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Wednesday, 18 January 2017

The Universe in 101 words: Could we see back in time?

One type of time travel that happens daily is seeing into the past: Light’s speed is limited, so the Universe is full of images from distant eras. A few of everyday examples are:

  • We see the Moon as it was 1.5 seconds ago. 
  • We see the Sun as it was eight minutes ago.
  • We stars as they were up to 13 billionyears ago.

So here’s a thought: If we could locate a huge reflective surface 32.5 million light years away*, and focus an incredibly powerful telescope on it, we could see the dinosaurs.

Although re-watching Jurassic Park would be simpler...

*32.5 million yars for the image of Earth to reach it, and 32.5 million years for the light to be reflected back  equals 65 million 

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