Across
- 2. the ancient model that the Earth stayed motionless at the center of the universe
- 5. the center of mass of 2 or more bodies
- 7. current model that shows Earth and the other planets orbit the sun
- 12. made of planets, stars, and other objects in space
Down
- 1. states that at one time, the entire universe was confined to a dense, hot supermassive ball that violently exploded 13.7 billion years ago
- 3. oval shape of a planet's orbit
- 4. a periodic oscillation of the Earth's axis that causes the precession of the poles to follow a wavy rather than a circular path
- 6. the movement of one object around the center of another object
- 8. process of turning or circling around something
- 9. motion of the Earth's axis as it traces out a circle
- 10. the science that studies the universe
- 11. the imaginary pole the Earth is tilted on