Answered>Order 4340

1.     Answer the following questions regarding the cosmic distance ladder:

a.    Edwin Hubble used Cepheid variable stars to determine the distance to nearby galaxies.  Explain how he did this.  (2 points)

b.    How did Hubble’s measurements resolve the Great Debate?  (1 point)

2.     Hubble’s Law describes the average motion of galaxies as seen from the Milky Way.

a.    You observe two galaxies moving away from the Milky Way.  Galaxy A has a speed of 500 km/s and Galaxy B has a speed of 750 km/s.  Which galaxy is further away? (1 point)

b.    Consider Galaxies A & B from part a).  How much farther from the Milky Way is the more distant galaxy compared to the closer one?  Express your answer as a ratio. (2 points)

3.     What would happen if all of the dark matterin the universe suddenly disappeared?  Explain your reasoning. (3 points)