Quiz

1. What are the three major types of galaxies?
2. How are galaxies grouped together?
3. How do we measure the distances to galaxies?
4. What is Hubble's law?
5. How do distance measurements tell us the age of the universe?
6. How do we observe the life histories of galaxies?
7. How did galaxies form?
8. How do galaxies differ?
9. What are quasars?
10. What is the power source for quasars and other active galactic nuclei?