How far away is a galaxy that is moving away from Earth at 100,000 km/s? Assume 50 km/s Mpc for the Hubble constant.
A) 2000 Mpc
B) more than 6 light years
C) 8000 Mpc
D) more than 4 light years
E) 2000 Mpc and more than 6 light years

Question

Quizplus · Accepted Answer

Using the Hubble's Law, velocity (v) = Hubble's constant (H) x distance (d). Rearranging for distance, d = v / H. Substituting the given values, d = 100,000 km/s / 50 km/s/Mpc = 2000 Mpc. Since 1 Mpc is approximately 3.26 million light years, 2000 Mpc is significantly more than 6 light years, making E the correct choice.

How Far Away Is a Galaxy That Is Moving Away