Question

7 - 8 a distant star is moving away from the earth at 1/3 of the speed of light. standing on the star, the light will travel towards the earth at the speed of light. how fast will light be moving as measured on the earth?
a. 1/3 of the speed of light
b. 2/3 of the speed of light
c. the speed of light
d. 1 - 1/3 of the speed of light
e. 1 - 2/3 of the speed of light

Explanation:

Step1: Recall the constancy of light - speed

According to the theory of relativity, the speed of light in a vacuum is a constant ($c$) for all observers, regardless of the motion of the source or the observer.

Step2: Determine the speed of light measured on Earth

No matter how the star is moving, the speed of light measured on Earth will be the speed of light in a vacuum. So the speed of light moving towards the Earth as measured on the Earth is the speed of light $c$.

Answer:

C. The speed of light