Chapter 22

2. is an object whose gravity is so great that no light can escape
4. is the apparent surface of a star
5. a large ball of gas held together by gravity with a core so hot that nuclear fusion occur
9. theory that the universe began from one point billion years ago and has been expanding ever since
12. is a graph that plots luminosity v. temperature of a star
13. is the wide, outermost layer of a stars atmosphere
14. a cloud of gas and dust
15. the true brightness of a object
17. spread light into different wavelengths
18. where hot gas moves up toward the surface and cooler gas moves deeper into the interior
19. a shell of cooler hydrogen above a stars core
22. hugh collection of stars

1. a hot, dense, slowly cooling sphere or carbon
3. measure of how bright it appears from Earth
6. the shift to a different wavelength
7. the orange-red layer above the photosphere
8. the distance light travels in one year
10. a process that occurs when the nuclei of several atoms combine into one larger nucleus
11. average distance between Earth and the Sun
16. an enormous explosion that destroys a star
20. matter that emits no light at any wavelength
21. a dense core of neutrons that remains after a supernova