What is an Asteroid?

Asteroids are small rocky or ice bodies that orbit the sun. They are sometimes called minor planets. Most asteroids are found in an orbit between Mars and Jupiter, and more than 7000 of them have been identified. Asteroids are smaller than any of the planets, and only a few have a diameter of over 30 km. The term asteroid is usually applied to objects larger than 1.6 km in diamter. One asteroid, called Ida, has a tiny moon of its own; this is the smallest known satelite in the Solar System. Asteroids were probably formed at the same time as the planets