Question

The andromeda galaxy is located approximately 2.5 million light- years from earth. Why is the light that reaches earth 2.5 million years old?

Answer 1

So, the Sun's light takes about 8.3 minutes to reach us. This means that we always see the Sun as it was about 8.3 minutes ago. ... The nearest large galaxy to us, Andromeda, is 2.5 million light-years away. So, we see Andromeda as it was 2.5 million years in the past.