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Q & A: seeing into the past

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Most recent answer: 02/18/2017
Q:
If the universe is about 14 billion years old , and started with a Big Bang, how can we see objects 14 billion light years away ? Surely that would indicate that we are seeing the position of these objects 14 billion years ago - at the birth of the universe.
- David lawes (age 66)
Cape Town
A:

It's a little more complicated than that, because the light is traveling through space that's been stretching out. It's unclear what the word "position" means since there's no absolute space, just changing distances between things. Your conclusion is still right in an important way. We see things from almost 14 billion years ago. The cosmic microwave background has been traveling almost freely since the universe became almost transparent, only a few hundred thousand years after the Big Bang. We can detect it and use little variations in the signal from different directions to see the small unevenness in that early universe.

Mike W.


(published on 02/18/2017)

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