lives of stars

4. blue and white core that is left behind
6. a spiral galaxy that our solar system is located in
7. active young galaxies with black holes in the center
13. best used to measure distance to near by stars
15. large cloud of gas and dust
16. brightness the star would have if it were at a standard distance from earth
18. universe exploded and became itself
19. what to spectographs do to light?
20. they spiral outward like pinwheels

1. the process which atoms combine to form heavier atoms
2. all the space and everything in it
3. an American astronomer who discovered galaxies
5. a group of single stars, stars systems, star clusters, dust, and gas bound together by gravity
8. contracting cloud of gas and dust with enough mass to form a star
9. many stars belong to larger groupings called?
10. to figure out a more accurate scale of the solar system
11. brightness seen from earth
12. many stars are part of two or more
14. a supergiant runs out of fuel and explodes suddenly
17. the distance that light travels in one year