05/05/2021
When you look into the night sky, you are looking back in 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; while Betelgeuse (pictured) in the constellation of Orion is 640 light-years away, so the light left the star around 1370, during the time of the Hundred Years’ War between England and France. Other stars we see are further away still, so we are seeing them much deeper in their past.
