• Question: If the big bang was proven to not happen, what would be the next scientithic predicition for the Earths exsistance?

    Asked by to Laurence on 17 Jun 2014. This question was also asked by .
    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 17 Jun 2014:

      By ‘Big Bang’, usually scientists mean an infinitely short amount of time, when all of the Universe was infinitely small (it had a zero volume). It’s really hard (I mean, kind of impossible) to imagine, but you shouldn’t think of the Big Bang as an ‘explosion’ that happened at some place. It’s more like the moment when all of the infinite space itself (and even time!!) appeared simultaneously, out of literally nothing.

      Currently, scientists don’t really understand what happens there. The Big Bang model doesn’t say why this happened, or how. Physicists (including myself) think that we need a better theory of fundamental physics to understand it (a theory that works when things are insanely HOT and insanely DENSE, something called quantum gravity, but we don’t know what it is yet), and that once we understand this theory, we will be able to explain what happened, that space wasn’t created out of zero volume (or if it was, why).

      We have enough evidence right now to know that 1) space is expanding, 2) about 14 billion years ago the Universe was VERY hot and VERY dense (to see why, just run the clock of an expanding Universe backward, it starts contracting and contracting…)

      So given those evidences, apart from a Big Bang, it could be a Big Bounce, meaning that infinitely far in the past, the universe started out really big and really empty. Then it contracted slowly until it was extremely dense and hot, to explain what we observe, but it never reached zero volume, instead it ‘Bounced’ back and started expanding again, and formed the expanding Universe we observed today.

      Another possibility is that the Universe goes through these cycles of expansion, contraction, bounce, expansion, contraction, bounce… for ever. That is called the ‘cyclic Universe’.

      There are also a lot more possibilities, some scientists spend their life inventing possible models to avoid the Big Bang singularity (the point where the Universe had zero volume and our theories break down).

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