Across
- 2. group of stars
- 5. hypothetical form of energy
- 8. this is so dense that light cannot escape the gravity
- 10. two stars orbiting each other
- 11. our galaxy
- 12. biggest group of stars
- 13. galaxy that only contains a few million to billion stars
- 14. stars that are grouped closely together
Down
- 1. change in frequency of a wave
- 3. ball of glowing gas
- 4. galaxies that are not spiral or elliptical
- 6. matter that we can't see but know exists
- 7. egg shaped rotating galaxy
- 9. arms that spiral outward off of spiral galaxies
- 10. cosmological explanation of how the universe formed