Solar system

​The solar system consists of the sun, the planets and other objects that revolve around it.​

The distance between objects in the solar system is not easily measured.

Astronomical unit (AU) is a unit of distance between Earth and the sun, about ​150 million kilometers.

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​The moon is .0025 AU away from Earth

Distances in the solar system

The sun is a gaseous body much larger than anything else in the solar system. In fact, the sun accounts for about 99.85 percent of the entire mass of the solar system.

The Sun

A planet is round, orbits the sun and has cleared out the region of the solar system along its orbit.

​​Planets

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The four inner planets, including earth, are closest to the sun. The are made of rock and metal.

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​The four inner planets have a solid, rocky surface.

​The inner planets

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The outer planets are farthest from the sun. They are very large and made of mostly gas and liquid.

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​all of the outer planets have rings. Saturn's are the most visible.

The outer planets.

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Dwarf Planets are planets that are large enough to form a spherical body but not large enough to clear the area of debris. There are 5 dwarf planets.

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​Eris and Pluto are the same size. Eris is 3x farther from the sun.

Pluto was considered the ninth planet in our solar system for many years. Astronomers now classify it as a dwarf planet. Asteroid Ida, identified in 1884, is the first observed asteroid with a moon.​

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Pluto and Ida