Asteroids

The asteroid belt lies between the orbits of Mars and Jupiter though some asteroids have been found within Earth's obit and beyond that of Jupiter.

The asteroid belt is composed of millions of rocky and metallic objects from the size of pebbles up to the largest asteroid, Ceres, which is 1 km in diameter.

Asteroids are probably material which was left over after the formation of the solar system although one theory suggests that they are the remains of a planet destroyed in a collision.

Asteroids occasionally strike Earth as here in Barringer, Arizona. An asteroid may have caused the extinction of the dinosaurs, could it happen again? In 1994 scientists had a very good look at the remains of comet Shoemaker Levy 9 crashing into Jupiter.

http://www.thepcmanwebsite.com/media/flash_asteroids/