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Does the big bang theory hold that there is a possibility that the whole of the observable universe came out from NOTHING? I mean if all of this universe was occupying an extremely small size of a Planck length, then it appears to be tempting that the universe before that was even smaller and smaller till we reach zero size. i.e. till we reach no universe. So the story of existence begins with nothing followed by the sudden emergence of the universe. Is that what the current big bang theory is claiming? Or is it an unsolved question?

Qmechanic
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Zuhair Al-Johar
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1 Answers1

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Here is the current Big Bang model, a cut in two space and one time dimension

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Note the fuzziness at the beginning , the Big Bang. Quantum mechanical behavior is introduced, so there is no longer a "point" for the Big Bang , but a probability locus, so no zero, as with all quantum mechanical states.

So it is not out of "nothing" but out of a probability locus.

Physicists expect that the underlying level of all classical theories is quantum mechanical, and an effective quantization of gravity is proposed, as gravity has not been definitively quantized yet, so it is still a matter of theoretical arguments .

Now if this probability locus is unique or if there are many universes ,again it is a matter of speculation.

anna v
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  • Thanks. But can you explain a little bit what "probability locus" means in terms of existence. I mean in some naive way. Does it mean "potential existence". – Zuhair Al-Johar Mar 17 '19 at 13:11
  • It is the same mathematically as the electron orbital in the hydrogen atom http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/eleorb.html . The modulus squared of the wavefunction of the universe at that time – anna v Mar 17 '19 at 15:17
  • Well this is not a naive explanation. However, I get from what you are saying, that the universe didn't come out from Nothing, but from a probability locus, whatever that could be, it's not the same as nothing. Since we hold "existence" to be dichotomous, then it comes from something! apparently something very small? that you call a probability locus, still the question begs itself, form where this probability locus came from? – Zuhair Al-Johar Mar 17 '19 at 18:32
  • In quantum mechanics, within the Heisenberg uncertainty principle, there is a possibitlity of particle antiparticle loops to exist for a delta(time). There are speculations on these lines, i.e. quantum mechanical , but it is all just that, speculations. example https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.121.251301 – anna v Mar 17 '19 at 19:11
  • I see. But uncertainty is only agnosticism. It appears from your output, that various models are saying that the universe didn't come from nothing. From where it came then? Answer: nothing known yet, just speculations. Possible further step into uncertainty: nothing can be known (even in the future), only speculations can ever be given. – Zuhair Al-Johar Mar 17 '19 at 19:29
  • The uncertainty is given mathematically within the variables of a concrete mathematical model. The hope for every phyiscs mathematical model is that there will be measurable and observable predictions that can be validated , as happened with the inflation model in the Big Bang.( and the Big Bang itself). What now are speculations may become validated models in the future. – anna v Mar 18 '19 at 05:22
  • Is it ever possible to have the best model being something that say that before the big bang was a vacuum? i.e. everything came from nothing. I'm could that be possible? or any such model won't be providing enough predictions. Or there is some essential argument against it? – Zuhair Al-Johar Mar 18 '19 at 05:28
  • the model I gave a link above is one such model, by positing matter antimatter universes the total energy comes out ofthe vacuum. If they manage to predict/explain measurements in our universe then it will be a valid model. – anna v Mar 18 '19 at 06:13
  • @CinaedSimson, can you please elaborate on your point? – Zuhair Al-Johar Mar 18 '19 at 10:56
  • @annav, perhaps what I would say now appears rather very ridiculous, but I'm just wondering if it is possible for the universe to keep becoming smaller and smaller in size without reaching a zero time limit, so it would have an infinite extension into the past, that of continual shrinking without an end. Is such a model on the table? – Zuhair Al-Johar Mar 18 '19 at 11:09
  • sure, the big crunch , another speculation https://en.wikipedia.org/wiki/Big_Crunch – anna v Mar 18 '19 at 13:40
  • @No, not that model. I'm speaking about the past of our universe, not the future. – Zuhair Al-Johar Mar 18 '19 at 17:40
  • I do not know about such models – anna v Mar 18 '19 at 18:03
  • I think the idea of a universe that is continually inflating as time goes forwards (i.e. towards the future), and continually shrinks as we go back in time, (i.e. towards the past); i.e., a bi-ended infinite universe, seem to be in some sense problematic, that no model have been posed with such properties. However, this is mathematically consistent. – Zuhair Al-Johar Mar 18 '19 at 18:23