what are Asteroid
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Asteroid belt
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Astronomical unit
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Comet
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Core
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Crust
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Fossil
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Gravity
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Greenhouse effect
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Greenhouse gas
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Mantle
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Meteor
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Meteorite
Orbit
Planet
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Solar system
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Space debris
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Star
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Asteroids are small, rocky objects that orbit the Sun. They are found mainly in the asteroid belt between Mars and Jupiter. Most asteroids are irregularly shaped and range in size from a few meters to hundreds of kilometers across. They are composed of rock and metal, and some contain ice and organic compounds. Asteroids are believed to be the remains of the building blocks that formed the planets.