Across
- 2. This is so dense that light cannot escape the gravity.
- 5. Matter that we can't see but know exists; does not emit electromagnetic radiation.
- 8. Two stars orbiting each other.
- 10. A large red-colored start that is collapsing inward on itself.
- 11. Galaxies that are not spiral or elliptical.
- 12. Biggest group of stars; may contain hundreds of thousands of stars.
- 14. Nuclear fusion in the star's core produces helium from hydrogen.
- 16. Groups of up to a few thousand stars that are loosely held by gravity.
Down
- 1. Egg-shaped rotating galaxy.
- 3. Ball of glowing gas at very high temperature.
- 4. Hypothetical form of energy, may make up as much as 71% of the energy in the universe.
- 6. Our galaxy
- 7. The study of the universe.
- 9. Arms that spiral outward off of spiral galaxies.
- 13. The leftover material in the core after a supernova explosion.
- 15. All of the star systems, galaxies, gas and dust.