Asteroid: A small rocky bodies orbiting the sun. Large numbers of these, ranging in size from nearly 600 miles (1,000 km) across to dust particles
Meteoroids: A small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.
Meteor: A small body of matter from outer space that enters the earth's atmosphere, appearing as a streak of light.
Meteorite: Is a meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground.
Comet: Is a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and gas that may form a tail that streams away from the sun.