Across
- 1. the sun is in the center of the solar system
- 3. used a telescope to discover many things including the phases of Venus
- 4. theory that the universe began as a singularity rapidly expanding
- 7. came up with the 3 laws of planetary motion
- 8. determined by the moon's orbit around the Earth
- 9. astronomer who proposed the heliocentric model of the solar system
- 11. as the universe expands, galaxies move ______ apart from each other
- 12. described gravity and inertia
- 13. determined by a planet's rotation on its axis
Down
- 2. planets orbit in this shape
- 4. the universe is 13.7 __________ years old
- 5. earth is the the center of the solar system
- 6. determine by a planet's revolution around the Sun
- 10. astronomer who proposed the geocentric model of the solar system