Asteroid Belt
http://en.wikipedia.org/wiki/Asteroid_belt
The Asteroid Belt is located between Mars and Jupiter. It is 2.3-3.3 AU from the Sun. It is home to millions of rocks known as asteroids. It contains thousands of objects with a diameter over 1km. Asteroids with a diameter between 10 and 10-4 m are classified as meteors. The total mass of the whole belt is approximately one thousandth of the Earth's. The four largest asteroids in order are Ceres, Vesta, Hygeia, and Pallas. These four account for more than half the mass of the whole Asteroid Belt. Ceres is the only dwarf planet in the Asteroid Belt. It has a diameter of 950km. The other three have diameters around 400km. The remaining objects can range down to be as small as dust particles. The asteroids are dispersed so widely that unmanned space crafts have made it through without collision. Large asteroids occasionally collide and break into smaller bodies that sometimes turn into a asteroid family. These are groups of asteroids whose orbital patterns and compositions are similar. Scientist think that asteroids are the remnants of the solar system that didn't form into a planet.