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Why the Universe Didn't Become a Black Hole

Posted by Soulskill on from the would-have-been-a-bit-dull dept.

StartsWithABang writes: With some 10^90 particles in the observable Universe, even stretched across 92 billion light-years today, the Universe is precariously close to recollapsing. How, then, is it possible that back in the early stages after the Big Bang, when all this matter-and-energy was concentrated within a region of space no bigger than our current Solar System, the Universe didn't collapse down to a black hole? Not only do we have the explanation, but we learn that even if the Universe did recollapse, we wouldn't get a black hole at all!

1 of 109 comments (clear)

  1. Short version by Livius · · Score: 4, Informative

    If at some point in the past the mass of the universe was in a volume wholly contained within its own Schwarzschild radius, why did the universe not become (or, more accurately, remain) a black hole?

    "...Schwarzschild’s solution is a static one, meaning that the metric of space does not evolve as time progresses. But there are plenty of other solutions—de Sitter space, for one, and the Friedmann-Lemaître-Robertson-Walker metric, for another—that describe spacetimes that either expand or contract."

    Literally everything else in the article was off-topic, and I can't help but feel this highly evasive 'answer' might have been "Ask Ethan" admitting he just didn't know.

    Which is a pity because it is a fascinating question.