You observe a distant galaxy apparently moving away at 1/3 the speed of light (v =c/3). If you could measure the speed that this galaxy's light is passing the Earth, you would get:
A) c/3
B) 2c/3
C) c
D) 4c/3
E) 5c/3

Question

Quizplus · Accepted Answer

The speed of light is constant in all inertial frames, so the speed that the galaxy's light is passing the Earth is still c, regardless of the galaxy's apparent velocity.

You Observe a Distant Galaxy Apparently Moving Away at 1/3