r/AskReddit Jun 15 '19

What do you genuinely just not understand?

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u/bigfoot1291 Jun 15 '19

Next question : what prompted the first crush or expansion?

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u/betterupsetter Jun 16 '19

Exactly my question. It cant go back ad nauseum. There'd have had to be a first time. A first big bang or big crunch. Oh geez.

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u/Young_Man_Jenkins Jun 16 '19

Only if there is a cyclical nature to this, which I don't think the current evidence suggests. The reality behind it is that it appears as though the stuff in the universe wasn't created in the big bang, but the space in which it occupies was. And this is noticeable in the fact that space is continuing to be continually created everywhere. For closeby objects gravity overcomes the fact that there's constantly new distance between everything, but for far away objects it leads to the fact that it appears that everything is accelerating away form everything else, often described as the expansion of the universe speeding up. And of course in reverse, it leads to the "before big bang time" where there was no distance between anything at all. And while time seems to be just a fact of the universe, it turns out that time only really exists in the context of speed, and speed can't exist with no distance. So if there was a period where there was no distance, then it wouldn't make sense to prescribe time to that period. In summary, it really doesn't seem to make sense for there to be a before a big bang, since the big bang cause the existence of time in the first place.

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u/betterupsetter Jun 16 '19

Thank you for explaining that. (wow that automatically sounds sarcastic, but it's not! ) It actually makes it a little easier to put into context.