Other asteroids have highly elliptical orbits that take them very close to the Sun. Occasionally, collisions and gravitational close encounters can push asteroids out of the asteroid belt and send them careening inward towards the sun. Occasionally, some of these particles may come close enough to the Earth to get caught by its gravity. They may enter the atmosphere as meteors. If they survive the heat of entry and strike the ground, the will be referred to as meteorites.
Scientists can study meteorites to learn more about the asteroids from which they originated.
Dirty Snowballs Comets are essentially large balls of rock and ice. The ice that forms a comet can consist of both water ice and frozen gases. Astronomers believe that comets may be formed from the very material that created the early solar system. Several missions are in the works to return samples from a comet in hopes that they will help us to better understand the history of our solar system. We all think of comets as having a tail.