Across
- 6. A galaxy that is neither elliptical nor spiral.
- 7. Tens of thousands of stars held together by gravity.
- 9. Nuclear fusion in the star's core produces helium from hydrogen.
- 12. The study of the universe.
- 13. Our Galaxy.
- 14. A ball of glowing gas at a very high temperature.
- 15. It appears as a rotating disk of stars and dust.
Down
- 1. An egg shaped, rotating galaxy.
- 2. A group of stars.
- 3. A galaxy that only contains a few million to a billion stars.
- 4. Two stars orbiting one another.
- 5. Hypothetical form of energy that makes up most of the universe.
- 8. An object so dense that nothing can escape it, not even light.
- 10. Everything in existence.
- 11. Method of measurement for stars that are relatively close to Earth.