Across
- 3. system of billion stars
- 4. complete turn
- 7. study of the universe
- 9. includes space and all matter
- 10. big bang: universe created by huge explosion
Down
- 1. shift: change in frequency
- 2. year: a unit used to measure light
- 5. curved path around something
- 6. system: the sun and the planets that orbit
- 8. law: redshifts in the spectra