Wrapped up in Time

'Told backwards down this rod of light… …Long extinct'
The stars in the night sky are light years away from us, meaning that by the time the photons have travelled from the star to our retinas, spans of time have passed. 
 
A light year is literally the distance light can travel in a year, so if you’re looking at something a light year away, you are seeing how it looked one year ago when its photons were first emitted and started their journey through space to your eye. 

Alpha Centuri, the closest star to Earth, is 4.7 light years away, meaning that when we look at it, we are seeing how it looked 4.7 years ago. No matter which star we look at, we are looking back in time, not seeing it as it is now.

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