Across
- 3. our galaxy
- 7. galaxies that are not spiral or elliptical
- 11. egg shaped rotating galaxy
- 12. group of stars
- 14. matter we cant see but we know it is there
- 15. two stars orbiting each other
Down
- 1. the study of the universe
- 2. light can not escape the gravity
- 4. tens of thousands of stars that are held tightly together by gravity
- 5. hypothetical form of energy, may make up as much as 71% of the energy in the universe
- 6. a galaxy that only contains a few million stars to a few billion stars
- 8. a big group of stars, may contain thousands of stars
- 9. nuclear fusion in the stars core produces helium from hydrogen
- 10. how astronomers explain the way the universe began
- 13. a change in frequency as a obsereveres eyes