Across
- 3. It keeps planets in elliptical orbits around the Sun
- 4. how many billion years ago did the universe begin
- 5. primarily made of rock and metal
- 7. theory that explains the formation/ beginning of the universe
- 9. how did the the solar system begin forming according to current theories?
- 10. planets that have not cleared their orbital path
Down
- 1. What evidence supports the Big Bang Theory
- 2. terrestrial planets have thin ones and gas Giants have thick ones
- 6. one way in which the solar system is still changing today
- 8. They have thick atmospheres composed mainly of hydrogen and helium