Big Idea 5 Vocabulary

4. The layer of air or other gases around it. Thin in inner planets and thick in outer planets.
8. The path of an object around a particular point in space.
10. A natural object that orbits a planet.
11. A large object in space that is made of gas and produces its own light.
13. The four planets closest to the sun; Mercury, Venus, Earth, or Mars.
14. A group of billions of stars, gas, dust, and objects that orbit the stars.
17. The four gas giants planets farthest from the sun; Jupiter, Saturn, Uranus, or Neptune.
18. A medium sized star. Closest star to Earth that provides light and heat energy.
19. The different ways the Moon looks from Earth over about a month. Repeats every month.

1. When the right half of the lit portion of the Moon is visible to us. It comes a week after New Moon.
2. A real or imaginary line through the center of an object, around which the object turns.
3. Phase when we can see the entire lit portion of the Moon.
5. Our home galaxy.
6. The spinning of an object around an axis or center.
7. An object made of rock, ice, dust, and gas that revolves around the Sun and has a tail.
9. A large chunk of rock and metal with an irregular shape that orbits the Sun and is much smaller than a planet.
12. The motion of one object around another object.
15. When the Moon cannot be seen because we are looking at the unlit half of the Moon.
16. A large body in space that orbits a star and does not produce its own light.