Across
- 2. These can be used to map the arms of spiral galaxies
- 4. Galactic disk that can spew hot gas into the galaxy
- 5. Flattened cloud of billions of stars
- 8. The disk of a galaxy
- 11. Extra mass lies in this
- 12. Mass that is invisible, neither emitting nor absorbing light
- 13. These lie outside of galaxies like the Milky Way
- 14. Galaxy that contains a disk and arms
- 15. Astronomers mark these for determining a distance from a galaxy
Down
- 1. Short spiral segments, often having a fluffy appearance
- 3. The most accurate way to find the mass of a galaxy
- 6. The relation between recession and distance
- 7. A cloud of gas collapsing to produce a galaxy
- 9. Galaxy that contains no visible gas and dust and lacks hot, bright stars
- 10. Chaotic mix of gas, dust, and stars, along with no clear bulge or arms