See the past time

The stars we see in the night sky are very far away from us, so far the star light we see has taken a long time to travel across space to reach our eyes. This means whenever we look out into the night and gaze at stars we are actually experiencing how they looked in the past. For example, the bright star Vega is relatively close to us at 25 light-years away, so the light we see left the star 25 years ago.