If a star is 10 parsecs away, how long ago did the light we see from it tonight begins its journey toward us?
A) 10 years
B) 0.1 years
C) 10,000 years
D) 32.6 years
E) 6100 years

Question

Quizplus · Accepted Answer

One parsec is equal to 3.26 light years. Therefore, the star is 32.6 light years away. Since the speed of light is about 3 x 10^5 km/sec, we can calculate that the light we see from the star tonight left the star about 32.6 years ago. So the answer is D) 32.6 years.

If a Star Is 10 Parsecs Away, How Long Ago