Across
- 5. first step of solar system formation
- 9. material clumping into protoplanets
- 10. object revolving around a planet
- 11. gas/dust cloud where stars & systems form
- 12. large collection of stars & systems
- 13. icy body with a tail near the Sun
Down
- 1. Fusion process that powers stars
- 2. rocky body, mostly in the asteroid belt
- 3. accretion disk forming
- 4. step where nebula began rotating
- 6. path of a celestial body
- 7. force pulling objects together
- 8. evidence universe is expanding