Problem
A. How did Hubble use Cepheid variables to prove that there were other galaxies outside the Milky Way?
B. What is Hubble's law and what does it say is happening to the universe?
C. What is cosmological redshift?
D. Compare and contrast the following galaxy types: radio, seyfert, quasars, and blazers
E. Why are quasars the most energetic objects ever discovered?
F. How does the redshift of a quasar relate to its formation and distance from Earth?