Question

What does it mean when we say that astronomical observations “look back in time”? Can we really see the past? Can we use this technique to see our own Past?

Answer 1

Looking At The Stars Is A Look Back In Time.

This question raises the fascinating issue of look-back times. Because of the finite speed of light, when you gaze up into the night sky, you are looking into the past. The bright star Sirius is 8.6 light years away. That means the light hitting your eye tonight has been traveling for 8.6 years. Put another way: When you look at Sirius tonight, you see it as it was 8.6 years ago.

In this technique you can not see the past