Across
- 3. have bold, symmetric two-armed patterns
- 5. orbital motion accord with Kepler laws of planetary motion
- 6. meaning woodly
- 7. a graph of orbital velocity versus radius in the disk of a galaxy
- 9. nonluminous material that is detected only by its gravitational influence
- 12. crowded part consisting more of old and cool stars like halo
- 13. standard light sources that astronomers could use to find distances.
- 14. disk of the galaxy
Down
- 1. The conjecture that spiral arms in disk galaxies are caused by a pressure wave
- 2. low density of the halo of the galaxy
- 4. flattened cloud of billions of stars
- 8. a spherical cloud of stars and clusters that contain no gas and dust
- 10. Long spiral pattern of bright stars,star cluster that extends from central to of the edge of the disk
- 11. 100 parsecs about 3300 ly