Question

If the distance from earth to alpha centauri is 4.34 light-years, then a) alpha centauri is the closest star to earth. b) we see alpha centauri as it was four years ago. c) the distance is equal to 4.34 astronomical units. d) alpha centauri is four times farther from earth than the sun.

Answer 1

We see alpha centauri as it was 4.34 years ago.

Answer 2

If the distance from earth to alpha centauri is 4.34 light-years, then

b) we see alpha centauri as it was 4.34 years ago.

Because the light emitting from it will reach to us after 4.34 years. So we will be seeing it as it was 4.34 years ago.