Unit 6-1

2. n., an imaginary line around which Earth spins or rotates
5. n., the force that keeps Earth in an orbit around the Sun
6. n., on order of succession, or one thing after another
9. n., the Sun and all of the heavenly bodies that orbit it
14. adj., not following the normal pattern
15. n., fuzzy clouds made of ice, rock, and dust that look like streaks of light in the night sky
16. n., a group of stars that form a figure in the sky
17. n., a person whose work is, or who studies, astronomy

1. n., a large group of stars
3. n., everything that exists, including Earth, the planets, the stars, and the Sun
4. n., the changing views of the Moon
7. n., the degree of coldness or hotness in an environment
8. n., the outside parts or outermost layers of something
10. n., a complete circle or turn of Earth around the Sun
11. v., revolves around in space
12. n., small objects that orbit the Sun
13. n., a substance, such as air, that can expand to take the shape of the space available