| A | B |
|---|
| asteroid | Any minor planet that orbits thesun between Mars and Jupiter |
| coma | Spherical region of glowing gas which surrounds the nucleus of a comet |
| comet | Relatively small, icy body having a very eccentric orbit around the sun |
| head | Nucleus and coma of a comet |
| Leonids | Shower of meteors occuring about November 17 which appears to be coming out of the constellation Leo |
| meteor | Mass of stone or metal that enters the earth's atmosphere from space and glows as it falls through the atmosphere |
| meteorite | Meteor that survives the fall through the earth's atmosphere and hits the ground |
| meteoroid | A mass of stone or matal that orbits the sun which can become a meteor |
| nucleus | Relatively dense central part of a comet's head |
| periodic comet | Comet that keeps returning because of an elliptical orbit |
| Perseids | Shower of meteors occuring each August which appears to be coming out of the constellation Perseus |
| tail | Long, tenuous streamer behind the head of a comet |
| train | Lighted trail behind a fireball |
