A Journey Through Our Solar System

- 18 Jan 2010

From the OSR Blog

Our solar system is an awesome sight and contains an array of planets, moons, stars, comets, and asteroids, along with the Sun. All of the planets in the solar system revolve around the Sun, which is itself a giant star. But this is not all there is to outer space. The Sun revolves around the center of our galaxy, the Milky Way, and the Milky Way is just a small part of a larger group of galaxies. The area of space occupied by our solar system is tiny when compared to the rest of outer space and the Universe, which contains billions of other galaxies.

Our solar system is unique because it is the only one found, so far, that contains all of the properties for sustaining life. Other galaxies may contain stars similar to the Sun, but the Sun is what allows us to have life. The Sun’s gravity keeps Earth and the other planets in the solar system from flying off into deep space, and the Sun keeps the Earth warm, allowing living things to flourish. Without the heat from the Sun, our planet would be completely frozen and not allow life to exist.

The solar system is also unique for its location. Because we are relatively far away from other stars, we do not suffer from potential harmful effects related to exploding stars, gas clouds, and other sources of radiation. In addition, the outer planets of our solar system provide protection to the Earth from dangerous bodies such as large comets and asteroids.

1. Planets

Our solar system contains eight planets. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto used to be designated as a planet but was re-categorized as a ‘dwarf planet’ a few years ago. All of the planets revolve around the Sun. The planets closest to the Sun, which are Mercury, Venus, Earth, and Mars, are called inner planets, and the planets further away, which are Jupiter, Saturn, Uranus, Neptune, and Pluto, are called outer planets. The inner planets are separated from the outer planets by the Asteroid Belt. The four outer planets of Jupiter, Saturn, Uranus, and Neptune each have rings around them.


The planet Mercury is the closest planet to the Sun. It is a small and rocky planet, and it has no moons.


The planet Venus is the 2nd planet from the Sun. It was named after the Roman Goddess Venus. Like Mercury, it has no moons.

  • Venus: A site with scientific data and other interesting facts about the planet Venus.
  • Venus: A site with scientific data and interesting facts about Venus, including mythology.


The planet Earth is the largest of the inner planets. It has one moon and is the only planet that has all the means to support life.


The planet Mars is small and rocky. Its nickname is the ‘Red Planet’ due to the color of its soil. Mars has two moons.

  • Mars: A site with interesting facts about the planet Mars from the National Maritime Museum.
  • Mars: The Red Planet: This site contains some interesting facts about Mars.


The planet Jupiter is the largest of all the planets. Its surface is made up of a thick layer of hydrogen gas. Jupiter has at least 16 officially recognized moons.

  • Jupiter: This site has a lot of interesting information and several fun facts about Jupiter.


The planet Saturn is the 2nd largest of all the planets. It has 18 known moons and is famous for its beautiful rings.

  • Saturn: This site has a ton of information about the planet Saturn, including information about missions to the planet and about its moons.
  • Saturn: This site contains a lot of scientific data about Saturn and also information about its physical characteristics and its moons.


The planet Uranus is the 3rd largest of all the planets. It is unique in that it is tilted on its side and actually spins that way. It has at least 27 known moons.

  • Uranus: This site has many interesting facts about the planet Uranus.
  • Uranus: This site has information about the physical aspects of Uranus.


The planet Neptune is bluish in color due to the methane gas found in its atmosphere. It contains rings like Saturn and has about 13 known moons.

  • All About Neptune: This site has several interesting facts about the planet Neptune.
  • Neptune: This site has interesting information and scientific data about Neptune.


Pluto was once considered a planet, but because of its small size it is now considered a dwarf planet. It is smaller than seven moons found in our solar system. One of Pluto’s three moons is just slightly smaller than itself.

  • Pluto: This site has lots of interesting facts about the planet Pluto.

2. Sky Wonders

Many wonders can be seen in the vast sky. Aside from planets and stars, other phenomena such as lunar and solar eclipses, comets, asteroids, and meteor showers can be seen. By studying the wonders in our own galaxy, scientists are able to learn more about our world and to use that knowledge in seeking evidence and information about other possible worlds far away.

Aphelion, Perihelion and Opposition

Aphelion and perihelion are terms that refer specifically to objects that orbit the sun. Aphelion is the furthest point from the sun of a planet’s orbit, and perihelion is the closest point. The term opposition refers to the position of two objects in space when they are 180° apart. In astronomy terms, it usually refers to the position of planets when they are in opposition with the sun.

  • Mars Opposition: This site describes the opposition of Mars which occurred in 2003 along with other unique facts about the planet.
  • Perihelion and Aphelion: This site helps to explain the terms aphelion and perihelion in regard to planetary motion.

Lunar Eclipses

Lunar eclipses happen when the moon passes through the Earth’s shadow. Unlike with a solar eclipse, it is not dangerous to look directly at a lunar eclipse. This is because the moon does not produce its own light.

  • Lunar Eclipse: This site tells what a lunar eclipse is and how it forms.

Meteor Showers

Meteor showers are narrow streaks of light often seen shooting across the night sky. They are often referred to as shooting stars or falling stars, but they are not stars at all. They are just simply dust particles that are burning up in the Earth’s atmosphere.

Red Shift

The light waves that are sent out from galaxies have been found to be shifted toward the red end of the light spectrum. Studies have indicated that red shifted galaxies are moving further away from our own galaxy and doing so at a faster rate of speed. This means that the Universe is expanding and doing so at an ever-quickening pace.

  • Red Shift: This page from Georgia State University explains what a red shift is.

Solar Eclipses

Solar eclipses happen when the moon passes in front of the sun and blocks the sun’s light from the Earth. It is not recommended to look directly at the sun during a solar eclipse because the brightness level that can be experienced after the eclipse occurs can cause permanent damage to the eyes.

3. Constellations

A constellation can be defined as a group of stars that can be seen in a particular region of the sky at night. Different ones can be seen throughout various times of the year depending upon the hemisphere you are in. The constellations have distinctive patterns that allow them to be recognized fairly easily. They have provided civilizations throughout history with a means to tell the stars apart and thus to be able to tell what time of the year it is. This was especially important to farmers in ancient civilizations. In astronomical terms, a constellation consists of a defined area of the sky that contains all of the celestial objects within that area.


The Andromeda constellation is the furthest object in space that can be seen with the naked eye. It is approximately 250 million light years away. It is best viewed in the fall in the northern hemisphere.

  • Andromeda: This site give basic information about the Andromeda constellation, including its mythological history.

The Big Dipper

The Big Dipper is part of the constellation called Ursa Major, the Great Bear. The Big Dipper played a huge part in early US history, as it was used in the Underground Railroad to help fleeing southern slaves find their way north.

  • Big Dipper: This site has information and pictures to help people identify the Big Dipper.
  • The Great Bear Constellation: This site contains information about the constellations Ursa Major and Ursa Minor.

Canis Major – The Great Dog

Canis Major is a constellation that represents one of Orion’s dogs. Orion is a mythical Greek hunter who also has a constellation named after him. The brightest star in the Canis Major constellation is Sirius. This star is also the brightest in the entire sky.

  • Canis Major, the Great Dog: This site gives a few facts about Canis Major along with a great picture showing the layout of the constellation.
  • Canis Major: This site from Michigan State University gives some facts about Canis Major and has a star map.

Cygnus – The Swan

Cygnus is a northern constellation whose name mean swan. This constellation is sometimes called the Northern Cross because of its shape.

  • Cygnus: This site from the Harvard-Smithsonian Center for Astrophysics gives information about the constellation Cygnus, particularly its mythological history.

Gemini – The Twins

The constellation Gemini is a constellation of the zodiac. Its alpha and beta stars represent the twin brothers Castor and Pollux. Two annual meteor showers are associated with this constellation.

  • Surfing Gemini – The Twins: This site from the Fox Valley Astronomical Society gives a lot of information about the constellation Gemini, including mythological history and a star map.

Orion – The Great Hunter

The constellation Orion is named after the Greek mythological hunter named Orion. This constellation is visible throughout the world and is one of the most recognized. Orion has one annual meteor shower associated with it.

Scorpius – The Scorpion

The constellation Scorpius is another zodiac constellation. The name Scorpius comes from the fact that its pattern resembles a scorpion. There are two annual meteor showers associated with this constellation.

  • Scorpius: This site from the Hawaiian Astronomical Association gives the mythological history of Scorpius along with some star maps and other images.

Taurus – The Bull

Taurus, known as the Bull, is another of the zodiac constellations and is one of the oldest recognized constellations. It has one annual meteor shower associated with it.

  • Taurus: This site from the Birmingham University Guild of Students gives some basic mythological history for the constellation along with some pictures and information detailing the features of Taurus.

Other Constellations

There are a total of 88 officially recognized constellations. Twelve of the constellations refer to the Zodiac. The others are constellations of the northern and southern hemispheres.

  • Alphabetical listing of Constellations: This site from the University of Wisconsin contains an alphabetical listing with links to the 88 constellations.
  • The Constellations: This site from the University of Illinois has a brief introduction to the constellations and also a chart with links, abbreviations, and meanings behind the constellation names.
  • Guide to the Constellations: This site contains a guide with descriptions of the individual constellations.

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