shone, roughly answered the purpose of a watch. The description of the portable dial has generally been mixed up with that of the fixed dial, as if it had been merely a special case, and the same principle had been the basis of both; whereas there are essential points of difference between them, besides those which are at once apparent. In the fixed dial the result depends on the uniform angular motion of the sun round the fixed style ; and a small error in the assumed position of the sun, whether due to the imperfection of the instrument, or to some small neglected correction, has only a trifling effect on the time. This is owing to the angular displacement of the sun being so rapida quarter of a degree every minute-that for the ordinary affairs of life greater accuracy is not required, as a displacement of a quarter of a degree, or at any rate of one degree, can be readily seen by nearly every person. But with a portable dial this is no longer the case. The uniform angular motion is not now available, because we have no determined fixed plane to which we may refer it. In the new position, to which the observer has gone, the zenith is the only point of the heavens he can at once practically find ; and the basis for the determination of the time is the constantly but very irregularly varying zenith distance of the sun. At sea the observation of the altitude of a celestial body is the only method available for finding local time; but the perfection which has been attained in the construction of the sextant (chiefly by the introduction of telescopes) enables the sailor to reckon on an accuracy of seconds instead of minutes. Certain precautions have, however, to be taken. The observations must not be made within a couple of hours of noon, on account of the slow rate of change at that time, nor too near the horizon, on account of the uncertain refractions there; and the same restrictions must be observed in using a portable dial. To compare roughly the value (as to accuracy) of the fixed and the portable dials, let us take a mean position in Great Britain, say 54° lat., and a mean declination when the sun is in the equator. It will rise at 6 o'clock, and at noon have an altitude of 36°,that is, the portable dial will indicate an average change of one-tenth of a degree in each minute, or two and half times slower than the fixed dial. The vertical motion of the sun increases, however, nearer the horizon, but even there it will be only one-eighth of a degree each minute, or half the rate of the fixed dial, which goes on at nearly the same speed throughout the day. Portable dials are also much more restricted in the range of latitude for which they are available, and they should not be used more than 4 or 5 miles north, or south of the place for which they were constructed. We shall briefly describe two portable dials which were in actual use. Dial on a Cylinder.A hollow cylinder of metal (fig. 7), 4 or 5 inches high, and about an inch in diameter, has a lid which admits of toler- ably easy rotation. A IT "1 hole in the lid receives the style, shaped some- what like a bayonet; and the straight part of the style, which, on account of the two bends, is lower than the lid, projects horizontally out from the cylinder to a distance of 1 or 1|- inches. When not in use the style would be taken out and placed inside the cylinder. A horizontal circle is traced on the cylin-der opposite the projecting style, and this circle is divided into 36 approximately equidistant intervals. These intervals represent spaces of time, and to each division is assigned a date, so that each month has three dates marked as follows :January 10, 20, 31; February 10, 20, 28 ; March 10, 20, 31; April 10, 20, 30, and so on,always the 10th, the 20th, and the last day of each month. Through each point of division a vertical line parallel to the axis of the cylinder is drawn horn top to bottom. Now it will be readily understood that if, upon one of these days, the lid be turned so as to bring the style exactly opposite the date, and if the dial be then placed on a horizontal table so as to receive sun-light, and turned round bodily until the shadow of the style falls exactly on the vertical line below it, the shadow will terminate at some definite point of this line, the position of which point will depend on the length of the stylethat is, the distance of its end from the surface of the cylinderand on the altitude of the sun at that instant. Suppose that the observations are continued all day, the cylinder being very gradually turned so that the style may always face the sun, and suppose that marks are made on the vertical line to show the extremity of the shadow at each exact hour from sunrise to sunsetthese times being taken from a good fixed sun dial,then it is obvious that the next year, on the same date, the sun's declination being about the same, and the observer in about the same latitude, the marks made the previous year will serve to tell the time all that day. Constrvction.Draw a straight line ACB parallel to the top of the card (fig. 8) and another DCE at right angles to it; with C as centre, and any convenientTadius CA, describe the semi-circle AEB belovi the horizontal. Divide the -whole arc AEB into 12 equal parts at the points r, s, t, &c, and through these points draw perpendi-culars to the diameter ACB, these lines mil he the hour lines, viz., the line through r will be the xi ..i line ; the line through s the line, and so on ; the hour line of noon viiH be the point A What we have said above was merely to make the principle of the instrument clear, for it is evident that this mode of marking, which would require a whole year's sunshine and hourly observation, cannot be the method employed. The positions of the marks are, in fact, obtained by calculation. Corresponding to a given date, the declination of the sun is taken from the almanac, and this, together with the latitude of the place and the length of the style, will constitute the necessary data for computing the length of the shadow, that is, the distance of the mark below the style for each successive hour. We have assumed above that the declination of the sun is the same at the same date in different years. This is not quite correct, but, if the dates be taken for the second year after leap year, the results will be sufficiently approxi-mate. The actual calculations will oSer no difficulty. When all the hour marks have been placed opposite to their respective dates, then a continuous curve, fining the corresponding hour-points, will serve to find the time for a day intermediate to those set down, the lid being turned till the style occupy a proper position between the two divisions. The horizontality of the surface on which the instrument rests is a very necessary condition, especially in summer, when, the shadow of the style being long, the extreme end will shiit rapidly for a small deviation from the vertical, and render the reading uncertain. The dial can also be used by holding it up by a small ring in the top of the lid, and prcbably the verticality is better ensured in that way. Portable Dial on a Card.This neat and very ingenious dial is attributed by Ozanam to a Jesuit Father, De Saint liigaud, and probably dates from the early part of the 17th century. Ozanam says that it was sometimes called the capuchin, from some fancied resemblance to a cowl thrown back. itseli ; by subdivision of the small ares Ar, rs, st, kc, we may draw the hour lines corresponding to halves and quarters, but this only where it can be done without confusion. Draw ASD making with AC an angle equal to the latitude of the place, and let it meet EC in D, through which point draw FD6 at right angles to AD. With centre A, and any convenient radius AS, describe an arc of circle RST, and graduate this arc by marking degree divisions on it, extending from 0° at S to 23J° on each side at R and T. Next determine the points on the straight line FDG where radii drawn from A to the degree divisions on the arc would cross it, and care-fully mark these crossings. The divisions of RST are to correspond to the sun's declination, south declinations on RS and north declinations on ST. In the other hemisphere of the earth this would be reversed ; the north declinations would be on the upper half. Now, taking a second year after leap yer.r (because the declina-tions of that year are about the mean of each set of four years), find the days of the month when the sun has these different declina-tions, and place these dates, or so many of them as can be shown without confusion, opposite the corresponding marks on FDG. Draw the sun-line at the top of the card parallel to the line ACB ; and, near the extremity, to the right, draw any small figure intended to form, as it were, a door of which a b shall be the hinge. Care must be taken that this hinge is exactly at right angles to the sun-line. Make a fine open slit c d right through the card and extending from the hinge to a short distance on the door,the centre line of this slit coinciding accurately with the sun-line. Now, cut the door completely through the card ; except, of course, along the hinge, which, when the card is thick, should be partly cut through at the back, to facilitate the opening. Cut the card right through along the line FDG, and pass a thread carrying a little plummet W and a very small bead P ; the bead having sufficient friction with the thread to retain any position when acted on only by its own weight, but sliding easily along the thread when moved by the hand. At the back of the card the thread terminates in a knot to hinder it from being drawn through ; or better, because giving more friction and abetter hold, it passes through the centre of a small disc of carda f rac tion of an inch In diameterand, by a knot, is made fast at the back of the disc. To complete the construction,with the centres F and G, and radii FA and GA, draw the two arcs AY and AZ which will limit the hour lines; for in an observation the bead will always be found between them. The forenoon and afternoon hours may then be marked as indicated in the figure. The dial does not of itself dis-criminate between forenoon and afternoon ; but extraneous circum-stances, as, for instance, whether the sun is rising or falling, will settle that point, except when close to noon, where it will always be uncertain. To rectify the dial (using the old expression, which means to pre-pare the dial for an observation),open the small door, by turning it about its hinge, till it stands well out in front. Next, set the thread in the line FG opposite the day of the month, and stretching it over the point A, slide the bead P along till it exactly coincide with A. To find the hour of the day,hold the dial in a vertical position in such a way that its plane may pass through the sun. The verti-cality is ensured by seeing that the bead rests against the card without pressing. Now gi adually tilt the dial (without altering its vertical plane), until the central line of sunshine, passing through the open slit of the door, just falls along the sun-line. The hour line against which the bead P then rests indicates the time. The sun-line drawn above has always, so far as we know, oeen used as a shadow-line. The upper edge of the rectangular door was the prolongation of the line, and, the door being opened, the dial was gradually tilted until the shadow cast by the upper edge exactly coincided with it. But this shadow tilts the card one-quarter of a degree more than the sun-line, because it is given by that portion of the sun which just appears above the edge, that is, by the upper limb of the sun, which is one-quarter of a degree higher than the centre. Now, even at some distance from noon, the sun will sometimes take a considerable time to rise one-quarter of a degree, and by so much time will the indication of the dial be in error. The central line of light which comes through the open slit will be free from this error, because it is given by light from the centre of the sun. The card-dial deserves to be looked upon as something more than a mere toy. Its ingenuity and scientific accuracy give it an educa-tional value which is not to be measured by the roughness of the results obtained, and the following demonstration of its correct-ness will, it is hoped, usefully close what we have to say on this subject. Demonstration.Let H (fig. 9) be the point of suspension of the plummet at the time of observation, so that the angle DAH is the north declination of the sun, P, the bead, resting against the hour-line YX. Join OX, then the angle ACX is the hour angle from noon given by the bead, and we have to prove that this hour-angle is the correct one corresponding to a north latitude DAC, a north declination AH and an altitude equal to the angle which the sun-line, or its parallel AC, makes with the horizontal. The angle PHQ will be equal to the altitude, if HQ be drawn parallel to DC, for the pair of lines HQ, HP will be respectively at right angles to the sun-line and the horizontal. Draw PQ and JIM parallel to AC, and let them meet DCE in M and N respectively. Let HP and its equal HA be represented by a. Then the follow- ing values will be readily deduced from the figure : AD a cos. decl., DH = a sin. decl., PQ a sin. alt. CX = AC = AD cos. lat. a cos. decl. cos. lot. PN = CV = CX cos. ACX = a cos. decl. cos. lat. cos. ACX. NQ = MH = DH sin. M DH =a sin. iecl. sin. lat. (o_othe angle MDH - DAC = latitude). And, since PQ = NQ + PN, we have, by simple substitution, a sin. alt. a sin. decl. sin. lat. +a cos. decl. cos. lat. cos ACX ; or, dividing by a throughout. sin. alt. =sin. decl. sin. lat. +cos. decl. cos. lat. cos. ACX . . . (At wnich equation determines the hour angle ACX shewn by the bead. To determine the hour-angle of the sun at the same moment, let fig. 10 lepresent the celestial sphere, HR the horizon, P the poley and Z the zenith, and S the sun. From the spherical triangle PZS, we have cos. ZS=eos. PS cos. ZP + sin. PS sin. ZP cos. ZPS but ZS = zenith distance = 90°-altitude ZP-90°-PR -90° -latitude PS = polar distance = 90° - declination, therefore, by substitution sin. alt. =sin. decl. sin. lat. + cos. dccl. cos. lat. cos. ZPS . . . (B) and ZPS is the hour-angle of the sun. A comparison of the two formula; (A) and (B) shows that the hour-augle given by the bead will be the same as that given by the sun, and proves the theoretical accuracy of the card-dial. Just at sun-rise or at sun-set, the amount of refraction slightly exceeds half a degree. If, then, a little cross m (see fig. 8) be made just below the sun-line, at a distance from it which would subtend half a degree at c, the time of sunset would be found corrected for refrac-tion, if the central line of light were made to fall on cm. The following list includes the principal writers on dialling whose works have come down to us, and to these we must refer for descriptions of the various constructions, some simple and direct, others fancitul and intricate, which have been at different times employed : Ptolemy, Ana-lemma, restored by Commandine ; Vitruvius, Architecture ; Sebastian Munster, Horologiographia ; Orontius Fineus, De Ilorologiis Solaribus; Mutio Oddi da Urbino, Horologi Solari; Dryander, De Horologiorum Compositions ; Conrad Gesner, Pandectce ; Andrew Schoner, Gnomonica;; F. Commandine, Horolo-giorum Descriplio ; Joan. Bapt. Benedictas, De Gnomonum XJsu ; Georgius Schömberg, Exegesis Fundamentorum Gnomonicorum ; Joan. Solomon de Caus, Horologes Solaires ; Joan. Bapt. Trolta, Praxis Horologiorum ; Uesargues, Manière Universelle pour poser l'Essieu, &c. ; Ath. Kircher, Ars magna Lucis et Umbra ; Hallum, Explicatio Horologii in Horto Regio Fondini ; Joan. Mark, Tracta-tus Horologiorum ; Clavius, Gìiomonices de Ilorologiis. Also among more modem writers, Deschales, Ozanam, Schottus, Wollius, Picard, Lahire, Walper ; in German, Paterson, Michael, Müller ; and among English writers, Foster, Wells, Collins, Lead- better, Jones, Leybourn, Emerson, and Ferguson. See also Meikle's article in former editions of the present work. (H. G.) In one of the Courts of Queen's College, Cambridge, there is an elaborate sun-dial dating from the end of the 17th or beginning of the 18th century, and around it a series of numbers which make it avail-able as a moon-dial when the moon's age Is known.

Something abnormal is cruising toward us. Something little and cold and uncommonly quick. Nobody knows where it originated from, or where it is going. However, it’s not from around here. This is an interstellar comet – an old chunk of ice and gas and residue, framed on the solidified edges of a far off star, which some fortunate characteristic of gravity has hurled into our way. To space experts, the comet is a consideration bundle from the universe – a bit of a spot they will always be unable to visit, a key to every one of the universes they can’t legitimately watch. It is just the second interstellar intruder researchers have found in our nearby planetary group. Also, it’s the first they’ve had the option to get a decent take a gander at. By following the comet’s development, estimating its sythesis and checking its conduct, analysts are looking for pieces of information about the spot it originated from and the space it crossed to arrive. They have just discovered a carbon-based particle and potentially water – two natural synthetic compounds in such an outsider item. As the Sun sinks behind the Tennessee mountains, and stars wink into see, cosmologist Doug Durig ascends onto the housetop of his observatory, controls up his three telescopes and points them skyward. Consistently, the comet becomes greater and more brilliant in the sky, ousting surges of gas and residue that may present pieces of information to its history. On Dec. 8, it will make its closest way to deal with Earth, offering scientists a very close look before it zooms once more into the solidifying, featureless void.

In newly released footage from the University of Western Ontario, a bright, slow-moving fireball was captured in the skies near Toronto, Canada on December 12, 2011 by remote cameras watching for meteors. Although this meteor looks huge as it burns up in Earth’s atmosphere, astronomers estimate the rock to have been no bigger than a basketball. Footage reveals it entered the atmosphere at a shallow angle of 25 degrees, moving about 14 km per second. It first became visible over Lake Erie then moved toward the north-northeast. See below for the video. But in a meteorite-hunter alert, Peter Brown, the Director of Western’s Centre for Planetary & Space Exploration said that data garnered from the remote cameras suggest that surviving fragments of the rock are likely, with a mass that may total as much as a few kilograms, likely in the form of many fragments in one gram to hundreds of a gram size range. “Finding a meteorite from a fireball captured by video is equivalent to a planetary sample return mission,” said Brown. “We know where the object comes from in our solar system and can study it in the lab. Only about a dozen previous meteorite falls have had their orbits measured by cameras so each new event adds significantly to our understanding of the small bodies in the solar system. In essence, each new recovered meteorite is adding to our understanding of the formation and evolution of our own solar system.” Brown and his team are interested in hearing from anyone who may have witnessed or recorded this event, or who may have found fragments of the freshly fallen meteorite. See UWO’s website for contact information. Another camera view of the meteor: Western Meteor Group’s Southern Ontario Meteor Network sensor suite has seven all-sky video systems designed to automatically detect bright fireballs. At 6:04 p.m. on December 12, six of the seven cameras of Western’s Southern Ontario Meteor Network recorded this meteor. In a press release, UWO said the fireball’s burned out at an altitude of 31 km just south of the town of Selwyn, Ontario. It is likely to have dropped small meteorites in a region to the east of Selwyn near the eastern end of Upper Stony Lake. See the map of the projected path below. Although this bright fireball occurred near the peak of the annual Geminid meteor shower, the astronomers say it is unrelated to that shower.

Authors: GRAVITY Collaboration: S. Lacour, M. Nowak, J. Wang, et. al. First Author’s Institution: LESIA, Observatoire de Paris, Universite PSL, CNRS, Sorbonne Universite, Univ. Paris Diderot, Max Planck Institute for Extraterrestrial Physics Status: Published in Astronomy & Astrophysics [closed access] and arXiv [open access] TRAPPIST-1 might be the best known system with multiple planets, but HR 8799 has quite a few cool things going for it, too. It’s one of the first systems discovered with direct imaging (actually taking pictures of the planets themselves), and since then people have been observing its four planets moving around in their orbits. The kinds of planets we see around HR 8799 are also very different than those around TRAPPIST-1. The transit method, used to discover the 7 terrestrial TRAPPIST-1 planets, is better suited to find planets very close to their host stars. Direct imaging, on the other hand, is best for the biggest, furthest out planets – young super-Jupiters and brown dwarfs, orbiting 10s to 100s of AU from their stars. Direct imaging is also able to provide useful information about planetary orbits – it’s really clear to see where each of the HR 8799 planets is (as in Figure 1), whereas with the transit or radial velocity methods it takes a bit more untangling to sort through the overlapping signals of multiple planets. The goal is to determine the orbits, masses, and compositions of these kinds of giant planets, so that we can understand what they’re like and how they formed. For example, looking at the composition of the atmosphere, we can observe how much carbon there is compared to oxygen (the C/O ratio) to figure out where it formed in the protoplanetary disk. The D/H ratio (deuterium to hydrogen) can tell us about how many icy bodies (like Kuiper Belt Objects) a planet must have accreted in its past. This all sounds great, having a way to trace the formation of big planets – so what’s the catch? Because of the immense challenges of directly imaging a faint exoplanet around a bright star and the limited sizes of our telescopes, we don’t have the spatial resolution needed to really precisely constrain the orbits of these planets or see fine details in their spectra. That’s where today’s paper comes in, describing the first observations of an exoplanet using optical interferometry, a technique that allows for higher spatial resolution by combining multiple telescopes in clever ways. Interferometry comes up a lot in radio astronomy, such as with ALMA or the recent black hole image from the Event Horizon Telescope. It’s possible to use this same technique for optical/visible light, too. The idea is to use multiple telescopes, separated by some distances (known as the baselines), to collect light from an object simultaneously. It’s possible to combine these observations, and then it’s as if you’re observing with a “virtual” telescope the size of the baseline, which is much larger than any one individual telescope mirror. A larger telescope means better spatial resolution, which is exactly what we need to constrain the orbits and spectra of directly imaged planets. The authors used the ESO’s VLTI (Very Large Telescope Interferometer) and its GRAVITY instrument to use this technique on one of the HR 8799 planets – specifically, planet e, the one closest to the star. This is a really tricky process, since it requires precise knowledge of the telescope position and movement and more. But, they did it, and obtained the most precise astrometry (position information) of HR 8799 e yet. Their measurements narrowed down the position to tens of microarcseconds, orders of magnitude more precise than what direct imaging has done (see Figure 2). Combined with some previous analysis of the orbits of the whole HR 8799 system, this observation shows us that the planets around HR 8799 aren’t coplanar – that is, some of them must have orbits that are tilted relative to the plane of the whole system. GRAVITY can also do spectroscopy – see Figure 3 for the spectrum of HR 8799 e! The authors compared this to atmospheric models, which generate spectra for different kinds of atmospheres that the authors can then compare to the observed spectrum. They determined that HR 8799 e is likely an L-type brown dwarf, with a cool temperature of around 1150 K. Observations like this can help tease out what’s going on with the L/T transition, an important evolutionary stage for brown dwarf atmospheres. Many other planetary systems should be observable with GRAVITY, and the team has already set their sights on some of the well-known directly imaged planets, like Beta Pictoris b. Overall, this is an exciting first result for a promising new technique – orbital monitoring and spectroscopy with this precision can really help us understand directly imaged systems. In the future, larger baseline interferometry could maybe even resolve exoplanetary surfaces, showing clouds and other features!

Does a permanently shadowed crater at the Moon’s South Pole harbor frozen water? Enough to supply a lunar outpost? How much ultraviolet and cosmic radiation would astronauts be exposed to if they stayed on the moon for a week or longer? Where are the best—and worst—landing sites on the Moon? These are some of the questions that NASA plans to answer with its two new lunar missions. After waiting out a thunderstorm, NASA’s Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite rocketed off the launch pad at Kennedy Space Center in Cape Canaveral, Florida, at 5:32 p.m. Eastern Daylight Time on June 18, 2009. This photograph captures the pair of spacecraft as they were lifting off. In under than two minutes, the spacecrafts had reached an altitude of 11.3 miles and were preparing to ditch the spent rocket that had gotten them off the ground. At 5:46, the second stage rocket fired for the first time, pushing the spacecraft through the atmosphere at more than 12,000 miles per hour. At 6:09, the rocket fired again for five minutes, catapulting the two spacecraft toward the Moon. The Lunar Reconnaissance Orbiter hung on to the coasting rocket for about 8 minutes before separating. In four days, it will reach the Moon, where it will go into orbit just 31 miles above the surface. The Lunar Crater Observation and Sensing Satellite is holding on to the spent rocket. In October, it will hurl the empty rocket toward a crater at the South Pole and use its sensors to figure out whether the resulting debris contains water ice. Later, the spacecraft itself will crash into the crater. The debris kicked up by the collision will be so tremendous that it will probably be visible from Earth with a good amateur telescope. The point of these lunar missions is to collect the kinds of information we need to return astronauts to the moon. But the point of going to the moon is to learn about the Earth and our solar system (and ultimately, the universe). More than four billion years ago, as our solar system was forming, a planetary object roughly the size of Mars smacked into the Earth. The collision shattered the small planet and probably vaporized the upper layers of Earth’s surface. The debris—part Earth, part destroyed planet—remained in orbit around the Earth. Eventually, the debris aggregated into the Moon. If this theory, widely accepted among astrophysicists, is correct, then the formation of the Earth is inextricably tied to the formation of the Moon. And because the Moon’s surface has not been endlessly remodeled by plate tectonics, volcanoes, or erosion, it should be able to tell us things about how the Earth came to be that our planet itself never will. NASA photographs provided courtesy of the Kennedy Space Flight Center Public Affairs Office. Caption by Rebecca Lindsey. After waiting out a thunderstorm, NASA’s Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite rocketed off the launch pad at Kennedy Space Center in Cape Canaveral, Florida, at 5:32 p.m. Eastern Daylight Time on June 18, 2009. This photograph captures the pair of spacecraft as they were lifting off.

Questions about electron degenerate stellar remnants. A white dwarf, also known as a degenerate dwarf, is a type of stellar remnant. It forms from the pressured core during the death of medium stars not capable of exerting enough gravity to overcome electron resistance. White dwarfs have masses on average of about 0.5 to 0.6 Solar Masses, although there are some exceptions. A white dwarf exerts faint luminosity, that will fade over time as the light it emits are from thermal temperature which will run out over time. A white dwarf mainly contains helium with possible heavy elements such as carbon and oxygen, and a debatable coating of hydrogen. If a white draws enough mass(i.e. 1.4 solar masses), electron resistance is overcome by gravity and the white dwarf collapses into a 1a supernova. Once a white dwarf cools, it becomes a black dwarf. No black dwarfs exist due to the cooling time being longer than the current age of the universe.

Where there once was 158, there is now more… Globular clusters, that is. Thanks to ESO’s VISTA survey telescope at the Paranal Observatory in Chile, the Via Lactea (VVV) survey has cut through the gas and dust of the Milky Way to reveal the first star cluster that is far beyond our center. But keep your eyes on the prize, because as dazzling as the cluster called UKS 1 is on the right is, the one named VVV CL001 on the left isn’t as easy to spot. Need more? Then keep on looking, because VVV CL001 isn’t alone. The next victory for VISTA is VVV CL002, which is shown in the image below. What makes it special? It’s quite possible that VVV CL002 is the closest of its type to the center of our galaxy. While you might think discoveries of this type are commonplace, they are actually out of the ordinary. The last was documented in 2010 and it’s only through systematically studying the central parts of the Milky Way in infrared light that new ones turn up. To add even more excitement to the discovery, there is a possibility that VVV CL001 is gravitationally bound to UKS 1, making it a binary pair! However, without further study, this remains unverified. Thanks to the hard work of the VVV team led by Dante Minniti (Pontificia Universidad Catolica de Chile) and Philip Lucas (Centre for Astrophysics Research, University of Hertfordshire, UK) we’re able to feast our eyes on even more. About 15,000 light years away on the other side of the Milky Way, they’ve turned up VVV CL003 – an open cluster. Due the intristic faintness of these new objects, it’s a wonder we can see them at all… In any light! Original Story Source: ESO Press Release.

Scientists using the MeerKAT radio telescope have discovered a unique and previously-unseen flare of radio emission from a binary star in our galaxy. The MeerKAT radio telescope in the Northern Cape of South Africa has discovered an object which rapidly brightened by more than a factor of three over a period of three weeks. This is the first new transient source discovered with MeerKAT and scientists hope it is the tip of an iceberg of transient events to be discovered with the telescope. Astronomers call an astronomical event "transient" when it appears or disappears, or becomes fainter or brighter over seconds, days, or even years. These events are important as they provide a glimpse of how stars live, evolve, and die. Using an assortment of telescopes around the globe, the researchers determined that the source of the flare is a binary system, where two objects orbit each other approximately every 22 days. While the cause of the flaring and the exact nature of the stars that make up the system is still uncertain, it is thought to be associated with an active corona - the hot outermost part of the brighter star. The source of the observed activity is located in the Southern constellation of Ara and was found to be coincident with a giant star about two times as massive as the Sun. The orbital period was determined using optical observations with the Southern African Large Telescope (SALT). Fortuitously, the star is sufficiently bright to have also been monitored by optical telescopes for the last 18 years and is seen to vary in brightness every three weeks, matching the orbital period. "This source was discovered just a couple of weeks after I joined the team, it was amazing that the first MeerKAT images I worked on had such an interesting source in them. Once we found out that the radio flares coincided with a star, we discovered that the star emits across almost the entire electromagnetic spectrum from X-ray to UV to radio wavelengths." said Laura Driessen, a PhD student at The University of Manchester who led this work. Patrick Woudt, Professor and Head of the Astronomy Department at The University of Cape Town said: "Since the inauguration in July 2018 of the South African MeerKAT radio telescope, the ThunderKAT project on MeerKAT has been monitoring parts of the southern skies to study the variable radio emission from known compact binary stars, such as accreting black holes. "The excellent sensitivity and the wide field of view of the MeerKAT telescope, combined with the repeat ThunderKAT observations of various parts of the southern skies, allows us to search the skies for new celestial phenomena that exhibit variable or short-lived radio emission." Professor Ben Stappers from The University of Manchester said: "The properties of this system don't easily fit into our current knowledge of binary or flaring stars and so may represent an entirely new source class." The MeerKAT telescope is sweeping the sky for sources that vary on timescales from milliseconds to years, and will significantly improve human understanding of the variable radio sky. The discovery of this new transient with MeerKAT demonstrates how powerful this telescope will be in the search for further new transient events. Rob Adam, Director of the South African Radio Astronomy Observatory (SARAO) said: "Once again we see the potential of the MeerKAT telescope in finding interesting and possibly new astrophysical phenomena, as well as the power of the multi-wavelength approach to the analysis of observations." Dr. David Buckley from the South African Astronomical Observatory, who leads the SALT (Southern African Large Telescope) transient follow-up programme, commented: "This is a perfect example of where coordinated observations across different wavelengths were combined to give a holistic view of a newly discovered object. "This study was one of the first to involve coordination between two of South Africa's major astronomy facilities and shows the way for future such work."

The Little Ice Age was a period of cooling that occurred after the Medieval Warm Period. Although it was not a true ice age, the term was introduced into scientific literature by François E. Matthes in 1939, it has been conventionally defined as a period extending from the 16th to the 19th centuries, but some experts prefer an alternative timespan from about 1300 to about 1850. The NASA Earth Observatory notes three cold intervals: one beginning about 1650, another about 1770, the last in 1850, all separated by intervals of slight warming; the Intergovernmental Panel on Climate Change Third Assessment Report considered the timing and areas affected by the Little Ice Age suggested independent regional climate changes rather than a globally synchronous increased glaciation. At most, there was modest cooling of the Northern Hemisphere during the period. Several causes have been proposed: cyclical lows in solar radiation, heightened volcanic activity, changes in the ocean circulation, variations in Earth's orbit and axial tilt, inherent variability in global climate, decreases in the human population. The Intergovernmental Panel on Climate Change Third Assessment Report of 2001 described the areas affected: Evidence from mountain glaciers does suggest increased glaciation in a number of spread regions outside Europe prior to the twentieth century, including Alaska, New Zealand and Patagonia. However, the timing of maximum glacial advances in these regions differs suggesting that they may represent independent regional climate changes, not a globally-synchronous increased glaciation, thus current evidence does not support globally synchronous periods of anomalous cold or warmth over this interval, the conventional terms of "Little Ice Age" and "Medieval Warm Period" appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries.... Hemispherically, the "Little Ice Age" can only be considered as a modest cooling of the Northern Hemisphere during this period of less than 1°C relative to late twentieth century levels; the IPCC Fourth Assessment Report of 2007 discusses more recent research, giving particular attention to the Medieval Warm Period. When viewed together, the available reconstructions indicate greater variability in centennial time scale trends over the last 1 kyr than was apparent in the TAR.... The result is a picture of cool conditions in the seventeenth and early nineteenth centuries and warmth in the eleventh and early fifteenth centuries, but the warmest conditions are apparent in the twentieth century. Given that the confidence levels surrounding all of the reconstructions are wide all reconstructions are encompassed within the uncertainty indicated in the TAR; the major differences between the various proxy reconstructions relate to the magnitude of past cool excursions, principally during the twelfth to fourteenth and nineteenth centuries. There is no consensus regarding the time when the Little Ice Age began, but a series of events before the known climatic minima has been referenced. In the 13th century, pack ice began advancing southwards in the North Atlantic, as did glaciers in Greenland. Anecdotal evidence suggests expanding glaciers worldwide. Based on radiocarbon dating of 150 samples of dead plant material with roots intact, collected from beneath ice caps on Baffin Island and Iceland, Miller et al. state that cold summers and ice growth began abruptly between 1275 and 1300, followed by "a substantial intensification" from 1430 to 1455. In contrast, a climate reconstruction based on glacial length shows no great variation from 1600 to 1850 but strong retreat thereafter. Therefore, any of several dates ranging over 400 years may indicate the beginning of the Little Ice Age: 1250 for when Atlantic pack ice began to grow; the Little Ice Age ended in the latter half of the 19th century or early in the 20th century. The Little Ice Age brought colder winters to parts of North America. Farms and villages in the Swiss Alps were destroyed by encroaching glaciers during the mid-17th century. Canals and rivers in Great Britain and the Netherlands were frozen enough to support ice skating and winter festivals; the first River Thames frost fair was in 1608 and the last in 1814. Freezing of the Golden Horn and the southern section of the Bosphorus took place in 1622. In 1658, a Swedish army marched across the Great Belt to Denmark to attack Copenhagen; the winter of 1794–1795 was harsh: the French invasion army under Pichegru was able to march on the frozen rivers of the Netherlands, the Dutch fleet was locked in the ice in Den Helder harbour. Sea ice surrounding Iceland extended for miles in every direction; the population of Iceland fell by half, but that may have been caused by skeletal fluorosis after the eruption of Laki in 1783. Iceland suffered failures of cereal crops and people moved away from a grain-based diet; the Norse colonies in Greenland starved and vanished by the early 15th century, as crops failed and livestock could Hermann Jansen was a German architect, urban planner and university educator. Hermann Jansen was born in 1869 was the son of the pastry chef Francis Xavier Jansen and his wife Maria Anna Catharina Arnoldi. After visiting the humanistic Kaiser-Karls-Gymnasium in Aachen, Jansen studied architecture at the RWTH Aachen University in Karl Henrici. After graduation in 1893, Jansen worked in an architectural office in Aachen. 1897 drew Jansen to Berlin, in 1899 created his own business with the architect William Mueller. In the same year he made the designs for the later-named Pelzer tower in his home town of Aachen. In 1903 he took over the publication of the architecture magazine "The Builder", first published in 1902 in Munich. In the years prior to 1908, the District of Berlin and its surrounding towns and cities had witnessed immense growth due to private investment. Due to the unplanned nature of growth in the city, several key urban challenges surfaced; these included the provision of housing, capacity for efficient transport, the demand for public open spaces. With pressures mounting, the city saw planning a means of directing growth, in 1908 put forth the ‘Groẞ-Berlin' competition. The competition required planners and architects to put forth design that would link central Berlin with surrounding towns in the regions to form a metropolis, spanning from the historic center to outer suburbs. Jansen was among the planners who submitted a comprehensive plan for a Greater Berlin, when the competition closed in 1910 his was awarded equal first place. Jansen's proposal dubbed "The Jansen-plan" stood as the first comprehensive plan to be commissioned for Greater Berlin. Under the Jansen plan, development of Berlin would be arranged around a small inner ring and a larger outer ring of green space comprising parks, gardens and meadows, which would be connected via green-corridors radiating outward from the compact inner-city; the central focus of green space in Jansen's design was well received and laid the foundation for the creation and safeguarding of open spaces across Berlin. In addition to his focus on public space, Jansen's plan received accolades for the attention drawn to overcrowding in central Berlin, with a proposed fast transport system aimed at integrating the center of the city with peripheral areas. What made this aspect of Jansen's plan for Berlin so popular was the creation of positive dwellings in areas of urban expansion; these dwellings came in the form of single houses within small settlements with the intention of creating new opportunities for Berlin's less-privileged social classes to live outside the city center. Due to the onset of World War I, Jansens's plan was only implemented, however evidence of his work can still be found to some extent in the cityscape. Jansen's competition winning work was showcased at the General Town Planning Exhibition held on 1 May 1910 at the Royal Arts Academy, known today as Berlin University of the Arts; the exhibition was among the first to give comprehensive account of planning and the built environment. Following its unexpectedly popular reception in Berlin many sections, including Jansen's plan, were featured at the Town Planning Conference in London that year. In 1918, Jansen was in the Royal Prussian Academy of Arts in Berlin and recorded in their Senate and received the title of professor. On the occasion of his 50th Birthday, he was awarded an honorary doctorate by the Technical University in Stuttgart as the founder and leader of the modern urban art, he was a member of the Advisory Council of the Prussian cities Ministry of Public Works. He was a member of the Association of German Architects. In 1920, Hermann Jansen was appointed as associate professor of urban art at the Technische Hochschule Charlottenburg resigning in 1923. Jansen in 1930 became professor of urban planning at the University of Arts Berlin, he contributed to plans across Germany including. Jansen planned for foreign cities such as Riga, Łódź, Bratislava and Madrid. In the 1930s he prepared a city plan for Mersin, in 1938 the Mersin Interfaith Cemetery was established in one of the locations that he proposed. Following the failure of existing urban planning measures to address the uncontrolled growth experienced in Turkey's newly established capital Ankara, 1927 saw the Turkish Government put forth an international competition to create a comprehensive development plan for the new city. The government invited three prominent European planners to the competition, Frenchman Léon Jaussely and Germans Joseph Brix and Hermann Jansen. In 1929 the competition concluded with the jury declaring Jansen's proposal to be the winner, following which he was commissioned with preparing detailed development plans for the capital city. Jansen's master plan for Ankara placed particular emphasis on the historical context of the region, stressing the importance of the new settlement sitting adjacent to the existing old city rather than enveloping it within the new design. Jansen called for the compulsory integration of green belts and areas within the city to promote a healthy urban environment extending this vision to the housing stock, which were designed to incorporate both front and rear gardens. A defining feature of Jansen's master plan for Ankara was his division of the city into functionally specialized zones, an unfamiliar concept when compared to traditional Turkish urban form; this included 18 residential sections, each Jérémie Pauzié was a Genevan diamond jeweler and memoirist, known for his work for the Russian Imperial court and the Imperial Crown of Russia, which he created with the court's jeweler Georg Friedrich Ekart. Throughout his working life Pauzié, who held the title Principal Diamond Expert and Court Jeweller, made jewellery and gifts for the Russian nobility and the Imperial family, he recorded his life in the book of ‘Memoirs of a Court Jeweller Pauzié, published by the Russian history journal ‘Russkaya Starina’ in 1870. Pauzié studied for seven years with Benedict Gravero in Saint Petersburg, in the end of the 1730s started his own jewellery workshop. Hs speciality was work with diamond and other jewels, he did not have much experience with noble metals. For work on metals, he hired subcontractors. In this period, Pauzié produced jewellery for local noblemen, was admitted to the Imperial court. In 1761, Empress Elizabeth died, Ekart, the chief court jeweller, was charged in making a funeral crown. His solution proved to be suboptimal, Pauzié was asked to repair the crown. After that, he got access to the court, was considered to be Ekart's chief rival; when the reign of Catherine the Great started, Ekart was charged with making the Imperial Crown, Pauzié decorated it with jewels, against Ekart's will. In 1764, Pauzié left Saint Petersburg and went back to Switzerland, where in 1770 he became the citizen of Geneva. Pauzié was commissioned to work with Ekart, the Russian Imperial court's jeweler, to create the Great Imperial Crown of Russia, created for the coronation of Catherine the Great in 1762; the crown was made in the style of classicism and constructed of two gold and silver half spheres, representing the eastern and western Roman empires, divided by a foliate garland and fastened with a low hoop. The crown contains 75 pearls and 4,936 Indian diamonds forming laurel and oak leaves, the symbols of power and strength, is surmounted by a 398.62 carat ruby spinel that belonged to the Empress Elizabeth, a diamond cross. After Catherine the Great's coronation the crown continued to be used as the coronation crown of all Romanov emperors, till the monarchy's abolition and the death of last Romanov, Nikolas II in 1918. It is considered to be one of the main treasures of the Romanov dynasty, is now on display in the Moscow Kremlin Armoury Museum in Russia, his work formed part of the art jewellery exhibitions, including The Art of the Goldsmith & the Jeweler at A La Vieille Russie in New York and Carl Fabergé and Masters of Stone Carving: Gem Masterpieces of Russia at the Dormition Belfry of the Moscow Kremlin Museums in Moscow. In 2013 the Jérémie Pauzié name was acquired by French luxury group Vendôme Private Trading. «Culture» Discovery. Escape of the diamond master Pauzié. January, 2015 Notes of the Court Jeweler Jeremie Posier 1729-64, ed. A A Kunin, in Russkaya Starina, 1870 Alexander Solodkoff, Orfèvrerie russe du XVIIe au XIXe siècle, 1981, A la Vieille Russie, The Art of the Goldsmith & the Jeweler, 1968, no. 174, illus. P. 76 Sidler, Catalogue officiel du Musée de l'Ariana, Genève, Ville de Genève / Atar, 1905. 234 p.. P. 126, n° 47 Eisler, William. The Dassiers of Geneva: 18th-century European medallists. Volume II: Dassier and sons: an artistic enterprise in Geneva and Europe, 1733-1759. Lausanne, 2005. Pp. 361– 362, fig. 47, repr. n/b Golay, Laurent. Alexandra Karouova et al.. Suisse-Russie. Des siècles d'amour et d'oubli, 1680- 2006. Lausanne, Musée historique de Lausanne. P. 55, repr. coul. Jeffares, Neil. Dictionary of pastellists before 1800. London, Unicorn Press, 2006. P. 622, non repr. Edition critique introduite et commentée du mémoire de Jérémie Pauzié, joaillier à la Cour de Russie de 1730 à 1763 / Mélanie Draveny, Mémoire de licence dactyl. Lettres Genève, 2004

Billions of years ago, Earth’s magnetic field may have gotten a jump-start from a turbulent magma ocean swirling around the planet’s core. Our planet has generated its own magnetism for almost its entire history (SN: 1/28/19). But it’s never been clear how Earth created this magnetic field during the planet’s Archean Eon — an early geologic period roughly 2.5 billion to 4 billion years ago. Now, computer simulations suggest that a deep layer of molten rock-forming minerals known as silicates might have been the culprit. “There’s a few billion years of Earth’s history where it’s difficult to explain what was driving the magnetic field,” says Joseph O’Rourke, a planetary scientist at Arizona State University in Tempe who was not involved with this study. This new result, he says, is a “vital piece of the puzzle.” Today, Earth’s magnetism is likely generated in the planet’s outer core, a layer of liquid iron and nickel. Heat escaping from the solid inner core drives flows of fluid that create circulating electric currents in the outer core, turning Earth’s innards into a gigantic electromagnet. The outer core, however, is a fairly recent addition, appearing roughly a billion or so years ago, and ancient rocks preserve evidence of a planetwide magnetic field much earlier than that. So, some other mechanism must have been at work during Earth’s formative years. One candidate for Earth’s first go at a magnetic field is a sea of liquid rock hypothesized to once have surrounded the young planet’s nascent core. To see if this ocean of molten silicates is a viable option, Lars Stixrude, a geophysicist at UCLA, and colleagues developed computer simulations to estimate the electrical properties of silicates at extreme temperatures and pressures. The team found that, at pressures more than 10 million times Earth’s surface atmospheric pressure and temperatures comparable to those on the surface of the sun, silicates conduct electricity well enough to produce a planetwide magnetic field. The strength of that field, the team reports February 25 in Nature Communications, roughly matches measurements of fossil magnetic fields in rocks that are about 2 billion to 4 billion years old. Around the end of the Archean, the team suggests, the magma ocean would have cooled and solidified, possibly handing over magnetic field duties to an increasingly turbulent core. The study is “an extremely important step forward in understanding the history of Earth’s magnetic field,” O’Rourke says. What’s more, it might also be relevant to other worlds today. “It’s not just a curiosity of ancient history,” he says. Super-Earths, rocky planets a few times as massive as Earth, might retain enough internal heat to sustain a deep silicate ocean for much longer than our planet did. These planets are also the most common worlds found outside the solar system. The mechanism behind Earth’s early magnetic field, the team speculates, may therefore be operating in large rocky planets throughout the universe.

According to ancient and medieval science, aether (//), also spelled æther or ether and also called quintessence, is the material that fills the region of the universe above the terrestrial sphere. The concept of aether was used in several theories to explain several natural phenomena, such as the traveling of light and gravity. In the late 19th century, physicists postulated that aether permeated all throughout space, providing a medium through which light could travel in a vacuum, but evidence for the presence of such a medium was not found in the Michelson–Morley experiment, and this result has been interpreted as meaning that no such luminiferous aether exists. The word αἰθήρ (aithḗr) in Homeric Greek means "pure, fresh air" or "clear sky". In Greek mythology, it was thought to be the pure essence that the gods breathed, filling the space where they lived, analogous to the air breathed by mortals. It is also personified as a deity, Aether, the son of Erebus and Nyx in traditional Greek mythology. Aether is related to αἴθω "to incinerate", and intransitive "to burn, to shine" (related is the name Aithiopes (Ethiopians; see Aethiopia), meaning "people with a burnt (black) visage"). In Plato's Timaeus (58d) speaking about air, Plato mentions that "there is the most translucent kind which is called by the name of aether (αἰθήρ)" but otherwise he adopted the classical system of four elements. Aristotle, who had been Plato's student at the Akademia, agreed on this point with his former mentor, emphasizing additionally that fire has sometimes been mistaken for aether. However, in his Book On the Heavens he introduced a new "first" element to the system of the classical elements of Ionian philosophy. He noted that the four terrestrial classical elements were subject to change and naturally moved linearly. The first element however, located in the celestial regions and heavenly bodies, moved circularly and had none of the qualities the terrestrial classical elements had. It was neither hot nor cold, neither wet nor dry. With this addition the system of elements was extended to five and later commentators started referring to the new first one as the fifth and also called it aether, a word that Aristotle had not used. Aether did not follow Aristotelian physics either. Aether was also incapable of motion of quality or motion of quantity. Aether was only capable of local motion. Aether naturally moved in circles, and had no contrary, or unnatural, motion. Aristotle also noted that crystalline spheres made of aether held the celestial bodies. The idea of crystalline spheres and natural circular motion of aether led to Aristotle's explanation of the observed orbits of stars and planets in perfectly circular motion in crystalline aether. Medieval scholastic philosophers granted aether changes of density, in which the bodies of the planets were considered to be more dense than the medium which filled the rest of the universe. Robert Fludd stated that the aether was of the character that it was "subtler than light". Fludd cites the 3rd-century view of Plotinus, concerning the aether as penetrative and non-material. See also Arche. Quintessence is the Latinate name of the fifth element used by medieval alchemists for a medium similar or identical to that thought to make up the heavenly bodies. It was noted that there was very little presence of quintessence within the terrestrial sphere. Due to the low presence of quintessence, earth could be affected by what takes place within the heavenly bodies. This theory was developed in the 14th century text The testament of Lullius, attributed to Ramon Llull. The use of quintessence became popular within medieval alchemy. Quintessence stemmed from the medieval elemental system, which consisted of the four classical elements, and aether, or quintessence, in addition to two chemical elements representing metals: sulphur, "the stone which burns", which characterized the principle of combustibility, and mercury, which contained the idealized principle of metallic properties. This elemental system spread rapidly throughout all of Europe and became popular with alchemists, especially in medicinal alchemy. Medicinal alchemy then sought to isolate quintessence and incorporate it within medicine and elixirs. Due to quintessence's pure and heavenly quality, it was thought that through consumption one may rid oneself of any impurities or illnesses. In The book of Quintessence, a 15th-century English translation of a continental text, quintessence was used as a medicine for many of man's illnesses. A process given for the creation of quintessence is distillation of alcohol seven times. Over the years, the term quintessence has become synonymous with elixirs, medicinal alchemy, and the philosopher's stone itself. With the 18th century physics developments, physical models known as "aether theories" made use of a similar concept for the explanation of the propagation of electromagnetic and gravitational forces. As early as the 1670s, Newton used the idea of aether to help match observations to strict mechanical rules of his physics. However, the early modern aether had little in common with the aether of classical elements from which the name was borrowed. These aether theories are considered to be scientifically obsolete, as the development of special relativity showed that Maxwell's equations do not require the aether for the transmission of these forces. However, Einstein himself noted that his own model which replaced these theories could itself be thought of as an aether, as it implied that the empty space between objects had its own physical properties. Despite the early modern aether models being superseded by general relativity, occasionally some physicists have attempted to reintroduce the concept of aether in an attempt to address perceived deficiencies in current physical models. One proposed model of dark energy has been named "quintessence" by its proponents, in honor of the classical element. This idea relates to the hypothetical form of dark energy postulated as an explanation of observations of an accelerating universe. It has also been called a fifth fundamental force. Aether and light The motion of light was a long-standing investigation in physics for hundreds of years before the 20th century. The use of aether to describe this motion was popular during the 17th and 18th centuries, including a theory proposed by Johann II Bernoulli, who was recognized in 1736 with the prize of the French Academy. In his theory, all space is permeated by aether containing "excessively small whirlpools". These whirlpools allow for aether to have a certain elasticity, transmitting vibrations from the corpuscular packets of light as they travel through. This theory of luminiferous aether would influence the wave theory of light proposed by Christiaan Huygens, in which light traveled in the form of longitudinal waves via an "omnipresent, perfectly elastic medium having zero density, called aether". At the time, it was thought that in order for light to travel through a vacuum, there must have been a medium filling the void through which it could propagate, as sound through air or ripples in a pool. Later, when it was proved that the nature of light wave is transverse instead of longitudinal, Huygens' theory was replaced by subsequent theories proposed by Maxwell, Einstein and de Broglie, which rejected the existence and necessity of aether to explain the various optical phenomena. These theories were supported by the results of the Michelson–Morley experiment in which evidence for the motion of aether was conclusively absent. The results of the experiment influenced many physicists of the time and contributed to the eventual development of Einstein's theory of special relativity. Aether and gravitation Aether has been used in various gravitational theories as a medium to help explain gravitation and what causes it. Few years later, aether was used in one of Sir Isaac Newton's first published theories of gravitation, Philosophiæ Naturalis Principia Mathematica (the Principia, 1687). He based the whole description of planetary motions on a theoretical law of dynamic interactions. He renounced standing attempts at accounting for this particular form of interaction between distant bodies by introducing a mechanism of propagation through an intervening medium. He calls this intervening medium aether. In his aether model, Newton describes aether as a medium that "flows" continually downward toward the Earth's surface and is partially absorbed and partially diffused. This "circulation" of aether is what he associated the force of gravity with to help explain the action of gravity in a non-mechanical fashion. This theory described different aether densities, creating an aether density gradient. His theory also explains that aether was dense within objects and rare without them. As particles of denser aether interacted with the rare aether they were attracted back to the dense aether much like cooling vapors of water are attracted back to each other to form water. In the Principia he attempts to explain the elasticity and movement of aether by relating aether to his static model of fluids. This elastic interaction is what caused the pull of gravity to take place, according to this early theory, and allowed an explanation for action at a distance instead of action through direct contact. Newton also explained this changing rarity and density of aether in his letter to Robert Boyle in 1679. He illustrated aether and its field around objects in this letter as well and used this as a way to inform Robert Boyle about his theory. Although Newton eventually changed his theory of gravitation to one involving force and the laws of motion, his starting point for the modern understanding and explanation of gravity came from his original aether model on gravitation.[self-published source?] - Celestial spheres - Dark matter - Energy (esotericism) - Etheric body - Etheric force - Etheric plane - Radiant energy - George Smoot III. "Aristotle's Physics". lbl.gov. Archived from the original on 20 December 2016. Retrieved 20 December 2016. - Carl S. Helrich, The Classical Theory of Fields: Electromagnetism Berlin, Springer 2012, p. 26. - "Aether". GreekMythology.com. Archived from the original on 20 December 2016. Retrieved 20 December 2016. - "AITHER". AETHER : Greek protogenos god of upper air & light ; mythology : AITHER. Retrieved January 16, 2016. - Pokorny, Julius (1959). Indogermanisches etymologisches Wörterbuch, s.v. ai-dh-. - Αἰθίοψ in Liddell, Scott, A Greek–English Lexicon: "Αἰθίοψ , οπος, ὁ, fem. Αἰθιοπίς , ίδος, ἡ (Αἰθίοψ as fem., A.Fr.328, 329): pl. 'Αἰθιοπῆες' Il.1.423, whence nom. 'Αἰθιοπεύς' Call.Del.208: (αἴθω, ὄψ):— properly, Burnt-face, i.e. Ethiopian, negro, Hom., etc.; prov., Αἰθίοπα σμήχειν 'to wash a blackamoor white', Luc.Ind. 28." Cf. Etymologicum Genuinum s.v. Αἰθίοψ, Etymologicum Gudianum s.v.v. Αἰθίοψ. "Αἰθίοψ". Etymologicum Magnum (in Greek). Leipzig. 1818. - Fage, John (2013-10-23). A History of Africa. Routledge. pp. 25–26. ISBN 978-1317797272. Retrieved 20 January 2015. ...[Africa's Indian Ocean] coast was called Azania, and no 'Ethiopeans', dark skinned people, were mentioned amongst its inhabitants. - Plato, Timaeus 58d. - Hahm, David E. (1982). "The fifth element in Aristotle's De Philosophia: A Critical Re-Examination". The Journal of Hellenic Studies. 102: 60–74. doi:10.2307/631126. JSTOR 631126. - G. E. R. Lloyd), Aristotle: The Growth and Structure of his Thought, Cambridge: Cambridge Univ. Pr., 1968, pp. 133-139, ISBN 0-521-09456-9. - Grant, Edward (1996). Planets, Stars, & Orbs: The Medieval Cosmos, 1200-1687 (1st pbk. ed.). Cambridge [England]: Cambridge University Press. pp. 322–428. ISBN 978-0-521-56509-7. - Robert Fludd, "Mosaical Philosophy". London, Humphrey Moseley, 1659. Pg 221. - The Alchemists, by F. Sherwood Taylor page 95 - The book of Quintessence Archived 2015-09-24 at the Wayback Machine, Early English Text society original series number 16, edited by F. J. Furnivall - The Dictionary of Alchemy, by Mark Haeffner - Margaret Osler, Reconfiguring the World. The Johns Hopkins University Press 2010. (155). - Einstein, Albert: "Ether and the Theory of Relativity" (1920), republished in Sidelights on Relativity (Methuen, London, 1922) - Dirac, Paul (1951). "Is there an Aether?". Nature. 168 (4282): 906–907. Bibcode:1951Natur.168..906D. doi:10.1038/168906a0. - Zlatev, I.; Wang, L.; Steinhardt, P. (1999). "Quintessence, Cosmic Coincidence, and the Cosmological Constant". Physical Review Letters (Submitted manuscript). 82 (5): 896–899. arXiv:astro-ph/9807002. Bibcode:1999PhRvL..82..896Z. doi:10.1103/PhysRevLett.82.896. - Whittaker, Edmund Taylor, A History of the Theories of Aether and Electricity from the Age of Descartes to the Close of the 19th Century (1910), pp. 101-02. - Michelson, Albert A. (1881). "The Relative Motion of the Earth and the Luminiferous Ether" (PDF). American Journal of Science. 22 (128): 120–129. Bibcode:1881AmJS...22..120M. doi:10.2475/ajs.s3-22.128.120. - Shankland, R. S. (1964). "Michelson-Morley Experiment". American Journal of Physics. 32 (1): 16. Bibcode:1964AmJPh..32...16S. doi:10.1119/1.1970063. - Rosenfeld, L. (1969). "Newton's views on aether and gravitation". Archive for History of Exact Sciences. 6 (1): 29–37. doi:10.1007/BF00327261. - Newton, Isaac."Isaac Newton to Robert Boyle, 1679." 28 February 1679. - James DeMeo (2009). "Isaac Newton's Letter to Robert Boyle, on the Cosmic Ether of Space - 1679". orgonelab.org. Archived from the original on 20 December 2016. Retrieved 20 December 2016. - Andrew Robishaw (9 April 2015). The Esoteric Codex: Esoteric Cosmology. Lulu.com. p. 6. ISBN 9781329053083. Retrieved 20 December 2016.[self-published source]

Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place... The Space and Astronomy Agora |What I Found Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To Posted by Jessica Lynn on January 22, 2000 15:29:09 UTC : : 1. What is a black hole? A black hole is defined by the escape velocity that would have to be attained to escape from the gravitational pull exerted upon an object. For example, the escape velocity of earth is equal to 11 km/s. Anything that wants to escape earth's gravitational pull must go at least 11 km/s, no matter what the thing is — a rocket ship or a baseball. The escape velocity of an object depends on how compact it is; that is, the ratio of its mass to radius. A black hole is an object so compact that, within a certain distance of it, even the speed of light is not fast enough to escape. | | 2. How is a black hole created? A common type of black hole is the type produced by some dying stars. A star with a mass of about 10 - 20 times the mass of our Sun may produce a black hole at the end of its life. In the normal life of a star there is a constant tug of war between gravity pulling in and pressure pushing out. Nuclear reactions in the core of the star produce enough energy to push outward. For most of a star's life, gravity and pressure balance each other exactly, and so the star is stable. However, when a star runs out of nuclear fuel, gravity gets the upper hand and the material in the core is compressed even further. The more massive the core of the star, the greater the force of gravity that compresses the material, collapsing it under its own weight. For small stars, when the nuclear fuel is exhausted and there are no more nuclear reactions to fight gravity, the repulsive forces among electrons within the star eventually create enough pressure to halt further gravitational collapse. The star then cools and dies peacefully. This type of star is called the "white dwarf." When a very massive star exhausts its nuclear fuel it explodes as a supernova. The outer parts of the star are expelled violently into space, while the core completely collapses under its own weight. To create a massive core a progenitor (ancestral) star would need to be 10 - 20 times more massive than our Sun. If the core is very massive (approximately 2.5 times more massive than the Sun), no known repulsive force inside a star can push back hard enough to prevent gravity from completely collapsing the core into a black hole. Then the core compacts into a mathematical point with virtually zero volume, where it is said to have infinite density. This is referred to as a singularity. When this happens, escape would require a velocity greater than the speed of light. No object can reach the speed of light. The distance from the black hole at which the escape velocity is just equal to the speed of light is called the event horizon. Anything, including light, that passes across the event horizon toward the black hole is forever trapped. | | 3. Since light has no mass how can it be trapped by the gravitational pull of a black hole? Newton thought that only objects with mass could produce a gravitational force on each other. Applying Newton's theory of gravity, one would conclude that since light has no mass, the force of gravity couldn't affect it. Einstein discovered that the situation is a bit more complicated than that. First he discovered that gravity is produced by a curved space-time. Then Einstein theorized that the mass and radius of an object (its compactness) actually curves space-time. Mass is linked to space in a way that physicists today still do not completely understand. However, we know that the stronger the gravitational field of an object, the more the space around the object is curved. In other words, straight lines are no longer straight if exposed to a strong gravitational field; instead, they are curved. Since light ordinarily travels on a straight-line path, light follows a curved path if it passes through a strong gravitational field. This is what is meant by "curved space," and this is why light becomes trapped in a black hole. In the 1920's Sir Arthur Eddington proved Einstein's theory when he observed starlight curve when it traveled close to the Sun. This was the first successful prediction of Einstein's General Theory of Relativity. One way to picture this effect of gravity is to imagine a piece of rubber sheeting stretched out. Imagine that you put a heavy ball in the center of the sheet. The weight of the ball will bend the surface of the sheet close to it. This is a two-dimensional picture of what gravity does to space in three dimensions. Now take a little marble and send it rolling from one side of the rubber sheet to the other. Instead of the marble taking a straight path to the other side of the sheet, it will follow the contour of the sheet that is curved by the weight of the ball in the center. This is similar to how the gravitation field created by an object (the ball) affects light (the marble). 4. What does a black hole look like? A black hole itself is invisible because no light can escape from it. In fact, when black holes were first hypothesized they were called "invisible stars." If black holes are invisible, how do we know they exist? This is exactly why it is so difficult to find a black hole in space! However, a black hole can be found indirectly by observing its effect on the stars and gas close to it. For example, consider a double-star system in which the stars are very close. If one of the stars explodes as a supernova and creates a black hole, gas and dust from the companion star might be pulled toward the black hole if the companion wanders too close. In that case, the gas and dust are pulled toward the black hole and begin to orbit around the event horizon and then orbit the black hole. The gas becomes heavily compressed and the friction that develops among the atoms converts the kinetic energy of the gas and dust into heat, and x-rays are emitted. Using the radiation coming from the orbiting material, scientists can measure its heat and speed. From the motion and heat of the circulating matter, we can infer the presence of a black hole. The hot matter swirling near the event horizon of a black hole is called an accretion disk. John Wheeler, a prominent theorist, compared observing these double-star systems to watching women in white dresses dancing with men in black tuxedos within a dimly lit ballroom. You see only the women, but you could predict the existence of their invisible partners because of the women's' spinning and whirling motions around a central axis. Searching for stars whose motions are influenced by invisible partners is one way in which astronomers search for possible black holes. | | 5. Is a black hole a giant cosmic vacuum cleaner? The answer to this question is "not really." To understand this, first consider why the force of gravity is so strong close to a black hole. The gravity of a black hole is not special. It does not attract matter differently than any other object does. At a long distance from the black hole the force of gravity falls off as the inverse square of the distance, just as it does for normal objects. Mathematically, the gravity of any spherical object behaves as if all the mass were concentrated at one central point. Since most ordinary objects have surfaces, you will feel the strongest gravity of an object when you are on its surface. This is as close to its total mass as you can get. If you penetrated the spherical object, getting closer to its core, you would feel the force of gravity get weaker, not stronger. The force of gravity you feel depends on the mass that is interior to you, because the gravity from the mass behind you is exactly canceled by the mass in the opposite direction. Therefore, you will feel the strongest force of gravity from an object, for example a planet, when you are standing on the planet's surface, because it is on the surface that you are closest to its total mass. Penetrating the surface of the planet does not expose you to more of the planet's total mass, but actually exposes you to less of its mass. Now remember the size of a black hole is infinitesimally small. Gravity near a black hole is very strong because objects can get extremely close to it and still be exposed to its total mass. There is nothing special about the mass of a black hole. A black hole is different from our ordinary experience not because of its mass, but because its radius has vanished. Far away from the black hole, you would feel the same strength of gravity as if the black hole were a normal star. But the force of gravity close to a black hole is enormously strong because you can get so close to its total mass! For example, the surface of the Earth where we are standing is 6378 km from the center of the Earth. The surface is as close as you can get and still be exposed to the total mass of the Earth. Thus, it is where you will feel the strongest gravity. If suddenly the Earth became a black hole (impossible!) and you remained at 6378 km from the new Earth-black hole, you would feel the same pull of gravity as you do today. For example, if you normally weigh 120 lbs, you would still weigh 120 lbs. The mass of the Earth hasn't changed, your distance from it hasn't changed, and therefore you would experience the same gravitational force as you feel on the surface of normal Earth. But with the Earth-black hole, it would be possible for you to get closer to the total mass of the Earth. Let's say that you weigh 120 lbs standing on the surface of normal Earth. As you venture closer toward the Earth-black hole you would feel a stronger and stronger force. If you went to within 3189 km of the Earth-black hole you would weigh 480 lbs! For the same exercise with the Earth as we normally experience it, if you dug your way to 3189 km of the center, you would weigh less than at the surface, a mere 60 lbs, because there would be less Earth mass interior relative to you! As another example, consider the Sun. If the Sun suddenly became a black hole (equally impossible!), the Earth would continue on its normal orbit and would feel the same force of gravity from the Sun as usual! Therefore, to be "sucked up" by a black hole, you have to get very close; otherwise, you experience the same force of gravity as if the black hole were the normal star it used to be. As you get close to a black hole, relativistic effects become important; for example, the escape velocity approximates and eventually reaches the speed of light and some very strange things like the "event horizon effect" begin to happen. For details, consult any popular book on black holes. | | 6. Do all stars become black holes? Only stars with very large masses can become black holes. Our Sun, for example, is not massive enough to become a black hole. Four billion years from now when the Sun runs out of the available nuclear fuel in its core, our Sun will die a quiet death. Stars of this type end their history as white dwarf stars. More massive stars, such as those with masses of 10 - 20 times our Sun's mass, may eventually create a black hole. When a massive star runs out of nuclear fuel it can no longer sustain its own weight and begins to collapse. When this occurs the star heats up and some fraction of its outer layer, which often still contains some fresh nuclear fuel, activates the nuclear reaction again and explodes in what is called a supernova. The remaining innermost fraction of the star, the core, continues to collapse. Depending on how massive the core is, it may become either a neutron star and stop the collapse or it may continue to collapse into a black hole. The dividing mass of the core, which determines its fate, is about 2.5 solar masses. It is thought that to produce a core of 2.5 solar masses the ancestral star should begin with about 10 - 20 solar masses. A black hole formed from a star is called a stellar black hole. | | 7. How many types of black holes are there? According to theory, there might be three types of black holes: stellar, supermassive, and miniature black holes — depending on their size. These black holes have also formed in different ways. Stellar black holes are described in Question 6. Supermassive black holes likely exist in the centers of most galaxies, including our own galaxy, the Milky Way. They can have a mass equivalent to billions of suns. In the outer parts of galaxies (where our solar system is located within the Milky Way) there are vast distances between stars. However, in the central region of galaxies, stars are packed very closely together. Because everything in the central region is tightly packed to start with, a black hole in the center of a galaxy can become more and more massive as stars orbiting the event horizon can ultimately be captured by gravitational attraction and add their mass to the black hole. By measuring the velocity of stars orbiting close to the center of a galaxy, we can infer the presence of a supermassive black hole and calculate its mass. Perpendicular to the accretion disk of a supermassive black hole, there are sometimes two jets of hot gas. These jets can be millions of light years in length. They are probably caused by the interaction of gas particles with strong, rotating magnetic fields surrounding the black hole. Observations with the Hubble Space Telescope have provided the best evidence to date that supermassive black holes exist. The exact mechanisms that result in what are known as miniature black holes have not been precisely identified, but a number of hypotheses have been proposed. The basic idea is that miniature black holes might have been formed shortly after the "Big Bang," which is thought to have started the Universe about 15 billion years ago. Very early in the life of the Universe the rapid expansion of some matter might have compressed slower-moving matter enough to contract into black holes. Some scientists hypothesize that black holes can theoretically "evaporate" and explode. The time required for the "evaporation" would depend upon the mass of the black hole. Very massive black holes would need a time that is longer than the current accepted age of the universe. Only miniature black holes are thought to be capable of evaporation within the existing time of our universe. For a black hole formed at the time of the "Big Bang" to evaporate today its mass must be about 1015g (i.e., about 2 million pounds), about twice the mass of the current Homo sapien population on planet Earth. During the final phase of the "evaporation," such a black hole would explode with a force of several trillion times that of our most powerful nuclear weapon. So far, however, there is no observational evidence for miniature black holes. | | 8. When were black holes first theorized? Using Newton's Laws in the late 1790s, John Michell of England and Pierre LaPlace of France independently suggested the existence of an "invisible star." Michell and LaPlace calculated the mass and size — which is now called the "event horizon" — that an object needs in order to have an escape velocity greater than the speed of light. In 1967 John Wheeler, an American theoretical physicist, applied the term "black hole" to these collapsed objects. | | 9. What evidence do we have for the existence of black holes? Astronomers have found convincing evidence for a supermassive black hole in the center of the giant elliptical galaxy M87, as well as in several other galaxies. The discovery is based on velocity measurements of a whirlpool of hot gas orbiting the black hole. Hubble Space Telescope data produced an unprecedented measurement of the mass of an unseen object at the center of the galaxy. Based on the kinetic energy of the material whirling about the center (as in Wheeler's dance, see Question 4 above), the object is about 3 billion times the mass of our Sun and appears to be concentrated into a space smaller than our solar system. For many years x-ray emission from the double-star system Cygnus X-1 convinced many astronomers that the system contains a black hole. With more precise measurements available recently, the evidence for a black hole in Cygnus X-1 is very strong. | | 10. How does the Hubble Space Telescope search for black holes? A black hole cannot be viewed directly because light cannot escape it. Effects on the matter that surrounds it infer its presence. Matter swirling around a black hole heats up and emits radiation that can be detected. Around a stellar black hole this matter is composed of gas and dust. Around a supermassive black hole in the center of a galaxy the swirling disk is made of not only gas but also stars. An instrument aboard the Hubble Space Telescope, called the Space Telescope Imaging Spectrograph (STIS), was installed in February 1997. STIS is the space telescope's main "black hole hunter." A spectrograph uses prisms or diffraction gratings to split the incoming light into its rainbow pattern. The position and strength of the line in a spectrum gives scientists valuable information. STIS spans ultraviolet, visible, and near-infrared wavelengths. This instrument can take a spectrum of many places at once across the center of a galaxy. Each spectrum tells scientists how fast the stars and gas are swirling at that location. With that information, the central mass that the stars are orbiting can be calculated. The faster the stars go, the more massive the central object must be. STIS found the signature of a supermassive black hole in the center of the galaxy M84. The spectra showed a rotation velocity of 400 km/s, equivalent to 1.4 million km every hour! The Earth orbits our Sun at 30 km/s. If Earth moved as fast as 400 km/s our year would be only 27 days long! | | A few words from the scientist: When we got together last summer it was a particularly exciting time to be creating a lesson about black holes. A new instrument on HST had just become the ideal science instrument to find and study supermassive black holes that reside in the center of galaxies. Among the remarkable things HST can accomplish with this instrument, the Imaging Spectrograph (STIS), will be a black hole survey. STIS is something like a "Cosmic Speed Gun" - when Hubble is pointed at a galaxy it can determine the speed of material that circulates the galactic center. The faster stuff moves around the center, the more massive that center must be. With high-school-level physics we can determine the mass of these supermassive black holes. Just as we know the mass of our Sun by observing the planets in their orbits about the Sun, we will know the mass of the black holes that reside in the center of each and every galaxy in which we point the STIS "speedgun." The real STIS image of the central region of galaxy M84 is used in the "Amazing Space Black Hole Activity." As more STIS results accumulate, it seems that many, if not most, galaxies have supermassive black holes at their center. In my research I have studied gravity on a much smaller scale. I use the circulation of our oceans and atmosphere to test how this motion affects the gravitational field of the earth. For example, satellites orbiting the Earth exhibit measurable changes in their orbits as a result of El Niño. In fact, when you get up and leave the computer terminal you will be changing the Earth's gravitational field by a very small amount. Of course, your walking across the room is not measurable from space. However, it would be an interesting experiment to see how many teachers would have to get up and walk across their rooms to cause a measurable change in the Earth's gravitational field. The gravitational phenomena that occur on Earth and in our solar system are many times smaller in magnitude and scale and not nearly as bizarre as those that occur in and around a black hole. I hope that the activities developed in this lesson plan will capture students' imagination, provide them with a better understanding of our universe, and let them have fun all at the same time. Daniel Steinberg Unless otherwise specified, web site content Copyright 1994-2020 John Huggins All Rights Reserved Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" are trademarks of John Huggins

The NASA Chromospheric Layer Spectropolarimeter-2 ,or CLASP-2 sounding rocket mission, was successfully conducted on April 11 from the White Sands Missile Range in New Mexico, launched aboard a NASA Black Brant IX sounding rocket at 12:51 p.m. EDT — the CLASP-2 payload flew to an altitude of 170 miles before descending by parachute. The payload was recovered and is reported in good condition. Good data was received and the science team is reported to be happy with the results of the mission. CLASP-2, the acronym for Chromospheric Layer Spectropolarimeter-2, is a sounding rocket mission. Smaller, more affordable and faster to design and build than large-scale satellite missions, sounding rockets offer a way for the team to test their latest ideas and instruments — and achieve rapid science results. The CLASP-2 instrument uses ultraviolet light to look for hidden details in a complex region of the Sun's atmosphere called the chromosphere. Scientists hope that CLASP-2 experiment will help unlock new clues about how the Sun's energy travels up through the layers of its atmosphere, and eventually out into space. The Sun was observed for about five minutes and images were captured, as well as polarization spectra — observations that restrict incoming light to a specific direction and then record the intensity of individual wavelengths of ultraviolet light. The NASA team's focus was on obtaining polarization measurements that have never before gathered at these ultraviolet wavelengths. CLASP-2 is a follow-on mission to the Chromospheric Lyman-Alpha Spectro-Polarimeter, which offered the first-ever polarization measurements of ultraviolet light emitted from the sun's chromosphere. Previous polarization measurements were restricted to visible and infrared light emitted from other regions of the Sun’s atmosphere. Polarization measurements are important as they provide information on the strength and direction of the Sun's magnetic field, which plays a central role in sculpting the solar atmosphere. Understanding how the magnetic field works is vital to predicting powerful solar activity and protecting space and Earth technology from potential damage from geomagnetic storms. On the ground, researchers will use advanced computer modeling to interpret the data collected by CLASP-2 and better understand how the energy moves through the chromosphere. And even as CLASP-2 uncovers new information, scientists working with its data will rely on data from other observatories to help put those details in context. CLASP-2's launch and data collection will be coordinated with two satellites: NASA's Interface Region Imaging Spectrograph, or IRIS--a satellite observatory that captures non-polarized spectra and images of the Sun’s atmosphere--and the joint JAXA/NASA Hinode satellite observatory, making magnetic measurements at the Sun’s surface as well as images and spectroscopy in the much hotter atmospheric layer known as the corona. Also taking coordinated data are the Dunn Solar Telescope in Sunspot, New Mexico, and the Goode Solar Telescope in Big Bear, California. CLASP-2 is an international collaboration led by NASA's Marshall Space Flight Center with contributions from Japan, Spain and France. CLASP-2 is supported through NASA’s Sounding Rocket Program at the agency’s Wallops Flight Facility in Virginia. NASA’s Heliophysics Division manages the sounding rocket program.

In just over one weeks time, Mercury will pass in front of the Sun. Although Mercury only covers 0.004% of the surface of the Sun, this is a rare event and hence worthwhile to have a closer look at, although you should, of course, never “look” at the Sun directly without proper protection. As only one of three bodies in the solar system (this is ignoring a vast number of tiny rocks and asteroids orbiting the sun in an orbit smaller than Earths orbit), Mercury is able to pass in front of the Sun. But while the Moon treats us with a (partial or total) solar eclipse, and Venus presents itself as a well visible black dot during a venus transit, Mercury is farthest away from the Earth and is hence fairly smal. Here is an image of the last Transit of Mercury in 2003: The image was recorded using a 90mm maksutov telescope with 1250mm focal length on slide film. Graphical illustration of the transit. With a well protected telescope, one can see Mercury starting to nibble at the sun at 13:12h CEST for about three minutes, after which the whole of Mercury is visible in front of the sun. At 16:56h CEST Mercury is closest to the center of the Sun and heads again for the rim, which he will reach at 20:37h and after another three minutes, at 20:40h, Mercury will have left the disk of the Sun. At that time, the Sun almost sets in Aachen, but is still three degrees above the horizon. For exact times, CalSky is a very good tool to do the calculations. Due to the tiny diameter of Mercury, the transit is not visible to the (well protected) naked eye. If you do not have the proper equipment to pbserve the transit yourself, there are many events in and around Germany where you can enjoy the transit under professional assistance. And of course, there will be an event at the Sternwarte Aachen. If everything fails, there are some livestreams, e.g. at the Peterberg in the Saarland or, possibly the safest option regarding weather, the NASA stream with images of the solar observatory SDO: http://mercurytransit.gsfc.nasa.gov. Fingers crossed for perfect weather like in 2003, when the transit was perfectly visible here in Aachen. EDIT: Here is another list with observations in the German area: and for the rest of the world:

The next NASA mission to Mars, the InSight lander, will include some additional experimental technology: the first deep-space CubeSats. Two small CubeSats will fly past the planet as the lander is descending through the atmosphere; this will be the first time CubeSats have been used in an interplanetary mission. If all goes well, the technology will provide NASA with a new way to quickly transmit status information about the main spacecraft after it lands on Mars. The twin CubeSats will be known together as Mars Cube One (MarCO), and are being built by NASA’s Jet Propulsion Laboratory (JPL). CubeSats are basically smaller versions of traditional satellites, using off-the-shelf technologies. Dozens have already been launched into Earth orbit and many have been designed by university students. A basic CubeSat is a box roughly 4 inches (10 centimeters) square, with larger CubeSats being multiples of that unit. MarCO’s design is a six-unit CubeSat—about the size of a briefcase – with a stowed size of about 36.6 centimetres (14.4 inches) by 24.3 centimetres (9.5 inches) by 11.8 centimetres (4.6 inches). MarCO will launch from Vandenberg Air Force Base, Calif., on the same United Launch Alliance Atlas V rocket as the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, in March 2016. After launch, the two CubeSats will separate from the Atlas V booster and travel independently to Mars. They will then deploy two radio antennas and two solar panels. The high-gain, X-band antenna will direct radio waves the same way that a parabolic dish antenna does. “MarCO is an experimental capability that has been added to the InSight mission, but is not needed for mission success,” said Jim Green, director of NASA’s planetary science division at the agency’s headquarters in Washington. “MarCO will fly independently to Mars.” While InSight is descending through the Martian atmosphere on Sep. 28, 2016, it will also relay information in the UHF radio band to the Mars Reconnaissance Orbiter (MRO), which will then forward it back to Earth. One downside, however, is that MRO cannot simultaneously receive information over one band while transmitting on another, which means that confirmation of a successful landing might be received by the orbiter an hour before it is transmitted to Earth. MarCO could nicely solve that problem, as its softball-sized radio provides both UHF (receive only) and X-band (receive and transmit) functions capable of immediately relaying information received over UHF. As previously reported, NASA has already started testing of the InSight lander at the Lockheed Martin Space Systems facility near Denver, Colo. According to Stu Spath, InSight program manager at Lockheed Martin Space Systems in Denver: “The assembly of InSight went very well and now it’s time to see how it performs. The environmental testing regimen is designed to wring out any issues with the spacecraft so we can resolve them while it’s here on Earth. This phase takes nearly as long as assembly, but we want to make sure we deliver a vehicle to NASA that will perform as expected in extreme environments.” “It’s great to see the spacecraft put together in its launch configuration,” said InSight Project Manager Tom Hoffman at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “Many teams from across the globe have worked long hours to get their elements of the system delivered for these tests. There still remains much work to do before we are ready for launch, but it is fantastic to get to this critical milestone.” Future versions of MarsCO could be used as a “bring-your-own” communications relay option for use by future Mars missions in the critical few minutes between Martian atmospheric entry and touchdown. They might even be used later for other planetary missions, and could be incorporated into newer mission technologies such as LightSail, which just this week successfully completed a low-Earth orbit test of deploying its solar sails, despite a few glitches. LightSail itself is a CubeSat spacecraft which is designed to use solar sailing technology, using energy from the Sun as propulsion, as a means of traveling through the Solar System. Such missions could be a reliable yet less expensive way to explore the outer Solar System as apposed to conventional rockets. In related Mars news, the newest Mars orbiter, MAVEN, recently took ultraviolet images of auroras in the Martian atmosphere. “It really is amazing,” said Nick Schneider who leads MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument team at the University of Colorado. “Auroras on Mars appear to be more wide-ranging than we ever imagined.” Known as “Christmas lights” by researchers, the auroras “circled the globe and descended so close to the Martian equator that, if the lights had occurred on Earth, they would have been over places like Florida and Texas.” Instead of a global magnetic field like Earth has, Mars’ disjointed magnetic fields sprout out of the ground like mushrooms, mostly in the southern hemisphere. They are thought to be the remains of a global magnetic field which did exist previously but has long since mostly decayed. The Mars Reconnaissance Orbiter had also recently detected impact glass on Mars for the first time, which may also offer additional clues to the possibility of past life. On Earth, impact glass has been found to contain organic material from previously living microbes and even bits of plants. Both of the Mars rovers, Curiosity and Opportunity, as well as the orbiters, are currently still waiting out the Mars solar conjunction, where Mars passes almost directly behind the Sun from Earth’s perspective, temporarily cutting off communications with rovers and orbiters (this time from June 7 to June 21). Curiosity is sitting in Marias Pass and Opportunity at the entrance to Marathon Valley while they wait for the conjunction period to end. Curiosity also recently received an upgrade to its Chemistry and Camera (ChemCam) instrument, which provides information about the chemical composition of targets by zapping them with laser pulses and taking spectrometer readings of the induced sparks, as well as taking detailed images through a telescope. This article was first published on AmericaSpace.

As intelligent as we are, as human’s we aren’t endowed with the most powerful of eyes. Sure, most of us can see the full glory of the ROYGBIV rainbow, but, it requires special devices for us to perceive specific frequencies of the electromagnetic spectrum. Indeed, perception plays a big part of the entire equation. As humans, we can only tell our narrative from our own point of view. Mystical as the celestial bodies may be, some of the most wondrous things can actually be explained by once you factor in our limitations. While the Moon certainly appears to change color during certain moments of the year, in truth, nothing much changes on the moon, it’s always the same color. So what makes the color of the Moon appear to change? Well, turns out it’s actually a combination of two things, our viewing angle paired with the composition of Earth’s atmosphere. To travel around the Earth, the Moon takes about a month. As it moves about the Earth, you need to also remember that Earth is not stationary, rather, it’s spinning on its axis. Importantly, the Earth and Moon are always in orbit around the sun. With this in mind, it’s clear to see why the Moon usually has a different route through the sky each night. When the Moon is hanging really low in the sky i.e. close to the horizon, you may have noticed that it appears to be brilliantly orange. If you’ve ever been curious about what causes this, then, you’ll be glad to know it’s because you’re viewing the Moon through much more of Earth’s atmosphere than when the Moon is up there in the sky. As mentioned earlier, the Earth is beautifully made. Our home planet’s atmosphere consists of a sphere of gases. When you’re viewing the Moon when it straight above the Earth, you’re actually looking through a thin band of the atmosphere. On the other hand, when you’re viewing the Moon when it’s close to the horizon, you’re viewing through a thicker layer of Earth’s atmosphere. Since Earth’s atmosphere consists of a plethora of airborne particles that absorb and scatter light, shorter wavelength’s of light are likely to be more scattered than longer wavelengths. On the flip side, blue light consists of shorter wavelengths, therefore, this kind of light easily get scattered. Given this background, it’s perfectly understandable why both the Sun and the Moon appear red when rising or setting. Since these are usually moments when the celestial bodies are near the horizon, your eyes are only able to perceive them once the light from them goes through the max amount of atmospheric exposure. As a natural satellite, the Moon does not produce any light of its own. Instead, it’s fully dependent on the Sun to provide light. When total lunar eclipses occur (i.e. when the Earth is situated between the Sun and the Moon), the Moon adapts a reddish hue since there’s almost zero sunlight hitting the lunar surface. This Red Moon happening is at times referred to as Blood Moon. While there are a ton of mythologies about this phenomenon, the reddish coloration is brought about by Rayleigh scattering. This is actually the same concept we covered earlier about how Earth’s atmospheric content (dust, moisture, and cloud levels), contribute towards the color of the Moon. The phrase “Once in a Blue Moon” is actually quite common. That said, the Moon rarely actually looks blue. From data, we know that Blue Moons happens every 3 years or so. Unique from the Red Moon scenario, Blue Moons can occur during any lunar phase. The Blue Moon hue emanates from increased dust or smoke particles in the atmosphere. Incidences like massive forest fires and volcanic eruptions occasionally trigger the emergence of the Blue Moon phenomenon. That wraps up our review on what makes the color of the Moon to change. We’re confident you’ve been able to pick up a thing or two about how the Blue Moon and Red Moon arise. The Moon has captivated the human imagination throughout history. Though it is ever-present, there is so little we know. We wanted to bring the Moon closer, to bring all of our stargazing dreams into reality. With the inspiration of holding the moon in your hands, AstroReality creates the most precisely made Moon model – LUNAR Pro, that satisfies your space curiosity. Besides the planetary models, AstroReality is bringing space to your everyday life, for you to experience the Moon in a brand new way. We designed and crafted the Moon Mug that gives you a sip of Moon together with the Moon Phase of tonight in Augmented Reality. Be one of the first to experience the Moon Mug by signing up our email newsletter today, and stay tuned with the latest updates from AstroReality.

NASA’s Juno probe arrived at Jupiter and performed orbital insertion on Independence Day in 2016 after a five-year journey from Earth. Shortly after orbital insertion, planetary observation commenced, and it continues to study the massive planet’s properties today. Juno is helping NASA learn more about Jupiter’s magnetic field, atmospheric composition & pressure, and more. Equipped with JunoCam, the probe has sent back countless high-detail images that peer into Jupiter’s chaotic clouds. Despite some initial issues with its onboard computer system and a few sticky engine valves, NASA improvised by keeping Juno in its current orbit. This makes collecting data a little slower than initially anticipated, but it still works for all the scientific observations that are planned. Image Credit: NASA/JPL-Caltech On Monday, June 10th, Juno came within viewing distance of the Great Red Spot, a massive storm that some researchers think has existed for centuries. NASA seized the opportunity to capture high-detail images of the Great Red Spot with JunoCam, which are expected to surface “in the coming days.” "For generations people from all over the world and all walks of life have marveled over the Great Red Spot," said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. "Now we are finally going to see what this storm looks like up close and personal." Juno came within 5,600 miles of the cloud tops just above the Great Red Spot, which provided a bird’s-eye view of everything there is to see. While there, Juno’s instruments went on full alert, ready to capture raw data for astronomers to analyze. While many compare the Great Red Spot to a hurricane on Earth, its properties are actually very different. It rotates more quickly, it’s significantly larger, and has lasted longer without a water source than any Earthly hurricane. NASA says that this big storm is 1.3x the width of the Earth, spanning over 10,000 miles. It will be a waiting game until the images are processed, received, and released to the public. From the sound of things, it shouldn’t be long now before we get our first glimpse. These will be some of the most detailed images anyone has ever seen of the Great Red Spot to date, so we're just as excited as the rest of the world to see what Juno captured.

A large asteroid visits our fair corner of the solar system this week, and with a little planning you may just be able to spot it. Near Earth Asteroid (NEA) 285263 (1998 QE2) will pass 5.8 million kilometres from the Earth on Friday, May 31st at 20:59 Universal Time (UT) or 4:59PM EDT. Discovered in 1998 during the LIncoln Near-Earth Asteroid Research (LINEAR) sky survey looking for such objects, 1998 QE2 will shine at magnitude +10 to +12 on closest approach. Estimates of its size vary from 1.3 to 2.9 kilometres, with observations by the Spitzer Space Telescope in 2010 placing the ballpark figure towards the high end of the scale at 2.7 kilometres in diameter. 1998 QE2 would fit nicely with room to spare in Oregon’s 8 kilometre-wide Crater Lake. Though this passage is over 15 times as distant as the Earth’s Moon, the relative size of this space rock makes it of interest. This is the closest approach of 1998 QE2 for this century, and there are plans to study it with both the Arecibo and Goldstone radio telescopes to get a better description of its size and rotation as it sails by. Expect to see radar maps of 1998 QE2 by this weekend. “Asteroid 1998 QE2 will be an outstanding radar imaging target… we expect to obtain a series of high-resolution images that could reveal a wealth of surface features,” said astronomer and principal JPL investigator Lance Benner. An Amor-class asteroid, 1998 QE2 has an orbit of 3.77 years that takes it from the asteroid belt between Mars and Jupiter to just exterior of the Earth’s orbit. 1998 QE2 currently comes back around to our vicinity roughly every 15 years, completing about 4 orbits as it does so. Its perihelion exterior to our own makes it no threat to the Earth. This week’s passage is the closest for 1998 QE2 until a slightly closer pass on 0.038 Astronomical Units on May 27th, 2221. Note that on both years, the Earth is just over a month from aphelion (its farthest point from the Sun) which falls in early July. Of course, the “QE2” designation has resulted in the inevitable comparisons to the size of the asteroid in relation to the Queen Elizabeth II cruise liner. Asteroid designations are derived from the sequence in which they were discovered in a given year. 1998 QE2 was the 55th asteroid discovered in the period running from August 1st to 16th 1998. Perhaps we could start measuring asteroids in new and creative units, such as “Death Stars” or “Battlestars?” But the good news is, you can search for 1998 QE2 starting tonight. The asteroid is currently at +12th magnitude in the constellation Centaurus and will be cruising through Hydra on its way north into Libra Friday on May 31st. You’ll need a telescope to track the asteroid as it will never top +10th magnitude, which is the general threshold for binocular viewing under dark skies. Its relative southern declination at closest approach means that 1998 QE2 will be best observed from northern latitudes of +35° southward. The farther south you are, the higher it will be placed in the sky after dusk. Still, if you can spot the constellation Libra, it’s worth a try. Many observers in the southern U.S. fail to realize that southern hemisphere sites like Omega Centauri in the constellation Centaurus are visible in the evening low to the south at this time of year. Libra sits on the meridian at local midnight due south for northern hemisphere observers, making it a good time to try for the tiny asteroid. Visually, 1998 QE2 will look like a tiny, star-like point in the eye-piece of a telescope. Use low power and sketch or photograph the field of view and compare the positions of objects about 10 minutes apart. Has anything moved? We caught sight of asteroid 4179 Toutatis last year using this method. 1998 QE2 will also pass near some interesting objects that will serve as good “guideposts” to track its progress. We find the asteroid about 5° north of the bright +2.5 magnitude star Iota Centauri on the night of May 28th. It then crosses the border into the constellation Hydra about 6° south of the +3 magnitude star Gamma Hydrae (Star Trek fans will recall that this star lies in the Neutral Zone) on May 29th. Keep a careful eye on 1998 QE2 as it passes within 30’ (about the diameter of a Full Moon) of the +8th magnitude galaxy Messier 83 centered on May 28th at 19:00 UT/3:00 PM EDT. This will provide a fine opportunity to construct a stop-motion animated .gif of the asteroid passing by the galaxy. Another good opportunity to pinpoint the asteroid comes on the night on Thursday, May 30th as it passes within 30’ of the +3.3 magnitude star Pi Hydrae. From there, it’s on to closest approach day. 1998 QE2 crosses into the constellation Libra early on Friday May 31st. The Moon will be at Last Quarter phase and won’t rise until well past local midnight, aiding in your quest. At its closest approach, 1998 QE2 have an apparent motion of about 1 angular degree every 3 hours, or about 2/3rds the diameter of a Full Moon every hour. This isn’t quite fast enough to see in real time like asteroid 2012 DA14 was earlier this year, but you should notice its motion after about 10 minutes at medium power. Passing at ~465 Earth diameters distant, 1998 QE2 will show a maximum parallax displacement of just a little over 7 arc minutes at closest approach. For telescopes equipped with setting circles, knowing the asteroid’s precise position is crucial. This allows you to aim at a fixed position just ahead of its path and “ambush” it as it drifts by. For the most precise positions in right ascension and declination, be sure to check out JPL’s ephemeris generator for 1998 QE2. After its closest passage, 1998 QE2 will pass between the +3.3 & +2.7 magnitude stars Brachium (Sigma Librae) and Zubenelgenubi (Alpha Librae) around 4:00 UT on June 1st. Dedicated observers can continue to follow its northeastward trek into early June. Slooh will also be carrying the passage of 1998 QE2 on Friday, May 31st starting at 5:00 PM EDT/21:00 UT. Of course, the hypothetical impact of a space rock the size of 1998 QE2 would spell a very bad day for the Earth. The Chicxulub impact basin off of the Yucatán Peninsula was formed by a 10 kilometre impactor about 4 times larger than 1998 QE2 about 65 million years ago. We can be thankful that 1998 QE2 isn’t headed our way as we watch it drift silently by this week. Hey, unlike the dinosaurs, WE have a space program… perhaps, to paraphrase science fiction author Larry Niven, we can hear the asteroid whisper as we track its progress across the night sky, asking humanity “How’s that space program coming along?”

SOFIA – Facts About NASA’s Flying Infrared Telescope ✈ Big Eye In The Sky On The Sky! The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne 2.5m (8.2 ft) telescope which conducts infrared observations from the back of a modified Boeing 747 Jumbo jet. SOFIA is a joint project of NASA and the German Aerospace Center to operate an infrared observatory above the water vapour in Earth’s atmosphere. Despite being late and over budget, SOFIA's telescope made its first observation in late May 2010. Interesting Fun Facts About SOFIA The Airborne Infrared Observatory SOFIA, which is largely run by NASA, is the successor to NASA’s previous ‘eye in the sky’; the Kuiper Airborne Observatory and has a planned lifetime of 20-years. SOFIA is by far the most powerful plane based telescope in the world, making observations that even the best ground-based infrared telescopes cannot make due to the water vapour in the atmosphere distorting their observations. The Boeing 747 aircraft previously flew as a passenger airliner for Pan America and United Airlines before NASA purchased the plane. Pan Am even named the aircraft the Clipper Lindbergh in honour of the famous aviator Charles Lindbergh. From the late 1990’s to 2010, extensive alterations (and testing), were made to incorporate a large 2.5 meters (8.2 ft) reflecting telescope designed specifically for infrared observations and an external door that opens to the atmosphere while in flight above 41,000 ft. The aircraft is based in California at NASA's Armstrong Flight Research Center, but due to the 747's range, observations anywhere in the world can be made. SOFIA Studying The Universe In Infrared Studying the Universe using only visible light (the light you see with your eyes which represents only a small portion of the energy spectrum) reveals only a small portion of the possible ways you can view an object in space, so SOFIA is designed to observe the Universe in the infrared light section of the electromagnetic spectrum (which includes x-rays, infrared, visible light, radio waves etc). Infrared observatories are especially important as many objects in space don’t even emit visible light (these would appear invisible to our eyes), but emit infrared ‘light’ instead! Another common problem is that gas, debris and dust in space blocks visible light but allows infrared to pass through which SOFIA can then observe! Either way, we need sensitive airborne observatories like SOFIA to get a clear view of these infrared objects! Some of the more interesting astronomical objects that SOFIA studies are: - Star birth and death - Formation of new protoplanetary discs (new Solar Systems!) - ID interstellar molecules - Observing the atmospheres of Planets, Comets and Asteroids of our own Solar System, often during occultations - Nebulae and dust clouds - Supermassive black holes which reside at the centre of galaxies

NASA measures water loss of an interstellar comet for the first time We don’t get all that many visitors in our quiet corner of the galaxy. In fact the comet 2I/Borisov is only the second interstellar visitor we’ve welcomed to our solar system, following ‘Oumuamua in 2017. Despite whizzing around the Sun at 100,000 mph (161,000 km/h) late last year, scientists have managed to quantify the amount of water it shed on this leg of the journey, the first time they have achieved such an insight into an interstellar comet. The inbound 2I/Borisov was first detected in August last year and made its closest approach to the Sun four months later. This provided scientists with plenty of opportunity to train their instruments on the interstellar comet, detecting the first signs of water and gas molecules and studying its chemical makeup in impressive detail. As frozen balls of gas and dust, comets shed substantial amounts of material as they warm on approach to the Sun, and those originating outside the solar system are no different. Surface materials such as carbon dioxide heat up and turn into gas, while water vaporizes when it comes within 230 million miles (370 million kilometers) of our star. When this happens, the water molecules are busted apart by sunlight and a molecule called hydroxl is produced. NASA’s Neil Gehrels Swift Observatory is perfectly equipped to measure hydroxl, as it can pickup the unique signature of UV light the molecule emits using its Ultraviolet/Optical Telescope (UVOT). The Neil Gehrels Swift Observatory team used this instrument to make six observations of 2I/Borisov between September and February. In the month of November, as it closed in on the Sun, the team detected a 50-percent increase in hydroxl and, by extension, water. At the height of its water-shedding activity, the team says 2I/Borisov was losing eight gallons (30 L) of water a second, which would fill a bathtub in 10 seconds. In all, the team believes the comet shed nearly 61 million gallons (230 million L) of water on its journey through our solar system, more than enough to fill 92 Olympic-sized swimming pools. “We’re really happy that Swift’s rapid response time and UV capabilities captured these water production rates,” says co-author Dennis Bodewits. “For comets, we express the amount of other detected molecules as a ratio to the amount of water. It provides a very important context for other observations.” These other observations include a new understanding of the comet’s minimum size, with the scientists calculating 2I/Borisov to measure just 0.74 km (0.45 mi) across. The team also believes that at least 55 percent of the comet’s surface was actively shedding material when it flew by the Sun, which is at least 10 times the active area on typical solar system comets. The video below provides an overview of the discovery, while the research was published in The Astrophysical Journal Letters.

Washington: The US space agency NASA is planning to send a small satellite about the size of a briefcase -- also known as a CubeSat which will use lasers for the first time to detect naturally occurring surface ice believed to be at the bottom of craters on the Moon that have never seen sunlight. Called Lunar Flashlight, it will also be the first planetary spacecraft to use a "green" propellant, a new kind of fuel that is safer to transport and store than the commonly used spacecraft propellant hydrazine, NASA said on Monday. "A technology demonstration mission like Lunar Flashlight, which is lower cost and fills a specific gap in our knowledge, can help us better prepare for an extended NASA presence on the Moon as well as test key technologies that may be used in future missions," said John Baker, Lunar Flashlight project manager at NASA's Jet Propulsion Laboratory in Southern California. Over the course of two months, Lunar Flashlight will swoop low over the Moon's South Pole to shine its lasers into permanently shadowed regions and probe for surface ice. Found near the North and South Poles, these dark craters are thought to be "cold traps" that accumulate molecules of different ices, including water ice. The molecules may have come from comet and asteroid material impacting the lunar surface and from solar wind interactions with the lunar soil. "The Sun moves around the crater horizon but never actually shines into the crater," said said Barbara Cohen, principal investigator of the mission at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Because these craters are so cold, these molecules never receive enough energy to escape, so they become trapped and accumulate over billions of years." Lunar Flashlight's four-laser reflectometer will use near-infrared wavelengths that are readily absorbed by water to identify any accumulations of ice on the surface. Should the lasers hit bare rock as they shine into the South Pole's permanently shadowed regions, their light will reflect back to the spacecraft, signaling a lack of ice. But if the light is absorbed, it would mean these dark pockets do indeed contain ice. The greater the absorption, the more widespread ice may be at the surface, NASA said. Lunar Flashlight will be one of 13 secondary payloads aboard the Artemis I mission, the first integrated flight test of NASA's Deep Space Exploration Systems, including the Orion spacecraft and Space Launch System (SLS) rocket. Under the Artemis program, astronauts and robots will explore more of the Moon than ever before. Robotic missions begin with commercial lunar deliveries in 2021, humans return in 2024, and the agency will establish sustainable lunar exploration by the end of the decade.

Last week the robotic Dawn spacecraft ended its year-long mission to asteroid Vesta, becoming the first spacecraft ever to visit this far off world located between Mars and Jupiter, in the Solar System’s main asteroid belt. … Vesta shows evidence of being a leftover from the early years of our Solar System, a building block for rocky planets like Earth. Vesta’s ancient surface shows heavy cratering and long troughs likely created by huge impacts. The minor planet’s low gravity allows for surface features like huge cliffs and a large mountain that reaches twice the height of Earth’s Mount Everest, visible at the image bottom. Vesta, however, spanning about 500 kilometers across, is only the second most massive object in the asteroid belt. And so, two weeks ago, Dawn fired its gentle ion rockets and has begun chasing the most massive: Ceres. If everything goes as planned, Dawn will reach Ceres in 2015. SEE COMPLETE TEXT

As per the latest research, scientists have now revealed that the Sun, which appears to be the same every day to us, is in fact, changing over time. The scientists have long known this fact as they use properly-filtered telescopes which helps them understand the difference each time they look at the Sun. These filtered telescopes have been revealing fiery disk often speckled with dark sunspots which are considered to be heavily magnetized. These magnetized sunspots crackle with solar flares which are magnetic explosions that illuminate Earth with flashes of X-rays and extreme ultraviolet radiation. According to NASA's recent revelation, our Sun is filled with many sunspots and magnetic explosions. However, after every 11 years or so, these sunspots fade away. The fading away of these sunspots brings a period of relative calm which is scientifically denoted as Solar Minimum. The Dean Pesnell of NASA's Goddard Space Flight Center said that it is a regular sunspot cycle of the Sun. The researchers have revealed that the sun is heading towards solar minimum now as sunspots were relatively higher in 2014 and the count has been significantly going down with every year passing. The researchers are expecting the count to be lower than before in 2019-2020 as well. According to scientists, Solar Minimum effects are different and eyebrow-raising and intense activities such as sunspots and solar flares subside and the solar activity simply changes form. Dean Pesnell, a project scientist of the Solar Dynamics Observatory, said that during solar minimum, we can see the development of long-lived coronal holes. The coronal holes are reportedly considered as vast regions in the sun’s atmosphere. These vast regions are openings of Sun’s magnetic field that allow streams of solar particles to escape the sun as the fast solar wind. According to the Pesnell, these vast regional holes are present and visible throughout a solar cycle. However, during the time of Solar Minimum, Coronal holes can last for a long time (expectedly six months or more). According to research, Solar Minimum will affect the Earth's magnetic field due to the streams of solar wind and will change the space weather effects near Earth. The Solar wind from coronal holes will temporarily create disturbances in the Earth’s magnetosphere, called geomagnetic storms, auroras, and disruptions to communications and navigation systems. The space weather during solar minimum will also affect Earth’s upper atmosphere on satellites in low Earth orbit changes. This means that the Earth’s upper atmosphere will cool down which is generally heated and puffed up by ultraviolet radiation from the sun. However, the heat at the upper atmosphere of our planet helps Earth to drag debris and keep the low Earth orbit clear of manmade space junk. Apart from this, the solar minimum will change the space weather significantly which will lead to an increase in the number of galactic cosmic rays that reach Earth’s upper atmosphere. These Galactic cosmic rays are high energy particles which are a result of distant supernova explosions and other violent events in the galaxy. According to MD of NASA's Goddard Space Flight Center, the sun’s magnetic field weakens and provides less shielding from these cosmic rays during a solar minimum which will directly increase the threat to astronauts travelling through space.

Super-Earth discovered around the second nearest stellar system An international team finds an exoplanet with three times the mass of the Earth around the red dwarf Barnard, the closest star to the Sun after the Alpha Centauri system The team has used observations taken in 18 years combined with the CARMENES planet-hunter spectrograph at Calar Alto Observatory Just six light-years away, Barnard's star moves in Earth's night sky faster than any other star. This red dwarf, smaller and older than our Sun, is among the least active red dwarfs known, so it represents an ideal target to search for exoplanets. Now, an international team led by researchers from the Spanish National Research Council (CSIC) has found a cold Super-Earth orbiting around the Barnard´s star, the second closest star system to Earth. It is the first time that astronomers have discovered this type of exoplanet using the radial velocity method. The results of the study are published in the journal Nature. “After a very careful analysis, we are over 99% confident that the planet is there, since this is the model that best fits our observations”, assures the leader of the study, Ignasi Ribas, CSIC researcher at the Space Sciences Institute (ICE) and the Institute of Space Studies of Catalonia (IEEC). “However, we must remain cautious and collect more data to nail the case in the future, because natural variations of the stellar brightness resulting from starspots can produce similar effects to the ones detected”. A SUBTLE STELLAR WOBBLE The subtle wobble of the star has caught the attention of astronomers for some time. Since 1997 several instruments have collected a large number of measurements on that oscillation movement. A 2015 analysis suggested that the wobble could be caused by a planet with an orbital period of about 230 days. But more measurements were required. Attempting to confirm the hypothesis, astronomers have regularly observed the Barnard´s star with high precision spectrometers such as CARMENES, at Calar Alto Observatory. The technique consists on using the Doppler effect on the starlight to measure how the speed of an object in our line of sight changes over time. "With the radial velocity method, precision spectrometers are used to measure the Doppler effect. When an object moves away from us, the light we observe becomes slightly less energetic and redder. On the contrary, when the star approaches us, the light becomes more energetic and bluish", says Ribas. "When we re-analyzed all the combined measurements, a clear signal arose at a period of 233 days. This signal implies that the Barnard´s star approaches and moves away from us at about 1.2 meters per second - approximately the walking speed of a person - and it is best explained by a planet orbiting it", says Ribas . The planet candidate, called Barnard's star b (or GJ 699 b), is a super-Earth with a minimum of 3.2 Earth masses. It orbits its red star every 233 days near the snow-line, a distance where water freezes. Lacking atmosphere, its temperature is likely to be about -170ºC, which makes it unlikely that the planet can sustain liquid water on the surface. "Exoplanets so small and so far away from their parent star have not been discovered before using the Doppler technique", says Ribas. This means that astronomers are getting better at finding and exploring a relatively new kind of planets outside our Solar System. “We all have worked very hard on this result”, says Guillem Anglada-Escudé from Queen Mary University of London and co-leader of the study. “This is the result of a large collaboration organised in the context of the Red Dots project, which is why it has contributions from teams all over the world including semi-professional astronomers coordinated by the AAVSO”. Cristina Rodríguez-López, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) and co-author of the paper, comments on the significance of this finding. "This discovery means a boost to continue on searching for exoplanets around our closest stellar neighbours, in the hope that eventually we will come upon one that has the right conditions to host life". I.Ribas et al. “A super-Earth planet candidate orbiting at the snow-line of Barnard’s star”, to appear in the journal Nature on 15 November 2018 The German-Spanish Calar Alto Observatory is located at Sierra de los Filabres, north of Almería (Andalucía, Spain). It is jointly operated by the Instituto Max Planck de Astronomía in Heidelberg, Germany, and the Instituto de Astrofísica de Andalucía (CSIC) in Granada, Spain. Calar Alto has three telescopes with apertures of 1.23m, 2.2m and 3.5m. A 1.5m aperture telescope, also located at the mountain, is operated under control of the Observatorio de Madrid. COMMUNICATION – CALAR ALTO OBSERVATORY prensa @ caha.es 958230532

RS Ophiuchi is a famous recurrent nova. Recently it had an outburst, brightening from magnitude 11 (hundred times fainter than faintest star visible to the naked eye) to fifth magnitude - faint but visible to the naked eye. Novae have been known for centuries. They are a "new stars", appearing in the sky where no star was before. We now know that they are sudden brightening of a faint pre-existing star. Brightness increase is typically about a factor of 10,000. Novae occur when gas accreting onto a white dwarf builds up on the surface of the white dwarf until it detonates, in a sharp onset thermonuclear runaway reaction. A white dwarf, you will remember, is the compact (few thousand kilometer radius - or about Earth size) degenerate remnant core of a main sequence star which has exhausted the fuel available for fusion in its core. The white dwarf is held up by the pressure of relativistic electrons in the highly dense core - crudely speaking, the electrons repel when pushed together providing a pressure which hold the white dwarf up against gravity. Famously, there is a maximim mass for white dwarfs, the Chandrasekhar limit of about 1.4 times the mass of the Sun. The material detonating in novae is on the surface, it is transferred to the white dwarf from a companion star, either a close main sequence companion, or an more evolved red giant star. The typical white dwarf has a mass of about half the mass of the Sun. Some have lower masses, and there is a spread of masses up to almost, but not quite, 1.4 times the mass of the Sun. If a white dwarf reaches the Chandrasekhar mass, then something has to give. The internal pressure is not enough to support the stars own weight. Either the star collapses - and the collapse either stops when a new source of pressure halts it, such as neutron degeneracy; or it doesn't halt, and a black hole forms; or the star blows up leaving now remnant. The mass accreting onto a white dwarf add mass to the white dwarf. It comes down in a steady trickle. Novae occur when the fresh material has built up to thick enough a layer that the combined pressure and temperature at the bottom of the layer can trigger a thermonuclear reaction which then runs away over the whole surface of the white dwarf. The energy released in the detonation is higher than the binding energy of the matter on the surface of the white dwarf, so matter is blown off into space. Big question is, how efficiently does the explosion couple to the mass - is more mass blown off than accreted? ie is there net accumulation of mass, or net loss of mass during novae. Now, there are two classes of novae - classical novae, and recurrent novae. The latter repeat on decadal time scales. They are rare. Now, realistically classical novae probably are mostly also recurrent, it is just that the recurrence interval is probably longer than the time we have been reliably observing the sky. RS Oph is one of the more reliably recurrent novae, having erupted 6 times in the last century or so. Recent papers in Nature here and here make a strong case that the recent outburst in RS Oph was asymmetric, and that the models closely constrain the white dwarf mass, the accretion rate of mass between outbursts, and the mass ejected. These are interconnected, since we measure the luminosity of the material accreting on the white dwarf, which depends both on the mass accretion rate and the white dwarf mass. The somewhat surprising result is that the RS Oph primary mass is high, in fact just about 1.4 times the mass of Sun. Further, the mass loss during outbursts is less than the estimated accreted mass between outbursts, so the primary is gaining mass. Quite quickly in fact. It should hit the Chandrasekhar limit in order million years, maybe less, maybe a little bit longer. So recurrent novae now have a strong case for being massive systems, accreting net mass quite rapidly and heading for the Chandrasekhar limit. So what. Well, the original stella nova - Tycho's Nova of 1572, was a supernova. There are two types of supernovae, type I and II, each divided into subtypes. As it happens, types Ib and Ic are actually of type II, but type Ia supernovae are of a genuinely different type. Type II supernovae are the deaths of massive stars; type Ia supernovae are the detonation of a Chandrasekhar limit mass white dwarf. They are relatively rare, maybe 1 in 5 supernova is type Ia, for about one per 300 years in the Milky Way. They are also incredibly important in modern cosmology. Type Ia supernovae are very luminous and can be detected from a very long way away, from billions of light years away. They also appear to be very uniform in luminosity and therefore are good standard candles. As such, they have been used to measure the geometry of the universe to large distances, and to show the universe is accelerating with time, implying the existence, and increasing dominance of dark energy. There are several possible ways to make a type Ia. When I were a lad, the favoured channel was the merger of two massive white dwarfs in close orbit through gravitational radiation. This will probably work, but we have never seen two white dwarfs which were both massive enough and close enough. If type Ia occur every 300 years, there have been about 50 million in the Milky Way to date, give or take. For obscure reasons we think type Ia supernovae take time to develop, their progenitors hang around for a while, so there ought to be millions of type Ia progenitors in the galaxy. So lots, but not too many... Merging white dwarfs were problematic as type Ia progenitors, since their combined mass is unlikely to be just exactly the Chandrasekhar limit, if it is over, it is likely to be way over maybe 10-20%. Which would make type Ia poor standard candles, some would be overluminous. Recurrent novae were another possible type Ia progenitor, they're good, they gain mass slowly and creep up on the Chandrasekhar limit, making good standard candles. A problem though was whether recurrent novae were actually gaining mass. Now it appears we know that they are. However, Della Valle and Livio in 1996 looked at know recurrent novae, and give ~ million year lifetimes and net mass gain, you find the recurrent novae in the Milky Way reach the Chandrasekhar mass at the rate of about 5 per hundred thousand years. Which is much lower than the 3 per thousand years we estimate the type Ia rate to be! So recurrent novae are probably progenitors of type Ia supernovae, but look like they may be the minority formation channel, they are too rare. Some other channel ought to dominate the type Ia formation. Current suspicion falls on Supersoft x-ray sources - these are bright, "soft" x-ray sources. They are hot, but not very hot, and quite luminous. They are similar to recurrent novae, we think, white dwarf primaries accreting from secondary stars, but the difference is that we think the accretion rate is such that there is steady fusion on the surface. So no outbursts, no novae. So we have good new evidence that the classical candidate to be the progenitor of the very important type Ia supernova, is in fact a type Ia progenitor. And, simultaneously, we infer that this formation mechanism is the minority contributor to type Ia formation. Most of them likely come from another source. There you go. Nice painting. The evidence for "cosmic acceleration" is based entirely upon redshifts, in the case of Type Ia supernovae from objects which we still don't completely understand. Very nice painting. The evidence for cosmic acceleration is pivoted on the type Ia redshifts, but that by itself is not conclusive, you need the CMB and the evidence for relatively high baryon mass to dark matter density from, for example, clusters of galaxies, to really make the case intriguing. Type Ia are relatively well understood; in particular the issue of overluminous WD-WD merger progenitors would bias in the "wrong" direction, a contamination of overluminous type Ia in the "standard candle" sample would make the acceleration larger, not make it go away. You need something that will make type Ia (appear) fainter for the acceleration evidence to weaken.

The bright stars of the Summer Triangle shine from high in the southern skies during the evenings in September. Three bright stars — Vega, Deneb, and Altair — that are actually part of the their own constellations, mark the “corners” of the triangle. Deneb is one of the brightest stars in the sky. Shining with the brightness of 170,000 suns, this star is 2,500 light years away. The combination of actual brightness and distance makes it the 19th brightest star seen in the sky at night. Compared to its neighbor, Vega appears as the 5th brightest star, although it is only 60 times brighter than our sun and 25 light years distant. The third star, Altair, ranks as the 12 brightest star with an actual brightness of about 11 suns with a distance of 17 light years. The brightness that a star appears in our sky is related to the star’s actual brightness and distance. Deneb is part of the constellation Cygnus, the swan. It represents its tail. The head of the swan is marked by Albireo. Look at this star through a small telescope. It will reveal a wonderful double star, one golden, one blue. |Moon Phases September 2011| On September 3, the moon appears near the bright star Delta Scorpii as seen from mid-latitudes. The moon can been seen covering the star from the southeastern US. This link provides more details. For others, the moon appears very close to the star with the bright star Antares nearby. The Autumnal Equinox occurs at 4:05 a.m. CDT on September 23. At this time, the sun is directly above the earth’s equator. On this date at noon the sun will go directly overhead for people living at the equator. For residents of mid-latitudes, the sun will about halfway up in the south at noon, rising at the east direction point and setting at the west cardinal direction. The equinox also brings equal daylight and darkness at 12 hours each. From this date until the Vernal Equinox in March, the length of nighttime is longer than daylight hours. Mercury is usually difficult to see as it rapidly shuttles from morning sky to evening sky. During early September, Mercury makes a brief appearance in the morning sky. The chart above shows Mercury and Regulus, the bright star in Leo, at 6 a.m. on September 9. Locate an observing spot with a clear horizon. Looking with binoculars locate Mercury and Regulus in a close pairing. Venus begins its evening appearance late in the month. Venus passed behind the sun in mid-August. Venus and Earth are like two cars on a race track; Earth is in an outside lane and Venus an inside lane. Along with a shorter course, Venus moves faster than Earth. In September, Venus is nearly on the other side of the track and the infield spectators (the sun) are blocking our view of the planet. It will move faster and catch up to our planet and move between us in the sun (inferior conjunction) in June 2012. As the chart above indicates, the sunset time between Venus and sun will be between about 30 minutes and 45 minutes throughout September. Sharp observers may note it very close to the horizon in the west after sunset. Binoculars will be helpful. As Venus begins to catch up to Earth, it will appear longer and longer in the western evening sky, outshining all other objects in the night sky besides the moon. It can be easily mistaken for lights on an airplane. As Venus closes in on Earth, it will grow brighter until April 30. The greatest separation (marked greatest elongation on the diagram) between Venus and the sun is March 27, 2012, with Venus setting nearly 7 hours after the sun. It’ll be a spectacular sight in the spring night sky, when the tilt of the solar system provides marvelous views of the inner solar system. Venus will make interesting viewing as it passes bright stars and other planets during its evening appearance. We will note them here in future postings. Mars is visible in the eastern, predawn sky. Late in the month, the moon appears near Mars. The chart above shows Mars with the moon and bright distant stars (Pollux, Castor, and Procyon) on September 22 and 23. During September, Mars shines nearly equal to the bright stars in its background. While distinctly reddish-orange, the moon helps identify it late in the month. Jupiter shines brightly from the eastern sky during late evenings as it rises in the east around 10 p.m. early in the month. It is in the sky until sunrise and it dominates the southern sky just before sunrise. Late in the month, it rises in the east around 9 p.m. The chart above shows the moon and Jupiter on September 15 and September 16. The bright star Hamal is nearby. Saturn disappears into the sun’s bright sunlight as it moves behind the sun in October. We’d appreciate reading what you are observing. Please post any interesting observations in the comments section.

ann12042 — Annonce ALMA Telescope Upgrade to Power New Science 5 juin 2012 Before its construction is even completed, the new telescope ALMA — the Atacama Large Millimeter/submillimeter Array — is embarking on an upgrade that will help astronomers investigate the earliest galaxies and search for water in other planetary systems. The oversight board for ALMA has authorised the design and building of an additional set of receivers with state-of-the-art performance, which will enable the telescope to access a part of the spectrum of light that it cannot currently study. ALMA is the world’s largest astronomy project, and this powerful new facility on the Chajnantor plateau in Chile is giving astronomers insight into both how the Universe and its galaxies have evolved since the Big Bang, and how stars and planetary systems formed in our own galaxy. Although only half of its final total of 66 antennas are currently in place at the high-altitude site in northern Chile (see ann12035), ALMA is already operating and making scientific observations with a partial array (see for example eso1137 and eso1216). ALMA observes the Universe in radio waves: light which is invisible to our eyes. Extremely weak signals from space are collected by the ALMA antennas and focussed onto the receivers, which transform the faint radiation into an electrical signal. The new “Band 5” receivers will be able to detect electromagnetic radiation with wavelengths between about 1.4 and 1.8 millimetres (211 and 163 gigahertz), one of the ranges of the spectrum to which Earth's atmosphere is partially transparent, which allows the light to reach the ALMA antennas. The new receivers were originally designed, developed, and prototyped by Onsala Space Observatory’s Advanced Receiver Development group, based at Chalmers University of Technology in Gothenburg, Sweden, in collaboration with the Rutherford Appleton Laboratory, UK, and ESO, under the European Commission (EC) supported Framework Programme FP6 (ALMA Enhancement) starting in 2006. Six of these receivers have been built under the FP6 contract and supplied to ALMA (see ann1098). Over the next five years, all 66 of ALMA’s antennas will be equipped with these new receivers. To do this, including spares, another 67 units need to be built. These will be provided by Europe with contributions from the United States. The European Southern Observatory (ESO) will place the European contract for the cryogenically cooled receivers, and oversee their development. The consortium leader will be NOVA, the research school for astronomy in the Netherlands. The receivers will be fabricated by NOVA in partnership with Onsala Space Observatory’s Advanced Receiver Development group. In North America, the National Radio Astronomy Observatory (NRAO) will build the high-precision oscillators that will tune the receivers, so that the output from all antennas can be precisely combined to make high-resolution images. The receivers will be used to study some of the earliest galaxies in the Universe and will help us to understand when some of the first stars formed. They will also enhance astronomers' abilities to measure the presence of water — a molecule essential to life — in the dusty disks where planets are believed to form, and in the atmospheres of planets and comets in our own Solar System. Water in space can be tricky to measure accurately, because of the confusing effects of observing through the water vapour in Earth's atmosphere. The way in which ALMA's Band 5 receivers will measure water reduces some of these difficulties. The decision to fund this enhancement of ALMA, even before the telescope is completed, was made by the ALMA Board in April 2012. On 9 May 2012, the decision was approved by ESO's Finance Committee. The upgrade is expected to be completed in 2016. ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. - More about ALMA at ESO - The Joint ALMA Observatory - Press release at Chalmers - NOVA, the research school for astronomy in the Netherlands - Announcement from the Joint ALMA Observatory ALMA Enhancement Programme Co-ordinator, ESO Tel: +49 89 3200 6630 ESO ALMA Public Information Officer Tel: +49 89 3200 6759 À propos de l'annonce

100 years ago today, on Thursday, November 25th, 1915, Albert Einstein presented his General Theory of Relativity. After having been working on it for eight years he finished one of the most beautiful and robust scientific theories. In these 100 years, the theory has passed from not being accepted at first, to not having found any deviation from the observations and experimental tests. In 1905 Einstein presented his special theory of relativity, that unified space and time, matter and energy. This first theory showed us how these values depended on the observer and changed our view of space and time as non being rigid, but deformable. At that time, many scientists were about to find it: Poincare, Lorentz, Fitzerald. Indeed, these scientists had already found the equations that Einstein presented in his theory. But they didn't understand their meaning. They though those mathematical expressions weren't but artifacts to get to the right numbers to agree with experiments. They believed they didn't have any physical significance, though. Einstein, in a very elegant manner, presented those same equations from simple principles and gave them physical meaning. Conceptually, he had to work on the theory for ten years to understand it, and only three weeks to develop the mathematics to describe the phenomena. The General Theory of Relativity went the other way round. He visualized the physical theory with one thought experiment, but he needed eight years to develop the mathematical description. The Special theory was on the air in science at the time Einstein came through it. If it hadn't been him, another would have presented and understood it in a few years. The General theory was much more complex to envision, and Einstein had the great vision of a bright mind that could have taken decades to others at that time. It was not a straightforward work, Einstein went back and forth and had to learn mathematical concepts he didn't know. Due to the geometric aspect of the theory, it soon attracted the attention of many mathematicians. The first test to the new theory was the total eclipse of the Sun in 1919 (Einstein had preciously calculated the orbit of Mercury, where Newton's theory had a little discrepancy, Einstein's theory hadn't). At that time, the equipment was not very precise and the pictures taken by Eddington in that eclipse wouldn't have been published today . But he was right. Since then, the theory of relativity has been tested in many different ways, showing always to be a correct theory [2, 3, 4, 5, 6, 7, 8, 9, 10]. But we have not yet managed to reconcile General Relativity with Quantum Mechanics. The fact that the first rules physics when huge masses are in play, and the latter rules physics of elementary particles makes it difficult to observe or design experiments where both aspects are into play. Masses of elementary particles don't have enough mass to create a detectable gravitational field. There are many theories that try to unify both of them. The most relevant are string theory and quantum loop gravity. Both approaches introduce new perspectives to our view of the universe and matter, but their predictions are far from being tested, which makes it almost impossible to verify whether one of them is correct. Physics final goal is to describe Nature and we need to test theories. If one theory doesn't describe Nature, it doesn't matter how beautiful it is, we can not consider it as a real physical theory. Also, the dark matter and dark energy conundrums we are dealing with in the latest years, have pushed some physicists to think that, maybe, General Relativity has to be reconsidered and it needs some modifications to account for the Universe as a whole. In any case, up to date, none of this alternative gravity theories has better success than relativity to describe the universe with or without the dark sector. But, besides the unification with quantum mechanics, and the understanding of dark matter and dark energy, the last 100 years have given us great success of General Relativity. We understand much better the universe, stars, galaxy formation that we did one century ago. And we also have General Relativity in our pockets. Due to the difference in speed and in gravitational field between us and the GPS satellites, our clocks don't run at the same pace as those in the satellites. There is a difference of 43 nanoseconds in one whole day. This difference is predicted by relativity and it might seem small, but if we don't consider it in the GPS protocol, our devices would be wring by 11 kilometers after 24 hours, making this positioning system useless. So, we should be very happy and thankful to Einstein and his General Relativity for letting us understand better our Universe, and for helping us drive our way to where we are going to have our turkey this Thanksgiving Day. Physicist, working in quantum optics and nonlinear dynamics in optical systems. Loves to communicate science.

Swirling bands of eroded, layered rock, reminiscent of the edges of Alaskan ice sheets, and an array of light and dark mottled patterns blanket the frigid floor of Mars' south pole, where NASA's newly named Mars Polar Lander will touch down in late 1999. The new images of the landing zone for the Mars Polar Lander, taken by the camera aboard NASA's Mars Global Surveyor, confirm that this strange, layered terrain in the south polar region represents a dramatic departure from the now-familiar Martian landscapes observed by the Viking landers and Mars Pathfinder. In December 1999, the next lander in a steady series begun by Pathfinder will set down in this uncharted territory to dig for traces of frozen, subsurface water. "Despite ground fog that obscures part of the surface in these images, we can see much more surface detail than we've ever seen before, which suggests that the 75-degree south latitude landing zone is quite a bit more rugged and geologically diverse than we had previously thought," said Dr. Michael Malin of Malin Space Science Systems, Inc., San Diego, CA. Malin is principal investigator for the Global Surveyor camera and the cameras on the 1998 missions, the Mars Polar Lander and its newly named partner, the Mars Climate Orbiter. In the current images from Mars Global Surveyor, obtained during an aerobraking orbit from about 1,700 miles above the planet's surface, objects about 48 feet across can be resolved. Once the spacecraft reaches its final mapping orbit early next year, at an average of 234 miles above the surface, the camera will be able to resolve ground features as small as seven to nine feet across. This greater clarity will enable views of objects as small as boulders or as subtle as sand dunes. Over the next year, the Global Surveyor images will be used in concert with other spacecraft data such as that obtained by its thermal emission spectrometer to better characterize the geology of the Martian south pole. After Global Surveyor has reached its mapping orbit, data from the spacecraft's laser altimeter, which measures the height and roughness of Martian surface features, will be combined with the imaging data to aid the final choice of landing sites. "We have a wonderful opportunity in the next year to study this region with data from Mars Global Surveyor, which underscores the true advantage of conducting a continuing program of Mars exploration," said Dr. John McNamee, Mars Surveyor '98 project manager at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. "We will be able to characterize the geology of the whole region and find the best spot to land, one that presents a balance between lander safety and scientific interest. This process does not have to be finalized until June 1999, five months after the lander has been launched and six months before it lands." The new landing site images are available on the Internet at JPL's Mars News web site and at the Malin Space Science Systems web site at: The images are being studied while the 1998 Mars Climate Orbiter and Mars Polar Lander are undergoing key hardware integration and testing at Lockheed Martin Astronautics, Denver, CO. The spacecraft are currently being prepared for transfer to the Lockheed Martin environmental test chambers to ensure that they can survive and operate in the extreme conditions at Mars. At the completion of this testing, the spacecraft will be flown separately to NASA's Kennedy Space Center, FL, for integration with their launch vehicles. The 1998 Mars lander and orbiter missions are designed to learn more about the history of Mars' climate and the behavior of related Martian volatiles, such as water vapor and ground ice. The orbiter, scheduled for launch on Dec. 10, will conduct a two- year primary mission to profile the Martian atmosphere and map its surface. The lander, scheduled for liftoff on Jan. 3, 1999, will carry out a three-month mission to search for traces of subsurface water in this frozen, layered terrain and any evidence of a physical record of climate change. To meet these scientific objectives, the orbiter will carry a rebuilt version of the Pressure Modulated Infrared Radiometer (PMIRR) that was lost with Mars Observer in 1993. This atmospheric sounder will observe the global distribution and time variation of temperature, dust, water vapor and condensates in the Martian atmosphere. PMIRR is a collaboration between JPL, Oxford University and Russia's Space Research Institute. Like Mars Global Surveyor, the Mars Climate Orbiter carries a dual camera system, contained in an amazingly compact package about the size of a pair of binoculars. The Mars color imager's one-pound wide-angle camera will return daily low-resolution global views of the planet's atmosphere and surface, while its medium-angle camera will provide higher resolution (30 feet per pixel) images. The medium-angle camera will build global and regional maps of Mars in multiple colors over the course of the mission. These maps will be used to characterize surface properties and changes in the distribution of dust. The 1998 lander carries three scientific packages: the Mars descent imager, provided by Malin, which will view the landing site at increasingly higher resolution as the lander descends to the surface of Mars; the atmospheric lidar experiment, provided by the Russia space institute, which will monitor the presence and height of atmospheric hazes, coupled with a miniature microphone furnished by The Planetary Society, Pasadena, CA, to record the sounds of Mars; and the Mars Volatile and Climate Surveyor (MVACS) package, led by principal investigator Dr. David Paige of the University of California, Los Angeles. MVACS includes a surface stereo imager based on the Mars Pathfinder camera, both built at the University of Arizona; a meteorology package, built at JPL; a robotic arm, also built at JPL, to acquire soil samples and close-up images of the surface and subsurface; and the thermal and evolved gas analysis experiment, built at the University of Arizona. JPL will oversee mission operations with the spacecraft team at Lockheed Martin Astronautics and the instrument teams located at their home institutions during the lander and orbiter missions. "MVACS and the other science experiments are tailor-made for the exploration of Mars' south pole," said Dr. Richard Zurek, project scientist at JPL. "The robotic arm, which is reminiscent of the Viking arm and scoop that were used to carry out biology experiments in the mid-1970s, is, in fact, much more versatile. It can reach farther out, dig up to three feet below the surface and then place soil samples in a miniature oven, called the evolved gas analysis experiment, where the samples are 'cooked' and analyzed for chemical and gas content." Piggybacking on the Mars Polar Lander are two small 4.5- pound microprobes provided by NASA's New Millennium technology validation program. Deployed before landing, they will penetrate and embed themselves beneath the Martian surface to study subsurface materials. A CD-ROM with the names of students from all over the world will also be flown on the lander. Signatures may be submitted via the Internet to: The Mars Polar Lander and the Mars Climate Orbiter are the second set of launches in a long-term NASA program of Mars exploration known as the Mars Surveyor Program. The missions are managed by JPL for NASA's Office of Space Science, Washington, DC. Lockheed Martin Astronautics, Denver, CO, is NASA's industry partner in the mission. Return to ISPEC News || Go to the ISPEC News Archive

Is Planet 9 really a black hole? (10 October 2019) Is there a black hole in our solar system? Physicists have speculated that the orbits of huge chunks of rock and ice in the outer solar system might have been influenced by a new planet called Planet 9. It’s thought that Planet 9 could have a mass five to 20 times bigger than the Earth. Now a team of researchers from Durham University and the University of Illinois have come up with a new theory that Planet 9 might be a small black hole left over from the Big Bang. They looked at six unexpected events when astronomers saw the light of a star being bent by the gravitational effect of a large object. These events correspond to objects with a mass five to 20 times bigger than the Earth, like primordial black holes left over from the beginning of the universe 13.8 billion years ago. The researchers describe this anomaly as “remarkable”. It suggests that the likelihood of Planet 9 being a black hole is similar to the likelihood of it being a planet. The researchers say they can’t rule out that Planet 9 might be a planet, but add that the experimental search for what the object is should be extended. It’s easier to look for a planet - which reflects light from the Sun and gives out thermal radiation - than a black hole that doesn’t emit such radiation. This could make it more difficult to spot if Planet 9 really is an ancient black hole. However, the researchers add that it’s reasonable to expect that the black hole might be surrounded by a dark matter halo. If this dark matter converts into observable particles, the halo surrounding the black hole would produce high-energy photons that could be seen when searching for x-rays and gamma rays. This could provide evidence that Planet 9 is a black hole. Find out more Discover more about Physics at Durham.

Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at Messier 26 open star cluster. Enjoy! Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so that others wouldn’t make the same mistake. Consisting of 100 objects, the Messier Catalog would come to be viewed by posterity as a major milestone in the study of Deep Space Objects. One of these objects is Messier 26, an open star cluster located about 5,000 light years from the Earth in the direction of the Scutum Constellation. While somewhat faint compared to other objects that share its section of the sky, this star field remains a source of mystery to astronomers, thanks to what appears to be a low-density star field at its nucleus. When this cloud of stars formed some 89 million years ago, it was probably far more compact than today’s size of a 22 light year span. At a happy distance of about 5,000 light years from our solar system, we can’t quite see into the nucleus to determine just how dense it may actually be because of an obscuring cloud of interstellar matter. However, we do know a little bit about the stars contained within it. As astronomer James Cuffey suggested in a paper titled “The Galactic Clusters NGC 6649 and NGC 6694“, which appeared in July 1940 issue of The Astrophysical Journal: “The relations between color and apparent magnitude show that NGC 6694 contains a well-defined main sequence and a slight indication of a giant branch. A zone of low star density 3′ from the center of NGC 6694 is noted. The ratio between general and selective absorption is estimated from the available data on red color indices in obscured clusters. Although uncertain in many cases, the results tend to confirm the ratio predicted by the law of scattering.” However boring a field of stars may look upon first encounter, studies are important to our understanding how our galaxy evolved and the timeline incurred. As Kayla Young of the Manhasset Science Research team said: “Star Clusters are unique because all of the stars in the cluster essentially have the same age and are roughly the same distance from Earth. Therefore, the purpose was to determine if a correlation exists between mean absolute magnitude and age of a star cluster. The absolute magnitude for star cluster NGC 6694 was calculated to be about 1.34 + .9. Using the B-V (Photometric Analysis) data ages were also calculated. After a scatter plot was created, the line of best fit demonstrated an exponential relation between the age and absolute magnitude.” History of Observation: Messier 26 was first observed by Charles Messier himself on June 20th, 1764. As he wrote of the discovery at the time: “I discovered another cluster of stars near Eta and Omicron in Antinous [now Alpha and Delta Scuti] among which there is one which is brighter than the others: with a refractor of three feet, it is not possible to distinguish them, it requires to employ a strong instrument: I saw them very well with a Gregorian telescope which magnified 104 times: among them one doesn’t see any nebulosity, but with a refractor of 3 feet and a half, these stars don’t appear individually, but in the form of a nebula; the diameter of that cluster may be 2 minutes of arc. I have determined its position with regard to the star o of Antinous, its right ascension is 278d 5′ 25″, and its declination 9d 38′ 14″ south.” Later, Bode would report a few stars with nebulosity – a field that simply wouldn’t resolve to his telescope. William Herschel would spare it but only a brief glance, saying: “A cluster of scattered stars, not rich.” While John Herschel would later go on to class it with its NGC designation, it was Admiral Smyth who would most aptly describe M26 for the true galactic cluster we know it to be. As he wrote upon viewing it in April of 1835: “A small and coarse, but bright, cluster of stars, preceding the left foot of Antinous, in a fine condensed part of the Milky Way; and it follows 2 Aquilae by only a half degree. The principle members of this group lie nearly in a vertical position with the equatorial line, and the place is that of a small pair in the south, or upper portion of the field [in telescope]. This neat double star is of the 9th and 10th magnitudes, with an angle [PA] = 48 deg, and is followed by an 8th [mag star], the largest [brightest] in the assemblage, by 4s. Altogether the object is pretty, and must, from all analogy, possess affinity among its various components; but the collocation and adjustment of these wondrous firmamental clusters, and their probable distances, almost stun our present faculties. There are many astral splashes in this crowded district of the Galaxy, among which fine specimens of what may be termed luminiferous ether, are met with.” Locating Messier 26: Finding Messier 26 in binoculars is easy as far as location goes – but not so easy distinguishing it from the starfield. Begin with the constellation of Aquila and its brightest star – Alpha. As you move southwest, count the stars down the Eagle’s back. When you reach three you are at the boundary of the constellation of Scutum. While maps make Scutum’s stars appear easy to find, they really aren’t. The next most easily distinguished star in the line in Alpha Scutii. Aim your binoculars or finderscope there and you’ll see northern Epsilon and southern Delta to the east. Messier 26 is slightly southeast of Delta and will appear as a slight compression in the starfield, and you will be able to resolve a few individual stars to larger ones. Using a finderscope, it will appear as a very vague brightening – perhaps not seen at all depending on your finder’s aperture. In even a small telescope, however, you’ll be pleased with what you see! Medium magnification will light up this 8th magnitude galactic star cluster and mid-sized instruments will fully resolve it. Power up! See how many stars you can – and can’t – resolve in this dusty, curtained, distant beauty! And here are the quick facts to help you on your way! Object Name: Messier 26 Alternative Designations: M26, NGC 6694 Object Type: Open Galactic Star Cluster Right Ascension: 18 : 45.2 (h:m) Declination: -09 : 24 (deg:m) Distance: 5.0 (kly) Visual Brightness: 8.0 (mag) Apparent Dimension: 15.0 (arc min) We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

One of the greatest successes in the recent Italian scientific history, BeppoSAX (Satellite for Astronomy X, "Beppo" like the nickname of the Italian astronomer Giuseppe Occhialini, one of the pioneers in the study of cosmic rays) was born from a cooperation between the Italian Space Agency (ASI) and the Netherlands Agency for Aerospace Programs (NIVR). Launched on April 30th, 1996, BeppoSAX made an outstanding scientific impact in the study of high energies. Already in 2002, when the mission was about to end, there were more than 1500 scientific publications based on the data provided by BeppoSAX. The main goal of the mission was to study the cosmic emissions of X-rays, which were impossible to study from Earth due to the shielding of the atmosphere. Specifically, the mission aimed at contributing to the study of cosmic phenomena that simultaneously emit radiations across a broad range of energy levels, in order to understand the related astrophysical mechanisms. In fact, BeppoSAX’s ace in the hole was a particularly broad spectral coverage (the range of observable emissions ‘energy levels), ranging from 0,1 to over 200 KeV. It was the first mission capable of studying X-ray sources across such a broad energy range. In this way, SAX was able to contribute to the study of a wide variety of cosmic phenomena such as compact galactic sources, active galactic nuclei, clusters of galaxies, remains of supernovae, normal galaxies, stars, gamma-ray bursts. The major successes actually came from the observation of gamma-ray bursts (GRB), 'lightnings' of extremely energetic gamma rays coming from the Universe; before this mission, their origin had always been an enigma for astrophysicists. By showing the X-ray emission that accompanies the gamma-ray range, BeppoSAX allowed to reconstruct some key pieces of the puzzle. Throughout its life the satellite observed more than 30 gamma-ray bursts and was able to immediately launch warning signals to other space or ground-based instruments at their onset. Guided by BeppoSAX observations, astronomers from all over the world found out that these mysterious gamma-ray bursts come from extremely remote galaxies and have the same level of energy that you would obtain by annihilating into light the entire mass of our Sun, in a few instants. In other words, they are the largest explosion in the Universe after the Big Bang. The great expertise shown in this area by the Italian scientific and technological community (further shown with the launch into orbit of the AGILE gamma-ray astronomy satellite) guaranteed a prominent role to Italy in NASA’s SWIFT and Fermi missions, this latter dedicated to the great Italian physicist due to the significant contribution given by our country in this area.

Chances are good that you’ve thought about the concept of gravity once or twice. If you’ve ever taken a high school physics class, you might have heard that gravity is an invisible force that is responsible for keeping you planted on the earth. At the beginning of the 20th century, the young Albert Einstein was also interested in gravity. The accepted theory of gravity at that time had first been put forth by Isaac Newton in the 17th century, and it had seen great success in physics for centuries. But Einstein was bothered by one of the key foundations of Newton’s gravity: that space and time are both independent, absolute entities. In his Principia Mathematica, Newton stated that “Absolute, true, and mathematical time, of it self and from its own nature, flows equably without relation to anything external… absolute space, in its own nature, without relation to anything external, remains always similar and immovable”. In the early 20th century, physicists were just beginning to understand electricity and magnetism, and while carefully scrutinizing these developments Einstein came up with a new idea: that space and time are not distinct, absolute quantities as Newton said, but rather that they are intertwined in a very special way. Putting the dimensions of space and time together, into what we now call spacetime, turned out to be necessary to avoid paradoxical outcomes in electricity and magnetism. But the concept of spacetime also leads to some very strange outcomes. A new theory of gravity, called General Relativity, is one of these outcomes. In General Relativity — Einstein’s theory of gravity — gravity is the curvature of spacetime itself. Physicists often say that spacetime is the “fabric of the cosmos”, but it’s not exactly made up of “stuff”, so how can it be curved? This is difficult to conceptualize, but one can use an analogy to understand a little better. If you were to place a baseball on a spandex sheet of fabric, the ball would distort the sheet by bending it. A bowling ball would also bend the sheet, even more than the baseball. If you took a marble and added it to the sheet, the marble would follow the spandex surface, curving around the bowling ball (an orbit). This is the essence of Einstein’s gravity: massive objects bend spacetime, and in turn, spacetime tells matter how to move. Now we’re ready to talk about gravitational waves. Imagine for a moment that you rotate the bowling ball about its vertical axis on the spandex sheet. The bowling ball has a smooth surface and is round, so there isn’t any effect on the sheet. However, if we took a pair of bowling balls and rotated them around each other, ripples would begin to spread outward on our spandex sheet. Similarly, if we took a bowling ball that wasn’t quite round (maybe with a lump of cement stuck to a side) and tried to rotate the ball, the lump would “catch” on the spandex and create ripples. These ripples, produced either by two objects orbiting each other (we call this a binary system), or a lumpy object rotating about its axis, are gravitational waves. They propagate radially outward from the objects that produce them and travel at the speed of light. As you can imagine, this means that gravitational waves are being produced all the time, all over the universe, from all kinds of systems: the moon and Earth in their orbit; a pair of ice-skaters spinning while holding hands; a football wobbling from a poor throw; a distant rotating planet with mountains. When the gravitational waves produced by any of these examples hit matter like you and I, the effect they have is to stretch and squeeze it. All the stretching and squeezing happens in the direction that’s perpendicular to the gravitational wave’s travel path (using more technical physics lingo, we would say that gravitational waves are transverse). The amount of stretching and squeezing is extraordinarily small because gravity is actually fairly weak [just think: you can defy the entire gravitational pull of the earth just by jumping or using a refrigerator magnet to pick up a paper clip!]. To produce “big” gravitational waves, we have to look for waves that are produced by something called compact objects. To explain what a compact object is, imagine that you have a large round bread roll. The roll is made up of ordinary atoms and has mass; we could weigh it on a kitchen scale, and measure its diameter. Now imagine squashing the roll with your hands until it forms a dense lump of bread. If we place the squashed bread roll on our scale, it would have the same weight as it did before. It contains the same number and type of atoms it had before we squashed it. But now, the roll occupies a much smaller region of space, and the bread is more dense than it was before. It is now a compact object. Compact objects bend spacetime in a much more extreme way than other objects, and as a result, the gravitational waves they produce stretch and squeeze matter enough that we can actually detect it. Don’t get too excited about the amount of stretching, though. The most compact astrophysical objects in the universe (that we know of) are black holes and neutron stars, which are dead remnants of very massive stars. If a “big” gravitational wave produced by a pair of orbiting black holes or neutron stars were to hit you head-on, your height would only change by one thousandth the diameter of a proton! Detecting gravitational waves is thus a very tricky business; the detectors we use must be capable of measuring changes in length that are smaller than the atoms the detectors are made of! We will discuss the methods that we use to construct such detectors and conduct searches for gravitational waves in a future blog post. But before you go, it’s important to understand why any of this matters. One reason we’re interested in detecting gravitational waves is to test Einstein’s gravity. Although we have significant experimental evidence that supports General Relativity, there are feasible contending theories that are similar and vary only from Einstein’s in the way that gravitational waves behave. So far, our detections of gravitational waves have continued to support Einstein’s theory, but it is important to continue to test this. The second reason to search for gravitational waves is to learn from them. Every telescope ever built has relied on light of some form (x-ray, gamma ray, infrared, visible, radio, etc.) to observe the universe. Gravitational wave detectors are completely different; they use gravity instead of light to observe the universe. This allows us to study systems, such as black hole binaries, that can’t be directly studied using light. We now have the potential to unlock mysteries about black holes, neutron stars, stellar evolution, the Big Bang and much more. And that’s not all. Any time our species has found a new way to observe the universe around us, we find unexpected things, things we didn’t even know that we didn’t know. There is no reason to suspect that this will be any different. We’re standing on the cutting edge of a new observational experience for mankind, and there are all kinds of beautiful, bizarre and unexpected things to be discovered! Stay tuned to hear more about gravitational waves from the IGC. In the meantime, if you’ve got questions, I love to talk science! Feel free to email me. —A blogpost about a recent paper by Beatrice Bonga (author of this post), Brajesh Gupt and Nelson Yokomizo— Have you ever wondered what the shape of our universe is? It turns out that you only need three categories to classify all the possibilities for the shape of our universe: closed, flat or open. The closed category contains all shapes that look like a 3-dimensional sphere or any deformation of it. To visualize this better, let me give you some examples in two dimensions: the surface of a potato and the earth are both deformations of a 2-dimensional sphere. The flat category is like a 3-dimensional plane, with a sheet of paper (whether it is crumbled or not) being an easy to visualize example in two dimensions. The open category contains all shapes that look saddle shaped (or any deformation of it of course). Is there a way to tell which category our universe belongs to? Observations from cosmology are so far all consistent with a flat universe, which also happens to be the easiest to visualize and do calculations with. This is typically the reason why most data is analyzed using the assumption that that our universe is flat. However, data is becoming increasingly more precise. So is there a chance that our universe is curved after all? We would be like the people of ancient Greece who were able to determine that the surface of the Earth is curved even though it looked flat from their perspective. This question has been studied by numerous physicists. One of the most amazing data available in cosmology is the Cosmic Microwave Background (CMB). The CMB is radiation emitted when our universe was ~380,000 years old and we are able to observe this radiation now with incredible precision. You could think of it as the baby picture of our universe because our universe is now close to 14 billion years old. To be precise, if you compare the age of our universe with a 100 year old person, the CMB is a picture of a one-day old baby. By analyzing this baby picture carefully, we don’t just learn things about the universe when it was 380,000 years old but also about the years before. During one of those earlier years, the universe underwent a phase of inflation (for more information about inflation, see Anne-Sylvie’s blog post). This phase is important to understand our approach to the question: is it possible that our universe is not flat, but closed? So how does one usually study the shape of our universe? Typically, when studying the CMB one calculates how the data should look at the end of inflation in their favorite inflationary model and then apply Einstein’s and Boltzmann equations to evolve this data to today. This data is then compared to the baby picture we observe today and the better the match between the evolved data and the actual observations of the CMB, the better the calculated form of our data at the end of inflation was. Scientists so far have looked at the effect of a closed universe on the evolution from the end of inflation to today, but they have not calculated how a closed model changes the data at the end of inflation. This is what we did. We then evolved it with the known evolution equations and compared it to what we observe today. What did we find? The calculated data at the end of inflation looks different, however, the differences are small and the data remains consistent with a flat model. The differences between the flat and the closed model appear at large scales, for which the closed model does moderately better than the flat model, but at these scales the observational error margins are also largest. Thus, the difference is statistically not very significant. If you want to know more, you can find the pre-print of our article here. You can also always shoot me an email if you have more questions. My research interests revolves around inflationary cosmology. Owing to several observations that started with Edwin Hubble, we know that our universe is in expansion. On very large scales, the distance separating two objects grows, as the fabric of spacetime expands more and more. This means that, if we look back in the past, the universe was much smaller, hotter and denser than it is today. The model that describes most accurately the history and evolution of the Universe today is called the Λ-CDM (or concordance) model. According to the theory, about thirteen billion years ago, all the matter and energy of the universe was forming an insanely dense, hot and homogeneous soup. Well, actually, the soup was not completely homogeneous; some inhomogeneities, however extremely minute, were present. And the existence of these inhomogeneities in our primordial soup had dramatic consequences. Indeed, as they were denser, they could attract more matter, which would make these regions even denser. Therefore, as billions of years passed, the overdense regions saw their density increase, while the underdense regions became less and less filled with matter. This led to the growth of large scale structures that we observe today, such as clusters of galaxies. A relic of those very homogeneous times is the faint radio signal, called Cosmic Microwave Background (CMB), that we receive from all the directions in the sky. Here is a picture taken by the Planck satellite: On this picture, we see a snapshot of the universe when it was approximately 380 thousand years old. The red and blue spots show the tiny differences in temperature (or in density) of the universe. At this time, the fluctuations in temperature are one part in a hundred thousand! Therefore, from very small inhomogeneities present in the early universe, were born today’s galaxies and stars and nebula and all the rest. But where were those inhomogeneities coming from? This question can be answered by the paradigm of inflation, which describes a phase of exponentially accelerated expansion of our spacetime at the beginning of the Universe. While we don’t have strong observational evidence for inflation yet, it solves many of the problems of the Λ-CDM model of cosmology, and therefore many physicists are working on inflation. Inflation didn’t last long, but was quite considerable; in about 10-32 seconds, the universe expanded by a factor of more than 1026! During that time, the small quantum fluctuations in density of the pre-inflationnary universe were brought to large, classical scales. And that’s how the primordial inhomogeneities were born! So, we have a mechanism explaining the existence of the small inhomogeneities of the early universe. But there exists a large variety of ways to implement that mechanism. How do we set apart all the models that cosmologists came up with? By studying the statistics of the inhomogeneities. In particular, we can look at correlation functions. These functions describe the correlation between two – or more – points in the sky that are separated by a specific angle. And what we see is that the statistics of the fluctuations is very well described by a Gaussian distribution. But small deviations from this Gaussian statistics, that we call non-Gaussianities, could tell us a lot about the history of the universe, and it would help tremendously in discriminating the different inflationary models. Therefore, cosmologists are really excited to observe non-Gaussianities in the near future! Over the history of mankind, the understanding of our Universe has evolved and matured, thanks to remarkable advancements both on theoretical and experimental fronts in the fields of quantum mechanics and general relativity (GR). Quantum mechanics describes the physics at small scales such as the scale of sub-atomic particles, while gravity is weak and remains practically inert. On the other hand, the large scale structure of the universe is dictated by gravity, which is governed by GR, while quantum mechanics plays no role. Both theories have proved to be robust in their own territory under various theoretical and experimental tests. Unfortunately, it turns out that, as they are, GR and quantum mechanics do not play well with each other when brought under the same umbrella. This leaves us clueless about the situations when the size of the system is small enough for quantum physics to be important and at the same time gravity is so strong that it cannot be neglected anymore. The very early stage of our own Universe is an example of such a situation, where neither GR nor quantum mechanics can alone be trusted. Although the large scale structure of the universe is very well explained by Einstein’s theory of general relativity (GR), it fails to provide a consistent picture of the early stages of the universe, due to the presence of cosmological singularities such as the big bang. Evolving Einstein’s equations backwards in time from the conditions observed in a large macroscopic universe today, we see that the universe keeps contracting and the space-time curvature keeps increasing, until the universe reaches an extremely high curvature regime where the classical GR description is not reliable. In fact, if one naively continues evolving Einstein’s equations in this regime, one encounters the big bang singularity. To gain a reliable understanding of the physics in such cases one needs an amalgamation of ideas from both GR and quantum mechanics: a quantum theory of gravity. Loop quantum gravity (LQG) is one of the leading approaches to quantum gravity, which gives a consistent picture of the discrete quantum structure of space-time geometry (as opposed to the continuum description given by GR). The quantum space-time geometry provided by LQG opens up new avenues to explore the physics of the early universe and cosmological singularities under the paradigm of loop quantum cosmology (LQC). One of the key features of the discrete quantum geometry of LQG is that when the space-time curvature is sub-Planckian, equations of LQC are extremely well approximated by those of classical GR. The difference becomes important when the space-time curvature becomes significant for quantum discreteness to kick in. This leads to the resolution of the big-bang singularity via a quantum bounce, which serves as a smooth quantum geometric bridge between the current expanding branch of our universe and a contracting phase that should have existed in the far past (Fig.2). In the paradigm of LQC, the history of the Universe is different from that in the standard GR. As shown in Fig.2, there exists a quantum geometric pre-inflationary phase. The origin of quantum perturbations which result in the formation of cosmic microwave background (CMB), and that of the large scale structure observed today, can now be traced all the way back to the quantum gravity regime. Due to a modified pre-inflationary dynamics of LQC, these quantum fluctuations experience a different background evolution than in the standard paradigm, which can in principle have observational imprints on the temperature and the polarization power spectrum observed in the CMB. Understanding the evolution of the quantum fluctuations and extracting out loop quantum geometric imprints in the recent observational data are among the main directions of research pursued by the scientists at IGC. In forthcoming articles, I will describe different aspects of LQC and its connection with observations, in particular, with the CMB anomalies observed by the recent Planck and WMAP missions. Cosmic-rays, that is, the high energy subatomic particles, which constantly bombard the Earth’s atmosphere, were discovered by Victor Hess in 1912 in a series of very daring, high altitude balloon flights. With the measurements they made, Hess and his team showed that the ionization level of air in the atmosphere increases with altitude, a confirmation that extra-terrestrial high-energy particles, were constantly impacting atmospheric molecules. Fifty years later, in the Volcano Ranch experiment, led by John Linsley, the first ultra-high energy cosmic ray (UHECR) with energy exceeding 1020 eV, roughly 1 billion times higher than the energy of protons accelerated at the Large Hadron Collider, was discovered. This discovery led to the development of the scientific field dedicated to the search for the origin of UHECRs, the most energetic particles ever produced after the Big Bang. When a 1020 eV particle collides with an air molecule in the upper atmosphere, a shower of lower energy particles develops in the atmosphere. By the time the shower reaches ground level, millions of these lower energy, secondary particles have been produced, and the footprint of the shower can extend more than 3 km2 across, that is, roughly 1/3rd of the surface area of State College, PA. By studying the air showers, scientists can measure the properties of the original cosmic ray particles. The world’s largest UHECR detector, the Pierre Auger Observatory (hereafter Auger), is located in the Pampa Amarilla, in the Mendoza region of Argentina. The experiment covers an area of 3000 km2, that is, more than 30 times the surface area of Paris. Auger consists primarily of two types of extensive air-shower detectors. Water Cherenkov surface stations, and Fluorescence telescopes. The water Cherenkov stations are large plastic tanks, each containing 10 tonnes of purified water that register the blueish Cherenkov light which gets produced when particles travelling at the speed of light collide with the water molecules inside the tank. There are 1660 such stations, spaced 1.5 km apart, forming the Auger surface array. They have 100% duty cycle. At the four edges of the array, surrounding the surface detectors are 27 fluorescence telescopes. These operate only on dark moonless nights, detecting the fluorescence light produced by the de-excitation of nitrogen molecules as the shower propagates in the atmosphere. The power produced by a single UHECR shower is roughly that produced by a single 60 watt light bulb travelling at the speed of light, so this is a challenging measurement. The combination of the fluorescence technique and surface detectors allows us to see UHECR showers in “hybrid” mode, providing the most accurate measurement of the properties of the air shower. The origin of UHECRs is a mystery. In what kinds of sources do particles get accelerated to 5×1019 eV? It is this question that scientists working in Auger have been addressing. Although we don’t yet have a definitive answer, there are certain minimal requirements that an astrophysical source must satisfy in order to be a plausible UHECR accelerator. A simple requirement can be stated as follows: the Larmor radius of the particle in the magnetic field of the source, must be larger than the radius of the acceleration site, in order for the particle to be effectively confined in the source. This requirement is what limits the energy to which protons can be accelerated in the Large Hadron Collider; the strength of the magnets, and the radius of the tunnel. This simple argument, known as the Hillas criterion, rules out many known classes of powerful astrophysical sources as possible UHECR acceleration sites: supernova explosions, regular galaxies, including our own Milky Way, white dwarf stars, etc.; the list is long. It only leaves a few known source classes as possible UHECR accelerators, all of which are extragalactic: gamma-ray bursts, active galactic nuclei, neutron starts, and rare, powerful shocks in the intergalactic medium. Two features of the intergalactic propagation of UHECRs make us hopeful that we can discover the origin of UHECRs, by finding associations between known powerful astrophysical accelerators and UHECR arrival directions. Firstly, cosmic rays with energy exceeding 5×1019 eV have a short propagation horizon. They are so energetic that when they collide with a photon from the Cosmic Microwave Background, the cosmic photons that are left over from the Big Bang, they produce a Pi meson (or pion). This is an interaction that results in significant energy loss (generally between 14-50%) for the cosmic ray. The average distance that a 6×10^19 eV a stripped Hydrogen nucleus (i.e. a proton) can travel, while retaining 0.23 of it’s energy is 100 megaparsecs (Mpc): a small distance in extragalactic terms. An analogous (and often smaller) horizon exists for heavier elements such as Helium, Carbon, Oxygen, Iron, Silicon: other frequently observed cosmic ray species. In summary, independent of the chemical composition, the sources of UHECRs must be powerful astrophysical accelerators within ~100 Mpc. Secondly UHECRs are expected to experience small deflections, after they escape their sources, in the weak magnetic fields that permeate the intergalactic medium. A 5×1019 eV proton is expected to experience a deflection, θ, of 3 degrees or less, over 100 Mpc of propagation. Therefore, the arrival direction of protons are expected to exhibit a correlation with the positions of their sources, within a few degrees. Deflections scale linearly with charge Z, as θZ(E) = Z x θproton(E), hence heavier nuclei are expected to have more significantly deviated arrival directions. Searches for associations so far, have not resulted in statistically significant correlations between known extragalactic sources, and observed UHECR arrival directions (see e.g. Oikonomou et al. 13, Oikonomou et al. 15, Abreu et al. 14). The absence of a clear correlation is slightly disappointing, as well as puzzling: we still haven’t solved this mystery! This absence of associations could mean that UHECRs are heavy nuclei (e.g. Carbon nuclei), thus suffering large deflections, and not pointing back to their sources, or that magnetic fields in the direction of (at least some of) the sources of UHECRs are stronger than we previously inferred from independent astrophysical measurements. Other possibilities include an origin of UHECRs in some unknown population of astrophysical sources, or something more exotic, like the decay of supermassive primordial particles left over from the Big Bang. Despite the lack of a clear answer so far, the origin of UHECRs remains a very active research topic within the Auger Collaboration, and beyond. As more data get collected with existing, and future experiments, we will get closer to the answer to this mystery. Two of the major questions in the field of high-energy astrophysics are how and where cosmic rays are accelerated. However, tracing cosmic rays back to their origins is a bit tricky: since they are charged particles, they bend in the Galactic magnetic fields on their way to Earth. Luckily, there are also gamma rays associated with these cosmic ray acceleration processes. Gamma rays are neutral, so they point back to their sources, and are therefore excellent candidates to learn more about cosmic ray processes. These sources include supernova explosions, gamma-ray bursts, and active galactic nuclei and are some of the most intense, highest-energy events known in the Universe. The High Altitude Water Cherenkov (HAWC) Observatory is a fairly new experiment dedicated to studying these gamma rays. This observatory looks very different from the astronomical observatories you may be familiar with: it consists solely of giant (~5 meter tall) tanks of water which detect gamma rays using a unique method known as the Water Cherenkov technique. When a cosmic ray or gamma ray hits the Earth’s atmosphere, it interacts with the air molecules and starts a cascade of electromagnetic particles via the processes of Bremsstrahlung emission (resulting in the emission of photon) and pair creation (an electron and a positron are created). Each successive step of the chain reaction has exponentially more particles, with each individual particle having less energy than those in the previous step, until the energy of the individual particles hits some critical energy and the shower begins to die out. HAWC is built at an altitude of 4100m on the saddle point between Pico de Orizaba and Sierra Negra in Mexico, where the number of air shower particles is much greater than at sea level. It consists of an array of 300 tanks of water, each of which is 7.3 meters in diameter, 5 meters high, and has four photomultiplier tubes at the bottom. When the charged particles from the air shower reach the array, they are traveling faster than the phase velocity of light in water. This leads to an emission of a faint blue light known as Cherenkov radiation, which is amplified by the photomultiplier tubes. By looking at the pattern of hits in all the tanks during an event, we can determine where in the sky the event came from as well as its approximate energy. For example, an event with an energy of >10 TeV is expected to hit every tank in the array, while a smaller event would only hit a fraction of the tanks. Gamma/hadron separation techniques are employed to separate the gamma rays from the extremely large background of cosmic rays (Here is a fun game to see if you can distinguish gamma rays from cosmic rays by eye!). HAWC officially finished construction and was inaugurated last spring, but opportunistic data taking with the partially completed array was taken during the construction phase. A few papers with early results have already been published, with many more to come. HAWC operates 24 hours a day, making it a perfect experiment to survey the entire overhead sky in gamma rays. In addition to searching for new TeV gamma-ray sources, it is capable of monitoring existing sources for flares to get a sense of the time variability of these possible cosmic ray accelerators as well as searching for transients such as gamma-ray bursts. There are also exciting implications for multi-messenger astrophysics. In addition to notifying other observatories of flaring sources as mentioned above, it can also extend the spectra of sources to higher energies than satellite experiments are capable of. This is especially interesting because the energy range that HAWC operates in is where we expect to see differences in the spectra of gamma rays originating from electron accelerations vs. those originating from hadronic accelerators. HAWC also shares information with non-gamma-ray experiments. An example of this would be the IceCube Neutrino Observatory: both experiments study similar energies and can see the same part of the sky. Both neutrinos and gamma rays are expected in hadronic cascades. The future is bright for HAWC. Even though the experiment is still in its infancy and the ~100 collaboration members are still busy sifting through early data, an upgrade consisting of a sparse array of smaller “outrigger” tanks was recently funded and will begin construction soon. This will increase the effective area of the detector and in turn, its sensitivity to the higher energy (>10 TeV) air showers. The following video was produced to feature the Institute for Gravitation & the Cosmos on APS TV, an initiative of the American Physical Society. “The centers have a lot of synergies among them and as a result the institute is much greater than its parts.” -Abhay Ashtekar, Director of IGC

Until that is, you notice that in its center is a towering fountain of gas spewing from its core, looking very much like flames licking out into space. Sounds cool, right? Yeah, it’s actually way cooler than that. It’s not a fountain: it’s actually a pair of enormous bubbles, vast shells of gas being inflated by some ridiculously energetic engine inside the galaxy’s heart, one lobe above and the other below the galaxy’s midplane. And those bubbles are blasting out high energy X-rays. Take a look: That image is a combination of Hubble Space Telescope data in visible light (the kind we see, shown in orange and blue) and observations from the Chandra X-Ray Observatory (shown in purple). You can see the spiral arms traced out in the Hubble image, punctuated with point-like X-rays sources seen by Chandra along them (probably compact objects like black holes and neutron stars gobbling down material from stars orbiting them). But then in the center is that amazing structure. The visible light part looks like a popped bubble, but the X-ray data betray that; here is the Chandra observation by itself: Ah, there’s the bubble! And you can see the other bubble below it, much harder to see in the combined image due to the interference of the disk of the galaxy. The upper bubble is a staggering 4,900 light years in size, and the lower one somewhat smaller though still huge at 3,600 light years across. The X-ray data show that they look like soap bubbles, with a bright rim but a dimmer interior. That’s a hallmark of a thin spherical shell, like a … well, like a bubble. Looking around the edge we are looking through more material, so it appears brighter there. And they are bright. In just X-rays the upper bubble glows with more than a million times the energy of our Sun. That’s a huge amount of energy! Whatever is driving these structures is incredibly powerful, both to create that much emission as well as being able to push out so much gas into intergalactic space at speeds of hundreds of kilometers per second. What could possibly generate that much power? Actually, in this case, we don’t know. But there’s another example of such superbubbles much closer to us that provides clues: Our own Milky Way. Expanding outward from the center of our galaxy are two similar bubbles, detectable in gamma rays (seen by the Fermi space telescope). It turns out our bubbles are much bigger — fully 50,000 light-years long, half the diameter of the galaxy! — and moving much faster, at about 1,000 kilometers per second. Astronomers argued for years over their cause: Could they be blown by the supermassive black hole in the heart of the Milky Way, or could they be the result of incredibly vigorous star formation? Black holes can blow a fierce wind. If materials fall into one too rapidly, it forms a disk around the black hole and heats up to temperatures of millions of degrees. A witch’s brew of forces can then drive a flow of subatomic particles screaming away, in what’s called a black hole wind. On the other hand, when gas clouds give birth to thousands or even millions of stars, many of these stars are massive, hot, and incredibly luminous. They too can drive a powerful wind. So which is it? In the Milky Way, it turns out the culprit is star formation! The way the energy is being emitted is much better fit by zillions of stars pumping this energy into the gas than a black hole wind. But that’s us. What about NGC 3079? That’s harder to say. It does have a supermassive black hole, and it is active — you can see it as a purple glow in the middle of the two lobes. But that doesn’t mean it’s to blame here. It could also be a star formation. We’re not sure yet. Interestingly, the sheer power of the X-rays coming from the lobe indicate the presence of fierce magnetic fields there too. As fast-moving gas slams into slower-moving gas, it creates shock waves, and the magnetic field gets tangled up. Subatomic particles trapped inside literally get bounced around, accelerating between them until they gain so much energy the magnetism can’t hold them anymore. They then are flung away at just under the speed of light, becoming what we call cosmic rays. In general, that sort of thing is more consistent with star formation, but we just don’t have enough data to distinguish the two. I find that rather amazing. By coincidence, two very different phenomena both have about the same ability to drive the formation of these bubbles, and we can’t always be sure which one is behind it. Our puzzlement isn’t too surprising, though. After all, we haven’t been doing these sorts of observations very long, and we still have a lot to learn. I’m all for that. I like learning, and I love it when we’re presented with a mystery we have to untangle. I have little doubt astronomers will eventually figure this one out. And when they do, there will more galaxies seen with these bubbles, and certainly more weird structures previously unseen that we’ll want to understand. Galaxies are immense structures and filled literally to overflowing with amazing things. We’ll be at this for a long, long time.

Although the primary purpose of Deep Space 2 is to test new technologies for use in future science missions, the two probes are also miniature data-gathering laboratories. The probes will penetrate the south polar layered deposits of Mars near the landing site of the Mars Polar Lander. These layered deposits are believed to contain a record of changes in the climate of Mars, in the form of dust and water ice. Each probe will use microinstruments in the forebody to 1) collect a sample of soil and analyze it for the presence of water, 2) measure how quickly the probe cools after penetration to give scientists information on the physical properties of the soil, and 3) measure how fast each probe slows down in the atmosphere-to determine the pressure and temperature of the atmosphere-and in the ground, to estimate the hardness of the soil and to look for layers. Data from the forebody will be collected and relayed to Mars Global Surveyor, which is currently orbiting Mars on a mission to map the planet. Deep Space 2's scientific objectives complement those of the Mars Polar Several spacecraft around a planet could give scientists valuable information about different locations on a planet, as well as provide the kind of information that a single spacecraft could not. Networks of seismic stations (like those used on the Earth for many purposes, including detecting earthquakes), for instance, can tell scientists about the structure of a planet deep below its surface. A network of meteorological stations on Mars could help scientists understand the atmosphere of the planet. Penetrators deployed around a planet can give scientists information about the rocks and soil in many locations, rather than in just one or two. So, why haven't networks of spacecraft ever been sent to another planet? Standard spacecraft are too large, and therefore too costly, to launch in large numbers. In contrast, dozens of miniaturized spacecraft could be launched at an affordable cost. Thus the Deep Space 2 probes could pave the way to make networks of scientific stations on other planets a reality. The Mars Rock - Are we alone in the universe? Science's and theology's most talked about rock is the 1.6 kgs (4.2 lb.), potato-shaped meteorite ALH84001. It was discovered on the Allan Hills ice field in Antarctica in 1984. The geochemical composition of the gas trapped within the rock is such a close match to the unique composition of the Martian atmosphere that it provides solid evidence that the rock comes from Mars. The rock formed beneath the Martian surface 4.5 billion years ago, and thus dates back to a very early period in the formation of Mars. There is evidence that water seeped into the rock 3.6 billion years ago, when the climate of Mars was much warmer and wetter than it is now. This rock remained under the surface until 16 million years ago, when it was blasted into space by an asteroid striking the Martian surface. The rock drifted through space until it fell to Earth 13,000 years ago. Mars Rock ALH84001 The evidence for life having once existed in ALH84001 is a bit circumstantial. There are four separate observations that suggest the work of tiny bacteria: - Tiny, spherical blobs of carbonate, about the same diameter as a human hair, have a shape and geochemistry similar to those formed in muddy sediments by bacteria. - Two minerals, magnetite (an iron oxide) and pyrolite (an iron sulfide), are found on the rim of the carbonate. Their shape and chemistry also resemble minerals created - Other carbon compounds (polycyclic aromatic hydrocarbons, or PAHS) that are typically created by organic means are present. - Extremely tiny (1/1000th of a human hair) tubular and ovoid-shaped structures were discovered using a scanning electron microscope. Although smaller than microorganism seen to date on Earth, they are distinctly bug-shaped! Bug-shaped structures found in the Mars Rock Each of these four structures could have formed through geologic processes without the help of microorganisms. Their coincidence in the meteorite can most easily be explained by the presence of bacteria, but does not provide conclusive evidence of life. There's more to learn about Life on Mars in at the Johnson Space Center website, or see the original paper published in Science in 1996 by McKay et al. Front row: Suzanne Smrekar, Jet Propulsion Laboratory; Albert Yen, Jet Propulsion Laboratory; Aaron Zent, NASA/Ames Research Center; Marsha Presley-Holloway, Northern Arizona University; Paul Morgan, Macquarie University and Northern Arizona University. Back row:Jeffrey Moersch, NASA/Ames Research Center; David Catling, NASA/Ames Research Center; Ralph Lorenz, University of Arizona; Julio Magalhaes, NASA/Ames Research Center. Missing: Bruce Murray, California Institute of Technology; James Murphy, New Mexico State University DS2 will estimate the soil conductivity (how quickly heat is transferred) on Mars by measuring how fast the forebody approaches the ambient ground temperature. To determine the thermal response of the forebody, a series of experiments were run at JPL on an engineering model of the forebody. These experiments were done in a vacuum chamber to achieve the same low conductivity environment created by the extremely low atmospheric pressures found on Mars. Inside the sealed chamber, the engineering model forebody was suspended on a pulley system, heated, and plunged into a large bucket of glass beads to simulate the thermal effects of the emplacing a relatively warm probe into the frigid Martian ground. Glass beads are used because they have a well-known low thermal conductivity. Comparing the data obtained in these experiments to the data returned from Mars will make it possible to use the temperature data to estimate the soil conductivity. A very high conductivity will indicate large amounts of ice in the subsurface. A very low conductivity is likely to indicate fine-grained wind-deposited dust. This page last updated: October 29, 1999 For comments and suggestions, or to request |Deep Space 2 Outreach and Education| |Jet Propulsion Laboratory| |4800 Oak Grove Avenue| |Pasadena, CA 91109||

The super Map of Dark Matter Exploiting the effect of the gravitational lens and the power of the instrumentation of the Space Telescope, a team of scientists has managed, a few years ago, to reconstruct the distribution of dark matter in the cluster of galaxies called Abell 1689 with unprecedented detail. A few years ago we had the news of the discovery of five galaxies in the early universe exploiting the phenomenon of gravitational lensing observations with the Herschel satellite. With the same methodology, but with the observations of the Hubble Space Telescope, a team of astronomers has managed to draw more detailed map to date of dark matter, the invisible and enigmatic element that seems to constitute the majority of the mass of ‘universe. Dan Coe of NASA’s Jet Propulsion Laboratory in Pasadena, California, along with other researchers, has harnessed the power of Hubble’s Advanced Camera for Surveys to track the distribution of invisible matter in the massive galaxy cluster called Abell 1689, which lies 2.2 billion light years from us. The gravitational pull generated from storage deflects the light radiation produced by the galaxies that lie behind the cluster with respect to our line of sight, thus acting as a real lens. This effect is more intense the higher the concentration of matter – visible but especially dark – which is located in the cluster. And considering this effect, astronomers have estimated the amount of dark matter in Abell 1689, finding that in the central area of storage under its concentration is much greater than indicated by the computer simulations. It is a surprising discovery, which was advanced by a few billion years the time when this cluster should be formed. This map proved a veritable mine of information on the role of dark energy in the early stages of formation of the universe. First analyzes of data emerge indeed in important indication that galaxy clusters can therefore be formed more quickly than previously thought, before the effects produced by dark energy body block their growth. Dark energy – the more enigmatic “actor” in the evolution of the universe – in fact plays an antagonistic role to the gravitational pull exerted by dark matter. The dark energy galaxies are getting away from each other, stretching the space between them and effectively blocking the formation of large scale structures such as clusters of galaxies. And just to understand how it is done this tug of war between opposing forces is immeasurable certain to know what was the distribution of dark matter in the early universe. To investigate more thoroughly these fundamental aspects to reconstruct the evolution of the universe and its structures in the first billion years after the Big Bang, astronomers are planning new observational campaigns on other clusters of galaxies to study the influence of dark energy. A major program of Hubble, which will analyze the dark matter in galaxy clusters, is the Cluster Lensing and Supernova survey with Hubble (CLASH). In this survey, the space telescope will study 25 clusters, for a total of a month cumulative observations, distributed over the next three years. The galactic agglomerates which were selected emit intense flows of X-rays, the signal of the presence of large quantities of hot gas inside them and therefore of great mass concentrated in them, just as Abell 1689.

July 4th is a special date in American history, and this year it will, for space exploration enthusiasts be doubly meaningful, as it will mark the point at which we have been examining and exploring Mars continuously for 20 years without a single break. Of course, attempts to explore and understand Mars began much earlier than that. We first started launching missions to the Red Planet far back in the 1960s. The first successful mission – the United States’ Mariner 4 probe – shot past Mars in July 1965, returning just 22 fuzzy images as it did so, travelling too fast and without any fuel to achieve orbit. In 1969, and total overshadowed by the Apollo 11 mission to the Moon, Mariner 6 also flew by Mars in July, and was followed in August by its twin, Mariner 7, becoming the first dual mission to visit another world in the solar system. The first American mission to orbit Mars was Mariner 9, which arrived in orbit in November 1971, the exact time Mars was wreathed in a series of globe-spanning dust storms. Fortunately, the space vehicle had a planned orbital life of around 18 months, and successfully waited out the storms before returning the most spectacular images of Mars yet seen – including the mighty Tharsis volcanoes and the great gash of the Vallis Marineris, named in honour of the probe. Russia also finally successfully reach Mars orbit in 1971 with the dual Mars 2 and Mars 3 missions. The former arrived just days after Mariner 9, and the latter became the first mission to successfully deploy a lander to the surface of Mars – although the craft ceased transmitting just 15 seconds after a safe landing had been confirmed, probably due to the dust storms. Unlike Mariner 9, the Russian orbiters had a shorter operational lifespan, and both ceased operations before the dust had fully cleared, resulting in them being classified as “partially successful” missions. Then, in 1976 came the twin Viking Missions, comprising two pairs of orbiter and lander vehicles. Even now it remains one of the most ambitious robotic missions ever undertaken. The Viking 1 orbiter and lander combination launched on August 20th, 1975 and arrived in Mars orbit on June 19th, 1976. Viking 2 departed Earth on September 9th, 1975 and arrived in Mars orbit on August 7th, 1976. Viking Lander 1 had been scheduled to depart its orbiter and attempt a landing on Mars on July 4th, 1976 – the 200th anniversary of America’s independence. However, images of the landing site taken by the orbiter revealed it to be far rougher terrain than had been thought, so the landing was delayed while an alternative site was surveyed. The lander eventually touched-down on July 20th, 1976, marking the seventh anniversary of the first mission to land on the surface of the Moon. Viking lander 2 touched down half a world away on September 3rd, 1976. Viking really was a landmark – and controversial – mission. Landmark, because they utterly changed our understand over Mars during years both orbiters and landers operated. Controversial because it is still argued to this day by some that two of the five life-seeking experiments carried by each of the landers did find evidence of Martian microbes living in the planet’s regolith, although it seems more likely that the positive results – in both cases, from the same two experiments – were the result of inorganic chemical reactions between mineral in the Martian soil samples and elements within the experiments. After Viking the came a pause. While missions continued to be launched to Mars by the USA and Russia in the 1980s and early 1990s, none of them were successful. It was not until 1997 that the current trend of having vehicles continuously operating around and on Mars began – and which NASA has been celebrating, having been the stalwart of the 20-year effort of these 24/7 operations. This run technically started in early November 1996, with the launch of NASA’s Mars Global Surveyor (MGS) mission. It was followed a month later by the NASA Pathfinder Mission. By a quirk of orbital mechanics, the Pathfinder Mission – designed to test the feasibility of placing a lander and small rover on Mars – arrived at Mars first, performing a successful aerobraking and landing on July 4th, 1996. The Pathfinder lander arrived in Ares Vallis on Mars, an ancient flood plain in the northern hemisphere in an innovative way. A conventional aerodynamic heat shield protected the craft through initial entry into, and deceleration through, the upper reaches of Mars’ tenuous atmosphere. Having slowed from a velocity of several thousand kilometres an hour to just over 1300 km/h, allowing a supersonic parachute to be deployed. This slowed the vehicle’s descent to around 256 km/h and lowering the vehicle to just 355 metres above the surface of Mars, where several things happened. Firstly, a tetrahedron cocoon of protective airbags was inflated all around the vehicle in less than a second. A set of rocket motors in the back shell beneath which the airbags and lander were suspended, then fired. These slowed the vehicle almost to a hover about 15-20 metres above the ground, at which point the tether connecting the cocooned lander was cut, and the lander fell to the ground, bouncing several times before coming to rest and the airbags were deflated and drawn back underneath the lander. The triangular lander was designed to right itself while unfolding its three solar power “petals”, however, this was not required as the lander came to a stop the right way up, allowing the petals to be deployed, and – after check-out tests – the little Sojourner rover was command to drive down off of the lander and onto the surface of Mars. The same system would later be used for the MER rover missions. As a proof of concept mission, Pathfinder was not intended to be a long duration mission. Just 65 cm (25.6 in) long and 48 cm (19 in) wide, the 10.5 kg (23 lb) Sojourner rover had a top speed of 1 cm a second, so it could never roam far from its base station; in fact it never went further than about 12 metres (39 ft) from the base station, which acted as a communications relay as well as studying the Martian atmosphere and imaging Sojourner in action. Nevertheless, the mission exceeded expectations, lasting some 3 months, with the little rover examining 16 points of interest with its humble 0.3 megapixel cameras and its on-board spectrometer. The Mars Global Surveyor vehicle arrived in orbit around Mars even while Pathfinder was operating on the surface. It was the precursor to NASA’s still-operational Mars Reconnaissance Orbiter (MRO), carrying out a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface, as well as acting as a communications relay for missions on the surface of Mars and performed monitoring relay activities for sister orbiters during aerobraking into their orbits around Mars. Until the arrival of MRO in 2006 – the two missions overlapped slightly, and might have run in parallel – MGS had the most powerful imagining system ever sent to Mars. In fact, such was the success of the MGS cameras, an even high-resolution system was made a core element of MRO, which uses many similar elements to MGS. The mission returned some of the clearest evidence for the effects of water action on the surface of Mars, and the primary mission of 1 year 9 months was twice extended (by a year and then a further 11 months), before the mission switched to its Relay Mode, supporting other Mars missions – a role it performed for close to four further years. MGS might well have continued operating into the 2010s have it not been for an error while attempting to reorient a solar panel on November 2nd, 2006, resulting in the loss of communications. Despite several attempts to re-acquire and correctly orient the vehicle between then and the end of 2006, MGS we declared lost. Nevertheless, the wealth of information it provided is huge, and sits alongside that of MRO’s ongoing work. Further missions to Mars followed between 1997 and 2001 all of which failed in one way or another, except for NASA’s Mars Odyssey mission. Today, Odyssey holds the record for the longest continuing mission in Mars orbit – 16 years, 2 months and 24 days at the time of writing. Designed to detect evidence of past or present water and ice on Mars, as well as study the planet’s geology and radiation environment, Odyssey frequently sits in the shadow of the more glamorous MRO and rover missions, and is responsible for mapping the distribution of water in the surface of Mars, working in concert with the Phoenix Lander mission. As well as acting as a communication relay, Odyssey has also surveyed the landing sites for NASA’s MER roves, the Phoenix Lander and the Mars Science Laboratory. Despite several faults and a couple of failures aboard the craft, it is hoped that it will be able to continue its mission well into the 2020s. 2003 marked the start of the time when things really got busy around and on Mars. It was in this year that Europe launched it Mars Express vehicle, and NASA launched its two Mars Exploration Rovers, Spirit and Opportunity. Mars Express arrived in Mars orbit on Christmas Day, 2005. The mission had already captured hearts and minds across Europe and around the world, not so much because of the orbiter vehicle, but because of its additional payload – the British-built Beagle 2 lander. If Mars Express was ambitious for a first time planetary mission be the European Space Agency, Beagle 2 was downright cheeky. Never really a part of the original mission, the opportunity to add a lander came along quite late. As a “bolt on mission” it was outside of normal European Space Agency funding channels, so those trying to build the lander had to rely on other means for funding – and initially, the UK government was only minimally interested. Nevertheless, in typical British boffin fashion, and blessed with a gift for showmanship, the late Professor Colin Pillinger led the UK’s efforts to finance and build the lander, even in the face of changing requirements from ESA. Beagle 2 had also been due to land on Mars on Christmas Day 2005 – and I was actually there, in the UK’s “mini mission control” on the day, along with dozens of others, as Colin and his team nervously waited for confirmation that the clam-like lander was safely on Mars and calling home. The signal never came. It was not until 2014 – and sadly after Colin had passed away – that it was finally confirmed Beagle 2 had safely landed on Mars, but had suffered a mechanical failure which prevented a solar panel from deploying and allowing it to establish contact with any of the vehicles orbiting Mars. Nevertheless, Mars Express has gone on to be one of the most successful Mars missions, easily equalling that of NASA’s MRO, carrying out high-resolution imaging and mineralogical mapping of the surface, radar sounding of the subsurface structure down to the permafrost, precise determination of the atmospheric circulation and composition, and study of the interaction of the atmosphere with the interplanetary medium. As noted, the Mars Reconnaissance Orbiter mission arrived in orbit in 2006. In just over a decade of operations, it has utterly revolutionised our view of Mars, and has been responsible for some of the most remarkable images yet captured around the Red Planet. It was the HiRISE camera on MRO which in 2014, confirmed Beagle 2’s presence on Mars, and also for images like the one below. As I’ve written about NASA’s MER rovers elsewhere in this blog, I’ll move on to NASA’s Phoenix mission of 2008, which landed near the north polar cap of Mars on a mission to search for environments suitable for microbial life on Mars, and to research the history of water there. The static lander was successful in locating shallow subsurface water ice – in fact the blast from the vehicle’s landing thrusters may have blown away surface dust and material to reveal ice under the lander. Given the high latitude in which the lander touched down, the vehicle’s solar panels received less and less sunlight as the Martian winter progressed, until in November 2008, a critical threshold was crossed and the lander went into a power-conserving safe mode. Even so, it wasn’t until 2010 that the mission was officially drawn to a close, just in case the lander managed to revive itself under summer time sunlight. Today, Mars is home to eight operational missions: MER Opportunity, Mars Odyssey, MRO, Mars Express, MSL Curiosity, India’s Mars Orbiter Mission, NASA’s MAVEN orbiter, and Europe’s Trace Gas Orbiter. In 2018 these should be joined by NASA’s InSight lander, and in 2020 by MASA’s Curiosity-like Mars 2020 rover and Europe’s ExoMars rover, all of which mark our continuing drive to understand the most Earth-like of the other worlds in our solar system, and also prepare the way for human missions to Mars. More than that, however, they demonstrate the creative ingenuity of humankind as we seek to slake our thirst for knowledge about the worlds around us and the cosmos in which we reside. To mark the 20th anniversary of their own continuous missions to Mars, NASA released a special video in June, highlighting everything from Pathfinder’s arrival in 1997 through to Curiosity, before looking to the future.

There are plenty of ways Earth could go. It could smash into another planet, be swallowed by a black hole, or get pummelled to death by asteroids. There’s really no way to tell which doomsday scenario will be the cause of our planet’s demise. But one thing is for sure - even if Earth spends the rest of its eons escaping alien attacks, dodging space rocks, and avoiding a nuclear apocalypse, there will come a day when our own Sun will eventually destroy us. This process won’t be pretty, as Business Insider’s video team recently illustrated when they took a look at what will happen to Earth when the Sun finally does die out in a blaze of glory. And as Jillian Scudder, an astrophysicist at the University of Sussex, explained to Business Insider in an email, the day might come sooner than we think. Bleeding Earth dry The Sun survives by burning hydrogen atoms into helium atoms in its core. In fact, it burns through 600 million tons of hydrogen every second. And as the Sun’s core becomes saturated with this helium, it shrinks, causing nuclear fusion reactions to speed up - which means that the Sun spits out more energy. In fact, for every billion years the Sun spends burning hydrogen, it gets about 10 percent brighter. And while 10 percent might not seem a lot, that difference could be catastrophic for our planet. "The predictions for what exactly will happen to Earth as the Sun brightens over the next billion years are pretty uncertain," Scudder said. "But the general gist is that the increasing heat from the Sun will cause more water to evaporate off the surface, and be held in the atmosphere instead. The water then acts as a greenhouse gas, which traps more incoming heat, which speeds up the evaporation." Before it ever even runs out of hydrogen, the Sun’s high energy light will bombard our atmosphere and "split apart the molecules and allow the water to escape as hydrogen and oxygen, eventually bleeding Earth dry of water", Scudder said. And it doesn’t end there. A 10 percent increase in brightness every billion years means that 3.5 billion years from today, the Sun will shine almost 40 percent brighter, which will boil Earth’s oceans, melt its ice caps, and strip all of the moisture from its atmosphere. Our planet, once bursting with life, will become unbearably hot, dry, and barren - like Venus. And as the steady thump of time drums down on our existence, the situation will only get more bleak. The Sun’s death rattle All good things eventually come to an end. Every book has a final chapter, every pizza has one last bite, and every person has a dying breath. And one day, about 4 or 5 billion years from now, the Sun will burn through its last gasp of hydrogen and start burning helium instead. "Once hydrogen has stopped burning in the core of the Sun, the star has formally left the main sequence and can be considered a red giant," Scudder said. "It will then spend about a billion years expanding and burning helium in its core, with a shell around it where hydrogen is still able to fuse into helium." As the Sun sheds its outer layers, its mass will decrease, loosening its gravitational hold on all of the planets. So all of the planets orbiting the Sun will drift a little further away. When the Sun becomes a full blown red giant, Scudder said, its core will get extremely hot and dense while its outer layer expands ... a lot. Its atmosphere will stretch out to Mars’ current orbit, swallowing Mercury and Venus. Although the Sun’s atmosphere will reach Mars’ orbit, Mars will escape, as it will have wandered past the reach of the Sun’s expanding atmosphere. Earth, on the other hand, has two options: either escape the expanding Sun or be consumed by it. But even if our planet slips out of the Sun’s reach, the intense temperatures will burn it to a sad, dead crisp. "In either case, our planet will be pretty close to the surface of the red giant, which is not good for life," Scudder said. Although more massive stars can begin another shell of fusing heavier elements when this helium is exhausted, the Sun is too feeble to generate the pressure needed to begin that layer of fusion, Scudder explained. So when the Sun’s helium dries up, it’s pretty much all downhill from there. From red giant to white dwarf Once the Sun has emptied its fuel reserves, it will become unstable and start to pulse. With every pulse, the Sun will shrug off layers of its outer atmosphere until all that’s left is a cold, heavy core, surrounded by a planetary nebula. With each passing day this core, known as a white dwarf, will cool and fade hopelessly out of existence as if it didn’t once host the most lively planet ever discovered in the sweeping canvas of the Universe. But who knows. Maybe the aliens will get to us first. This article was originally published by Business Insider. More from Business Insider:

Celebration of Space - April 10, 2020 This coming Sunday, April 12, 2020 is the date of Easter for this year. Regardless of how you feel about the Easter holiday, we are sure you have noticed that it doesn’t fall on the same day each year, like many of the other yearly holidays. This is because the date of the Easter holiday is astronomically calculated. To figure what day Easter will fall on for any given year, you need to know the date of the Vernal Equinox (first day of spring), and the date of the following full lunar phase. The Easter holiday will occur on the first Sunday after the first Full Moon after the Vernal Equinox. Since the first Full Moon to occur since the Vernal Equinox was the Full Pink Moon, which happened this past Tuesday, April 7th, that places the date of Easter this coming Sunday. Since the start of the year, Venus has been rising higher and higher in the western sky after sunset, as well as growing brighter. Venus reached Maximum Eastern Elongation on March 24, 2020, which is when Venus reaches the point in its orbit when the tangential angle, when viewed from Earth, forms a right angle with the Sun. Think of a triangle comprised of a straight line starting at Earth and ending at an inner planet, then another line from the inner planet (inferior) to the Sun, and a third line extending from the Sun to Earth. When the line from Earth to the inner planet and the line from the inner planet to the Sun form a right angle (90°), you have maximum elongation of the inner planet. Consequently, when the line from Earth to an outer (superior) planet and the line from the Sun to Earth form a right angle, you have quadrature of the outer planet Eastern Elongation means that the inner planet is at maximum elongation while being placed on the eastern side of the of the Sun in Earth’s sky. This past couple weeks, Venus has waned into its waning crescent phase, and will continue to wane until it reaches Inferior Conjunction on June 3, 2020, which is when Venus arrives in between Earth and the Sun. Though Venus will continue to wane well into a super thin crescent, it will continue to grow brighter because it is moving closer to us with each passing day. If you have a backyard telescope or high power binoculars, step outside each night over the next few months and catch a view of Venus in the western sky after sunset and notice the rate at which it wanes. Check out this image of Venus that I captured this past Monday, April 6, 2020 for remote physics labs at Brown University. Have a great holiday from all the astro-geeks at Frosty Drew Observatory in whatever way you celebrate.

An international team of astronomers, including Professor Tom Marsh and Dr Danny Steeghs from the University of Warwick, have shown that the two stars in the binary HM Cancri definitely revolve around each other in a mere 5.4 minutes. This makes HM Cancri the binary star with by far the shortest known orbital period. It is also the smallest known binary. The binary system is no larger than 8 times the diameter of the Earth which is the equivalent of no more than a quarter of the distance from the Earth to the Moon. The binary system consists of two white dwarfs. These are the burnt- out cinders of stars such as our Sun, and contain a highly condensed form of helium, carbon and oxygen. The two white dwarfs in HM Cancri are so close together that mass is flowing from one star to the other. HM Cancri was first noticed as an X-ray source in 1999 showing a 5.4 minutes periodicity but for a long time it has remained unclear whether this period also indicated the actual orbital period of the system. It was so short that astronomers were reluctant to accept the possibility without solid proof. The team of astronomers, led by Dr Gijs Roelofs of the Harvard-Smithsonian Center of Astrophysics, and including Professor Tom Marsh and Dr Danny Steeghs at the University of Warwick in the UK, have now used the world's largest telescope, the Keck telescope on Hawaii, to prove that the 5.4 minute period is indeed the binary period of the system. This has been done by detecting the velocity variations in the spectral lines in the light of HM Cancri. These velocity variations are induced by the Doppler effect, caused by the orbital motion of the two stars revolving around each other. The Doppler effect causes the lines to periodically shift from blue to red and back. The observations of HM Cancri were an ultimate challenge due to the extremely short period that needed to be resolved and the faintness of the binary system. At a distance of close to 16,000 light years from Earth, the binary shines at a brightness no more than one millionth of the faintest stars visible to the naked eye. Professor Tom Marsh from the University of Warwick said; “This is an intriguing system in a number of ways: it has an extremely short period; mass flows from one star and crashes down onto the equator of the other in a region comparable in size to the English Midlands where it liberates more than the Sun's entire power in X-rays. It could also be a strong emitter of gravitational waves which may one day be detected from this type of star system.” Dr Danny Steeghs of the University of Warwick, said " A few years ago we proposed that HM Cancri was indeed an interacting binary consisting of two white dwarfs and that the 5.4 minute period was the orbital period. It is very gratifying to see this model confirmed by our observations, especially since earlier attempts had been thwarted by bad weather." The article describing the observations of HM Cancri entitled Spectroscopic Evidence For a 5.4 Minute Orbital Period in HM Cancri will be published in the Astrophysical Journal Letters of March 10, 2010 "This type of observations is really at the limit of what is currently possible. Not only does one need the biggest telescopes in the world, but they also have to be equipped with the best instruments available", explains Professor Paul Groot of the Radboud University Nijmegen in the Netherlands. "The binary HM Cancri is a real challenge for our understanding of stellar and binary evolution," adds Dr Gijs Nelemans of the Radboud University."We know the system must have come from two normal stars that somehow spiralled together in two earlier episodes of mass transfer, but the physics of this process is very poorly known. The system is also a big opportunity for general relativity. It must be one of the most copious emitters of gravitational waves. These distortions of space-time we hope to detect directly with the future LISA satellite, and HM Cancri will be a cornerstone system for this mission." For further information please contact: Professor Tom Marsh, Department of Physics , University of Warwick +44 (0)24765 74739 [email protected] Or Dr Danny Steeghs, Department of Physics , University of Warwick Tel: +44 (0)247 657 3873 [email protected] Peter Dunn, Head of Communications Communications Office, University of Warwick, +44 (0)24 76 523708 or +44 (0)7767 655860 Full paper at: http://www.iop.org/EJ/abstract/2041-8205/711/2/L138 PR20 9th March 2010

From the ESA/HUBBLE INFORMATION CENTRE Astronomers have discovered that the well-studied exoplanet WASP-12b reflects almost no light, making it appear essentially pitch black. This discovery sheds new light on the atmospheric composition of the planet and also refutes previous hypotheses about WASP-12b’s atmosphere. The results are also in stark contrast to observations of another similarly sized exoplanet. Using the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope, an international team led by astronomers at McGill University, Canada, and the University of Exeter, UK, have measured how much light the exoplanet WASP-12b reflects — its albedo — in order to learn more about the composition of its atmosphere . The results were surprising, explains lead author Taylor Bell, a Master’s student in astronomy at McGill University who is affiliated with the Institute for Research on Exoplanets: “The measured albedo of WASP-12b is 0.064 at most. This is an extremely low value, making the planet darker than fresh asphalt!” This makes WASP-12b two times less reflective than our Moon which has an albedo of 0.12 . Bell adds: “The low albedo shows we still have a lot to learn about WASP-12b and other similar exoplanets.” WASP-12b orbits the Sun-like star WASP-12A, about 1400 light-years away, and since its discovery in 2008 it has become one of the best studied exoplanets (opo1354-https://www.spacetelescope.org/images/opo1354a/, opo1015-https://www.spacetelescope.org/images/opo1015a/, opo1436-https://www.spacetelescope.org/images/opo1436b/, heic1524-https://www.spacetelescope.org/news/heic1524/). With a radius almost twice that of Jupiter and a year of just over one Earth day, WASP-12b is categorised as a hot Jupiter. Because it is so close to its parent star, the gravitational pull of the star has stretched WASP-12b into an egg shape and raised the surface temperature of its daylight side to 2600 degrees Celsius. The high temperature is also the most likely explanation for WASP-12b’s low albedo. “There are other hot Jupiters that have been found to be remarkably black, but they are much cooler than WASP-12b. For those planets, it is suggested that things like clouds and alkali metals are the reason for the absorption of light, but those don’t work for WASP-12b because it is so incredibly hot,” explains Bell. The daylight side of WASP-12b is so hot that clouds cannot form and alkali metals are ionised. It is even hot enough to break up hydrogen molecules into atomic hydrogen which causes the atmosphere to act more like the atmosphere of a low-mass star than like a planetary atmosphere. This leads to the low albedo of the exoplanet. To measure the albedo of WASP-12b the scientists observed the exoplanet in October 2016 during an eclipse, when the planet was near full phase and passed behind its host star for a time. This is the best method to determine the albedo of an exoplanet, as it involves directly measuring the amount of light being reflected. However, this technique requires a precision ten times greater than traditional transit observations. Using Hubble’s Space Telescope Imaging Spectrograph the scientists were able to measure the albedo of WASP-12b at several different wavelengths. “After we measured the albedo we compared it to spectral models of previously suggested atmospheric models of WASP-12b”, explains Nikolay Nikolov (University of Exeter, UK), co-author of the study. “We found that the data match neither of the two currently proposed models.” . The new data indicate that the WASP-12b atmosphere is composed of atomic hydrogen and helium. WASP-12b is only the second planet to have spectrally resolved albedo measurements, the first being HD 189733b, another hot Jupiter. The data gathered by Bell and his team allowed them to determine whether the planet reflects more light towards the blue or the red end of the spectrum. While the results for HD 189733b suggest that the exoplanet has a deep blue colour (heic1312-https://www.spacetelescope.org/news/heic1312/), WASP-12b, on the other hand, is not reflecting light at any wavelength. WASP-12b does, however, emit light because of its high temperature, giving it a red hue similar to a hot glowing metal. “The fact that the first two exoplanets with measured spectral albedo exhibit significant differences demonstrates the importance of these types of spectral observations and highlights the great diversity among hot Jupiters,” concludes Bell.

Astronomers using NASA's Spitzer Space Telescope have discovered carbon molecules, known as "buckyballs," in space for the first time. Buckyballs are soccer-ball-shaped molecules that were first observed in a laboratory 25 years ago. They are named for their resemblance to architect Buckminster Fuller's geodesic domes, which have interlocking circles on the surface of a partial sphere. Buckyballs were thought to float around in space, but had escaped detection until now. "We found what are now the largest molecules known to exist in space," said astronomer Jan Cami of the University of Western Ontario, Canada, and the SETI Institute in Mountain View, Calif. "We are particularly excited because they have unique properties that make them important players for all sorts of physical and chemical processes going on in space." Cami authored a paper about the discovery that will appear online Thursday in the journal Science. Buckyballs are made of 60 carbon atoms arranged in three-dimensional, spherical structures. Their alternating patterns of hexagons and pentagons match a typical black-and-white soccer ball. The research team also found the more elongated relative of buckyballs, known as C70, for the first time in space. These molecules consist of 70 carbon atoms and are shaped more like an oval rugby ball. Both types of molecules belong to a class known officially as buckminsterfullerenes, or fullerenes. The Cami team unexpectedly found the carbon balls in a planetary nebula named Tc 1. Planetary nebulas are the remains of stars, like the sun, that shed their outer layers of gas and dust as they age. A compact, hot star, or white dwarf, at the center of the nebula illuminates and heats these clouds of material that has been shed. The buckyballs were found in these clouds, perhaps reflecting a short stage in the star's life, when it sloughs off a puff of material rich in carbon. The astronomers used Spitzer's spectroscopy instrument to analyze infrared light from the planetary nebula and see the spectral signatures of the buckyballs. These molecules are approximately room temperature; the ideal temperature to give off distinct patterns of infrared light that Spitzer can detect. According to Cami, Spitzer looked at the right place at the right time. A century from now, the buckyballs might be too cool to be detected. The data from Spitzer were compared with data from laboratory measurements of the same molecules and showed a perfect match. "We did not plan for this discovery," Cami said. "But when we saw these whopping spectral signatures, we knew immediately that we were looking at one of the most sought-after molecules." In 1970, Japanese professor Eiji Osawa predicted the existence of buckyballs, but they were not observed until lab experiments in 1985. Researchers simulated conditions in the atmospheres of aging, carbon-rich giant stars, in which chains of carbon had been detected. Surprisingly, these experiments resulted in the formation of large quantities of buckminsterfullerenes. The molecules have since been found on Earth in candle soot, layers of rock and meteorites. The study of fullerenes and their relatives has grown into a busy field of research because of the molecules' unique strength and exceptional chemical and physical properties. Among the potential applications are armor, drug delivery and superconducting technologies. Sir Harry Kroto, who shared the 1996 Nobel Prize in chemistry with Bob Curl and Rick Smalley for the discovery of buckyballs, said, "This most exciting breakthrough provides convincing evidence that the buckyball has, as I long suspected, existed since time immemorial in the dark recesses of our galaxy." Previous searches for buckyballs in space, in particular around carbon-rich stars, proved unsuccessful. A promising case for their presence in the tenuous clouds between the stars was presented 15 years ago, using observations at optical wavelengths. That finding is awaiting confirmation from laboratory data. More recently, another Spitzer team reported evidence for buckyballs in a different type of object, but the spectral signatures they observed were partly contaminated by other chemical substances. Source: NASA News Release For more information about Spitzer, visit: http://www.nasa.gov/spitzer

Utterly unkillable tardigrades will live to see our Sun die In about 5 billion years' time, our Sun will use up its reserves of hydrogen and begin to cool down and expand, cooking the Earth in a miasma of heat and radiation. Given our current trajectory, humans will probably be long gone by then anyway, but at least one lifeform will likely still be plodding along: the utterly unkillable tardigrade. According to a new study from Harvard and Oxford, it'll take nothing short of the death of the Sun to finally do the species in – which bodes well for the resilience of life as a whole. Tardigrades look a little goofy, and they often go by the unassuming nicknames of water bears or moss piglets. But don't let that fool you: these microscopic creatures may just be the hardiest lifeforms on the planet. By entering a state of suspended animation, they've been known to withstand temperatures as low as -272º C (-457.6º F) and as high as 150º C (302º F), they can live without food, water and oxygen for extended periods of time, and are fine with both the vacuum of space and the crushing pressures at the bottom of the deepest parts of the ocean. With this list of superpowers to their name, tardigrades are a good model for how tough life is overall. When scientists study large-scale threats to life on Earth, it's usually focused on our own survival, but in the grand scheme of things humans are a pretty fragile species. If, for example, a huge asteroid were to strike the planet, it might wipe out human civilization and a good chunk of other animals and plants on land and in the sea, but life would find a way to carry on without us. In fact, life on Earth has already endured five mass extinction events, in some cases killing 90 percent of all species. Tardigrades, however, are one of the few animals to have survived all of them, so to come up with an idea of the circumstances and likelihood of an event completely sterilizing all life on Earth, the Oxford and Harvard scientists looked at what it would take to wipe out these little go-getters. In short: the oceans will have to boil before life can be fully extinguished, and that's no easy feat. The researchers considered three astrophysical events that the universe could throw at us to achieve this: a large asteroid impact, a supernova or a gamma ray burst. A reasonably small space rock could wipe out land-based life, but according to the researchers, it would take something with the mass of Pluto before creatures in the Mariana Trench even noticed. Thankfully for all of us, nothing that big is zipping around anywhere near Earth – at least, as far as we know. In theory, a supernova meets all the criteria for bubbling the oceans right off the planet, but again, our planet's position in the galaxy saves us from that threat. The team calculated that for a supernova to blast the Earth with enough radiation to strip away the protective ozone layer, it would need to be less than 0.14 light-years away. But the nearest star, Proxima Centauri, is four light-years away and isn't big enough to go supernova anyway. Gamma ray bursts are the bigger, deadlier cousins of the supernova. It's thought that they occur when two neutron stars collide or when massive stars collapse into a black hole, and in doing so they unleash more energy into space than any other known phenomenon. As such, a burst could decimate Earth from a distance of 40 light-years, but again, we're pretty safe thanks to the fact that there aren't any candidates within that range. That leaves just one event that will no doubt boil the oceans right off the planet: the death of the Sun. Humanity's "best" efforts might leave the Earth uninhabitable by our fragile standards, but the tardigrade – and by extension, life itself – will likely continue to plod along for billions of years yet. By looking at the persistence of life in a wider, non-human-centric context, the researchers believe it paints a positive picture of the likelihood of life existing elsewhere in the universe, and thriving long enough for us to find it. "A lot of previous work has focused on 'doomsday' scenarios on Earth – astrophysical events like supernovae that could wipe out the human race," says David Sloan, co-author of the study. "Our study instead considered the hardiest species - the tardigrade. As we are now entering a stage of astronomy where we have seen exoplanets and are hoping to soon perform spectroscopy, looking for signatures of life, we should try to see just how fragile this hardiest life is. "To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected. Therefore it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on." The study was published in the journal Nature. Source: Oxford University

Stephen Hawking, like David Attenborough, believes earthlings are in for some tough times ahead. Hawking has said he thinks it’s “almost certain” that some kind of catastrophe like global warming or nuclear war will ravage earth within the next millennium, and thus, it’s “essential” that we start exploring our space colonization options. To that end, scientists have made some important discoveries concerning potentially habitable exoplanets and dwarf planets nearby, and now believe that some moons outside of the solar system might also be habitable. They believe that the now reassigned Kepler telescope will provide us with data about exomoons that may be conducive to life. A recent study by scientists from McMaster University and the University of Antioquia focuses on what makes these celestial bodies habitable. Heat and atmosphere are important factors, but they’re realizing that perhaps even more important than that is their magnetic fields. Temperature is an obvious factor, especially when it comes to liquid water. This relies on the relationship between a moon and the planet it orbits. Energy comes from the light and heat reflected by that planet, and in some cases, thermal emissions or extreme greenhouse effects can render a moon too hostile to live on. Io, Jupiter’s nearest moon, has an elliptical shape due to Jupiter’s gravity, and the resulting orbit produces friction that causes volcanoes. The position of a moon relative to its host planet is also crucial. Scientists have begun to examine the magnetic fields of planets, which over time impacts conditions on their satellites, especially given that most moons don’t have their own magnetic fields. A planet’s magnetosphere may extend huge distances, such as Jupiter’s, but their influence evolves over time, expanding with the decrease of stellar wind pressure. Researchers have attempted to determine how, how much, and over what period of time a planet’s magnetosphere will affect its moon(s), and are applying their mathematical models to potential future homes of the human race. They have concluded that when exomoons are far enough away from their host planets, more than 20 planetary radii, they essentially behave like planets orbiting a star. Light and heat from the host planet don’t affect them much, and they’ll never be within the influence of the host planet’s magnetosphere, which makes it unlikely that they’re candidates for life. Exomoons that are close to their host planets, fewer than 5 planetary radii, are likely to be absorbed into the planet’s magnetosphere fairly quickly. This decreases the chances for long-term colonization unlikely due to the light and heat from their proximity. Exomoons that are a moderate distance from their host planets, 5-20 planetary radii, might hold more promise. Depending on the planet’s size and characteristics, the magnetosphere would likely reach these exomoons in just over 4 billion years. Scientists believe that most exomoons fall within this range. We’re talking about a Goldilocks scenario here. An exomoon has to be firmly outside the habitable edge of a planet, but inside the planet’s magnetosphere. Researchers believe that by concentrating on the magnetic fields of planets, we might be able to narrow down the candidates for habitability. Stephen Hawking would approve.

In a random sky survey made in near-infrared light, Hubble found five tiny galaxies clustered together 13.1 billion light-years away. They are among the brightest galaxies at that epoch and very young -- existing just 600 million years after the big bang. The composite image taken in visible and near-infrared light, reveals the location of five tiny galaxies clustered together 13.1 billion light-years away. The circles pinpoint the galaxies. Credit: NASA, ESA, M. Trenti (University of Colorado, Boulder and Institute of Astronomy, University of Cambridge, U.K.), L. Bradley (Space Telescope Science Institute, Baltimore), and the BoRG team Galaxy clusters are the largest structures in the universe, comprising hundreds to thousands of galaxies bound together by gravity. The developing cluster, or protocluster, is seen as it looked 13 billion years ago. Presumably, it has grown into one of today's massive galactic cities, comparable to the nearby Virgo cluster of more than 2,000 galaxies. "These galaxies formed during the earliest stages of galaxy assembly, when galaxies had just started to cluster together," said Michele Trenti of the University of Colorado at Boulder and the Institute of Astronomy at the University of Cambridge in the United Kingdom. "The result confirms our theoretical understanding of the buildup of galaxy clusters. And, Hubble is just powerful enough to find the first examples of them at this distance." Trenti presented the results today at the American Astronomical Society meeting in Austin, Texas. The study will be published in an upcoming issue of The Astrophysical Journal. Most galaxies in the universe reside in groups and clusters, and astronomers have probed many mature galactic cities in detail as far as 11 billion light-years away. Finding clusters in the early phases of construction has been challenging because they are rare, dim and widely scattered across the sky. "We need to look in many different areas because the odds of finding something this rare are very small," said Trenti, who used Hubble's sharp-eyed Wide Field Camera 3 (WFC3) to pinpoint the cluster galaxies. "The search is hit and miss. Typically, a region has nothing, but if we hit the right spot, we can find multiple galaxies." Hubble’s observations demonstrate the progressive buildup of galaxies. They also provide further support for the hierarchical model of galaxy assembly, in which small objects accrete mass, or merge, to form bigger objects over a smooth and steady but dramatic process of collision and collection. Because the distant, fledgling clusters are so dim, the team hunted for the systems' brightest galaxies. These galaxies act as billboards, advertising cluster construction zones. From computer simulations, the astronomers expect galaxies at early epochs to be clustered together. Because brightness correlates with mass, the most luminous galaxies pinpoint the location of developing clusters. These powerful light beacons live in deep wells of dark matter, an invisible form of matter that makes up the underlying gravitational scaffolding for construction. The team expects many fainter galaxies that were not seen in these observations to inhabit the same neighborhood. The five bright galaxies spotted by Hubble are about one-half to one-tenth the size of our Milky Way, yet are comparable in brightness. The galaxies are bright and massive because they are being fed large amounts of gas through mergers with other galaxies. The team's simulations show that the galaxies eventually will merge and form the brightest central galaxy in the cluster, a giant elliptical similar to the Virgo Cluster's M87. The observations are part of the Brightest of Reionizing Galaxies survey, which uses Hubble's WFC3 to search for the brightest galaxies around 13 billion years ago, when light from the first stars burned off a fog of cold hydrogen in a process called reionization. The team estimated the distance to the newly found galaxies based on their colors, but the astronomers plan to follow up with spectroscopic observations, which measure the expansion of space. Those observations will help astronomers precisely calculate the cluster's distance and yield the velocities of the galaxies, which will show whether they are gravitationally bound to each other. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.Trent J. Perrotto Silicon 'neurons' may add a new dimension to computer processors 05.06.2020 | Washington University in St. Louis The broken mirror: Can parity violation in molecules finally be measured? 04.06.2020 | Johannes Gutenberg-Universität Mainz Humans rely dominantly on their eyesight. Losing vision means not being able to read, recognize faces or find objects. Macular degeneration is one of the major... In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria. Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding... An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links... Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem. Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain... In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications". Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very... 19.05.2020 | Event News 07.04.2020 | Event News 06.04.2020 | Event News 05.06.2020 | Life Sciences 05.06.2020 | Physics and Astronomy 05.06.2020 | Life Sciences

A comet recently spewed out a cluster of mini comets in ahuge outburst that was the largest ever witnessed by astronomers. A team of researchers began observing the comet17P/Holmes in October 2007, after it was reported that the object, about2.2 miles wide (3.6 km wide), had brightened by a million times in less than aday. UCLA researcher Rachel Stevenson and colleagues notedmultiple fragments flying rapidly away from the comet's nucleus. They continuedobserving for several weeks after the outburstusing the Canada-France-Hawaii Telescope in Hawaii and watched as the dustcloud ejected by the comet grew to be larger than the sun. The astronomers examined a sequence of images taken overnine nights using a digital filter that enhances small features. They foundnumerous tiny objects that moved away from the nucleus at speeds of up to 280mph (125 meters per second). These objects were too bright to simply be barerocks, but instead were more like mini comets, creating their own dust clouds asice on their surfaces sublimated directly to vapor. "Initially we thought this comet was unique simplybecause of the scale of the outburst," Stevenson said. "But we soonrealized that the aftermath of the outburst showed unusual features, such asthese fast-moving fragments, that have not been detected around other comets." Although the outburst was impressive in the telescopeimages, it wasn't visible to the naked eye. Scientists aren't sure of the exact cause of the outburst. Possibly,pressure inside the comet built up as it moved closer to the sun, untileventually part of the surface broke away, releasing a huge cloud of dust andgas, as well as larger fragments. Even after ejecting mini comets, the solid nucleus of cometHolmes survived and continued on its orbit, seemingly unperturbed. Holmes takes about 6 years to circle the sun, and travelsbetween the inner edge of the asteroid belt to beyond Jupiter. The comet is nowmoving away from the sun but will return to its closest approach in 2014, whenastronomers will examine it for signs of further outbursts. Stevenson will present the findings at the EuropeanPlanetary Science Congress in Potsdam, Germany on Wednesday. - The Greatest Comets of All Time - Video: Comets Through Time ... Myths and Mystery - Comet Image Gallery

The WISE (Wide-field Infrared Survey Explorer) mission isn’t wasting any time in making observations and releasing images. Already the new infrared observatory has spied its first comet and first near Earth asteroid, and today released a “sweet” collection of eye candy from across the universe. “We’ve got a candy store of images coming down from space,” said Edward (Ned) Wright of UCLA, the principal investigator for WISE. “Everyone has their favorite flavors, and we’ve got them all.” Four new, processed pictures illustrate a sampling of the mission’s targets — a bursting star-forming cloud, a faraway cluster of hundreds of galaxies, a wispy comet, and above, the grand Andromeda galaxy as we’ve never seen it before, with new details of its ringed arms of stars . Another image shows a bright and choppy star-forming region called NGC 3603, lying 20,000 light-years away in the Carina spiral arm of our Milky Way galaxy. This star-forming factory is churning out batches of new stars, some of which are monstrously massive and hotter than the sun. The hot stars warm the surrounding dust clouds, causing them to glow at infrared wavelengths. This image shows the beauty of a comet called Siding Spring. As the comet parades toward the sun, it sheds dust that glows in infrared light visible to WISE. The comet’s tail, which stretches about 10 million miles, looks like a streak of red paint. A bright star appears below it in blue. WISE is expected to find perhaps dozens of comets, and bagged its first one on January 22, 2010. WISE will help unravel clues locked inside comets about how our solar system came to be. The fourth WISE picture is of the Fornax cluster, a region of hundreds of galaxies all bound together into one family. These galaxies are 60 million light-years from Earth. The mission’s infrared views reveal both stagnant and active galaxies, providing a census of data on an entire galactic community. “All these pictures tell a story about our dusty origins and destiny,” said Peter Eisenhardt, the WISE project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “WISE sees dusty comets and rocky asteroids tracing the formation and evolution of our solar system. We can map thousands of forming and dying solar systems across our entire galaxy. We can see patterns of star formation across other galaxies, and waves of star-bursting galaxies in clusters millions of light years away.” Since WISE began its scan of the entire sky in infrared light on Jan. 14, the space telescope has beamed back more than a quarter of a million raw, infrared images. The mission will scan the sky one-and-a-half times by October. At that point, the frozen coolant needed to chill its instruments will be depleted. However, the team predicts the spacecraft will be still be operational for 3 additional months following the 10 month prime mission. So, stay tuned for more images from WISE!

Joseph Hooton Taylor, Jr. (born March 29, 1941) is an American astrophysicist and winner of the 1993 Nobel Prize in Physics, shared with his former student Russell Alan Hulse, for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation. Taylor was born in Philadelphia and educated at Haverford College (B.A. Physics 1963) and Harvard University (Ph.D. Astronomy 1968). After a brief research position at Harvard, Taylor went to the University of Massachusetts, eventually becoming Professor of Astronomy and Associate Director of the Five College Radio Astronomy Observatory. Taylor's thesis work was on lunar occultation measurements. About the time he completed his Ph.D., Jocelyn Bell discovered the first radio pulsars with a telescope near Cambridge, England. Taylor immediately went to the National Radio Astronomy Observatory's telescopes in Green Bank, West Virginia, and participated in the discovery of the first pulsars discovered outside Cambridge. Since then, he has worked on all aspects of pulsar astrophysics. In 1974, Hulse and Taylor discovered the first pulsar in a binary system, named PSR B1913+16 after its position in the sky, during a survey for pulsars at the Arecibo Observatory in Puerto Rico. Although it was not understood at the time, this was also the first of what are now called recycled pulsars: neutron stars that have been spun-up to fast spin rates by the transfer of mass onto their surfaces from a companion star. The orbit of this binary system is slowly shrinking as it loses energy because of emission of gravitational radiation. The predicted rate of shrinkage can be precisely predicted from Einstein's theory, and over a thirty-year period Taylor and his colleagues have made measurements that match this prediction to much better than 1% accuracy. There are now scores of binary pulsars known, and independent measurements have now confirmed Taylor's results. In 1980, he moved to Princeton University, where he is currently the James S. McDonnell Distinguished University Professor in Physics, having also served for six years as Dean of Faculty. Taylor has used this first binary pulsar to make high-precision tests of general relativity. Working with his colleague Joel Weisberg, Taylor has used observations of this pulsar to demonstrated the existence of gravitational radiation in the amount and with the properties first predicted by Albert Einstein. The Nobel Prize he and Hulse shared was the first ever given for work in General Relativity. In addition to the Nobel Prize, Taylor has been recognized with many other awards, including the first Heineman Prize of the American Astronomical Society, the Draper Medal of the National Academy of Sciences, the Tomalla Foundation Prize, the Magellanic Premium, the Carty Award for the Advancement of Science, the Einstein Prize, the Wolf Prize in Physics, and the Schwartzchild Medal. He was among the first group of MacArthur Fellows. He has served on many boards, committees, and panels, co-chairing the Decadal Panel of that produced the report Astronomy and Astrophysics in the New Millennium that established the United States's national priorities in astronomy and astrophysics for the period 2000-2010.

For the first time, astronomers have found two giant clusters of galaxies that are just about to collide. This observation can be seen as a missing 'piece of the puzzle' in our understanding of the formation of structure in the Universe, since large-scale structures--such as galaxies and clusters of galaxies--are thought to grow by collisions and mergers. The result was published in Nature Astronomy. Clusters of galaxies are the largest known bound objects and consist of hundreds of galaxies that each contain hundreds of billions of stars. Ever since the Big Bang, these objects have been growing by colliding and merging with each other. Due to their large size, with diameters of a few million light years, these collisions can take about a billion years to complete. After the dust has settled, the two colliding clusters will have merged into one bigger cluster. Because the merging process takes much longer than a human lifetime, we only see snapshots of the various stages of these collisions. The challenge is to find colliding clusters that are just at the stage of first touching each other. In theory, this stage has a relatively short duration and is therefore hard to find. It is like finding a raindrop that just touches the water surface in a photograph of a pond during a rain shower. Obviously, such a picture would show a lot of falling droplets and ripples on the water surface, but only few droplets in the process of merging with the pond.. Similarly, astronomers found a lot of single clusters and merged clusters with outgoing ripples indicating a past collision, but until now no two clusters that are just about to touch each other. An international team of astronomers have now announced the discovery of two clusters on the verge of colliding. This enabled astronomers to test their computer simulations, which show that in the first moments a shock wave is created in between the clusters and travels out perpendicular to the merging axis. "These clusters show the first clear evidence for this type of merger shock", says first author Liyi Gu from RIKEN national science institute in Japan and SRON Netherlands Institute for Space Research. "The shock created a hot belt region of 100-million-degree gas between the clusters, which is expected to extend up to, or even go beyond the boundary of the giant clusters. Therefore the observed shock has a huge impact on the evolution of galaxy clusters and large scale structures." Astronomers are planning to collect more 'snapshots' to ultimately build up a continuous model describing the evolution of cluster mergers. SRON-researcher Hiroki Akamatsu: "More merger clusters like this one will be found by eROSITA, an X-ray all-sky survey mission that will be launched this year. Two other upcoming X-ray missions, XRISM and Athena, will help us understand the role of these colossal merger shocks in the structure formation history." Liyi Gu and his collaborators studied the colliding pair during an observation campaign, carried out with three X-ray satellites (ESA's XMM-Newton satellite, the NASA's Chandra satellite, and JAXA's Suzaku satellite)and two radio telescopes (the Low-Frequency Array, a European project led by the Netherlands, and the Giant Metrewave Radio Telescope operated by National Centre for Radio Astrophysics of India).

Tonight, there will be a special astronomical event. The November “supermoon” is going to be especially close to Earth. This is going to offer an extraordinary sight. Regular skywatchers or those who simply want to see something special can look to the sky tonight. This full moon is special because it is going to be bigger and brighter than regular full moons. The Moon Will Be at Perigee Tonight A supermoon is a term that describes the full moon at its perigee. That means at the closest point to planet Earth during its lunar orbit. The orbit of the moon isn’t a perfect circle. The point where the moon is the farthest away from Earth is called the apogee. And when it is closest it’s called the perigee. This supermoon is going to be the most spectacular one that we have seen in almost 69 years. The next opportunity for the full moon to be this close to planet Earth is going to be on November 25, 2034. The lunar orbit is not a perfect circle for various reasons. Noah Petro is a deputy scientist at the Lunar Reconnaissance Orbiter mission at NASA. He explained why that is so. “The main reason why the orbit of the moon is not a perfect circle is that there are a lot of tidal, or gravitational, forces that are pulling on the moon,” says Noah Petro. He added that the orbit of the moon receives the impact from the gravity of Earth. But also receives an impact from the gravity of other planets from our solar system. So there are many gravitational forces that are pushing and pulling on the moon. This “gives us opportunities to have these close passes” and be able to take a closer look at the moon. Closest Supermoon in 69 Years The moon isn’t just going to be closer. Looking at the moon from Earth, even with the naked eye, it is going to appear larger in size. It is also going to shine brighter than on other night. Making an average, the moon orbits at a distance of 238,855 miles (384,400 km) from Earth. When the moon is at perigee it orbits closer. That makes appear 14 percent bigger and 30 percent brighter up in the sky. “We’re not talking about dramatic shifts in distance, but were talking about subtle differences that are noticeable if you’re used to looking at the moon,” says Noah Petro. Tonight’s supermoon is going to be approximately 221,524 miles (356,508 kilometers) from Earth. This is the closest full moon since January 26, 1948. Yet, it’s not the closest the moon has ever been since they started keeping records. That happened in January 1912. The supermoon is going to be at peak perigee during the morning of November 14 at 8:52 a.m. EST (1352 GMT). With the moon being this close to Earth, features on the surface of the moon can be observed. You can see things such as impact craters with the naked eye. It’s going to make for a fun night of moon gazing. Image source: here.

This news release from the Max Planck Institute describes evidence that supports the existence of gravitational waves, which at least one blogger here has insisted do not exist. Dr. Mona Clerico Max Planck Institute for Astrophysics and Max Planck Institute for extraterrestrial Physics Phone +49 89 30000-3980 Dr. Stefanie Komossa Max Planck Institute for extraterrestrial Physics Phone +49 89 30000-3577 Picture at http://www.mpe.mpg.de/news.html#1. Superkick: Black hole expelled from its parent galaxy Gravitational rocket propelled the monster at a speed of thousands of kilometres per second By an enormous burst of gravitational waves that accompanies the merger of two black holes the newly formed black hole was ejected from its galaxy. This extreme ejection event, which had been predicted by theorists, has now been observed in nature for the first time. The team led by Stefanie Komossa from the Max Planck Institute for extraterrestrial Physics (MPE) thereby opened a new window into observational astrophysics. The discovery will have far-reaching consequences for our understanding of galaxy formation and evolution in the early Universe, and also provides observational confirmation of a key prediction from the General Theory of Relativity (Astrophysical Journal Letters, May 10, 2008). When two black holes merge, waves of gravitational radiation ripple outward through the galaxy at the speed of light. Because the waves are emitted mainly in one direction, the black hole itself is pushed in the opposite direction, much like the recoil that accompanies the firing of a rifle or the launching of a rocket. The black hole is booted from its normal location in the nucleus of the galaxy. If the kick velocity is high enough, the black hole can escape the galaxy completely. The MPE team’s discovery verifies, for the first time, that these extreme events actually occur; up to now they had only been simulated in supercomputers. The recoiling black hole caught the astrophysicists’ attention by its high speed – 2650 km/s – which was measured via the broad emission lines of gas around the black hole. At this speed, one could travel from New York to Los Angeles in just under two seconds. Because of the tremendous power of the recoil the black hole, which has a mass of several 100 millions solar masses, was catapulted from the core of its parent galaxy. In addition to the emission lines from gas bound to the recoiling black hole, the astronomers were also struck by a remarkably narrow set of emission lines originating from gas left behind in the galaxy. This gas has been excited by radiation from the recoiling black hole. Gas that moves with the black hole – the so-called accretion disk gas – continues to “feed” the recoiling black hole for millions of years. In the process of being accreted, this gas shines in X-rays. In fact the team around Komossa also detected this X-ray emission from the disk around the black hole at a distance of 10 billion light years: by chance the region was scanned by the satellite ROSAT, and at the extreme end of the visual field an X-ray source was discovered the position of which corresponds with the distant galaxy. The new discovery is also important because it indirectly proves that black holes do in fact merge and that the mergers are sometimes accompanied by large kicks. This process had been postulated by theory, but never before confirmed via direct observation. Another implication of the discovery is that there must be galaxies without black holes in their nuclei – as well as black holes which float forever in space between the galaxies. This raises new questions for the scientists: Did galaxies and black holes form and evolve jointly in the early Universe? Or was there a population of galaxies which had been deprived of their central black holes? And if so, how was the evolution of these galaxies different from that of galaxies that retained their black holes? In a close interplay between theory and observation, the astrophysicists prepare to answer these questions. Various detectors on earth and in space, for example the space interferometer LISA, will be set on the track of gravitational waves. The discovery of the MPE team will provide new impetus for theorists to develop more detailed models of the superkicks and their consequences for the evolution of black holes and galaxies.

BOOMERanG Analysis Finds Flat Universe December 12, 1999 Newly released data from the 1997 North American test flight of BOOMERanG, which mapped anisotropies in the cosmic microwave background radiation (CMB) in a narrow strip of sky, show a pronounced peak in the CMB "power spectrum" at an angular scale of about one degree, strong evidence that the universe is flat. Analyzed at the Department of Energy's National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory, the new data also suggest the existence of a cosmological constant, a form of countergravitational "dark energy" thought to fill the universe. BOOMERanG stands for "balloon observations of millimetric extragalactic radiation and geophysics." The collaboration includes over two dozen researchers from seven countries; its principal investigators are Andrew Lange of the California Institute of Technology and Paolo de Bernardis of the University of Rome, "La Sapienza." Phillip Mauskopf of the University of Massachusetts is first author of a letter to Astrophysical Journal Letters announcing the measurement of the power-spectrum peak. In a second article, the BOOMERanG collaboration presents new, independent limits on the magnitude of any cosmological constant, a property of space that offsets gravitational attraction. Albert Einstein proposed the cosmological constant in 1917 but later retracted the idea. It was dramatically resurrected in 1998 when the international Supernova Cosmology Project based at Berkeley Lab, along with the High-Z Supernova Search Team centered in Australia, discovered that the expansion of the universe is not slowing down as it would be if gravity were not offset, but instead is speeding up. The BOOMERanG data were acquired in August, 1997, during a six-hour flight from National Aeronautics and Space Administration's National Scientific Balloon Facility in Palestine, Texas. The data were analyzed by NERSC's Julian Borrill, who worked closely with colleagues at the National Science Foundation's Center for Particle Astrophysics, located at the University of California at Berkeley, and at the Canadian Institute of Theoretical Astrophysics at the University of Toronto. Borrill notes that the BOOMERanG North America data set was so large — a partial map of the sky covering more than 200 square degrees and containing some 26,000 pixels — that a one-gigahertz serial processor would have required three months of continuous operation to extract the power spectrum, which is a measure of the structure of CMB anisotropies. By employing the parallel processing power of NERSC's "Mcurie" system (a Cray T3E supercomputer) and using the MADCAP software package he developed at NERSC, Borrill was able to shorten the running time to a matter of hours. MADCAP is short for the "microwave anisotropy dataset computational analysis package." Big as it is, Borrill says, the BOOMERanG North America data is only the first in a parade of data sets "of unprecedented quality and ever-increasing size." The MAXIMA 1 and MAXIMA 2 balloon flights have already produced substantially more data; their analysis is not complete. Late last year BOOMERanG LDB (for "long duration ballooning") completely circled the South Pole in ten and a half days, yielding a map of virtually the whole sky visible from the pole and a data set, whose analysis is still underway, that is more than 17 times as large as the test flight's. Satellites to be launched early next century will produce more data by orders of magnitude; the European Space Agency's PLANCK will map the sky in 10,000,000 pixels. "The memory required to process these CMB experiments increases as the square of the number of pixels, and the time increases as the cube," Borrill says. "Without new computers and new computational strategies, we won't be able to derive the detailed measurements of basic cosmological parameters the CMB experiments are designed to reveal." Borrill adds that "because of the power of our parallel machines and the depth of our experience with cosmic microwave background studies, NERSC is becoming the computing center of choice for analyzing CMB data from experiments all over the world. We want to maintain that status, but it will take hard work and fresh ideas."

When you look up at the night sky, all of the stars look the same. However, they actually come in different sizes and colours. The colour of the star depends on the temperature of the surface of the star. Despite what you may think, blue stars are much hotter than red stars! In fact, red stars are the coldest! The smallest red stars, which are called ‘red dwarfs’, are by far the most common type of star in our Milky Way Galaxy. Recently, using a big telescope, a team of astronomers has found that rocky planets that are not much bigger than Earth are very common around red dwarfs. Planets that are just a little bit bigger than ours are called ‘super-Earths’. The astronomers estimate that about 4 out of every 10 red dwarf stars in our Milky Way have super-Earths in orbit around them that are at the right distance from their stars to make it possible for liquid water to exist on the planets. (Too close to the star and the water would boil away, but it would freeze solid if the planet were too far from the heat of its star.) Since there are about 160 billion red dwarf stars in the Milky Way, this means that there may be tens of billions of worlds in our Galaxy that are not much bigger than the Earth and have oceans. This is an exciting discovery, as such planets could have alien life living on them! Our Sun is about 100 times wider than the Earth, but it is still a dwarf compared to other stars – a yellow dwarf, to be precise.

Black hole rethink after 11-year cosmic search fails to detect gravitational waves One hundred years since Einstein proposed gravitational waves as part of his general theory of relativity, an 11-year search performed with CSIRO’s Parkes telescope has shown that an expected background of waves is missing, casting doubt on our understanding of galaxies and black holes. A simulation of black holes merging. Illustration credit: © Michael Koppitz / Albert Einstein Institute. For scientists gravitational waves exert a powerful appeal, as it is believed they carry information allowing us to look back into the very beginnings of the universe. Although there is strong circumstantial evidence for their existence, they have not yet been directly detected. The work, led by Dr. Ryan Shannon (of CSIRO and the International Centre for Radio Astronomy Research), has just been published in the journal Science. Using Parkes, the scientists expected to detect a background ‘rumble’ of the waves, coming from the merging galaxies throughout the universe, but they weren’t there. The world-first research has caused scientists to think about the universe in a different way. Dr. Ryan Shannon (CSIRO and ICRAR). “In terms of gravitational waves it seems to be all quiet on the cosmic front. However by pushing our telescopes to the limits required for this sort of cosmic search we’re moving into new frontiers, forcing ourselves to understand how galaxies and black holes work,” Dr. Shannon said. The fact that gravitational waves weren’t detected goes against theoretical expectations and throws our current understanding of black holes into question. Galaxies grow by merging and every large one is thought to have a supermassive black hole at its heart. When two galaxies unite, the black holes are drawn together and form an orbiting pair. At this point, Einstein’s theory is expected to take hold, with the pair predicted to succumb to a death spiral, sending ripples known as gravitational waves through space-time, the very fabric of the universe. Although Einstein’s general theory of relativity has withstood every test thrown at it by scientists, directly detecting gravitational waves remain the one missing piece of the puzzle. Parkes Observatory, just outside the central-west New South Wales town of Parkes in Australia, hosts the 64-metre Parkes radio telescope, one of the telescopes comprising CSIRO’s Australia Telescope National Facility. To look for the waves, Dr. Shannon’s team used the Parkes telescope to monitor a set of ‘millisecond pulsars.’ These small stars produce highly regular trains of radio pulses and act like clocks in space. The scientists recorded the arrival times of the pulsar signals to an accuracy of ten billionths of a second. A gravitational wave passing between Earth and a millisecond pulsar squeezes and stretches space, changing the distance between them by about 10 metres — a tiny fraction of the pulsar’s distance from Earth. This changes, very slightly, the time that the pulsar’s signals arrive on Earth. The scientists studied their pulsars for 11 years, which should have been long enough to reveal gravitational waves. So why haven’t they been found? There could be a few reasons, but the scientists suspect it’s because black holes merge very fast, spending little time spiraling together and generating gravitational waves. “There could be gas surrounding the black holes that creates friction and carries away their energy, letting them come to the clinch quite quickly,” said team member Dr. Paul Lasky, a postdoctoral research fellow at Monash University. Whatever the explanation, it means that if astronomers want to detect gravitational waves by timing pulsars they’ll have to record them for many more years. “There might also be an advantage in going to a higher frequency,” said Dr. Lindley Lentati of the University of Cambridge, UK, a member of the research team who specializes in pulsar-timing techniques. Astronomers will also gain an advantage with the highly sensitive Square Kilometre Array telescope, set to start construction in 2018. Not finding gravitational waves through pulsar timing has no implications for ground-based gravitational wave detectors such as Advanced LIGO (the Laser Interferometer Gravitational-Wave Observatory), which began its own observations of the universe last week. “Ground-based detectors are looking for higher-frequency gravitational waves generated by other sources, such as coalescing neutron stars,” said Dr. Vikram Ravi, a member of the research team from Swinburne University (now at Caltech, in Pasadena, California).

A strange stellar pair nearly 7,000 light-years from Earth has provided physicists with a unique cosmic laboratory for studying the nature of gravity. The extremely strong gravity of a massive neutron star in orbit with a companion white dwarf star puts competing theories of gravity to a test more stringent than any available before. Once again, Albert Einstein’s General Theory of Relativity, published in 1915, comes out on top. At some point, however, scientists expect Einstein’s model to be invalid under extreme conditions. General Relativity, for example, is incompatible with quantum theory. Physicists hope to find an alternate description of gravity that would eliminate that incompatibility. A newly-discovered pulsar—a spinning neutron star with twice the mass of the Sun—and its white-dwarf companion, orbiting each other once every two and a half hours, has put gravitational theories to the most extreme test yet. Observations of the system, dubbed PSR J0348+0432, produced results consistent with the predictions of General Relativity. The tightly-orbiting pair was discovered with the National Science Foundation’s Green Bank Telescope (GBT), and subsequently studied in visible light with the Apache Point telescope in New Mexico, the Very Large Telescope in Chile, and the William Herschel Telescope in the Canary Islands. Extensive radio observations with the Arecibo telescope in Puerto Rico and the Effelsberg telescope in Germany yielded vital data on subtle changes in the pair’s orbit.

Do you remember what we talked about in the Article Thermal Control in Space? In this article we made a general introduction to thermal control, applied not only in space but in several fields. However, now we go a little step forward by describing the main heat sources that affect a spacecraft during its mission in the solar system. External heat sources are those that come from outside the considered system. In this case, we define the spacecraft as our system, so external sources are those caused by the environment. As you may know, neither conduction or convection take place in space. Conduction only happens within the spacecraft, as there is little matter in deep space, so no energy can be transferred through matter. Regarding convection, a flow is necessary for it to happen, which is not the case in deep space. Finally, only radiation remains, which is heat moving as energy waves. Hence, it is the only way to transfer heat in space. There are three main types of radiation: direct solar, albedo and planetary flux. However, other significant forms of environmental heating are, for instance, free molecular heating and charged-particle heating. Is it not clear? Let`s explore them in more detail. The Sun is the main energy source in the Solar System. As it is very hot, it emits a lot of radiation. Hence, it is directly responsible of the direct solar radiation and indirectly responsible for albedo. However, some questions arise: is it a constant effect, or does it depend on some parameters? As you may have guessed, intensity values through the Solar System depend on the distance from the Sun. Right! Different bodies receive light of an intensity inversely proportional to the square distance from this star, which is a conclusion of conservation of energy. Perihelion and apohelion Intensity variation with distance Moreover, you need to know that a very important parameter is the solar constant, defined as the intensity of sunlight at Earth’s mean distance from the Sun (1AU). Despite the fact that the Sun has activity cycles of 11 years duration the direct solar radiation is very stable, remaining almost constant. However, as the sunlight intensity varies with the distance from the Sun, the solar flux is maximum at the passage of the perihelion and minimum at the passage of the aphelion. This is caused by the elliptical orbit of our planet around the Sun. Nowadays, the intensity of sunlight has a maximum at winter solstice (1414 W/m2) while in summer solstice it presents a minimum (1322 W/m2) (See Figure below). Do you remember what happens in summer when we use black clothes? Much better to use white clothes right? No doubts about that. Albedo of planetary bodies refers to the same concept: how moons, planets or asteroids surfaces reflect sunlight from the Sun. Hence it is defined as the ratio between radiation reflected to total incident radiation. Zero stands for no reflection at all, (our black clothes) while one would be a white surface. Albedo is highly variable, depending on several factors such as the type of surface (continental regions or oceanic regions, ice, snow..) or the weather (clouds). For instance, if the orbit of the spacecraft goes over the terminator (the terminator is the moving line that separates the illuminated day side and the dark night side of a planetary body), the albedo heat load will approach zero, no matter what value of reflectivity it has, due to the fact that no reflection will take place (sunlight beams will be parallel to the planet surface). However, in the subsolar point, where the surface is perpendicular to the Sun’s rays, the heat load will be maximum. This phenomenon is shown in the Figure placed below. Incidence of solar beams on Earth surface Do you imagine a hot ball? All bodies at a temperature greater than 0K emit heat radiation. In the Solar System, the Sun is the primary source of energy, and it is responsible of the incident sunlight that heats the Earth. Hence, our planet will also become a heated ball and this heat will be emitted as radiation. This is the basic idea behind planetary radiation. Earth IRR radiation Free molecular heating At the beginning of this article I said: ”No convection in space!”. And it is true, but I would like to make some comments about a form of convection that may affect spacecraft in the outer part of the atmosphere. This type of environmental heating is caused by the bombardment of the spacecraft by individual molecules. This is the reason why this phenomenon only occurs when the spacecraft is placed in the outer part of the atmosphere, at the end of the launching phase, after the booster’s payload fairing is ejected or during reentry. All incident sunlight not reflected as albedo is absorbed by the moon or planet radiated by the Sun’s rays. Moreover, other aspects as the internal energy generated by the planet contribute to increase its total amount of energy. Eventually, this energy, known as planetary radiation or longwave radiation, is returned to space emitted by the planet. It is characterized by its variability, so its value changes a lot due to several factors, such as local temperature of the planet’s surface or the cloud cover. For instance, desert and tropical regions emit more longwave radiation than the colder ones. Meanwhile, radiation decreases with latitude, as it can be observed in the figure. In space there are two types of radiation: ionizing and non-ionizing radiation. The first one has enough energy to remove electrons from the orbits of atoms resulting in charged particles. The interaction with these charged particles heats up the spacecraft. In other words, the interaction with charged particles that are caused by ionizing radiation causes the spacecraft to heat up. Nevertheless, it is weaker than the previous heating sources being significant just in cryogenic temperatures where sensitive systems may be affected by these heat loads. For example, in the Van Allen belts regions there are several trapped charged particles, which can modify the temperature of the satellite. The last point is internal sources, which are related to the heat generated inside the spacecraft during its operation. As neither convection nor conduction take place in space, the heat generated by electronic components, batteries and other elements has a great impact on the spacecraft’s temperatures. This is because heat cannot be dissipated so easily as just radiation plays a major role in space. Hence, different devices are used to evacuate this heat. After this article introducing heat sources in space, we will talk about different strategies used to manage temperatures, so be patient and stay in touch! - IDEAS (Innovative Datasets for Environmental Analysis by Students). Solar Intensity. [Online]. 2015. url: http://www.geog.ucsb.edu/ideas/Insolation.html#intensity (visited on 12/03/2016). - North and South poles. Important climate differences. [Online]. 2015. url: https://wattsupwiththat.com/2015/02/13/north-and-south-poles-important-climate-differences/ (visited on 25/04/2016). - Exploring Biomes. Insolation and Angle of Incidence. [Online]. 2015. url: https://akbiomes.wordpress.com/2015/01/08/insolation-and-angle-of-incidence/ (visited on 12/03/2016). - Wikipedia. Black-body radiation. [Online]. 2015. url: https://en.wikipedia.org/wiki/Black-body_radiation (visited on 12/03/2016). - David G. Gilmore, Spacecraft Thermal Control handbook. 2nd ed. Vol. I: Fundamental Technologies. The Aerosapace Press, 2002. 837 pp. - José Meseguer and Isabel Pérez-Grande and Ángel Sanz-Andrés, Spacecraft Thermal Control. NASA, What is space radiation? http://srag-nt.jsc.nasa.gov/spaceradiation/what/what.cfm (visited on 25/03/2016).

So this may be an incorrect assumption, but from my knowledge solar systems are heliocentric and there are always suns. (I realize to be a solar system there must be a sun semantically.) But it seems to me that planets and stars are just bodies of mass, so are there cases of solar systems where the star is just one of the bodies of the system and orbits around a super massive planet? And similarly are there 'solar systems' without stars, where there are a group of planets orbiting a massive planet at the center of the system? Generally, astronomical bodies rotate around their common center of mass, not the one or the other body. If one of the bodies is much heavier, the center of mass is much nearer to its center, sometimes even inside the larger body. For example, Earth and Sun both rotate around a point that is much nearer to the Sun's center than to the Earth's center, as the sun is much heavier. Looking from the outside, it seems as Earth rotates around the Sun, while the Sun just wobbles a bit in sync. But the reason for that is exclusively the masses of the bodies, not their being-a-star or not-being-a-star. Your theoretical example of a super-heavy planet and a lighter star would result in the star seemingly rotating around the planet; however, here you need to look at why a star is a star: Stars are created by gravity that is compressing the mass to a level that starts fusion, and thereby a star. In your example, either the 'light star' wouldn't make it into a star (and be a light body/planet), or the 'super-heavy planet' becoming a much brighter star (or both of it). That reverses the roles effectively. Looking at it this way, the bodies in a system rotate always around the center of the mass, which is near the largest mass, which will be the first star of the system (if any). So your first constellation is not possible. The second is well possible - if neither of the bodies has enough mass to become a star, they will be still rotating around each other the same way, with the heaviest body being nearest the center. Such a system would be dark and basically invisible from some distance. We wouldn't be able to find them. From my knowledge solar systems are heliocentric and there are always suns. (I realize to be a solar system there must be a sun semantically.) Just a semantic note, systems of stars and planets different from our own are referred to as stellar systems. The solar system refers specifically to our own stellar system since solar means "of or relating to our own Sun". To remark on this point though, yes this is (somewhat) true. All stellar systems are heliocentric in that all bodies orbit the central star (or stars) of that system. What is technically more true is that all systems are barycentric, in that all bodies (including the star) orbit the common center of mass, known as the barycenter. It just so happens that the star tends to have $>99\%$ of the mass of any stellar system and so the barycenter is very very close to the center of the star. Our own Sun does actually have a measurable orbit around this barycenter. Where it gets really interesting is when you have a stellar system with more than one star. In this case, the barycenter is no longer near the center of any particular star and so you have noticeable orbits of the stars. But it seems to me that planets and stars are just bodies of mass, so are there cases of solar systems where the star is just one of the bodies of the system and orbits around a super massive planet? As stated above, all bodies orbit the barycenter. The location of the barycenter depends on the masses of all the bodies in the system and will be closest to the most massive body. Think of the barycenter as a weighted mean of the positions of all the bodies, where the weight is the respective body's mass (because that's exactly what it is). That's just how the math works out. It is impossible then for the objects in a stellar system to orbit a less massive body as the barycenter could never be closest to that body. And similarly are there 'solar systems' without stars, where there are a group of planets orbiting a massive planet at the center of the system? The only possible case would be a system which doesn't technically have a star. It is quite possible that a system might try to form but just not have enough matter to get very big. The central object would try to become a star, but might not actually be big enough to start shining. We call these objects brown dwarfs. There are almost assuredly systems which have no official stars and the central body is a brown dwarf that every other body in the system orbits around. Whether you want to consider this brown dwarf a "massive planet" is a bit hazy.

March 30, 2020 In an Electric Universe, galaxies evolve because large-scale plasma discharges form Birkeland currents. To those familiar with ideas like electricity in space, the cosmos appears to be interlaced with electric circuits made up of energized filaments at every scale. At the largest scale, there are electromagnetic loads in the circuits converting electrical energy into rotational energy. They are known as galaxies. Why stars in galaxies tend to coalesce in long arcs like bright beads on a line is one of a hundred mysteries that conventional cosmology must confront. No gravity-only hypothesis can resolve the issue of star formation, in general, but what is seen within the barred spirals and elliptical whirlpools that congregate in million-light-year clusters continues to elude explanation. Filaments expand and explode, throwing off plasma that can accelerate to near light-speed. Jets from opposite poles of a galaxy end in energetic clouds emitting X-ray frequencies. These phenomena owe their explanations to plasma science and not gas kinetics, gravity, or particle physics. Astrophysicists see electromagnetic fields but since they do not see the underlying electricity, they are at a loss. Astronomers maintain that galaxies are clouds of hydrogen gas and intergalactic dust that are assembled by gravity until they coalesce into glowing thermonuclear fires. They also believe that most galaxies contain black holes of unbelievable magnitude. It is those protean gravity gods that supposedly cause galaxies to spin, jets of gamma and X-rays to appear, and “radio lobes” sometimes larger than the parent galaxy to form. Electricity requires charged particles to move. Something not considered when researchers attempt to explain structure in the Universe is that for charged particles to move, they must move in a circuit. Energetic events cannot be explained by local conditions, alone. The effects of an entire circuit must be considered. For that reason, while the consensus scientific worldview only permits isolated “islands” in space, the Electric Universe emphasizes connectivity with an electrically active network of “transmission lines” composed of the aforementioned Birkeland current filaments. In plasma, electrons are stripped from atomic nuclei, since electron orbital dynamics can be overcome by thermionic and other energy sources. When regions in plasma develop excess charge electric discharges can take place, forming magnetic sheaths along the axes of discharge. If there is enough charge flow, the sheaths will glow; sometimes forming other sheaths. Those regions of isolated charge, or “cells”, are known as double layers. Double layers induce intense electric fields, which accelerate charged particles. When electric charge spirals in an electromagnetic field, X-rays, extreme ultraviolet, and sometimes gamma rays are detected. Those electromagnetic forces create filaments that tend to attract each other in pairs. Electric fields that form along plasma strands can generate an attractive force orders of magnitude greater than gravity. Although, due to their isolated sheathes, instead of merging, Birkeland currents twist into helices that rotate faster as they become more tightly compressed. To repeat: plasma physics fits observations and behaviors better than kinetics or gravity. As previously written, plasma is not a substance, it is an emergent phenomenon, so it can not be analyzed in terms of its component parts, it arises in response to complicated interactions. The filaments of electric charge that move in closed circuits through plasmas can attract matter to them over vast distances. Double layers might glow in visible or infrared light. However, plasma might also initiate dark discharges. Perhaps those are the filamentary “dark lanes” seen by astronomers. The Milky Way galaxy shares characteristics with the rest of its galactic family. Its halo of stars, its filamentary structures, lobes of radiation, its microwave haze, and other observed phenomena point to the Milky Way’s electrical nature. The Thunderbolts Picture of the Day is generously supported by the Mainwaring Archive Foundation.

The first ever infrared analysis of the atmosphere of Neptune’s moon Triton revealed the presence carbon monoxide and methane. As summer hit the moon’s southern hemisphere, observations made at the Very Large Telescope (VLT) based at the European Southern Observatory (ESO) showed the thin atmosphere to vary with seasons. “We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly,” says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics. On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton’s southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton’s surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune’s 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000. Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton’s atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon. Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton’s upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper “film” that feeds the atmosphere. While the majority of Triton’s atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by Voyager 2, and only now confirmed in this study from Earth, plays an important role as well. Of Neptune’s 13 moons, Triton is by far the largest, and, at 2700 kilometers in diameter (or three quarters the Earth’s Moon), is the seventh largest moon in the whole Solar System. Since its discovery in 1846, Triton has fascinated astronomers thanks to its geologic activity, the many different types of surface ices, such as frozen nitrogen as well as water and dry ice (frozen carbon dioxide), and its unique retrograde motion. Observing the atmosphere of Triton, which is roughly 30 times further from the Sun than Earth, is not easy. In the 1980s, astronomers theorised that the atmosphere on Neptune’s moon might be as thick as that of Mars (7 millibars). It wasn’t until Voyager 2 passed the planet in 1989 that the atmosphere of nitrogen and methane, at an actual pressure of 14 microbars, 70 000 times less dense than the atmosphere on Earth, was measured. Since then, ground-based observations have been limited. Observations of stellar occultations (a phenomenon that occurs when a Solar System body passes in front of a star and blocks its light) indicated that Triton’s surface pressure was increasing in the 1990′s. It took the development of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES) at the Very Large Telescope (VLT) to provide the team the chance to perform a far more detailed study of Triton’s atmosphere.

Stars are enormous balls of hot gas located many trillions of miles away, but when they're observed from the Earth, they appear as tiny shining dots visible in the night sky. In a new study, astronomers made a precise measurement of the mass of a nearby "white dwarf," a star that has reached the end of its life cycle. But how, exactly, can that be done? How do scientists "weigh" the mass of a gaseous sphere light-years away? "Just about the only way we have as astronomers for measuring masses of stars and planets and galaxies is by their gravitational influence on one another," said Terry Oswalt, a professor of engineering physics at Embry-Riddle Aeronautical University, who wrote a commentary about the recent white-dwarf measurement for the journal Science. In other words, if a satellite is in orbit around Jupiter, it's possible to estimate Jupiter's mass by measuring the effects of the planet's gravity on the satellite's orbit. [The 18 Biggest Unsolved Mysteries in Physics] Such estimates can be done with stars as well. Sensitive instruments, such as NASA's Kepler space telescope, can detect planets orbiting stars on the other side of the Milky Way by measuring tiny changes in the velocity of the stars as the planets "tug" on them in their orbits, Oswalt explained. These measurements can also provide researchers with information about the stars' masses. When two stars orbit each other, as is the case of binary stars, astronomers can measure their motion using the so-called Doppler effect, which relies on the same principle as a police radar gun, according to Oswalt. However, this technique requires the objects to be observable. "There are several indirect ways you can estimate a star's mass from its [light] spectrum, but they depend upon a detailed model of its atmosphere, which you never know for sure is correct," Oswalt said. The new technique, described in a study published online June 7 in the journal Science, allows astronomers to assess the masses of stars and other celestial objects, including the inherently dim white dwarfs, black holes and rogue planets (worlds that have been flung from their solar system), all of which are difficult to observe with telescopes. The study, led by astronomers at the Space Telescope Science Institute in Baltimore, demonstrated how the researchers measured a nearby white dwarf called Stein 2051 B. The technique relies on the influence that gravity exerts on light. "In his famous equation E =mc^2, Albert Einstein postulated that energy and mass are the same thing," Oswalt said. "Light is a tiny bit of energy and an even tinier equivalent of mass, but it also is affected by gravity." [8 Ways You Can See Einstein's Theory of Relativity in Real Life] Einstein also predicted that a ray of light from a distant star passing by an object would bend slightly as a result of the gravitational pull of that object. For the effect to be observable, the two objects have to come into a near-perfect alignment, which, Oswalt said, is quite rare. "As the light from the background star passes by the white dwarf, its direction of a straight line is bent, and that means that the light that we will see seems to be coming from a different direction than the actual star, and that makes the dwarf slowly move across the background star as if the background star made a little loop in the sky," Oswalt explained. "The basic idea is that the apparent deflection of the background star's position is directly related to the mass and gravity of the white dwarf — and how close the two came to exactly lining up," Oswalt added. The effect, called gravitational microlensing, was previously observed on a much greater scale during total eclipses or involving objects much farther away than Stein 2051 B. In these distant objects, gravity acts as a magnifying lens that bends the starlight and, as a result, brightens the light's source, according to Oswalt.In the case of very distant galaxies, an effect known as the Einstein ring — a deformation of the light due to gravity — could be observed. Observations of the near alignments, such as the one that enabled scientists to measure the bending of light caused by the nearby Stein 2051 B white dwarf, are currently rare. But Oswalt said new observatories, such as the European Space Agency's Gaia satellite, will allow astronomers to observe such events much more frequently and thus allow them to map those objects in the universe that have so far been difficult to study. Original article on Live Science.

The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of F-Lf (Hz) (4 2) 10(3) 5.3 1.7 10(4) F-part (Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on Mm in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998. (C) 2000 COSPAR. Published by Elsevier Science Ltd. |Titolo:||Study of cosmic rays and light flashes on board Space Station MIR: The SilEye experiment| |Data di pubblicazione:||2000| |Appare nelle tipologie:||1.1 Articolo in rivista|

There's chaos in the night sky, about 60 to 600 miles above Earth's surface. Called the ionosphere, this layer of Earth's atmosphere is blasted by solar radiation that breaks down the bonds of ions. Free electrons and heavy ions are left behind, constantly colliding. This dance was previously measured through a method called incoherent scatter radar in the northern hemisphere, where researchers beam radio wave into the ionosphere. The electrons in the atmosphere scatter the radio wave "incoherently". The different ways they scatter tell researchers about the particles populating the layer. Now, researchers have used radar in Antarctica to make the first measurements from the Antarctic region. They published their preliminary results on September 17, 2019 in the Journal of Atmospheric and Oceanic Technology. "Incoherent scatter radar is currently the most powerful tool available to investigate the ionosphere because it covers a wide altitudinal range and it observes essential ionospheric parameters such as electron density, ion velocity, ion and electron temperatures, as well as ion compositions," said Taishi Hashimoto, assistant professor at the National Institute of Polar Research in Japan. While these radars are powerful, they're also rare due to their size and power demand. Using the Program of the Antarctic Syowa Mesosphere-Stratosphere-Troposphere/Incoherent Scatter (PANSY) radar, the largest and fine-resolution atmospheric radar in the Antarctic, researchers performed the first incoherent scatter radar observations in the southern hemisphere in 2015. They also made the first 24-hour observation in 2017. While analyzing these observations, Hashimoto and the team expected to see significant differences between the southern measurements and the northern measurements, as Earth's lower atmosphere has a strong asymmetry between hemispheres. "Clearly, observations in the southern hemisphere are crucial to revealing global features of both the atmosphere and the ionosphere," Hashimoto said. It's not as simple as taking the measurements, however. Consider the radar as a pebble skipped across a pond's surface. The researchers want to learn how the pebble vertically displaces the water as it skips and eventually sinks. They aren't interested in the concentric ripples created at each skip, but they're so similar that it's difficult to discern which measurements are the ones needed. These ripples are known as field-aligned irregularities, and Hashimoto's team applied a computer program that can recognize the different signals and suppresses the irregularities that could obscure the data. "Our next step will be the simultaneous observation of ionosphere incoherent scatter and field-aligned irregularities, since the suppression and extraction are using the same principle from different aspects," Hashimoto said. "We are also planning to apply the same technique to obtain other types of plasma parameters, such as the drive velocity and ion temperature, leading to a better understanding of auroras." Other authors include Akinori Saito of the Division of Earth and Planetary Sciences at Kyoto University, Koji Nishimura and Masaki Tsutsumi of the National Institute of Polar Research, Kaoru Sato of the Department of Earth and Planetary Science at the University of Tokyo and Toru Sato of the Department of Communications and Computer Engineering at Kyoto University. About National Institute of Polar Research (NIPR) The NIPR engages in comprehensive research via observation stations in Arctic and Antarctica. As a member of the Research Organization of Information and Systems (ROIS), the NIPR provides researchers throughout Japan with infrastructure support for Arctic and Antarctic observations, plans and implements Japan's Antarctic observation projects, and conducts Arctic researches of various scientific fields such as the atmosphere, ice sheets, the ecosystem, the upper atmosphere, the aurora and the Earth's magnetic field. In addition to the research projects, the NIPR also organizes the Japanese Antarctic Research Expedition and manages samples and data obtained during such expeditions and projects. As a core institution in researches of the polar regions, the NIPR also offers graduate students with a global perspective on originality through its doctoral program. For more information about the NIPR, please visit: https:/ About the Research Organization of Information and Systems (ROIS) ROIS is a parent organization of four national institutes (National Institute of Polar Research, National Institute of Informatics, the Institute of Statistical Mathematics and National Institute of Genetics) and the Joint Support-Center for Data Science Research. It is ROIS's mission to promote integrated, cutting-edge research that goes beyond the barriers of these institutions, in addition to facilitating their research activities, as members of inter-university research institutes.

Space Rock Families (06:22) Collisional families are groups of objects that are similar in size, shape, and tilt as they orbit the sun. A massive object in the Kuiper Belt collides and breaks into fragmented pieces that become members of the same collisional family. Comets: Icy Rocks with Tails (04:38) Objects in the Kuiper Belt are occasionally kicked out of orbit, sent to drift into the inner solar system. These icy rocks become comets with tails of ice and dust. Pieces of the comet Shoemaker-Levy 9 crashed into Jupiter, leaving impact scars. Late Heavy Bombardment Period (02:12) From the beginning, collisions have been a fact of life in the universe. Earth's moon reveals the volatility of the Late Heavy Bombardment period in Earth's history. Refuge for Space Rocks (02:24) In the outer solar system the Kuiper belt is the final resting place for rocks left over from the Late Heavy Bombardment period. In the inner solar system, they collectively orbit in the asteroid belt. Impact Event and Extinction of Dinosaurs (03:45) Scientists are confident that a large fragment from a cosmic collision struck Earth 65 million years ago, leading to the extinction of dinosaurs. The dust cloud would have cut off the sun for years. Geological evidence proves the impact theory. Meteor Crater (03:33) Nearly 50,000 years ago, a 150-foot asteroid struck Earth, leaving a giant, bowl-shaped crater. Fragments contain large amounts of iridium, usually rare in Earth rocks. The Chicxulub impact crater is buried beneath 3000 feet of limestone. Cataclysmic Collision with Earth (04:49) A new study claims an ancient collision between two mega-asteroids spawned the killer rock that slammed into Earth and marked the beginning of the end for the dinosaurs. Scientists believe the rock came from the Baptistina asteroid family. Earth's Biggest Extinction Event (03:39) During the Permian-Triassic extinction or "the Great Dying," Earth was composed of Pangaea, a super-continent, and Panthalassa, the ocean. A seven-mile-wide rock collided with Earth and wiped out most life forms 250 million years ago. Scientific Study of Permian-Triassic Extinction (02:56) A team of scientists uncovers evidence that suggests an asteroid caused the Permian-Triassic extinction. They have uncovered a possible impact crater and claim to have samples of asteroid material from the collision with Earth. Volcanism and Extinction (02:19) Earth was undergoing severe volcanism 250 million years ago that was choking the atmosphere. Volcanism alone might not explain the mass extinction; it was probably helped along by an asteroid collision. Cosmic Upheaval (03:07) When galaxies get too close to one another, galactic crashes occur. NASA's Spitzer Space Telescope observes 4 super-massive galaxies colliding. The Milky Way will eventually merge with Andromeda galaxy. Star Collisions (02:56) Stellar collisions are rare because such enormous spaces exist between stars. When two stars collide, the new star is called a "blue straggler." Cosmic collisions will continue to occur as long as the universe exists. Credits: Cosmic Collisions (00:23) Credits: Cosmic Collisions For additional digital leasing and purchase options contact a media consultant at 800-257-5126 (press option 3) or [email protected].

In astronomy, a deep field is an image of a portion of the sky taken with a very long exposure time, in order to detect and study faint objects. The depth of the field refers to the apparent magnitude or the flux of the faintest objects that can be detected in the image. Deep field observations usually cover a small angular area on the sky, because of the large amounts of telescope time required to reach faint flux limits. Deep fields are used primarily to study galaxy evolution and the cosmic evolution of active galactic nuclei, and to detect faint objects at high redshift. Numerous ground-based and space-based observatories have taken deep-field observations at wavelengths spanning radio to X-rays, and the first deep-field image to receive a great deal of public attention was the Hubble Deep Field, observed in 1995 with the WFPC2 camera on the Hubble Space Telescope. Other space telescopes that have obtained deep-field observations include the Chandra X-ray Observatory, the XMM-Newton Observatory, and the Spitzer Space Telescope.

It’s been about three months since that infamous meteor broke up over Chelyabinsk, Russia. In that time, there’s been a lot of conversation about how we can better protect ourselves against these space rocks with a potentially fatal (from humanity’s perspective) gravitational attraction to Earth. This week, the European Space Agency officially inaugurated a “NEO Coordination Centre” that is intended to be asteroid warning central in the European Union. It will be the hub for early warnings on near-Earth objects (hence the ‘NEO’ in the name) under ESA’s space situational awareness program. ESA estimates that of the 600,000 asteroids and comets that orbit the Sun, about 10,000 of them are NEOs. (They define NEOs as asteroids or comets with sizes of several feet up to several tens of miles.) NASA, of course, is also gravely concerned about the threat NEOs present. Its administrator, Charles Bolden, talked about this at a Congressional hearing about asteroids in March. Before delving into the threat, Bolden took a metaphorical deep breath to talk about the dozens of asteroids — a meter or larger — that slam into Earth’s atmosphere each year. Most of them burn up harmlessly, and further, 80 tons of dust-like material rain on Earth daily. A notable meteor that did cause some damage took place about 100 years ago, in 1908, when an object broke up over an isolated area in Russia and flattened trees for miles. Bolden characterized that as a statistically one-in-a-thousand year event, but added that the “real catch” is this type of event could happen at any time. NASA, however, is seeking out those that cause a threat. It is supposed to find 90 per cent of asteroids 140 meters or larger by 2020, and is making progress towards that goal. (By comparison, the Chelyabinsk object was estimated at 17 to 20 meters.) So how to best monitor the threat? Bolden outlined a few ideas: crowdsourcing, coordinating with other federal agencies and making use of automatic feeds from different telescopes throughout the world (as NASA does right now.) Bolden emphasized that none of the asteroids we have found is on a collision course with the Earth. Still, NASA and other science experts are not complacent. In the same hearing, John Holdren — the president’s assistant on science and technology — recommended following a National Academy of Sciences report to spend upwards of $100 million a year on asteroid detection and characterization. To mitigate the threat, Holdren further recommended a visit to an asteroid by 2025, which would perhaps cost $2 billion.

Where is the interface between the cosmos and planet Earth? Everywhere. Watching birds fly across the shiny coin of the Harvest Moon last night was but one example. Every September anyone with a telescope magnifying 30x and up who happens to look at the full moon can’t help but notice the occasional silhouettes of migrating birds fluttering across the moon’s face. Many birds migrate at night both to conserve energy and avoid predators. Identifying the many warblers, blackbirds, sparrows, vireos, orioles and other species that fly across the moon while we sleep may be next to impossible, but seeing them is easy. Just for fun, I counted the birds in the five-minute interval between 10:57 and 11:02 p.m. last night while looking at the moon at 76x through my 10-inch telescope. The total came to 16, which multiplied by 12 yielded an hourly count of 192 birds. As you might suspect, most of those birds crossed the moon from north to south (about two-thirds) with the other third traveling either east to west or northeast to southwest. Only one little silhouette flapped back up north in the ‘wrong’ direction. Who knows. Maybe it veered off course to pursue a nighttime snack. According to the Chipper Woods Bird Observatory, located in Indianapolis, most nighttime migrators begin their flight right after sunset and and continue until about 2 a.m. Peak time is between 11 p.m. and and 1 a.m. Bird typically migrate at altitudes ranging from 1,500 to 5,000 feet, but on some nights, altitudes may range from 6,000 and 9,000 feet. I could tell the high ones from the low ones by their size and sharpness. Nearby birds flew by out of focus, while distant ones were very sharply defined and took longer to cross the moon. Watching birds pass across the moon is a very pleasant activity and reminiscent of meteor shower watching. At first you see nothing, then blip! a bird (meteor) flies by. You wait another minute and then suddenly two more appear in tandem. Both activities give you that delicious sense of anticipation of what the next moment might hold. The best time to watch the nighttime avian exodus is around full moon, when the big, round disk offers an ideal spotlight on the birds’ behavior. It’s a fine sight to see one of Earth’s creatures streak across an alien landscape, and another instance of how a distant celestial body “touches” Earth in unexpected ways. If you’d like to learn more about birdwatching by moonlight, check out the Chipper Woods webpage.

The MAGIC and CTA telescopes enable scientists to study gamma radiation in the universe. Gamma rays have the highest energy of the whole electromagnetic spectrum. They are produced along with the cosmic radiation that constantly strikes the Earth's atmosphere - and scientists have been trying to elucidate their origin for over 100 years. Gamma rays can be used to study very high energy objects in the universe. These include the remnants of supernova explosions as well as star-forming regions, pulsars and binary systems and other types of gamma ray sources in our galaxy. The telescopes also observe other galaxies, especially those with active supermassive black holes at their centers. Scientists from the Max Planck Institute for Physics are involved with both observatories. MAGIC is a twin telescope on the Canary Island of La Palma, while CTA is a major telescope array currently being built on La Palma and in Chile. In the year 1912, the scientist Victor Hess discovered that Earth is continually bombarded by subatomic particles from space. These particles, consisting mainly of protons, are known as cosmic rays. The source of cosmic rays remains obscure because galactic magnetic fields conceal the direction they come from. Gamma rays are generated at the same locations as cosmic rays, and since they have no electrical charge, they are not deflected by the magnetic fields and so maintain their crucial directional information. In this way, gamma rays lay a trail to the sources of cosmic radiation. Essentially, gamma radiation is simply light, but with a much higher frequency and far greater energy per photon than visible light. Telescopes cannot observe gamma rays directly, because the rays react with the molecules of Earth's atmosphere. This gives rise to showers of secondary particles, called air showers. Many of the secondary particles in air showers move faster than light in a transparent dielectric medium. This may sound surprising at first, but since the speed of light in air is a little lower than in a vacuum, it does not violate any law of physics. In 1934, Russian physicist Pavel Cherenkov proved that particles that move faster than light in air generate a kind of optical shock wave - a bluish glow known as Cherenkov light. These flashes are not visible to the human eye, as they are too short (only a few thousandths of a second) and too weak (compared to the brightness of the night sky). They can, however, be detected by gamma telescopes, as these are equipped with large reflectors that capture each and every particle of light. In addition, the imaging cameras on the telescopes have thousands of extremely sensitive and ultra-fast light sensors that can provide snapshots of the air showers in Cherenkov light, intergrated for only several nanoseconds. But that is not all. A further trick involves using a number of telescopes so that a great many images of the same gamma ray air shower are captured from different angles. This provides a very high level of accuracy when calculating the arrival direction. © 2019 Max Planck Institute for Physics, Munich

After a 9 month journey, NASA’s Mars Science Laboratory (MSL) rover has successfully landed on Gale Crater, Mars as of 5:32 UTC. “The Seven Minutes of Terror has turned into the Seven Minutes of Triumph,” said NASA Associate Administrator for Science John Grunsfeld, referring to the novel and risky landing system that had everyone on tenterhooks through those final moments. “The landing takes us past the most hazardous moments for this project, and begins a new and exciting mission to pursue its scientific objectives,” said MSL’s project manager Peter Theisinger. The successful landing of Curiosity marks the beginning of its Mars exploration mission, which aims to determine the habitability of Mars, both past and present. The spacecraft has already collected data on space radiation throughout it 8 month cruise to Mars, during which it was hit by five solar flares. This data will help scientists and engineers further their understanding of the effects of space radiation, and it is fundamental to the design of any future manned missions to Mars. The landing also validated NASA’s bold soft landing technique, where a jetpack – called Sky Crane – is used to slow the probe down from the more than 300 km/h it is travelling at once it releases it parachute, to a little over 2 km/h. At this point, the rover is lowered from the Sky Crane, from a height of more than 7 meters, using three nylon bridles, while an umbilical cord provides communication with the rover. Once Curiosity is safely on the ground, the bridles are cut and the umbilical is disconnected, and the Sky Crane flies away, crash-landing at a safe distance. This new approach to landing became necessary, as the ones used with previous missions – retrorockets (Viking, Phoenix) and airbags (Pathfinder, Mars Exploration Rovers) – were not feasible due to MSL’s mass and design: “With a payload this size, the rockets could kick up enough dust to compromise the rover and its instruments, and the rockets could excavate craters Curiosity would have to avoid as it drives away. Add to that the risk of a big, heavy vehicle driving down off the lander via an exit ramp to reach the surface.” said Steve Sell, Deputy Operations Lead for Entry, Descent, and Landing at the Jet Propulsion Laboratory. “Bags big enough to soften its landing would be too heavy or too costly to launch. Besides, you’d have to drop the payload so slowly for the bags to survive the load, you may as well place the rover right on its wheels.” The new landing technique also represents a significant improvement on landing precision: the landing ellipse for MSL was 20 by 7 km, whereas the ones for the Mars Exploration Rovers were 150 by 20 km. MSL was launched from Cape Canaveral on November 26, 2011, atop an Atlas V rocket. With its cruise to Mars complete, final preparations for entry, descent and landing (EDL) began on July 28, when the spacecraft performed its fourth and final trajectory correction maneuver. On July 31, the flight team configured the spacecraft for EDL by enabling the autonomous software that guided Curiosity. Meanwhile, Mars orbiting spacecraft such as NASA’s Mars Odyssey and Mars Reconnaissance Orbiter, as well as ESA’s Mars Express, prepared to track MSL’s arrival and relay its data back to Earth. The probe reached the top of Mars’ atmosphere at 5:25, and its wheels touched the ground at around 5:32 (UTC). The landing was described as on the good side of nominal, with error coming in lower than expected and well within provided margins. JPL engineers are still processing the streams of data, so more details should be available soon. Curiosity has already transmitted its first images back to Earth, with the first photograph of its own shadow already taking on iconic status. Over the following days, Curiosity’s flight team will deploy the probe’s instruments, and send images and videos back to Earth – among these will be the ones taken by MARDI, picturing the probe’s daring descent and landing on the red planet. And with its mast deployed, it can start to take its first 360 degree panorama of its landing site. Curiosity will then begin its exploration of Gale Crater and the flanks of Aeolis Mons, planned to last for one Mars year (approximately two Earth years). As Curiosity put it in its twitter feed: “To the entire team & fans back on Earth, thank you, thank you. Now the adventure begins. Let’s dare mighty things together!” Watch with Mission Control as word of Curiosity’s landing arrives:

eso1144 — Science Release Lutetia: a Rare Survivor from the Birth of the Earth 11 November 2011 New observations indicate that the asteroid Lutetia is a leftover fragment of the same original material that formed the Earth, Venus and Mercury. Astronomers have combined data from ESA’s Rosetta spacecraft, ESO’s New Technology Telescope, and NASA telescopes. They found that the properties of the asteroid closely match those of a rare kind of meteorites found on Earth and thought to have formed in the inner parts of the Solar System. Lutetia must, at some point, have moved out to its current location in the main asteroid belt between Mars and Jupiter. A team of astronomers from French and North American universities have studied the unusual asteroid Lutetia in detail at a very wide range of wavelengths to deduce its composition. Data from the OSIRIS camera on ESA’s Rosetta spacecraft , ESO’s New Technology Telescope (NTT) at the La Silla Observatory in Chile, and NASA’s Infrared Telescope Facility in Hawaii and Spitzer Space Telescope were combined to create the most complete spectrum of an asteroid ever assembled . This spectrum of Lutetia was then compared with that of meteorites found on Earth that have been extensively studied in the laboratory. Only one type of meteorite — enstatite chondrites— was found to have properties that matched Lutetia over the full range of colours. Enstatite chondrites are known to be material that dates from the early Solar System. They are thought to have formed close to the young Sun and to have been a major building block in the formation of the rocky planets , in particular the Earth, Venus and Mercury . Lutetia seems to have originated not in the main belt of asteroids, where it is now, but much closer to the Sun. “But how did Lutetia escape from the inner Solar System and reach the main asteroid belt?” asks Pierre Vernazza (ESO), the lead author of the paper. Astronomers have estimated that less than 2% of the bodies located in the region where Earth formed, ended up in the main asteroid belt. Most of the bodies of the inner Solar System disappeared after a few million years as they were incorporated into the young planets that were forming. However, some of the largest, with diameters of about 100 kilometres or more, were ejected to safer orbits further from the Sun. Lutetia, which is about 100 kilometres across, may have been tossed out from the inner parts of the young Solar System if it passed close to one of the rocky planets and thus had its orbit dramatically altered . An encounter with the young Jupiter during its migration to its current orbit could also account for the huge change in Lutetia’s orbit . “We think that such an ejection must have happened to Lutetia. It ended up as an interloper in the main asteroid belt and it has been preserved there for four billion years,” continues Pierre Vernazza. Earlier studies of its colour and surface properties showed that Lutetia is a very unusual and rather mysterious member of the asteroid main belt. Previous surveys have shown that similar asteroids are very rare and represent less than 1% of the asteroid population of the main belt. The new findings explain why Lutetia is different — it is a very rare survivor of the original material that formed the rocky planets. “Lutetia seems to be the largest, and one of the very few, remnants of such material in the main asteroid belt. For this reason, asteroids like Lutetia represent ideal targets for future sample return missions. We could then study in detail the origin of the rocky planets, including our Earth,” concludes Pierre Vernazza. The electromagnetic spectrum represents the complete range of wavelengths covered by the different types of electromagnetic radiation. Visible light is the most familiar form, but many others exist. Many of these types of radiation are used in everyday life, such as radio waves, microwaves, infrared and ultraviolet light and X-rays. Rosetta’s OSIRIS camera provided data in the ultraviolet, ESO’s NTT provided data in visible light, while NASA’s Infrared Telescope Facility in Hawaii and Spitzer Space Telescope provided data in the near-infrared and mid-infrared respectively. The enstatite chondrites (E chondrites) are a unique class of meteorites that account for only about 2% of the recovered meteorite falls. The unusual mineralogy and chemistry of E chondrites is consistent with formation relatively close to the Sun. This is further supported by isotope measurements (verified for oxygen, nitrogen, ruthenium, chromium and titanium): E chondrites are the only groups of chondrites that have the same isotopic composition as the Earth and Moon system. This strongly suggests that the Earth formed from enstatite chondrite-type materials and also that E chondrites formed at about the same distance from the Sun as the Earth. In addition it has been recently shown that formation from enstatite chondrite bodies can explain Mercury's unusual and previously inexplicable composition. This suggests that Mercury — like the Earth — largely accreted from enstatite chondrite-like materials. Some astronomers think that the gaseous giant may have been closer to the Sun in the early days of the Solar System, before moving outwards to its current position. This would have caused havoc in the orbits of other objects of the inner Solar System due to the huge gravitational pull of Jupiter. This research was presented in a paper, “Asteroid (21) Lutetia as a remnant of Earth’s precursor planetesimals”, to appear in the journal Icarus. The team is composed of P. Vernazza (Laboratoire d’Astrophysique de Marseille (LAM), France; European Southern Observatory, Germany), P. Lamy (LAM, France), O. Groussin (LAM, France), T. Hiroi (Department of Geological Sciences, Brown University, USA), L. Jorda(LAM, France), P.L. King (Institute for Meteoritics, University of New Mexico, USA), M.R.M. Izawa (Department of Earth Sciences, University of Western Ontario, Canada), F. Marchis (Carl Sagan Center at the SETI Institute, USA; IMCCE, Observatoire de Paris (OBSPM), France), M. Birlan (IMCCE, OBSPM, France), R. Brunetto (Institut d'Astrophysique Spatiale, CNRS, France). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”. Garching bei München,, Germany Laboratoire d'Astrophysique de Marseille, Directeur de Recherche Tel: +33 49 105 5932 ESO, La Silla, Paranal, E-ELT & Survey Telescopes Press Officer Garching bei München, Germany Tel: +49 89 3200 6655 Cell: +49 151 1537 3591

(Inside Science) -- It may the biggest and oldest question in science: Are we alone in the universe? If the answer is no, a second question arises: Who else is out there? Such questions have motivated a decades-long search for radio and light signals from intelligent beings on other planets. In a recent paper, Duncan Forgan, an astronomer at the University of St. Andrews in Scotland, analyzed how likely we are to intercept light beams sent between advanced civilizations in our galaxy. The short answer is: not very likely. But, Forgan argues, alien civilizations may choose to send their signals in a way that makes them easier for a third party to spot. If so, astronomers can still increase their chances of detecting intelligent life by designing searches to intercept such communications. Despite the recent discoveries of thousands of exoplanets orbiting far-off stars, nobody knows whether or how many other technological civilizations exist in the galaxy. But if any do, they may be far more advanced than we are. In that case they will probably have built telescopes powerful enough to detect life on other planets in the galaxy, and lasers powerful enough to send messages to them. We, by contrast, are still at least decades away from being able to announce our presence in such an obvious way. Although electromagnetic waves from radio and television broadcasts have been leaking into space for almost a century, such undirected signals rapidly weaken and are unlikely to be detectable beyond a few stars in our immediate neighborhood. Even so, a more advanced civilization could have, in the past two billion years, detected chemical evidence of life in Earth's atmosphere and aimed a laser at the planet, essentially to say "hello." Human astronomers are also beginning to analyze light that has passed through exoplanet atmospheres for such signatures of life. But even a signature that indicates life would not necessarily imply that the life is intelligent. So far, the optical search for extraterrestrial intelligence has focused mainly on the hope of receiving—and recognizing—an intentional, laser-encoded message. Researchers use dedicated telescopes or mine astronomical data collected for other purposes, like the Sloan Digital Sky Survey, to search for light pulses that could not be produced by any known object like a star. So far, no one has reported a light pattern that suggests an extraterrestrial intelligence. But rather than look for light beamed directly at us, astronomers could also try to intercept signals sent between two distant civilizations. If advanced beings have existed for millions of years, they may well have found each other and started talking. Eventually many light beams would penetrate the intergalactic darkness, creating a criss-crossing network of communication beacons. As our solar system revolves around the galactic center, could we meander into the path of one of these beams? In the new study, published October 27 on arXiv.org, on which papers are posted without formal peer review, Forgan sought to answer this question. He created a simulation in which technological civilizations were spread randomly throughout the part of the Milky Way known as the galactic habitable zone. While astronomers debate the exact dimensions of this zone, most agree it resembles a flattened doughnut around the galactic center with an outer radius large enough to encompass the sun's position at around 26,000 light-years from the center. Forgan also assumed that beings advanced enough to announce their presence would actually want to do so. Each civilization in Forgan's simulation communicated with one other civilization by sending out a laser beam. He ran the simulation multiple times, varying the number of civilizations and the angle through which their communication beams spread out as they traveled. In each run, Forgan calculated the probability that a random star like our sun would move into the path of one of the beams during a 4.5-billion year period. Unsurprisingly, he found that the chance of intercepting another civilization's messages increased as more civilizations joined the communications network. He also found that the interception probability increased dramatically as the angle through which the beams spread out increased. But the probability of accidentally wandering through a beam remained small as long as the beams were narrow, or collimated, like a typical laser. The beams would have to spread out about 1,000 times more widely than a standard laser pointer—in other words, more like a flashlight beam—before we have a decent chance of intercepting them, Forgan says. Sending out such a wide beam would require far more energy than emitting a tightly collimated one. Still, he says, it's worth designing optical extraterrestrial intelligence searches to look for weakly collimated signals. An advanced civilization with enough resources could design its beam to spread, increasing the chance a recipient will wander into it. Doing so would still require much less energy than sending out light or another type of electromagnetic radiation in every direction, and could give advanced civilizations the opportunity to stumble upon still-developing ones like us. "This gives you quite a nice compromise," says Forgan. "It gives you a wider range of civilizations you can hit." Forgan's analysis is "valuable," said astronomer Seth Shostak of the SETI Institute in Mountain View, California. "I'm glad he did it." With his mathematical model, Forgan has turned the possibility of intercepting extraterrestrial communication "from a hand-waving argument into a real simulation," Shostak added. While the results were similar to what most scientists in the field probably suspected, Shostak said the analysis "will make [researchers'] conversations a little bit more sober, because they have to count on aliens making a deliberate aim on our direction, it seems."

Perhaps the greatest and most fiercely contested race in modern science is the search for dark matter. Physicists cannot see this stuff, hence the name. However, they infer its existence because they can see its gravitational influence on the structure of galaxies and clusters of galaxies. It implies that the universe is filled with dark matter, much more of it than the visible matter we can see If they’re right, dark matter must fill our galaxy and our Solar System. At this very instant, we ought to be ploughing our way through a dense sea of dark matter as the Sun moves towards the constellation of Cygnus as it orbits the galactic centre. That’s why various groups are racing to detect this stuff using expensive detectors in deep underground caverns, which shield them from radiation that would otherwise swamp the signal. These experiments are looking for the unique signature that dark matter is thought to produce as a result of the Earth’s passage around the Sun. During one half of the year, the dark matter forms headwind as the Earth ploughs into it; for the other half of the year, it forms a tailwind. Indeed, a couple of groups claim to have found exactly this diurnal signature, although the results are highly controversial and seem to be in direct conflict with other groups who say they have not seen it. There’s a a straightforward way to make better observations that should solve this conundrum. The dark matter signal should vary, not just over the course of a year, but throughout the day as the Earth rotates. The dark matter headwind should be coming from the direction of Cygnus, so a suitable detector should see the direction change as the Earth rotates each day. There’s a problem, however: nobody has built a directional dark matter detector. That’s why a revolutionary new idea from an unlikely collaboration of physicists and biologists looks rather exciting. The group brings together diverse people, such as Katherine Freese at the University of Michigan in Ann Arbor, an astrophysicist and one of the leading thinkers in the area of dark matter, and George Church at Harvard University in Cambridge, a geneticist and a pioneer in the area of genome sequencing. These guys say they can overcome the problems with conventional dark matter detection by using DNA to spot dark matter particles. Their detector is unconventional, to say the least. Its basic detecting unit consists of a thin gold sheet with many strands of single-strand DNA hanging from it, like bead curtains or a hanging forest. Each strand of DNA is identical except for a label at the free hanging end, which identifies where on the gold sheet it sits. The idea is that a dark matter particle smashes into a heavy gold nucleus in the sheet, sending it careering out of the gold foil and through the DNA forest. The gold nucleus then severs DNA strands as it travels, cutting a swathe through the forest. These strands fall onto a collecting tray below, which is removed every hour or so. The segments can then be copied many times using a polymerase chain reaction, thereby amplifying the signal a billion times over. Since the sequence and location of each strand is known, it is straightforward to work out where it was cut, which allows the passage of the gold particle to be reconstructed with nanometre precision. The entire detector consists of hundreds or thousands of these sheets sandwiched between mylar sheets, like pages in a book. In total, a detector the size of a tea chest would require about a kilogram of gold and about 100 grams of single-strand DNA. The advantage of this design is manifold. First, the DNA sequence determines the vertical position of the cut to within the size of a nucleotide. That kind of nanometre resolution is many orders of magnitude better than is possible today. Second, this detector works at room temperature, unlike other designs which have to be cooled to measure the energy that dark matter collisions produce. And finally, the mylar sheets make the detector directional. Each sheet should absorb the gold nucleus of this energy after it has passed through the DNA forest. Any higher energy nuclei, from background radiation or cosmic rays for example, should pass through several ‘pages’, which allows them to be spotted and excluded. With the device facing in one direction, a dark matter particle strikes a gold nucleus, propelling it into the DNA forest. But in the other, the gold nucleus is propelled into mylar sheet where it is absorbed. That’s what makes it directional–the detector should only record events coming from one direction. This should allow the device to spot the change in dark matter signal each day, which in turn should make the detection much less statistically demanding. That’s a fascinating idea that’s likely to generate much interest. However, it’s not without some challenges of its own. First up, nobody really knowns how rapidly-moving, highly-ionised gold nuclei will interact with single strands of DNA or indeed with forests of them. This is something the team plans to study in some detail before a detector can be built. Then there is the challenge of making DNA strands that are long enough to present a reasonable ‘forest’ for gold nuclei to pass through. Church, Freese and co say they’d like strands consisting of 10,000 bases to create a forest that entirely absorbs the energy of a gold nucleus passing through it. By contrast, off-the shelf arrays offer DNA strands with only 250 bases or so. These guys say they’ll probably have to settle for strands of about 1000 bases. The DNA strands also have to hang straight down, rather than curled up. That’s a tall order over the area of a square metre or so that the detector will cover. At this scale, electric and magnetic fields trump gravity and these are likely to be a nuisance, particularly when it comes to collecting the severed DNA. So the team will have to devise some kind DNA ‘comb’ that straightens the hair. One idea is attaching a tiny magnet to the free end of each strand, allowing it to be pulled downward. The DNA strands will also have to be made from carbon-12 and 13, since carbon-14 is naturally radioactive and would otherwise produce an unwanted hiss of background noise. Using only very old carbon, in which all the carbon-14 has decayed, should do the trick. Finally, there is the significant engineering challenge in making metre square DNA arrays, collecting trays that catch the severed DNA strands and fitting them altogether into a working detector. There are more than a few unknowns in this approach which makes it high risk. But there is also high potential pay off because other designs for directional dark matter detectors are huge, complex and potentially vastly more expensive to build and run. That makes this approach exciting. The discoverers of dark matter are a shoe-in for a Nobel prize. Given these stakes, we might see some investment in this idea sooner rather than later. But there are also reasons to be cautious. A small but vocal minority of physicists say dark matter doesn’t exist, that other ideas better explain the structure of galaxies. If they’re right, we’ll one day look back on these efforts in the same way we think about the search for phlogiston or the debate about the spontaneous emergence of lower life forms: as a mildly amusing cul de sac of 21st century physics. Ref: arxiv.org/abs/1206.6809: New Dark Matter Detectors using DNA for Nanometer Tracking

A supernova is the colossal explosion that marks the end stages of the life of a giant star. Cosmologists use Type Ia supernovae as cosmic distance markers given the extreme uniformity of their light curves. Supernovae have been fundamental to discovering and studying the properties of dark energy. Members of the CosmoStat team have developed novel techniques for detecting these events. Supernovae are not only extremely luminous objects but they are also transient events, which makes their detection possible by looking for brightness variations on the sky. The CosmoStat team have exploited a technique known as Morphological Component Analysis to detect Type Ia supernovae with very few false detections in simulated data. This is exciting as improving the quality of a sample of supernovae detections can lead to improved constraints on cosmological parameters.

It may look like an out of focus picture of a luminous glazed donut, but it is actually the first successfully obtained image of a black hole, larger than our own solar system. The sound you’re about to hear after what I say next is the collective groaning despair of astronomers: How do we understand this astrologically? I ask because surely we can’t ascribe astrological planetary characteristics to another astronomical event/celestial body. Instead, a black hole would have to have its own astrological nature just as the Sun, Moon and planets do. I don’t claim to know exactly what it would or should be like, but I do think there is a way to understand the topic of black holes in some sort of astrological context. The Milky Way galaxy has a supermassive black hole at its center, as scientists suspect most galaxies do. From our perspective, our local black hole is located at the longitudinal degree of 26 Sagittarius. Interestingly, it seems our understanding of these bodies is tied to transits that approach this degree. Karl Schwarzschild was the first to solve Einstein’s field equations with exact answers, which essentially describe properties of a black hole. He did this while he was fighting in World War I! He sent a letter to Einstein describing his solutions on December 22nd 1915. He concluded the letter by saying “As you see, the war treated me kindly enough, in spite of the heavy gunfire, to allow me to get away from it all and take this walk in the land of your ideas.” Karl Schwarzschild was born with Mars at 27 Sagittarius, and the transiting Sun that day was at 29 Sagittarius, mere days after an exterior Sun-Mercury conjunction at 26 Sagittarius, in the vicinity of our own galaxy’s black hole. And while that could be dismissed as kind of a cute coincidence, it continues. David Finkelstein made the next breakthrough in black hole physics by identifying the Schwarzschild radius as the event horizon of what they called a “dark star”. David Finkelstein was born on July 19th 1929, when Saturn was at 25 Sagittarius. He published his first paper on black holes on May 15th 1958 at his Saturn Return, just 1 longitudinal degree from our own galaxy’s black hole. Carl Sagan re-popularized black holes with his phenomenally popular “Cosmos” PBS show, which premiered on September 28th 1980, when Neptune was at 20 Sagittarius, inching its way towards the longitudinal degree of our own galaxy’s black hole. A few years later in 1988, Stephen Hawking published his book “A Brief History Of Time” which again re-popularized exotic astronomical phenomena such as black holes. In this year, Saturn and Uranus were located between 24 Sagittarius-1 Capricorn, crossing over the longitudinal degree of our own galaxy’s black hole. So what do we make of this current news that we have achieved the first successful image of a black hole? Well the Event Horizon Telescope which captured this image was not just one telescope, but a global array of telescopes specifically designed to produce an image of a black hole. This project began on an unknown date in 2006, a year when Pluto was located between 24-26 Sagittarius, right in the vicinity of our own galaxy’s black hole. And now that the image has actually been released today on April 10th 2019, we see that Jupiter is at 24 Sagittarius, just 2 longitudinal degrees from our own galaxy’s black hole. So I think a good case can be made for the importance of our own local black hole at 26 Sagittarius for the topic of black holes in general. So if you see someone trying to link this news to the Saturn-Pluto conjunction or something, maybe send them this!

Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii (R⊕) range from low-density sub-Neptunes containing volatile elements1 to higher-density rocky planets with Earth-like2 or iron-rich3 (Mercury-like) compositions. Such astonishing diversity in observed small exoplanet compositions may be the product of different initial conditions of the planet-formation process or different evolutionary paths that altered the planetary properties after formation4. Planet evolution may be especially affected by either photoevaporative mass loss induced by high stellar X-ray and extreme ultraviolet (XUV) flux5 or giant impacts6. Although there is some evidence for the former7,8, there are no unambiguous findings so far about the occurrence of giant impacts in an exoplanet system. Here, we characterize the two innermost planets of the compact and near-resonant system Kepler-107 (ref. 9). We show that they have nearly identical radii (about 1.5-1.6R⊕), but the outer planet Kepler-107 c is more than twice as dense (about 12.6 g cm-3) as the innermost Kepler-107 b (about 5.3 g cm-3). In consequence, Kepler-107 c must have a larger iron core fraction than Kepler-107 b. This imbalance cannot be explained by the stellar XUV irradiation, which would conversely make the more-irradiated and less-massive planet Kepler-107 b denser than Kepler-107 c. Instead, the dissimilar densities are consistent with a giant impact event on Kepler-107 c that would have stripped off part of its silicate mantle. This hypothesis is supported by theoretical predictions from collisional mantle stripping10, which match the mass and radius of Kepler-107 c. - Pub Date: - February 2019 - Astrophysics - Earth and Planetary Astrophysics; - Astrophysics - Solar and Stellar Astrophysics - Published in Nature Astronomy on 4 February 2019, 35 pages including Supplementary Information material

A star already known to host five alien planets may actually be home to a whopping nine full-fledged worlds - a planetary arrangement that, if confirmed, would outnumber our own solar system and set a new record for the most populated system of extrasolar planets yet found. The sun-like star, called HD 10180, is located approximately 127 light-years away from Earth. In a previous study that was published in August 2010, astronomers identified five confirmed alien worlds and two planetary candidates. Now a new study confirms both previous candidates in the HD 10180 system, and also suggests that two more planets could be orbiting the star. This could bring the tally up to nine planets, said lead author Mikko Tuomi, an astronomer at the University of Hertfordshire in the U.K. Our solar system, by comparison, has eight official planets (with Mercury closest to the sun and Neptune at the farthest end). Pluto and several other smaller objects are considered dwarf planets, not full-blown worlds. "The data indicates that there are not only seven but likely as many as nine planets in the system," Tuomi told SPACE.com in an email interview. "The two new planets appear to have orbital periods of roughly 10 and 68 days and masses of 1.9 and 5.1 times that of Earth, which enables the classification of them as hot super-Earths, i.e. planets with likely scorchingly hot rocky surfaces." Tuomi re-analyzed observations collected between November 2003 and June 2010 by the planet-hunting HARPS spectrograph instrument, which is mounted on a 3.6-meter telescope at the European Southern Observatory in La Silla, Chile. [Infographic: Planets Large and Small Populate Our Galaxy] Since the newly detected candidates are still unconfirmed, more research is needed to determine if they are bona fide planets, and not erroneous signals. "While the existence of the larger of these two is well supported by the data, the signal corresponding to the smaller one exceeds the detection threshold only barely, which gives it a very small but non-eligible probability of being a false positive," Tuomi said. Since the planets in the HD 10180 system are too distant to be directly observed, astronomers use HARPS to monitor the gravitational pulls that the planets exert on their host star. The five previously confirmed planets are relatively large and orbit the parent star at intervals that range from just six days to 600 days. The two newly confirmed planets are also super-Earths, with one that orbits tightly around HD 10180, while the other has an orbit that swings beyond the others. Observations of the masses of the new planetary candidates and their distances from the star indicate that they likely have orbital periods of approximately 10 and 68 days. They are likely both rocky planets with surfaces hotter than that of Mercury, Tuomi added. But even if they are confirmed as actual planets, neither are located in a circumstellar region known as the habitable zone, where conditions could be suitable for liquid water to exist on a planet's surface. "They are certainly not in the habitable zone and likely have no prospects for hosting life," Tuomi said. "However, one of the Neptune-sized planets in the system with an orbital period of 600 days is actually in the middle of the habitable zone, which makes it an interesting target when the better detection methods enable us to observe moons orbiting exoplanets in the future." As instruments and observatories become more sophisticated, and as astronomers hone planet-hunting techniques, densely populated systems similar to HD 10180 and our own solar system could be discovered in greater numbers. "This certainly tells our methods are sufficient for detecting richly populated planetary systems," Tuomi said. "Just how common they are, we do not know based on only two examples. My guess would be that they are very common, though, because they are very hard to detect and we already have one when the precision of our instruments enables the detection of these systems only barely." The finding also suggests that similar planetary systems could be more common throughout the universe than was previously thought. "Scientifically this would not be of much significance because it has been suspected for a long time that such populous planetary systems exist in the universe," Tuomi said. "Philosophically, though, it shows that our very own solar system is not special in this respect either — systems with great numbers of planets are very likely common throughout the universe and it is only a matter of time when we find even richer systems." The study has been accepted for publication in the journal Astronomy and Astrophysics.

A feature resembling a candy cane appears at the center of this colorful composite image of our Milky Way galaxy's central zone. But this is no cosmic confection. It spans 190 light-years and is one of a set of long, thin strands of ionized gas called filaments that emit radio waves. This image includes newly published observations using an instrument designed and built at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Called the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO), the instrument was used in concert with a 30-meter radio telescope located on Pico Veleta, Spain, operated by the Institute for Radio Astronomy in the Millimeter Range headquartered in Grenoble, France. The central zone of our galaxy hosts the Milky Way's largest, densest collection of giant molecular clouds, raw material for making tens of millions of stars. This image combines archival infrared (blue), radio (red) and new microwave observations (green) from the Goddard-developed GISMO instrument. The composite image reveals emission from cold dust, areas of vigorous star formation, and filaments formed at the edges of a bubble blown by some powerful event at the galaxy's center. The image is about 750 light-years wide. Credit: NASA's Goddard Space Flight Center This image of the inner galaxy color codes different types of emission sources by merging microwave data (green) mapped by the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) instrument with infrared (850 micrometers, blue) and radio observations (19.5 centimeters, red). Where star formation is in its infancy, cold dust shows blue and cyan, such as in the Sagittarius B2 molecular cloud complex. Yellow reveals more well-developed star factories, as in the Sagittarius B1 cloud. Red and orange show where high-energy electrons interact with magnetic fields, such as in the Radio Arc and Sagittarius A features. An area called the Sickle may supply the particles responsible for setting the Radio Arc aglow. Within the bright source Sagittarius A lies the Milky Way's monster black hole. The image spans a distance of 750 light-years. Credit: NASA's Goddard Space Flight Center "GISMO observes microwaves with a wavelength of 2 millimeters, allowing us to explore the galaxy in the transition zone between infrared light and longer radio wavelengths," said Johannes Staguhn, an astronomer at Johns Hopkins University in Baltimore who leads the GISMO team at Goddard. "Each of these portions of the spectrum is dominated by different types of emission, and GISMO shows us how they link together." GISMO detected the most prominent radio filament in the galactic center, known as the Radio Arc, which forms the straight part of the cosmic candy cane. This is the shortest wavelength at which these curious structures have been observed. Scientists say the filaments delineate the edges of a large bubble produced by some energetic event at the galactic center, located within the bright region known as Sagittarius A about 27,000 light-years away from us. Additional red arcs in the image reveal other filaments. "It was a real surprise to see the Radio Arc in the GISMO data," said Richard Arendt, a team member at the University of Maryland, Baltimore County and Goddard. "Its emission comes from high-speed electrons spiraling in a magnetic field, a process called synchrotron emission. Another feature GISMO sees, called the Sickle, is associated with star formation and may be the source of these high-speed electrons." Two papers describing the composite image, one led by Arendt and one led by Staguhn, were published on Nov. 1 in the Astrophysical Journal. The image shows the inner part of our galaxy, which hosts the largest and densest collection of giant molecular clouds in the Milky Way. These vast, cool clouds contain enough dense gas and dust to form tens of millions of stars like the Sun. The view spans a part of the sky about 1.6 degrees across -- equivalent to roughly three times the apparent size of the Moon -- or about 750 light-years wide. To make the image, the team acquired GISMO data, shown in green, in April and November 2012. They then used archival observations from the European Space Agency's Herschel satellite to model the far-infrared glow of cold dust, which they then subtracted from the GISMO data. Next, they added, in blue, existing 850-micrometer infrared data from the SCUBA-2 instrument on the James Clerk Maxwell Telescope near the summit of Maunakea, Hawaii. Finally, they added, in red, archival longer-wavelength 19.5-centimeter radio observations from the National Science Foundation's Karl G. Jansky Very Large Array, located near Socorro, New Mexico. The higher-resolution infrared and radio data were then processed to match the lower-resolution GISMO observations. The resulting image essentially color codes different emission mechanisms. Blue and cyan features reveal cold dust in molecular clouds where star formation is still in its infancy. Yellow features, such as the Arches filaments making up the candy cane's handle and the Sagittarius B1 molecular cloud, reveal the presence of ionized gas and show well-developed star factories; this light comes from electrons that are slowed but not captured by gas ions, a process also known as free-free emission. Red and orange regions show areas where synchrotron emission occurs, such as in the prominent Radio Arc and Sagittarius A, the bright source at the galaxy's center that hosts its supermassive black hole. Francis Reddy | EurekAlert! New gravitational-wave model can bring neutron stars into even sharper focus 22.05.2020 | University of Birmingham Electrons break rotational symmetry in exotic low-temp superconductor 20.05.2020 | DOE/Brookhaven National Laboratory Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality. Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other... Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses. A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell... By studying the chemical elements on Mars today -- including carbon and oxygen -- scientists can work backwards to piece together the history of a planet that once had the conditions necessary to support life. Weaving this story, element by element, from roughly 140 million miles (225 million kilometers) away is a painstaking process. But scientists aren't the type... Study co-led by Berkeley Lab reveals how wavelike plasmons could power up a new class of sensing and photochemical technologies at the nanoscale Wavelike, collective oscillations of electrons known as "plasmons" are very important for determining the optical and electronic properties of metals. Proteins, the microscopic “workhorses” that perform all the functions essential to life, are team players: in order to do their job, they often need to assemble into precise structures called protein complexes. These complexes, however, can be dynamic and short-lived, with proteins coming together but disbanding soon after. In a new paper published in PNAS, researchers from the Max Planck Institute for Dynamics and Self-Organization, the University of Oxford, and Sorbonne... 19.05.2020 | Event News 07.04.2020 | Event News 06.04.2020 | Event News 22.05.2020 | Physics and Astronomy 22.05.2020 | Materials Sciences 22.05.2020 | Materials Sciences

Juno Spots, new circulating cyclone at the Jupiter South Pole: NASA’s Juno spacecraft spied on the new Jovian cyclone on November 3, 2019, during the 23rd Scientific Pass of the gas giant. Juno was launched on August 5, 2011, which included an ambitious mission to see Jupiter under dense clouds. On July 4, 2016, the probe finally reached the orbit of the giant planet. Shortly after their arrival, Juno’s cameras discovered huge cyclones surrounding the Jovian poles: nine in the north and six in the south. With each flyby, the data reinforced the idea that there were five wind shocks that revolved around the central pole at the south pole in a pentagonal pattern and that the system seemed stable. None of the six storms indicated permission to join other cyclones. Data from the Juno Jovian infrared aerial mapping instrument (JIRAM) indicates that we suffer from a cyclone of a cyclone around a hexagonal design in the center. A team member of Dr. Alessaro Mura, who is a researcher at the National Institute of Astrophysics of Rome. This new addition is smaller in stature than its six more established cyclone brothers. It is about the size of Texas. Perhaps JIRAM data from future fights will increase cyclones in the same way as its neighbors. New data from the JIRAM instrument indicates an average cyclonic wind speed of 362 km (225 mph) and comparable to the speeds found in its six most established polar allies. This infrared image, captured by Juno’s JIRAM instrument on November 4, 2019. And shows a new small cyclone (to the right of the image) grouped around the south pole of Jupiter. JunoCam of the investigation obtained a visible light image of the new cyclone. The researchers said that both datasets not only shed light on Jupiter’s atmospheric processes. But other gas giants such as Saturn, Uranus and Neptune are also being discovered. It also sheds light on the atmospheric processes of Earth’s cyclones. These cyclones are new climatic events that have not been seen or predicted before. Juno scientist Dr. Cheng Li told the University of California, Berkeley. Nature is revealing a new physics about the movement of liquids and how the atmospheres of giant planets work. We have begun to explain this through observations and computer simulations. Juno’s excess of the future will help us understand how cyclones evolve over time. Jupiter is the fifth planet from the Sun and the largest planet in the solar system: It is a gas giant with one thousandth of the mass of the Sun, but two and a half times the mass of all the other planets in our solar system. Jupiter is classified as a gas giant with Saturn, Uranus and Neptune. Together, these four planets are sometimes called Jovian or outer planets. The planet was known to ancient astronomers and was associated with the mythology and religious beliefs of many cultures. The Romans called the planet by the Roman god Jupiter. When viewed from Earth, Jupiter can reach apparent magnitudes of -2.94, which makes it the third brightest object on average in the night sky after the Moon and Venus. (Mars can briefly match Jupiter’s brightness at certain points in its orbit.) Jupiter is mainly composed of hydrogen with a quarter mass of helium; It can also have a rocky core of heavy elements. Due to its rapid rotation, Jupiter’s shape is an oblique spheroid (it is near a slight but noticeable bump around the equator). The outside atmosphere can be seen in multiple bands at different latitudes, resulting in turbulence and storms within their interaction limits. An important result is the Great Red Spot. A giant storm known to have been seen for the first time by a telescope since at least the 17th century. Around the planet there is a misty planetary ring system and a powerful magnetosphere. There are also at least 66 moons, including four large moons called Galilean moons. Which Galileo Galilei first discovered in 1610. Ganymede, the largest of these moons, has a larger diameter than Mercury. Jupiter has been discovered by the robotic spacecraft several times and especially during the first overflight missions of Pioneer and Vyzer and later by the Galileo orbiter. The most recent probe that traveled to Jupiter was the New Horizons spacecraft bound for Pluto in late February 2007. This probe used gravity to increase its speed from Jupiter. Future exploration objectives in the Jovian system include possible liquid oceans covered with ice on the Europa Moon. Jupiter has been known since ancient times and is visible to the naked eye in the night sky. In 1610, Galileo Galilei discovered the four largest moons of Jupiter using telescopes, the first observation of moons other than Earth. Jupiter is 2.5 times more massive than all other planets combined. So massive that its bicenter with the Sun is located on the surface of the Sun (1,068 Solar Ready from the center of the Sun). It is 318 times heavier than Earth, has 11 times its diameter and is 1300 times more than Earth. Many have called it a “failed star,” even compared to calling the asteroid a “failed Earth“. As impressive as it is, extrasolar planets with a much larger mass have been discovered. However, it is believed that for a planet with a diameter as large as its composition, adding additional mass will only result in gravitational compression (provided ignition occurs). There is no clear definition of what separates an increasingly large planet like Jupiter from a gray dwarf, although the latter has distinct spectral lines, but Jupiter must be approximately seventy times larger in any situation than it would become. The fastest rotation rate of any planet within the solar system is also that of Jupiter, which makes a complete revolution in its axis in less than ten hours, resulting in an easy view through an amateur Earth-based telescope. It is most famous feature is probably the Great Red Spot, which is a storm bigger than Earth. The planet is always covered with a layer of clouds. Jupiter is generally the fourth brightest object in the sky (after the Sun, the Moon and Venus; although sometimes Mars looks brighter than Jupiter, while others seem brighter than Jupiter). It has been known since ancient times. The discovery of Galileo Galilei. And that was the discovery of the four massive moons of Jupiter, Io, Europa, Ganymede and Callisto (now known as the Moon of Galilee), the first discovery of an astronomical range centered on Earth. This was an important point in favor of the heliocentric theory of Copernicus planetary movements; Galileo’s open support for Coparican’s doctrine got him into trouble with the investigation. Physical characteristics and environment: Jupiter is composed of a relatively small rocky core, surrounded by metallic hydrogen, surrounded by liquid hydrogen, surrounded by gaseous hydrogen. There is no clear boundary or surface between these various phases of hydrogen; Conditions mix easily from gas to liquid as soon as it descends. The amount of methane, water vapor, ammonia and “rock” in the atmosphere is detected. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine and sulfur. The outermost layer of the atmosphere consists of crystals of frozen ammonia. This atmospheric composition is very close to the composition of the solar nebula. Saturn has a similar structure, but Uranus and Neptune have very little hydrogen and helium. The upper atmosphere of jupiter undergoes a differential rotation, an effect first noticed by Giovanni Cassini (1690). The rotation of Jupiter’s polar atmosphere is ~ 5 minutes longer than in the equatorial atmosphere. In addition, clouds of clouds of different latitudes flow in opposite directions in the prevailing winds. The contradictions of these conflicting traffic patterns cause storms and turbulence. Wind speeds of 600 km / h are not uncommon. A particularly violent storm, approximately three times the diameter of the Earth, is known as the Great Red Spot. Juno solved the 39-year-old mystery of the power of Jupiter PhysOrg – June 7, 2018. Since NASA’s Vyzar 1 spacecraft flew from Jupiter in March 1979, scientists have wondered about the origin of Jupiter’s electricity. That meeting confirmed the existence of Jovian electricity. Which had prevailed for centuries. But when the venerable explorer was injured, the data showed that radio signals connected to electricity did not match the description of the radio signals generated by lightning here on Earth. In a new article published today in Nature, NASA’s Juno mission scientists describe the ways in which the rays in Jupiter really correspond to Earth’s electricity. However, somehow, there are two types of electric polar opposite. ‘Diamond Rain’ Saturn and Jupiter falls on the BBC – October 14, 2013: Diamonds used by silver screen stars can form on Saturn and Jupiter, American scientists have calculated. The new atmospheric data for gas giants indicates that carbon is as abundant as its luminous crystals, they say. Thunderstorms convert methane into soot (carbon), which falls into graphite and then into diamond pieces. Amateur astronomers working with professional astronomers have fired two fireballs this summer, illuminating the atmosphere of Jupiter, the first time that terrestrial telescopes have captured relatively small objects that burn in the atmosphere of a giant planet. On June 3, 2010 and August 20, 2010, respectively, two fireballs were produced, which produced bright sunspots on Jupiter that were visible through a garden telescope. The image of the northern lights was taken before the arrival of NASA’s Juno spacecraft the following week, which would spend a year monitoring the largest planet in the solar system. Jupiter is known for colored storms such as the Great Red Spot that continuously rotate in the planet’s atmosphere. But it is a powerful magnetic field, which means that there are bright light shows at its poles. Like Earth, auroras form when high-energy particles enter a planet’s atmosphere near their magnetic poles and collide with gas atoms. Jupiter has auroras. Like Earth, the magnetic field of the largest planet in our solar system is affected by a burst of charged particles from the Sun. This magnetic compression funnel moved the particles lower in the atmosphere toward the poles of Jupiter. There, atmospheric gases temporarily excite or stop electrons, after which, when de-excited or recombined with atmospheric ions, auroral light is emitted. The representation represented represents the magnificent magnetosphere around Jupiter in action. In the inserted image published last month, the Lunar X-ray Observatory and that orbits the Earth shows an unexpectedly powerful X-ray light emitted by the Jovian Auroras, represented in fake-colored violet. The Chandra box is mounted on an optical image taken at a different time by the Hubble space telescope. This dawn on Jupiter was observed in October 2011, when the Sun emitted a powerful coronal mass ejection (CME). Aurora on Jupiter. Three luminous points are formed by magnetic flux tubes that connect to the bottom of the Jovian moons Io (left), Ganymede and Europe. In addition, you can see a very bright almost spherical region, called the main ellipse, and a faint polar aurora. Jupiter has a very large and powerful magnetosphere. In fact, if you can see Jupiter’s magnetic field from Earth. It will appear five times larger than the full moon in the sky, despite being so far from the sky. This magnetic field picks up a large stream of particle radiation in the Jupiter radiation belt, in addition to producing a dramatic gas bull and a flow tube connected to the ion. Jupiter’s magnetosphere is the largest planetary structure in the solar system. Pioneer research confirmed the existence that Jupiter’s massive magnetic field is 10 times stronger than Earth’s and has 20,000 times more energy. The driver-sensitive devices discovered that the “north” magnetic pole of the Jovian magnetic field is at the geographic south pole of the planet. The axis of the magnetic field is inclined 11 degrees from the jovian rotation axis and is displaced from the center of the fluctuation of some way. The axis of the earth’s sphere. The pioneers measured the bow of the Jovian magnetosphere at a width of 26 million kilometers (16 million miles), with the magnetic tail extending beyond the orbit of Saturn. The data showed that the magnetic field fluctuates rapidly on the edge of the Jupiter Sun due to variations in pressure in the solar wind, an effect studied in more detail by the two spacecraft of the traveler. It was also discovered that high-energy atomic particle currents are ejected from the Jovian magnetosphere and go to Earth’s orbit. Energy protons were found and measured in the Georgian radiation belt. And electrical currents were detected between Jupiter and some of its moons, especially Io. The Great Red Spot is an anticyclonic storm on planet Jupiter 22 ° south of the equator; That lasted at least 300 years. The storm is enough to be visible through ground telescopes. It was first seen around 1665 by Cassini or Hooke. This dramatic view of the Great Red Spot of Jupiter and its surroundings was obtained by Vyzer 1 on February 25, 1979. When the spacecraft was 5.7 million miles (9.2 million kilometers) from Jupiter. Here you can see details of clouds as small as 100 miles (160 kilometers). The colorful and wavy cloud pattern to the left of the red spot is an exceptionally complex and variable wave motion region. To give an idea of the Jupiter scale, the white oval storm just below the Great Red Spot has the same diameter as the Earth. Such storms are not uncommon in the atmosphere of gas giants. Jupiter also has a white oval and a brown oval, which are less anonymous storms. White ovals consist of relatively cold clouds within the upper atmosphere. The brown oval is warm and is within the “normal cloud layer”. Such storms can last for hours or centuries. It is not really known what causes the red color of the Great Red Spot. Theories supported by laboratory experiments assume that the color may be due to “complex organic molecules, red phosphorus or other sulfur compound”, but consensus has not yet been reached. The Great Red Spot is remarkably stable, first seen 300 years ago. Several factors may be responsible for its longevity, such as the fact that it never finds solid surfaces, which causes its energy to spread and its movement is driven by the internal heat of Jupiter. Simulations suggest that the place absorbs small atmospheric disturbances. In early 2004, the Great Red Spot was about half as big as 100 years ago. It is not known how long the Great Red Spot will last. If it is the result of normal fluctuations. The Great Red Spot should not be confused with the Great Dark Spot, seen in the atmosphere of Neptune by Wager 2 in 1989. The Great Dark Spot was an atmospheric hole. Not a hurricane, and no longer existed since 1994 (although another location similar appeared further north). On October 19, 2003, Belgian astronomer Olivier Meekers photographed a black spot on Jupiter. Although this is not a rare occurrence, he caught the fantasy of some science fiction fans and conspiracy theorists who came to speculate that the location was evidence of nuclear activity in Jupiter. A month before Galileo hit the planet. starry. Galileo carried approximately 15.6 kg of plutonium-238 from a ceramic, such as 144 plutonium-134 granules as a source of energy. The individual granules (which would be expected to separate during entry) initially contained approximately 108 grams at 238 Pu (approximately Galileo in Jupiter introduced approximately 10% of each) and are reduced by a significant factor of approximately 100. Jupiter has 67 known moons. This gives Jupiter the largest number of moons with reasonably safe orbits of any planet in the solar system. The largest of all, the four Galilean moons and were discovered by Galileo Galilei in 1610 and were the first objects to orbit an object that was not the Earth or the Sun. Since the late nineteenth century, dozens of small Jovian moons have been discovered and have received the names of lovers, conquests or daughters of the Roman god Jupiter or his Greek counterpart Zeus. The Galilean moons are the largest and largest objects that orbit around Jupiter, with the remaining 63 moons and rings only 0.003% of the total orbital mass. Eight of Jupiter’s moons are regular satellites, which consist of Jupiter and almost circular orbits, which are not closely related to the equator of Jupiter. Galilean satellites have an almost spherical shape due to the mass of the planets. If they are in direct orbit around the Sun, they would be considered planets. The other four regular satellites are much smaller and closer to Jupiter; These serve as sources of dust that form the rings of Jupiter. The rest of Jupiter’s moons are irregular satellites with retrograde and retrograde orbits far removed from Jupiter and have greater inclination and eccentricities. These moons were probably captured by Jupiter from the solar orbits. Since 2003, 16 irregular satellites have been discovered and have not yet been named. He discovered a dozen new moons of Jupiter, including a ‘strange’ Science Daily – July 17, 2018. Jupiter has been found orbiting twelve new moons: 11 “normal” outer moons, and one they call “weirdo.” Astronomers first observed the moons in the spring of 2017, when they were looking for objects from the distant solar system as part of a search for a potentially larger planet beyond Pluto. Possible place of Hubble Jupiter Moon Europe PhysOrg – Water stains spreading on September 26, 2016. Astronomers using NASA’s Hubble Space Telescope have proposed that water vapor currents can be released from the surface of Jupiter’s moon Europe. Other Hubble observations that make this discovery indicate an icy moon with water vapor at high altitude. The observation raises the possibility that the missions of Europe can sample the ocean of Europe without drilling kilometers of ice. Hubble discovers the water vapor outlet of Jupiter’s Moon Europe Science Daily – December 12, 2013. NASA’s Hubble Space Telescope has observed water vapor over the southern polar region of Jupiter’s Moon Europe. Providing the first strong evidence of water flow from the lunar surface. It is already believed that Europe disturbs a liquid ocean beneath its icy crust, which makes the Moon one of the main objectives in the search for a habitable world away from Earth. This new discovery is the first observational evidence of water vapor removed from the lunar surface. New discovery of life at Jupiter’s Moon Europe Live Science – November 17, 2011 Scientists say that Europe, Jupiter’s icy moon, meets not one but two of the important requirements for life. For decades, experts have known about the vast underground ocean of the moon. A potential home for living organisms, and now a study suggests that the ocean usually lives for life through chaotic processes near the lunar surface. Get the required energy flow. Jupiter Moon’s Buried Lakes Avoca Antarctica Live Science – November 17, 2011. Some of the scariest regions on Earth are providing scientists with tempting signs of water just a few miles below the icy crust of Jupiter’s moon, Europe. The unique ice break on the moon for more than a year has surprised scientists. Some have argued that they are signs of the rupture of an underground ocean. While others believe that the crust is too thick for water to pass through. But new studies of ice formations in Antarctica and Iceland have provided clues for the construction of these puzzling features. Indicating that the water is close to the previously thought surface of the moon. Jupiter Moon holds ‘Magma Sea’ BBC – May 12, 2011: Io is the most volcanic world in the solar system. Scientists believe they now have a better idea of why. Jupiter’s moon emits about 100 times more lava on its surface every year than Earth. A reassessment of NASA’s Galileo probe data suggests that all this activity is being fed from a huge ocean of magma beneath the IO crust. Atmosphere Io PhysOrg – June 14, 2010: Ayo is one of the four moons of Jupiter that Galileo discovered after converting his new telescope to heaven. He and his contemporaries were surprised because he showed that celestial bodies could revolve around objects other than Earth. Jupiter’s Moon Europe has enough oxygen for life – October 17, 2009: New research suggests that Europe’s subsurface ocean has enough oxygen available to support oxygen-based metabolic processes for life on Earth. In fact, there may be enough oxygen to support complex organisms, similar to animals, that demand more oxygen than microorganisms. Scientists complete the first global geological map of Ganymede Jupiter satellite physics – September 16, 2009. Scientists have gathered the first global geological map of the largest moon in the solar system and, in doing so, have gathered new evidence about the formation of a large and icy satellite. The map actually gives us a complete understanding of the geological processes we see today that are shaped like a moon. Jupiter is a system of planetary rings, known as rings of the Jupiter or Jovian ring system. It was the third ring system discovered in the solar system after Saturn and Uranus. It was first thoroughly investigated by the Vyzer 1 space probe in 1979 and by the Galileo orbiter in 1990. It has also been seen from the Hubble and Earth space telescope for the past 23 years. The largest available telescopes are required for terrestrial ring observations. The Jovian ring system is weak and consists mainly of dust. It has four main components: a thick internal edge of particles known as the “halo ring”; A relatively bright, exceptionally thin “main ring”; And two wide, thick and faint “rings of Gossamer” exterior, named for the moons of the materials that are composed: Amalathea and Thebe. The main and crown rings have dust effects emanating from moons, adrasty and other unlikely parental bodies, resulting in high speed effects. The high-resolution images obtained by the New Horizons spacecraft in February and March 2007 revealed a rich fine structure in the main ring. In visible and near infrared light, the rings have a red color, which is neutral or blue, except red. The size of the dust in the rings varies, but the cross-sectional area is the largest for the redundant radius particles. Which is approximately 15 um in all the rings, except the halo. The halo ring probably dominates the submicrometry dust. Jupiter rings formed by the pattern of sunlight and photology. A new study reported that a weak extension of the outermost ring beyond the orbit of Jupiter’s Moon Tebe and others saw deviations from an accepted ring formation model, which resulted in shadows of dust particles and rings of light solar. They’re done. It turns out that the extended range of the outer ring and others in Jupiter’s rings are actually made in the shade. The legend: In Roman mythology, Jupiter played a role similar to that of Zeus in the Greek Pantheon. He was called Jupiter Optimus Maximus Soter (Jupiter Best, Greatest, Savior) as the patron deity of the Roman state, in charge of law and social order. He was the main deity of the Capitoline Triad along with Juno and Minerva. Jupiter is a compound of mercury derived from the Latin archaic Iovis and Pater (Latin for father), it was also used as a nominal case. Jove Iov-, is an English formation based on the root of the oblique cases of the Latin name. Your Vedic counterpart baby Dyaus. The name of the deity was also adopted as the name of the planet Jupiter, and it was the original name of the day of the week that would be known in English as Thursday (the etymological root can be traced to several Romance languages, including (ascended Iowm). Also included), genetic Iovis, root Iovi and ablative Iove – an irregular strain). Linguistic studies identify his name as derived from the Indo-European compound “O Padre Dios,” the Indo-European god from which Germanic tivez also derives (after which he was named Tuesday). The Greek Zeus and the French Judeys, Castilian Juves, Italian Giovids and you leave Catalans, all from Latin Iovis des, while the English take their Nordic counterpart, Thor). The largest temple in Rome was that of Jupiter Optimus Maximus on Capitoline Hill. Here he worshiped together with the Capitoline Triad, along with Juno and Minerva. Jupiter was also worshiped on Capitoline Hill in the form of a stone, known as Jupiter Lapis or Jupiter Stone, which was sworn as an oath stone. The temples of Jupiter Optimus Maximus or the Capitoline Triad as a whole were generally built by the Romans in the center of the new cities of their colonies. It was once believed that the Roman god Brihaspati was in charge of cosmic justice, and in ancient Rome, people swore Jove in their courts, singing “Por Jove!” As it is used to direct the general expression. It is still used as an antiquarian today. In addition, “jovial” is a common average adjective that is still used to describe people who are naturally cheerful, optimistic and intelligent. Jupiter in Greek mythology, Jupiter as Jade, is the king of heaven and earth and the king of all Olympic gods. Sometimes it is represented by throwing jagged lightning to remind humans that reality is created by the electromagnetic energy that carries the magic. And mystery of our hologram through the network’s consciousness towards zero points. In Roman mythology, Jupiter was known as the god of justice. He was appointed King of the Gods after his overthrow (Chronos in Greek mythology) of Lord Saturn and the Titans in a special meeting.

Astronomers have announced that they have detected molecular oxygen in a galaxy that’s about half a billion light-years away from our galaxy. This is an important discovery because it’s only the third time astronomers have detected molecular oxygen outside of our solar system, and the first time it has been detected outside the Milky Way. Oxygen is believed to be a very abundant element in the universe and is the third most abundant element behind hydrogen and helium. Astronomers search for oxygen using millimeter astronomy that can detect radio wavelengths emitted by molecules. Scientists also use spectroscopy to analyze the spectrum looking for wavelengths absorbed or admitted by specific molecules. While oxygen is the third most abundant element in the universe, astronomers historically find a surprising lack of oxygen molecules leaving scientists without a comprehensive picture of oxygen chemistry in the interstellar environment. Astronomers have detected oxygen in the Orion nebula, but they believe oxygen in space is bound up with hydrogen in the form of water ice that clings to dust grains. The Orion nebula is a place where new stars are born, and they believe that it’s possible intense radiation from very hot young stars shocks the water ice in the sublimation splitting molecules and thereby releasing the oxygen. The new galaxy where the team has discovered molecular oxygen is called Markarian 231. That galaxy is 561 million light-years away from Earth and is powered by a quasar. The galaxy also has an active supermassive black hole in the center, and its quasar is the closest quasar to Earth. Astronomers believe that Markarian 231 could have a pair of active supermassive black holes in the center spinning around each other at high speed. They believe that the active galactic nucleus is driving molecular outflow and producing continuous shocks that may release oxygen from water and molecular bonds. Molecular outflows in the galaxy are at high velocity according to the team. This is the first time the team has detected molecular auction emissions in a galaxy outside of our own. The team says that the detected oxygen emission is located in regions that are about 32,615 light-years away from the center of the Markarian 231 galaxy. The team was also able to determine that the abundance of oxygen compared to hydrogen was about 100 times higher than what was previously discovered in the Orion nebula.

Checking out the spin rate on a supermassive black hole is a great way for astronomers to test Einstein’s theory under extreme conditions – and take a close look at how intense gravity distorts the fabric of space-time. Now, imagine a monster … one that has a mass of about 2 million times that of our Sun, measures 2 million miles in diameter and rotating so fast that it’s nearly breaking the speed of light. A fantasy? Not hardly. It’s a supermassive black hole located at the center of spiral galaxy NGC 1365 – and it is about to teach us a whole lot more about how black holes and galaxies mature. What makes researchers so confident they have finally taken definitive calculations of such an incredible spin rate in a distant galaxy? Thanks to data taken by the Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency’s XMM-Newton X-ray satellites, the team of scientists has peered into the heart of NGC 1365 with x-ray eyes – taking note of the location of the event horizon – the edge of the spinning hole where surrounding space begins to be dragged into the mouth of the beast. “We can trace matter as it swirls into a black hole using X-rays emitted from regions very close to the black hole,” said the coauthor of a new study, NuSTAR principal investigator Fiona Harrison of the California Institute of Technology in Pasadena. “The radiation we see is warped and distorted by the motions of particles and the black hole’s incredibly strong gravity.” However, the studies didn’t stop there, they advanced to the inner edge to encompass the location of the accretion disk. Here is the “Innermost Stable Circular Orbit” – the proverbial point of no return. This region is directly related to a black hole’s spin rate. Because space-time is distorted in this area, some of it can get even closer to the ISCO before being pulled in. What makes the current data so compelling is to see deeper into the black hole through a broader range of x-rays, allowing astronomers to see beyond veiling clouds of dust which only confused past readings. These new findings show us it isn’t the dust that distorts the x-rays – but the crushing gravity. “This is the first time anyone has accurately measured the spin of a supermassive black hole,” said lead author Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics (CfA) and INAF — Arcetri Observatory. “If I could have added one instrument to XMM-Newton, it would have been a telescope like NuSTAR,” said Norbert Schartel, XMM-Newton Project Scientist at the European Space Astronomy Center in Madrid. “The high-energy X-rays provided an essential missing puzzle piece for solving this problem.” Even though the central black hole in NGC 1365 is a monster now, it didn’t begin as one. Like all things, including the galaxy itself, it evolved with time. Over millions of years it gained in girth as it consumed stars and gas – possibly even merging with other black holes along the way. “The black hole’s spin is a memory, a record, of the past history of the galaxy as a whole,” explained Risaliti. “These monsters, with masses from millions to billions of times that of the sun, are formed as small seeds in the early universe and grow by swallowing stars and gas in their host galaxies, merging with other giant black holes when galaxies collide, or both,” said the study’s lead author, Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and the Italian National Institute for Astrophysics. This new spin on black holes has shown us that a monster can emerge from “ordered accretion” – and not simply random multiple events. The team will continue their studies to see how factors other than black hole spin changes over time and continue to observe several other supermassive black holes with NuSTAR and XMM-Newton. “This is hugely important to the field of black hole science,” said Lou Kaluzienski, NuSTAR program scientist at NASA Headquarters in Washington, D.C. “NASA and ESA telescopes tackled this problem together. In tandem with the lower-energy X-ray observations carried out with XMM-Newton, NuSTAR’s unprecedented capabilities for measuring the higher energy X-rays provided an essential, missing puzzle piece for unraveling this problem.” Original Story Source: JPL/NASA News Release.

"What do we need to know about to discover life in space?" How can we estimate the number of technological civilizations that might exist among the stars? While working as a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake conceived an approach to bound the terms involved in estimating the number of technological civilizations that may exist in our galaxy. The Drake Equation, as it has become known, was first presented by Drake in 1961 and identifies specific factors thought to play a role in the development of such civilizations. Although there is no unique solution to this equation, it is a generally accepted tool used by the scientific community to examine these factors. -- Frank Drake, 1961 N = R* ∗ fp∗ ne∗ fl∗ fi∗ fc∗ L N = The number of civilizations in the Milky Way Galaxy whose electromagnetic emissions are detectable. R* = The rate of formation of stars suitable for the development of intelligent life. fp = The fraction of those stars with planetary systems. ne = The number of planets, per solar system, with an environment suitable for life. fl = The fraction of suitable planets on which life actually appears. fi = The fraction of life bearing planets on which intelligent life emerges. fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space. L = The length of time such civilizations release detectable signals into space. Within the limits of our existing technology, any practical search for distant intelligent life must necessarily be a search for some manifestation of a distant technology. In each of its last four decadal reviews, the National Research Council has emphasized the relevance and importance of searching for evidence of the electromagnetic signature of distant civilizations. Besides illuminating the factors involved in such a search, the Drake Equation is a simple, effective tool for stimulating intellectual curiosity about the universe around us, for helping us to understand that life as we know it is the end product of a natural, cosmic evolution, and for making us realize how much we are a part of that universe. A key goal of the SETI Institute is to further high quality research that will yield additional information related to any of the factors of this fascinating equation.

Minor Planet Center The Minor Planet Center (MPC) is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the Minor Planet Circulars. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC collects light curve photometry of minor planets. A key function of the MPC is helping observers coordinate follow up observations of possible near-Earth objects (NEOs) via its NEO web form and blog. The MPC is also responsible for identifying, and alerting to, new NEOs with a risk of impacting Earth in the few weeks following their discovery (see Potentially hazardous objects and § Videos). The Minor Planet Center was set up at the University of Cincinnati in 1947, under the direction of Paul Herget.:63 Upon Herget's retirement on June 30, 1978,:67 the MPC was moved to the SAO, under the direction of Brian G. Marsden.:67 From 2006–2015, the director of the MPC was Timothy Spahr, who oversaw a staff of five. As of February 2015[update], the Minor Planet Center is headed by interim director Matthew Holman. The MPC periodically releases astrometric observations of minor planets, as well as of comets and natural satellites. These publications are the Minor Planet Circulars (MPCs), the Minor Planet Electronic Circulars (MPECs), and the Minor Planet Supplements (MPSs and MPOs). An extensive archive of publications in a PDF format is available at the Minor Planet Center's website. The archive's oldest publication dates back to 1 November 1977 (MPC 4937–5016). - Minor Planet Circulars (M.P.C. or MPCs), established 1947, is a scientific journal that is generally published by the Minor Planet Center on the date of each full moon, when the number of reported observations are minimal due to the brighter night sky. The Circulars contain astrometric observations, orbits and ephemerides of minor planets, comets and certain natural satellites. The astrometric observations of comets are published in full, while the minor planet observations are summarised by observatory code (the full observations now being given in the Minor Planet Circulars Supplement). New numberings and namings of minor planets (also see Naming of Minor Planets), as well as numberings of periodic comets and natural satellites, are announced in the Circulars. New orbits for comets and natural satellites appear in the Circulars; new orbits for minor planets appear in the Minor Planets and Comets Orbit Supplement (see below). - The Minor Planet Electronic Circulars (MPECs) are published by the Minor Planet Center. They generally contain positional observations and orbits of unusual minor planets and all comets. Monthly lists of observable unusual objects, observable distant objects, observable comets and the critical list of numbered minor planets also appear on these circulars. Daily Orbit Update MPECs, issued every day, contain new identifications and orbits of minor planets, obtained over the previous 24 hours. - The Minor Planets and Comets Supplement (MPS) is published on behalf of IAU's Division F (Planetary Systems and Bioastronomy) by the Minor Planet Center. - The Minor Planets and Comets Orbit Supplement (MPO) is published on behalf of IAU's Division F by the Minor Planet Center. - Centres: Minor Planet Center. International Astronomical Union. Retrieved 20 April 2016. - Marsden, B. G.; Williams, G. V. (February–March 1998). "The NEO Confirmation Page". Planetary and Space Science. 46 (2–3): 299. Bibcode:1998P&SS...46..299M. doi:10.1016/S0032-0633(96)00153-5. - "Real time reporting of NEOCP follow up". NEOCP Blog. Minor Planet Center. Archived from the original on 2016-04-13. Retrieved 20 April 2016. - Donald E. Osterbrock & P. Kenneth Seidelmann (1987). "Paul Herget: 1908–1981" (PDF). Biographical Memoirs of the National Academy of Sciences. 57. National Academies Press. pp. 64–65. ISBN 9780585272801. OCLC 45729798. - Brian G. Marsden (July 1980). "The Minor Planet Center". Celestial Mechanics. 22: 63–71. Bibcode:1980CeMec..22...63M. doi:10.1007/BF01228757. - Galoche, J.L. (6 January 2015). "Minor Planet Center Director Steps Down". The Daily Minor Planet Blog. Minor Planet Center. Archived from the original on 2015-08-14. Retrieved 20 April 2016. - Gareth V. Williams (18 November 2010). "MPEC 2010-W10: Brian Marsden (1937 Aug. 5 – 2010 Nov. 18)". Minor Planet Electronic Circular. - Galoche, J.L. (4 February 2015). "Interim Director Appointed to the Minor Planet Center". The Daily Minor Planet Blog. Minor Planet Center. Archived from the original on 2015-05-26. Retrieved 1 December 2015. - "MPC: Publications". Minor Planet Center. Retrieved 6 May 2016. - "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 6 May 2016. - "Division F Planetary Systems and Astrobiology". International Astronomical Union. Retrieved 2017-11-07. - Official website - MPC/MPO/MPS Archive, all published circulars since 1977 (downloadable as PDF) - The MPC Orbit (MPCORB) Database - The Minor Planet Center Status Report, Matthew J. Holman, 8 November 2015 - Recent MPECs, list of most-recently-published Minor Planet Electronic Circulars

- Open Access Earth, Planets and Space volume 65, Article number: 16 (2013) For dust you are and to dust you will return Dust exists everywhere—in inter- and circum-planetary, inter- and circum-stellar, and even intergalactic, space—since its first creation in the Universe. The first generation of cosmic dust must have been produced less than 1 Gyr after the Big Bang, for the reason that more than 108 solar masses of dust has been found in distant QSOs powered by super-massive black holes sitting at the center of a galaxy at that age of the Universe. Since then dust has been continuously produced, processed, and destroyed in every single phase of the Universe. Dust forms by condensation out of rapidly cooling materials that flow outward from a dying star. Once injected into the interstellar medium or even into intergalactic space, dust suffers a variety of processes: ultraviolet irradiation, sputtering by cosmic rays, and shattering in a turbulent diffuse medium. In a dense medium, dust grows due to the accretion of atoms and molecules as well as coagulation, it catalyzes molecular reactions on its surface, and occasionally encounters the formation of a star. Star formation is both a sink and a source for cosmic dust; A portion of materials left over from star formation condenses into dust, which subsequently conglomerates into planetesimals. After the dissipation of the leftover materials, comets and asteroids supply dust into a circumstellar disk by ice sublimation and mutual collisions until the death of the star, which is, in turn, a sink and a source for cosmic dust. This is the life cycle of cosmic dust. To fully understand the life cycle of cosmic dust resembles putting together all the pieces of a jigsaw puzzle, because there is a considerable diversity of information on dust-related phenomena. Such diversity prevents the depiction of a complete picture of cosmic dust, due to the fact that many dust researchers are working independently in each field without any collaboration on the different aspects of cosmic dust. To overcome this adverse situation, we have been organizing a "Cosmic Dust" meeting as a session of the annual meeting of the Asia Oceania Geosciences Society (AOGS) since 2006. The Cosmic Dust series has been recognized as the most successful session of the AOGS Planetary Sciences Section. In 2012, the time was ripe for being free of the organizing restrictions of the AOGS meeting. Therefore, the 5th meeting of the Cosmic Dust series was totally independent of any international conference. As with the past meetings, the 5th meeting on Cosmic Dust was held in a relaxed and joyful atmosphere at the Center for Planetary Science (CPS), Kobe, Japan, between August 6–10, 2012. Seventy one experts in a variety of cosmic dust fields attended the meeting from Japan, Mainland China, Taiwan, Hong Kong, India, USA, France, Germany, Italy, Denmark, Finland, Poland, and Russia. The meeting ended with great success in achieving its primary objective, which was to provide an opportunity to develop human relations and scientific interactions among the participants. We should, however, mention that it was not straightforward to organize such a great international meeting by ourselves from scratch. We are very indebted to the local organizing committee of the meeting: Carsten Güttler, Hiroshi Kobayashi, Hiroki Senshu, Aki Takigawa, Koji Wada, and Tetsuo Yamamoto, for their dedication to make the meeting successful, and to the staff members of Kobe Convention & Visitors Association: Katsuhiko Fujita and Yoshihiro Hayashi for providing a number of services under the "MEET IN KOBE 21st Century" program, as well as the secretaries at CPS for their warm hospitality. Thanks to a word of encouragement by Mike Zolensky during the first "Cosmic Dust" meeting, we were determined to publish the proceedings of the Cosmic Dust series. The proceedings of the previous meetings have been published as special issues of Earth, Planets and Space (EPS) (see the previous prefaces: Vol. 62, p. 3; Vol. 63, p. 1019; Vol. 65, p. 127). As a natural consequence, this special issue of EPS serves as the proceedings of the 5th "Cosmic Dust" meeting. Although paper submission was not obligatory for the participants of the meeting, nineteen manuscripts were submitted to this special issue and underwent a review and revision process with the help of two reviewers for every manuscript. The subjects of the papers accepted for publication are as diverse as the topics covered by the meeting, owing to the ubiquity of dust in the Universe. As in the program of the meeting, the papers could be categorized into particular dusty environments: evolved stars (Yong Zhang and Sun Kwok), galaxies (Veronique Buat; Hiroyuki Hirashita and Hiroshi Kobayashi; Katarzyna Małek et al.; Agnieszka Pollo et al.; Enrique Lopez-Rodriguez et al.; Puthiyaveettil Shalima et al.), the interstellar medium (Jian Gao et al.), star-forming regions (Robert S. Botet and Rakesh K. Rai), debris disks (Harald Mutschke et al.), and the solar system (Jamey R. Szalay et al.; Nikolai Kiselev et al.; George J. Flynn et al.; Lev Nagdimunov et al.; Edith Hadamcik et al.). It is, however, worth pointing out that the categorization is not unique and should be used with caution, since some of the studies are essentially interdisciplinary. To help the reader become aware of the new findings of the papers included in this issue, we briefly summarize the contents here. Reliable corrections to the attenuation of stellar radiation by dust in galaxies are mandatory for measuring the star-formation rate and its evolution with redshift. The wavelength dependence of mean dust attenuation on a galactic scale has been derived from a statistical sample of galaxies at redshift from 1 to 2 at ultraviolet to far-infrared wavelengths in the rest frame of the galaxies and has been shown to have a stronger wavelength dependence than the dust extinction law in the Milky Way (Buat, this issue). This result is of great importance for recovering intrinsic stellar radiation spectra, which provide information on the star-formation history in galaxies. Since infrared emission from galaxies is a good tracer of star-formation activity, the large-scale structure of dusty galaxies represents the star-formation density field in the Universe. Thermal emission from dust in nearby star-forming galaxies, detected by the Japanese satellite AKARI’s All-Sky Far-Infrared Survey, was used to measure the angular and spatial clustering of such galaxies (Pollo et al., this issue). The resulting clustering properties indicate that AKARI All-Sky galaxies are essentially a star-forming population of nearby galaxies. Because most of the dust in galaxies is cold and emits far-infrared radiation, AKARI’s data are suitable for studying star-formation activities in galaxies. Far-infrared emission from dust was examined in detail through the spectral energy distribution (SED) of galaxies detected by AKARI in order to derive average SEDs as a function of infrared luminosity (Małek et al., this issue). Since the SEDs of galaxies are determined by the formation and evolution of dust in the galaxies, the SEDs reflect various physical processes of dust occurring in the interstellar medium. Among the processes that determine the size distribution of interstellar dust, shattering is one of the most effective mechanisms to feed small grains into the interstellar medium. Theoretical predictions for shattering were examined in detail to investigate how shattering affects the evolution of the dust size distribution in the interstellar medium (Hirashita and Kobayashi, this issue). The size distribution of interstellar dust seems to approach the same power-law distribution under shattering, irrespective of the size distribution of shattered fragments. A typical size of interstellar dust could be constrained by the forward scattering of starlight by interstellar dust observed as ultraviolet halos around bright stars. The scattering properties of interstellar dust in a thin foreground cloud of the bright star Spica were derived from numerical simulations of its UV halo which is located near the interaction zone between the Local Bubble and the Loop I superbubble (Shalima et al., this issue). The best-fit parameters might be interpreted as light scattering by abundant small grains produced by shock waves that formed the bubbles. The smallest end of the grain size distribution may be linked to long-chain carbon molecules, a study of which provides useful information on dust processing occurring in the interstellar medium and circumstellar environments. The wavelengths and band strengths observed in the infrared spectra of circumstellar shells around evolved stars may be accounted for by the excitation of C60 in a cluster state (Zhang and Kwok, this issue). UV-induced processing and dehydrogenation of mixed aromatic and aliphatic organic nanoparticles during the post-AGB phase of stellar evolution are the most likely formation route of fullerenes, which are then ejected into the interstellar medium. Since the properties of interstellar clouds vary from one line of sight to another, the size distribution of interstellar dust derived from an observation depends on the line of sight of the observation. The observed extinction curve toward the Galactic Center (GC) within the 1–19-µm spectral range is not well simulated by a model of dust in the diffuse interstellar medium (Gao et al., this issue). This suggests that the extinction toward the GC is caused by a combination of interstellar dust in diffuse clouds and dense clouds. Interstellar dust is known to align in magnetic fields and polarize stellar radiation by dichroic absorption, because of its non-sphericity. The magnetic field strength in the dusty torus around the active galactic nuclei IC 5063 was estimated through the near-infrared polarization caused by aligned, non-spherical dust (Lopez-Rodriguez et al., this issue). A simple model was sufficient to fit the near-infrared polarimetric data, but the dust alignment mechanism remains unknown and the dust properties are not well constrained. Dust coagulation in dense interstellar clouds results in non-spherical dust; in particular, aggregates of small grains whose light-scattering properties are of great importance for interpreting observational data. Optical properties of composite aggregates were studied in consideration of two coagulation processes for forming dust aggregates (Botet and Rai, this issue). The similarity, or dissimilarity, in the optical properties between composite aggregates and coated spheres might provide clues about coagulation processes in star-forming regions and protoplanetary disks. A spectral slope of the continuum absorption at far-infrared wavelengths is a diagnostic tool to infer dust masses, temperatures, and spatial distributions in protoplanetary disks and debris disks. A drastic change in the spectral slope for the continuum of far-infrared absorption was measured with olivine plates at low temperatures (Mutschke et al., this issue). Their results reveal that the crystalline silicate components of cold dust in the outer regions of protoplanetary disks and debris disks are hidden in the amorphous silicate components. While crystalline and amorphous silicates are important constituents of cometary dust, the major constituents are organic-rich carbonaceous materials encasing the silicates. Nanoscale organic coatings around mineral components of interplanetary dust particles (IDPs) were discovered by a synchrotron X-ray based STXM instrument (Flynn et al., this issue). Their findings are crucial to an understanding of how small grains grow into larger aggregates against high collisional velocities expected in protoplanetary disks. The presence of organic coatings most likely affects the light-scattering properties of cometary dust in the visible wavelength range, because silicates are transparent in the optical wavelength domain. The degree of linear polarization typical for dusty comets and left-handed circular polarization were observed for the recent comet C/2009 P1 (Garradd) (Kiselev et al., this issue). The measured circular polarization confirms the predominance of left-handed circular polarization in comets, which suggests the presence of chiral molecules in the organic refractory component of cometary dust. Circular polarization might be a powerful tool to identify prebiological organic matters in cosmic dust because the presence of homochirality in dust may result in circular polarization. A computer simulation of circular polarization by aggregates containing a homochiral biomolecule demonstrated that circular polarization increases with the size of aggregates (Nagdimunov et al., this issue). As the detection of extraterrestrial life is one of the driving forces behind astrobiology, circular polarization by prebiological organic matters in cosmic dust is of topical interest. Since organic compounds are also major constituents of aerosols in the atmosphere of Titan, their composition plays an important role in the optical properties of Titan’s aerosols. Light scattering by Titan aerosols was simulated by laboratory measurements of tholin particles with various CH4/N2 ratios and well-defined size distributions (Hadamcik et al., this issue). Linear polarization of Titan’s aerosols measured by Pioneer 11, Voyager 2, and DISR/Huygens is consistent with light scattering by aggregates of 100-nm-diameter grains. Pioneer 10 and 11 measured dust fluxes in interplanetary space up to 18 AU from the Sun, while the flux at larger heliocentric distances is of great interest to better understand the structure of the cold debris disk of our own planetary system. The Student Dust Counter on board the New Horizon Mission to Pluto provides the first in-situ measurements of dust fluxes beyond 18 AU from the Sun (Szalay et al., this issue). The good agreement between the dust production rate of Kuiper Belt objects derived from the measured fluxes, and the previous theoretical estimates, implies that interstellar dust is a minor component even in the outer solar system. The papers contained in this issue certainly add valuable pieces of information to a global picture of cosmic dust, but we are still missing a great number of pieces to complete the jigsaw puzzle of dust life cycles. This is the reasoning behind our motivation to continue organizing the Cosmic Dust meetings and publishing the meeting proceedings. We thank all the authors and the reviewers, as well as the editorial board of EPS and Terra Scientific Publishing Company (TERRAPUB), for their efforts regarding this special issue. We will be glad if this EPS special issue, as well as the Cosmic Dust meeting Series, will help the field of cosmic dust research take root in Asia and Oceania and flourish worldwide. Botet, R. S. and R. K. Rai, Shape effects in optical properties of composite dust particles, Earth Planets Space,65, this issue, 1133–1137, 2013. Buat, V., Dust attenuation in galaxies up to redshift ≃ 2, Earth Planets Space, 65, this issue, 1095–1100, 2013. Flynn, G. J., S. Wirick, and L. P. Keller, Organic grain coatings in primitive interplanetary dust particles: Implications for grain sticking in the Solar Nebula, Earth Planets Space, 65, this issue, 1159–1166, 2013. Gao, J., A. Li, and B. W. Jiang, Modeling the infrared extinction toward the galactic center, Earth Planets Space, 65, this issue, 1127–1132, 2013. Hadamcik, E., J.-B. Renard, A. Mahjoub, T. Gautier, N. Carrasco, G. Cernogora, and C. Szopa, Optical properties of analogs of Titan’s aerosols produced by dusty plasma, Earth Planets Space, 65, this issue, 1175–1184, 2013. Hirashita, H. and H. Kobayashi, Evolution of dust grain size distribution by shattering in the interstellar medium: Robustness and uncertainty, Earth Planets Space, 65, this issue, 1083–1094, 2013. Kiselev, N. N., V. K. Rosenbush, V. L. Afanasiev, S. V. Kolesnikov, S. V. Zaitsev, and D. N. Shakhovskoy, Linear and circular polarization of comet C/2009 P1 (Garradd), Earth Planets Space, 65, this issue, 1151–1157, 2013. Lopez-Rodriguez, E., C. Packham, S. Young, M. Elitzur, N. A. Levenson, R. E. Mason, C. Ramos Almeida, A. Alonso-Herrero, T. J. Jones, and E. Perlman, New insights into the study of magnetic field in the clumpy torus of AGN using near-infrared polarimetry, Earth Planets Space, 65, this issue, 1117–1122, 2013. Małek, K., A. Pollo, T. T. Takeuchi, E. Giovannoli, V. Buat, D. Burgarella, M. Malkan, and A. Kurek, Dusty Universe viewed by AKARI far infrared detector, Earth Planets Space, 65, this issue, 1101–1108, 2013. Mutschke, H., S. Zeidler, and H. Chihara, Far-infrared continuum absorption of olivine at low temperatures, Earth Planets Space, 65 this issue, 1139– 1143, 2013. Nagdimunov, L., L. Kolokolova, and W. Sparks, Polarimetric technique to study (pre)biological organics in cosmic dust and planetary aerosols, Earth Planets Space, 65, this issue, 1167–1173, 2013. Pollo, A., T. T. Takeuchi, A. Solarz, P. Rybka, T. L. Suzuki, A. Pȩpiak, and S. Oyabu, Clustering of far-infrared galaxies in the AKARI All-Sky Survey North, Earth Planets Space, 65, this issue, 1109–1116, 2013. Shalima, P., J. Murthy, and R. Gupta, Dust properties from GALEX observations of a UV halo around Spica, Earth Planets Space, 65, this issue, 1123–1126, 2013. Szalay, J. R., M. Piquette, and M. Horányi, The Student Dust Counter: Status report at 23 AU, Earth Planets Space, 65, this issue, 1145–1149, 2013. Zhang, Y. and S. Kwok, On the detections of C60 and derivatives in circumstellar environments, Earth Planets Space, 65, this issue, 1069–1081, 2013. About this article Cite this article Kimura, H., Inoue, A., Kolokolova, L. et al. Preface. Earth Planet Sp 65, 16 (2013). https://doi.org/10.5047/eps.2013.09.012 - Circular Polarization - Interstellar Medium - Protoplanetary Disk - Interstellar Dust

CAMBRIDGE, Mass. — For the first time, researchers have discovered three potentially habitable, Earth-like worlds orbiting an ultracool dwarf star 40 light-years away in another star system, according to a study published in the journal Nature. The ultracool dwarf star, known as TRAPPIST-1, isn’t the kind of star scientists expected to be a hub for planets. It’s at the end of the range for what classifies as a star: half the temperature and a tenth the mass of the sun. TRAPPIST-1 is red, barely larger than Jupiter and too dim to be seen with the naked eye or even amateur telescopes from Earth. But these tiny stars, along with brown dwarfs, are long-lived, common in the Milky Way and represent 25-50 percent of stellar objects in the galaxy, said study researcher Julien de Wit, a postdoctoral associate with MIT’s Department of Earth, Atmospheric and Planetary Sciences. They were largely overlooked until researcher Michaël Gillon of the University of Liège in Belgium decided to take a risk and study the space around one of these dwarves. It paid off. Over the course of 62 nights from September to December 2015, researchers led by Gillon used a telescope, also called TRAPPIST (transiting planets and planetesimals small telescope), to observe its starlight and changes in brightness. The team saw shadows, like little eclipses, periodically interrupting the steady pattern of starlight. Using a telescope that can detect infrared light added an advantage that visible light camera programs don’t provide. “It’s like standing in front of a lamp and throwing a flea across it,” said professor Adam Burgasser of the Center for Astrophysics and Space Science at the University of California San Diego. “It was only a 1 percent dip in light, but the specific pattern was a good sign of orbiting planets.” The planets are about the size of Earth and given the proximity of two of them to the dwarf star, they receive about four times the amount of radiation than we do from the sun, which suggests they are in the “habitable zone.” According to Burgasser, the “habitable zone,” determines how close a planet is to the star that it orbits and given the temperature of the planet based on that proximity, it could have water on the surface. This core ingredient for life as we know it also suggests there could be an atmosphere and habitable regions on the planets themselves. Less is known about the third outer planet, which receives twice the amount of radiation that Earth does, but it is potentially in the habitable zone as well. Like the moon, the researchers believe the two planets closest to the star are tidally locked. This means that the planets always face one way to the star. One side of the planet is perpetually night, while the other is always day. These results are just the beginning of a study that will continue for years. The researchers are already working on observations to see if the planets have water or methane molecules. The planets are the perfect target to be studied at 40 light-years away, but that doesn’t mean we will reach them anytime soon. With current technology, it would take millions of years for an expedition to reach these planets. But from a research perspective, they provide a close opportunity and the best target to search for life beyond Earth and our solar system. What we find also could change how we determine the creation of life as we know it. The telescopes these researchers use to study the planets are even more precise than Hubble. In 2018, they can begin using the James Webb Space Telescope, which will allow the scientists to observe the shell of an atmosphere if it exists for these planets, and even what chemicals comprise that atmosphere. It will also provide more detailed information about the planets’ composition, temperature and pressure, according to de Wit. The next generation of telescopes will also be able to search for the subtle signatures of biomarkers, like oxygen, de Wit said. Burgasser, who has made the study of dwarf stars his life’s work, says that TRAPPIST-1 was initially studied quite a bit, but the planets around it have not been revealed until now.

Atmospheric drag on the motion of satellites Atmospheric drag could slow down the motion of a satellite when its orbit is low enough to be affected by the friction of Earth's atmosphere. A low Earth-orbiting satellite is often placed just above the Earth's atmosphere (Fig.1), where there is almost no air to drag on the satellite and reduce its speed. For example, the Hubble Space Telescope (HST) has a low altitude orbit and operates at an altitude of 610 km with an orbital period of 97 minutes. Fig.1 Orbit of a low Earth-orbiting satellite (not to scale) The sunspot cycle 24 has begun in January 2010 and the solar activity will increase gradually. When there are intense solar activities bringing intense solar winds towards the earth, the upper atmosphere of the earth will heat up and expand to enclose the orbits of some low Earth-orbiting satellites in it (Fig.2). It will produce greater frictional drag against the motion of the satellite. Fig.2 Intense solar activities cause the expansion of the earth's upper atmosphere (atmosphere exaggerated for ease of explanation.) The drag would slow down the orbiting speed of the satellite. It will cause the satellite to de-orbit, decrease in altitude and eventually burn up in the atmosphere through its voyage back to the earth by gravitational force. Re-boosts in advance to maintain its orbit could extend the operational period of a satellite if it has enough fuel. Furthermore, the atmospheric density and composition in the lower atmosphere were also dependent on local time besides the solar activity. Scientists found that the atmospheric density below 200km was higher at nighttime. Thus, satellites operating at very low altitude orbits would experience even more frictional drag at nighttime.

Since landing at Gale crater, Mars, in August 2012, the Curiosity rover has searched for evidence of past habitability, such as organic compounds, which have proved elusive to previous missions. We report results from pyrolysis experiments by Curiosity’s Sample Analysis at Mars (SAM) instrument, focusing on the isotopic compositions of evolved CO2 and O2, which provide clues to the identities and origins of carbon- and oxygen-bearing phases in surface materials. We find that O2 is enriched in 18O (δ18O about 40‰). Its behaviour reflects the presence of oxychlorine compounds at the Martian surface, common to aeolian and sedimentary deposits. Peak temperatures and isotope ratios (δ18O from −61 ± 4‰ to 64 ± 7‰; δ13C from –25 ± 20‰ to 56 ± 11‰) of evolved CO2 indicate the presence of carbon in multiple phases. 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New IUPAC guidelines for the reporting of stable hydrogen, carbon, and oxygen isotope-ratio data. J. Res. Natl Inst. Stand. Technol. 100, 285 (1995). Rothman, L. S. et al. The HITRAN2012 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Trans. 130, 4–50 (2013). Mahaffy, P. R. et al. The imprint of atmospheric evolution in the D/H of Hesperian clay minerals on Mars. Science 347, 412–414 (2015). This work was funded by NASA’s Mars Exploration Program. We thank T. B. Griswold for figure production, R. H. Becker for discussion, and the technical team at the NASA Goddard Space Flight Center Planetary Environments Laboratory for laboratory support. The authors declare no competing interests Peer review information Nature Astronomy thanks Alberto Fairen and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. CO2 (isotopologue at m/z 45) evolved from aeolian (a), mudstone (except Vera Rubin Ridge) (b), sandstone (c) and Vera Rubin Ridge samples (d). e, O2 evolved from RN and CB samples. Data for samples in panels a–c have been normalized to a single portion aliquot. CO2 profile (isotopologue at m/z 44 or 45) from EGA analyses with laboratory test stands: carbonates (a); oxalates (b); acetates (c); benzoic and mellitic acids (d). The peak temperatures of CO2 evolved from Martian samples by SAM are compared with those from laboratory runs such as these to help identify the mineral phases present. The CaCO3 was the same synthetic material used for SAM flight model calibration. About this article Cite this article Franz, H.B., Mahaffy, P.R., Webster, C.R. et al. Indigenous and exogenous organics and surface–atmosphere cycling inferred from carbon and oxygen isotopes at Gale crater. Nat Astron 4, 526–532 (2020). https://doi.org/10.1038/s41550-019-0990-x Nature Astronomy (2020)

In what might be a evidence of planetary billiards, astronomers have found an exoplanet with an extremely odd orbit. The question is, was this planet the cue ball or the object ball? While most planets orbit around a star’s mid-section, this one – called XO-3b — is tilted about 37 degrees from the star’s equator. It’s also a massive planet, about 10 times the size of Jupiter. Such a misalignment must have occurred as a result of a disturbance, such as a collision with another object, sometime after the planet’s formation. But astronomers say they don’t yet know what caused the unusual orbit of XO-3b. Detecting this oddball orbit required a combination of good luck, advanced technology and ingenious methodology. The planet was discovered back in 2007 using the transit method by measuring how the star is dimmed by the planet passing in through the line-of-sight between Earth and the star. Using the Keck I telescope, detecting the planet itself was relatively easy, as it dimmed the star’s light by about 1 percent. But to go one step further and measure the angle of its orbit, meant that “we have to be sneaky about it,” said MIT physicist Joshua Winn, who led the team that measured the planet’s tilted orbit. It turns out that if a planet crosses the star’s disk at an angle to the star’s own rotation, it causes a distinctive pattern of change in the overall color of the star, as measured by a highly sensitive spectrograph, because of the Doppler shifts caused by the star’s rotation. Hints of such a spectral signature were seen last year by another team, but that team acknowledged that they could not be confident of their result. The new observations, carried out by Winn and his team in February at the Keck I Observatory in Hawaii, provided a clear, solid measurement of the planet’s distinctive tilt, determining the angle of the orbit to be about 37 degrees from the star’s equator. The results are reported in a paper in the Astrophysical Journal, which was recently posted online and will be published in the journal’s August issue. A majority of the exoplanet discovered so far are very large planets comparable to the gas giants in our solar system, but orbiting their stars much closer in (and thus faster). That’s because the method used to detect these planets makes it much easier to detect such close-in giants than smaller or more distant ones. In the case of XO-3b, it is about 13 times as massive as Jupiter, yet orbits its star with a period, or “year,” of just 3.5 days (Jupiter, by contrast, takes almost 12 years for an orbit). That size and closeness to its star are “unusual, even by the standards of exoplanets,” Winn says. Such “hot Jupiters” – so named because they resemble the solar system’s largest planet, but would be much hotter because of their proximity to their parent stars – could not have formed in the places they are seen now, according to accepted planet-formation theory. They must have formed much further out from the star, then migrated inward to their present positions. Astronomers have come up with different mechanisms to account for the migration: the gravitational attraction of other planets as they passed close by, or the attraction of the disk of dust and gas from which the star and its planets formed. Close encounters with other planets could greatly amplify a slight initial tilt, but attraction from the disk of material could not. Likely, a cataclysmic event occurred in this planet’s past.

This article was first published in The Tablet in December, 2005. I also ran it a year ago on this blog, before many of you became regular readers... and before I knew how to embed pictures. So I am running it again, with pictures this time. Every December, along with the Christmas rush and the endless round of holiday parties, planetary astronomers have another deadline facing them: the annual Lunar and Planetary Science conference. The meeting is in March; the deadline for submitting papers is early January. [For 2016, it's January 12.] It’s challenging enough to write up results on deadline; but what is harder, is that really you ought to have some results worth writing up. My last month has been a scramble as I try chasing after the faintest wisp of an idea to see if it has enough substance to talk about in front of a thousand highly critical peers. Lately [this was 2005] we’ve been observing Centaurs, objects so named because they’re half comet, half Kuiper Belt Object. Their orbits look like they originated out beyond Neptune and Pluto, but they are now traveling in eccentric paths that intersect the orbits of the major planets and will some day be deflected into the inner solar system, where their ices will boil away into the long streams we call comet tails. Some of them are seen to get systematically brighter and fainter over a few hours, implying that they are elongated objects showing us a broad side and a narrow side as they spin. But there’s an interesting connection between spin and shape: the spin wants to pull the object into an elongated shape, while gravity acts to counter that pull. And the innate strength of the body resists both. Measuring elongation against spin, you could in theory get some idea of how dense, or how strong, the body is. Actually coming up with real values for strength and density is much messier than I’ve just made it sound, however. My idea for a paper to submit to this meeting is to talk about some of the asteroids and small moons that we’ve already got shape and density data for: the handful that spacecraft have flown by and imaged, one or two others for which we have indirectly inferred shapes and masses. How does this spin-shape theory actually work for them? That’s meant digging through old papers, finding bits of data for a dozen different bodies, plotting one factor against another, scratching my head, looking for patterns... I found some patterns. Some of them, I expected; but some patterns are complete surprises, and I can’t see why they should exist. I’ve got one plot where the data points make two lovely parallel lines. Why lines? Why parallel? Why two of them? The trouble is, I only have a dozen or so data points. So this pattern could be pure coincidence. Or it could be hinting at something significant. Chance, or eureka? I have to decide which it is, now, before I invest any more time and effort into trying to get more data, or to figure out whatever significance this pattern might (or might not) have. My guess today could lead me to a golden opportunity – or a year’s wasted effort. I pace the cobblestone streets of Castel Gandolfo trying to make up my mind. And all around me people are celebrating the birth of a Saviour. It’s easy enough today to say the right words about peace on Earth, and follow the crowds to the manger scene. But 2000 years ago, the shepherds and the magi had only their hunches to follow. Were those really angels singing? Does that star mean something? How did they know? The Wise Men and the fishermen, the prostitute in Judea and the wealthy woman in Macedonia; what stirred them to jump to this new, strange Gospel of confessing and forgiving sin, to follow a baby born in a stable whose teachings got him hung upon a cross? All of life consists of judgement calls made with inadequate data. Our hunches are shaped by our histories and our knowledge, our fears and hopes. But ultimately they are mysterious... which is only right, as they are what lead us into Mystery itself. [The LPSC abstract can be found here. I never did write it up as a refereed paper; I was never completely convinced, myself, that the patterns were real. One of the great charms of the LPSC is that precisely such tentative ideas can be offered up to the scientific community, to see if they gain traction. This one never did. It happens.]

Pluto, which is only about two-thirds the size of our moon, is a cold, dark and frozen place. Relatively little is known about this tiny planet with the strange orbit. Its composition is presumed to be rock and ice, with a thin atmosphere of nitrogen, carbon monoxide and methane. The Hubble Space Telescope has produced only fuzzy images (above) of the distant object. Pluto's 248-year orbit is off-center in relation to the sun, which causes the planet to cross the orbital path of Neptune. From 1979 until early 1999, Pluto had been the eighth planet from the sun. Then, on February 11, 1999, it crossed Neptune's path and once again became the solar system's most distant planet. It will remain the ninth planet for 228 years. Pluto's orbit is inclined, or tilted, 17.1 degrees from the ecliptic -- the plane that Earth orbits in. Except for Mercury's inclination of 7 degrees, all the other planets orbit more closely to the ecliptic. Interestingly, a similar thing happens with Jupiter's moons: Many orbit on the ecliptic, but some are inclined from that plane. Did you wonder: Will Pluto and Neptune ever collide? They won't, because their orbits are so different. Pluto intersects the solar system's ecliptic, or orbital plane, twice as its orbit brings it "above," then "below" that plane where most of the other planets' revolve -- including Neptune. And, though they are neighbors Pluto and Neptune are always more than a billion miles apart. Some astronomers think Pluto may have wandered into the system of planets from a more distant region known as the Kuiper belt -- a region beyond the orbit of Pluto thought to contain Pluto-like objects and comets that orbit the sun in a plane similar to the planets of the solar system. If that's the case, Pluto is not a planet at all, but is probably more like a large asteroid or comet. Some have also suggested that it may have once been a moon of Neptune and escaped. The International Astronomical Union, the organization responsible for classifying planets, gives these reasons for questioning Pluto's status as a planet: · All the other planets in the outer solar system are gaseous, giant planets whereas Pluto is a small solid object · Pluto is smaller than any other planet by more than a factor of 2. · Pluto's orbit is by far the most inclined with respect to the plane of the solar system, and also the most eccentric, with only the eccentricity of Mercury's orbit even coming close · Pluto's orbit is the only planetary orbit which crosses that of another planet (during 1999 Pluto will again cross Neptune's orbit, thus regaining its status as the most distant planet) · Pluto's satellite, Charon, is larger in proportion to its planet than any other satellite in the solar system. Pluto has one moon, Charon, which was discovered in 1978. The satellite may be a chunk that broke off Pluto in a collision with another large object. Pluto was not discovered until 1930, by amateur American astronomer Clyde Tombaugh. Since Tombaugh's death in 1997, many astronomers have increasingly urged the International Astronomical Union, which names celestial objects, to strip Pluto of its status as a planet. After a news report generated a flurry of irate e-mails about the possible change, officials assured the world that Pluto would remain a planet. But it will also likely become the first in a new class of celestial object known as a TNO, or Trans-Neptunian Object. It seems Pluto may then have a sort of dual citizenship.

Two luminous eyes and a mouth stretched in a smile — such a telescope was found in distant space. An unusual combination of cosmic structures found in the galaxy cluster SDSS J0952 + 3434. The “Smile of the Universe” image was captured using the WFC3 camera of the Hubble telescope. There is nothing unusual in this combination. First, the galaxies that form the “face” are quite far from each other; the fact that they are so visible from Earth is just an accident. Secondly, the mouth-shaped galaxy also has its explanation. The light from it on its way to Earth passed by some massive object, as a result of which it was distorted. This phenomenon is called the “gravitational lensing effect”. The Hubble telescope made this photo as part of a mission to study star formation in distant galaxies. The WFC3 camera, due to its high resolution and sensitivity in the infrared and ultraviolet ranges, is excellent for this job. It provides an unprecedentedly clear picture of the star-forming regions.