The light we see from the moon when we look at it at night left its surface just over a second ago; the light we see from the sun left its surface just over eight minutes ago. Some of the stars that make up the constellations we see in the night sky are hundreds of light years away, which means the light we see left them centuries ago…. for me its astonishing that every time you look up at the night sky you are gazing back through time.