Instruct: Given a question, retrieve passages that answer the question.
Query: How does Mars get its red color?
Red is the color at the end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. The red sky at sunset results from Rayleigh scattering, while the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. Iron oxide also gives the red color to the planet Mars. The red colour of blood comes from protein hemoglobin, while ripe strawberries, red apples and reddish autumn leaves are colored by anthocyanins.
Several planets or dwarf planets in the Solar System (such as Neptune and Pluto) have orbital periods that are in resonance with each other or with smaller bodies (this is also common in satellite systems). All except Mercury and Venus have natural satellites, often called "moons". Earth has one, Mars has two, and the giant planets have numerous moons in complex planetary-type systems. Many moons of the giant planets have features similar to those on the terrestrial planets and dwarf planets, and some have been studied as possible abodes of life (especially Europa).
The timestamps printed on the photos in the NASA press release do not correspond to the actual time that the shadow was imaged, rather they represent the "image start time" of a vertically much larger original image. Mars Global Surveyor orbits Mars in a Sun-synchronous polar orbit with orbital period 117.65 minutes, moving from south pole to north pole, and continuously points its camera straight down. The result is an image in the form of a very long thin vertical strip, where the pixels in the top part of the image are imaged nearly one hour after those in the bottom part of the image. In principle the image could be as much as 43200 pixels high, but "downtrack summing" is used to merge adjacent lines. For instance, a downtrack summing factor of 27 causes every 27 lines to be merged into one, resulting in an image 1600 pixels high. Thus to determine the actual time that the Phobos shadow was imaged, it is necessary to locate the original image and measure how many pixels from the bottom of the image the shadow is found and add the corresponding offset to the image start time.
Spirit, also known as MER-A (Mars Exploration Rover – A) or MER-2, is a robotic rover on Mars, active from 2004 to 2010. It was one of two rovers of NASA's ongoing Mars Exploration Rover Mission. It landed successfully on Mars at 04:35 Ground UTC on January 4, 2004, three weeks before its twin, "Opportunity" (MER-B), which landed on the other side of the planet. Its name was chosen through a NASA-sponsored student essay competition. The rover became stuck in late 2009, and its last communication with Earth was sent on March 22, 2010.
The mission will seek signs of habitable conditions on Mars in the ancient past, and will also search for evidence —or biosignatures— of past microbial life. The rover is planned for launch in 2020 on an Atlas V-541, and the Jet Propulsion Laboratory will manage the mission. The mission is part of NASA's Mars Exploration Program.
NASA's "Mars Pathfinder" spacecraft, launched one month after Global Surveyor, landed on July 4, 1997. Its landing site was an ancient flood plain in Mars' northern hemisphere called Ares Vallis, which is among the rockiest parts of Mars. It carried a tiny remote-controlled rover called Sojourner, which was the first acting Mars rover that traveled a few meters around the landing site, exploring the conditions and sampling rocks around it. Newspapers around the world carried images of the lander dispatching the rover to explore the surface of Mars in a way never achieved before.
The largest and most conspicuous volcanoes on Mars occur in Tharsis and Elysium regions. These volcanoes are strikingly similar to shield volcanoes on Earth. Both have shallow-sloping flanks and summit calderas. The main difference between Martian shield volcanoes and those on Earth is in size: Martian shield volcanoes are truly colossal. For example, the tallest volcano on Mars, Olympus Mons, is 550 km across and 21 km high. It is nearly 100 times greater in volume than Mauna Loa in Hawaii, the largest shield volcano on Earth. Geologists think one of the reasons that volcanoes on Mars are able to grow so large is because Mars lacks plate tectonics. The Martian lithosphere does not slide over the upper mantle (asthenosphere) as on Earth, so lava from a stationary hot spot is able to accumulate at one location on the surface for a billion years or longer.
Among the notable discoveries was COROT-7b, discovered in 2009 which became the first exoplanet shown to have a rock or metal-dominated composition.
The USSR intended to have the first artificial satellite of Mars beating the planned American Mariner 8 and Mariner 9 Mars orbiters. In May 1971, one day after Mariner 8 malfunctioned at launch and failed to reach orbit, Cosmos 419 (Mars 1971C), a heavy probe of the Soviet Mars program M-71, also failed to launch. This spacecraft was designed as an orbiter only, while the next two probes of project M-71, Mars 2 and Mars 3, were multipurpose combinations of an orbiter and a lander with small skis-walking rovers that would be the first planet rovers outside the Moon. They were successfully launched in mid-May 1971 and reached Mars about seven months later. On November 27, 1971 the lander of Mars 2 crash-landed due to an on-board computer malfunction and became the first man-made object to reach the surface of Mars. On 2 December 1971, the Mars 3 lander became the first spacecraft to achieve a soft landing, but its transmission was interrupted after 14.5 seconds.
Mars 3 was an unmanned space probe of the Soviet Mars program which spanned the years between 1960 and 1973. Mars 3 was launched May 28, 1971, nine days after its twin spacecraft Mars 2. The probes were identical robotic spacecraft launched by Proton-K rockets with a Blok D upper stage, each consisting of an orbiter and an attached lander. After the Mars 2 lander crashed on the martian surface, Mars 3 lander became the first spacecraft to attain soft landing on Mars on 2 December 1971. It failed shortly after landing.The type of Orbiter was the Variant M-71 of the Bus/Obiter 4M-V. The primary purpose of the orbiter was to study the topography of the surface; analyze its soil composition; measure various properties of the atmosphere; monitor "solar radiation, the solar wind, and the interplanetary and martian magnetic fields". In addition, it served as a "communications relay to send signals from the lander to Earth".
The smallest known extrasolar planet that is likely a "gas planet" is Kepler-138d, which has the same mass as Earth but is 60% larger and therefore has a density that indicates a thick gas envelope.
On 19 May 2017, MOM reached 1,000 days (973 sols) in orbit around Mars. In that time, the spacecraft completed 388 orbits of the planet and relayed more than 715 images back to Earth. ISRO officials stated that it remains in good health.
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Mars 2020 is a Mars rover mission by NASA's Mars Exploration Program with a planned launch in July or August 2020. It will investigate an astrobiologically relevant ancient environment on Mars, investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and the potential for preservation of biosignatures within accessible geological materials. It will cache sample containers along its route for a potential future Mars sample-return mission.
Lava sometimes forms a tube as it moves away from the vent (opening from which lava flows from a volcano). The top of a stream of lava cools down, thereby forming a solid roof. Meanwhile, the lava continues moving in the tube. Often, when all the lava leaves the tube, the roof collapses, making a channel. These features are found on Mars. Some can be seen around Pavonis Mons, in the picture below. Some people have suggested that future colonists on Mars could use lava tunnels as shelters. They would offer great protection from radiation, especially ultraviolet radiation. Lava Channels on the flank of the volcano Pavonis Mons are pictured below in a picture from Mars Odyssey THEMIS. Sometimes the lava tube remains intact for a time. Lava will break out along the tube to accumulate or flow away. Lava flows often have a lobate appearance at the edges. A good view of such a lava tube is shown below.
Viking 1 was the first of two spacecraft (along with "Viking 2") sent to Mars as part of NASA's Viking program. On July 20, 1976, it became the second spacecraft to soft-land on Mars, and the first soft lander to successfully perform its mission. (The first spacecraft to soft-land on Mars was the Soviet Union's Mars 3 on December 2, 1971, which stopped transmitting after 14.5 seconds.) "Viking 1" held the record for the longest Mars surface mission of days (over 6¼ years) or Martian solar days, until that record was broken by "Opportunity" on May 19, 2010.
The dwarf planet Ceres is by far the largest asteroid, with a diameter of . The next largest are 4 Vesta and 2 Pallas, both with diameters of just over . Vesta is the only main-belt asteroid that can, on occasion, be visible to the naked eye. On some rare occasions, a near-Earth asteroid may briefly become visible without technical aid; see 99942 Apophis.
The cover of the album features an image by Viking 1, the first spacecraft to land on Mars; the album's liner notes include additional imagery of the planet's landscape as taken by the spacecraft on July 20, 1976. The text on the cover was done by fantastic artist Roger Dean, best known for his work on album covers for bands such as Yes. The album's title comes from the tour in the film "Total Recall".
Gravity on Mars is only about 38% as strong as it is on Earth, and the long-term effects of such reduced gravity are unknown. Astronauts who are weightless for long periods of time lose significant amounts of bone and muscle mass. It is unclear if the gravity on Mars is strong enough to avoid or minimize these health problems. The Mars Gravity Biosatellite was meant to provide data on how mammalian health is affected by long-term exposure to lower levels of gravity, focusing on bone loss, changes in bone structure, muscle atrophy, and changes in the inner ear. The results from the five-week mission experiment would have been compared against a variety of Earth-based controls, including vivarium, hindlimb suspension, partial weight suspension, flight habitat effects, and short-radius centrifuge testing.
Although their location in the asteroid belt excludes them from planet status, the three largest objects, Ceres, Vesta, and Pallas, are intact protoplanets that share many characteristics common to planets, and are atypical compared to the majority of "potato"-shaped asteroids. The fourth largest asteroid, Hygiea, has an undifferentiated interior, like the majority of asteroids. Between them, the four largest asteroids constitute half the mass of the asteroid belt.
While red is the color most associated with love, it also the color most frequently associated with hatred, anger, aggression and war. People who are angry are said to "." Red is the color most commonly associated with passion and heat. In ancient Rome, red was the color of Mars, the god of war—the planet Mars was named for him because of its red color.
"M. rubra" gets its red color from consuming cryptophytes, or algae, that contain a red pigment called phycoerythrin in their chloroplasts.  In the Columbia River estuary, "M. rubra" commonly preys on the cryptophyte "Teleaulax amphioxeia." From its prey, "M. rubra" also acquires specialty cellular organs in order to photosynthesize and effectively absorbs these compounds into its own body. This process is referred to as "acquired phototrophy", and for "M. rubra" includes the assimilation of chloroplasts, nuclei, and mitochondria During the day, the ciliates stay near the surface of the water to photosynthesize, which is how the red blooms are easily observed.
The design of the flag was originally conceived by NASA planetary scientist Pascal Lee during the 1998 Haughton-Mars Project arctic expedition to Devon Island, Canada. In addition to symbolizing liberty as a tricolour flag, the design evokes a vision of the "future history" of Mars in which the planet is transformed from red, to green, and then blue like the Earth. The red bar, which lies closest to the mast, symbolizes Mars as it is today. The green and blue symbolize stages in the possible terraforming of Mars, should humanity ever have the ability and will to undertake such a task; the ethics of terraforming remaining a matter of debate. Kim Stanley Robinson's popular science-fiction trilogy "Red Mars", "Green Mars", and "Blue Mars" also provided inspiration for the flag. Beyond any human-induced terraforming, the color sequence also depicts the environmental change Mars might experience on astronomical timescales as the Sun evolves into a red giant and Mars becomes warmer. In the Pantone Color Matching System (PCMS), the red is the "Red Clay" (18-1454), the green is the "Mint Green" (17-6333), and the blue is the "Imperial Blue" (19-4245).
The apparent colour of the Martian surface enabled humans to distinguish it from other planets early in human history and motivated them to weave fables of war in association with Mars. One of its earliest recorded names, Har decher, literally meant "Red One" in Egyptian. Its color may have also contributed to a malignant association in Indian astrology, as it was given the names "Angaraka" and "Lohitanga", both reflecting the distinctively red color of Mars as seen by the naked eye. Modern robotic explorers have shown that not only the surfaces, but also the skies above may appear red under sunlit conditions on Mars.