Question

Suppose that Hubble's constant were 20 kilometers per second per million light-years. How fast would we expect a galaxy 100 million light-years away to be moving? (Assume the motion is due only to Hubble's law.)

Answer 1

A galaxy 100 million light-years away would be moving away from us at a speed of 2000 kilometers per second if Hubble's constant is 20 kilometers per second per million light-years.

Step-by-step explanation:

Astronomers express the value of Hubble's constant in units of kilometers per second per million light-years. If Hubble's constant is 20 kilometers per second per million light-years, then a galaxy 100 million light-years away would be moving away from us at a speed of 2000 kilometers per second.