The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It consists of the following:
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The Sun: The star at the center of the Solar System, which contains 99.8% of the Solar Systems mass.
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Planets: There are eight planets in the Solar System, in order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The first four planets are terrestrial planets, while the last four are gas giants or ice giants.
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Dwarf planets: These are smaller than planets and are not considered full-fledged planets. Pluto is the most famous dwarf planet.
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Moons: There are more than 200 moons in the Solar System, with most orbiting the gas giants.
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Asteroids: These are small, rocky objects that orbit the Sun, mostly found in the asteroid belt between Mars and Jupiter.
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Comets: These are icy objects that orbit the Sun and have a tail that points away from the Sun.
The Solar System is located in an outer spiral arm of the Milky Way galaxy. It extends from the Sun, goes past the four inner planets, through the asteroid belt to the four gas giants, and on to the disk-shaped Kuiper Belt and far beyond to the teardrop-shaped heliopause. The edge of the Solar System is estimated to be about 9 billion miles (15 billion kilometers) from the Sun.
