| A | B |
|---|
| asteroid | a small, rocky body, which can range in size from a few hundred kilometers to less than a kilometer; The asteroids’ orbits lie mainly between those of Mars and Jupiter. |
| coma | the fuzzy, gaseous component of a comet’s head |
| comet | a small body made of rocky and metallic pieces held together by frozen gases; Comets generally revolve about the sun in an elongated orbit. |
| Jovian planet | the Jupiter-like planets: Jupiter, Saturn, Uranus, and Neptune; These planets have relatively low densities and are huge gas giants. |
| meteor | the luminous phenomenon observed when a meteoroid enters Earth’s atmosphere and burns up, popularly called a shooting star |
| meteorite | any portion of a meteoroid that reaches Earth’s surface |
| meteoroid | a small, solid particle that travels through space |
| nebula | a cloud of gas and/or dust in space |
| planetesimal | small, irregularly shaped body formed by colliding matter |
| terrestrial planet | any of the Earth-like planets, including Mercury, Venus, Mars, and Earth |
