| A | B |
|---|
| rotation | the spin of a body around its axis |
| period of revolution | the time that it takes a planet to go around the sun |
| location of asteroid belt | between Mars and Jupiter |
| orbit | the path of one body as it revolves around another |
| astronomical unit | the average distance from theh Earth to the sun, 8.3 light-minutes |
| light-year | the distance light travels in a year |
| light-second | the distance light travels in a second |
| planet | a very large body, bigger than an asteroid, in orbit around a star |
| sun | a star that makes up most of the mass of the solar system |
| moon | a natural body that orbits a planet |
| satellite | something that orbits a planet, can be natural or artificial |
| comet | small body of ice and rock that revoves around the sun in an irregular pattern |
| asteroid | object that arevolves around the sun, bigger than a meteoroid, in a regular pattern |
| meteroids | small rocky body orbiting the sun |
| meteor | a streak of light from meteroid |
| meteorite | a meteoroid that has struck Earth |
| Oort Cloud | an area that comets are believed to be |
| Kuiper Belt | an area of comets just outside of Neptune |
| Luna | the name of our moon |
| solar eclipse | when the moon blocks light from Earth |
| lunar eclipse | when the Earth blocks light from the moon |
| inner planets | Mercury, Venus, Earth and Mars |
| outer planets | Jupiter, Saturn, Uranus, Neptune and Pluto |
| terrestrial planets | Mercury, Venus, Earth and Mars |
| gas giants | Jupiter, Saturn, Uranus and Neptune |
| Which planets have rings? | Jupiter, Saturn, Uranus and Neptune |
| Which planets have no moons? | Mercury and Venus |
