Unit 2

6. planets – Jupiter, Saturn, Uranus & Neptune
9. (about 5000 years old) – Celtic 3-dimensional calendar
10. – a meteor that makes it to Earth’s surface
11. – also called “minor planets” are small rocky/metallic debris left over from the beginning of the solar system
13. is Latin for “earth” or “land”
17. – meteoroids burning up in Earth’s atmosphere
18. Planetology – comparing & contrasting properties of worlds to understand how they evolved

1. (1000 years old) – Mayan temple that was much more sophisticated than Stonehenge
2. Belt - region of the solar system past Neptune's orbit which contain minor & dwarf planets
3. – orbits the Sun; not a satellite; cleared out its orbit of debris & is round
4. – relatively small “dirty snowballs” that orbit the Sun in highly elongated orbits
5. – natural satellite orbiting a larger body
7. – the amount of the “compactness” of matter
8. – smaller pieces (<100m) of asteroids resulting from collisions
9. One star (the Sun); 8 major planets
12. Planet – massive enough to be a round body; has not cleared its orbit of debris
14. Belt – groups of asteroids between Mars & Jupiter
15. planets – Mercury, Venus, Earth & Mars
16. cloud - an immense spherical cloud surrounding the planetary system and extending approximately 3 light years from the Sun