An asteroid is not round like a planet. It looks like a rock. It is made of a stone or metal. An asteroid can be as small as a baseball. It can be bigger than eight football fields put end to end!

An asteroid is found in an asteroid belt. An asteroid belt contains millions of asteroids of all sizes. Scientists think that the asteroid belt was made after a planet exploded millions of years ago. They think there was once a planet between Mars and Jupiter. Now all that is left is the asteroid belt.

Asteroids orbit the sun. Most asteroids are about 2,000,000 (two million) miles from the sun. It takes an asteroid four to five Earth years to orbit the sun.

The largest rock in the asteroid belt is Ceres. Ceres is now called a dwarf planet. Several space probes have taken samples from the asteroid belt. These samples help scientists learn more about our solar system.