|MadSci Network: Astronomy|
If the universe is somewhere between 12 and 16 billion years old, would the stars have been noticeably closer together/denser than they are today for an observer looking up from the Earth 4 billion years ago? More generally, how far back in time would a human observer have to go before the night sky begins to look qualitatively different from how it looks today?
Re: What did the night sky look like 4 billion years ago?
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