A supernova that occurs 10,000 years from now in a galaxy 50,000 light-years away:
A)will be observed on Earth 10,000 years from now.
B)was observed on Earth 40,000 years ago.
C)will be observed on Earth 40,000 years from now.
D)was observed on Earth 50,000 years ago.
E)will be observed on Earth 50,0000 years from now.

Question

Quizplus · Accepted Answer

Because the light from the supernova will take 50,000 years to reach Earth, it will be observed here 50,000 years from now. Since the event is projected to occur 10,000 years from now, the observation will happen 40,000 years after it happened. Therefore, option C is the correct answer. The supernova will take 50,000 years for its light to reach Earth, so it will be observed on Earth 50,000 years from when it occurred. Since it will occur 10,000 years from now, it will be observed on Earth 40,000 years from now.

A Supernova That Occurs 10,000 Years from Now in a Galaxy