Across
- 3. round or flattened balls, old stars only
- 5. active young galaxies with black holes
- 7. people observed these patterns of stars in the night sky
- 8. measures of amount of light a star gives off
- 11. Instrument scientist use to spread light into different wavelengths
- 14. most stars are members of groups of ___ or more stars called solar systems.
- 15. distance the light travels in one year
Down
- 1. fusion happens from the heat and densest
- 2. used to determine a galaxy's size
- 4. measure of the amount of light received on earth.
- 6. the range of wavelengths that stars emit
- 9. credited with the classification system for galaxies
- 10. no regular shapes, bright young stars
- 12. bulge in middle and arms that spiral outward
- 13. huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity.