Chapter 20 Review Crossword

2. cloud of dust and gas where stars are born
3. The first stage in the life cycle of a star
6. Our galaxy and about 30 other nearby galaxies are all part of the __________ _________ cluster
9. During its main sequence, hydrogen atoms fuse together to form __________ in a star
11. Most stars are in this stage of their life cycle, including our sun
12. A spherical or egg-shaped galaxy is classified as _________
13. A galaxy with a red bulge in the middle and blue arms
14. Smaller, cooler stars are this color
17. unit of distance based on the distance light travels in a year
18. a huge sphere very hot gas that give off light and other radiation
19. This theory states that the universe began with an explosion
21. On an H-R diagram, this is plotted on the Y-axis
22. The name of our galaxy

1. Galaxies moving away
4. On an H-R diagram, this is plotted on the X-axis
5. Everything physical that exists in space and time is part of the _________
7. A group of galaxies is called a ____________
8. When our sun runs out of hydrogen, it will become a _______ __________ and fuse helium to produce heavier elements
10. Groups of clusters of galaxies are called ____________
15. Nuclear __________ takes place in stars
16. A collection of millions or billions of stars
19. Hotter stars that tend to have bigger masses are this color
20. Galaxies moving closer together