| A | B |
|---|
| planet | a large body that orbits a star |
| moon | an object that orbits a planet |
| solar system | the Sun and all the planets, moons, and other bodies traveling around it |
| inertia | the tendency of a moving object to stay in motion |
| asteroid | rocky or metallic objects that orbit the Sun |
| comet | a ball of ice and rock that orbits the Sun |
| meteoroid | a small rocky object that orbits the Sun in both the inner and outer regions of the solar system |
| meteor | a meteoroid that enters the Earth's atmosphere |
| meteorite | a meteoroid that strikes the Earth's surface |
| inner planets | planets closest to the Sun - Mercury, Venus, Earth, Mars |
| outer planets | larger planets beyond the asteroid belt - Jupiter, Saturn, Uranus, Neptune |
| gas giants | the outer planets with a small, metallic core and a thick atmosphere |
