Why do we have a night sky?

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Just saw a video of the hubble telescope zooming into a small patch of seemingly empty night sky revealing millions of stars and galaxies invisible to the naked eye.

Makes me wonder, if space is mostly empty and there’s possibly infinite number of stars and galaxies in any given part of the night sky, shouldn’t the night be as bright as the day?

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Anonymous 0 Comments

Olbers Paradox. This is in fact one of the strongest pieces of evidence for the expansion of the universe. This observation — that in an infinite or near-infinite universe, your eye should see the light from a star in every direction you look, but you don’t — means that it must be expanding, so that some of that light never reaches us. That results in the dark sky we see, with only some stars in the field of view. Still a lot though!

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