Across
- 3. a star that suddenly increases greatly.
- 5. a cloud of gas and dust in outer space.
- 6. a system of two stars.
- 10. is the name for the observation in physical cosmology.
- 11. a celestial object.
- 12. the measure of intrinsic brightness.
- 15. a star showing a sudden large increase in brightness.
Down
- 1. a very large star that is even brighter than a giant.
- 2. a contracting mass of gas.
- 4. is a specific area of the celestial.
- 7. is a stellar remnant.
- 8. a group of similar things or people.
- 9. a very large star of high luminosity.
- 13. the distance that light travels in one year.
- 14. a system of millions or billions of stars.