The small pieces of rocks or metals which revolve around the sun, in between the orbits of Mars and Jupiter are called asteroids. Asteroids are smaller than planets. Hence, they are also called minor planets. Each asteroid has its own orbit around the Sun. In fact, the orbits of asteroids are spread over a large distance forming a band.

The bright star-like objects with a long tail, approaching the sun in a highly elliptical orbit are called comets. It revolves in a specific orbit around the Sun. Unlike planets, the comets do not last forever in the solar system. It is because as they approach the sun, they lose a good amount of their mass in the form of gases and small chunks of rocks. Thus, they become smaller and smaller and finally disappear.

The bright star-like objects which appear suddenly in the sky and then for a few moments glow with a brilliant white flash of light falling towards the earth and finally disappear are called meteors. A meteor lasts for a very short time because the tiny rocky pieces (of which it is made), burn and vaporise completely in a few seconds due to the excessive heat produced by atmospheric friction.