Chapter 1 Crossword

2. The large, dark flat areas on the moon.
7. The most common gas in the atmosphere.
9. The apparent backward motion of a planet.
10. This person discovered three laws concerning how planets move.
13. The apparent curving of projectiles due to the earth's rotation.
14. The _______ of the earth is 23 1/2 degrees.
18. When the moon casts a shadow on the earth.
22. The pull of a planet or moon due to its mass.
23. Geocentric explanation for why some planets sometimes go backwards.
24. This person is known for creating a telescope from the spy glass.
25. This person described gravity as the force which holds a planet in orbit.
26. When the moon is closest to the earth.
29. The earth has this in abundance.
30. The second most common gas in the atmosphere.
31. The pattern of light and shadow observed on the moon over a period of 28 days.
32. The geocentric explanation for why a planet's brightness changes.

1. The most common surface feature of the moon.
3. The first day of summer and winter.
4. The earth is the center of the universe.
5. The name of the earth's moon.
6. The shift of position of closer stars compared to stars that are further away because we are going around the sun.
8. The path of the sun through the sky.
11. The name of a scientific device which demonstrates the earth's rotation.
12. The person who said the earth is the center of the universe.
15. When the earth casts a shadow on the moon.
16. The physical force which causes the earth to have a bulge as it rotates.
17. When the moon is furthest from the sun.
19. The person who discovered that the sky changes.
20. The first person to say the sun is in the center.
21. The amount of speed an object would need to escape a planet's (or moon's) gravity.
27. Channels for flowing lava on the moon.
28. The first day of fall and spring.