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Possible for the Big Bang to have come from The Universe before it?

  1. Sep 3, 2014 #1
    I am curious to know if it is theoretically possible for the origin of the Big Bang to have been the energy released from the ending of a Universe before it. Say the whole Universe ends up as two gigantic black holes devouring each other, then one wins, and eventually all the matter that ever existed in the Universe is compressed into that black hole getting smaller and smaller and smaller, till BANG! ~~~ Is this in any way possible in the realm of all possibilities? I understand I'm being farfetched, but just how farfetched am I being?

    My motivation here is related to a creative endeavor, fyi. So, please, don't hold back: too fantastical? Thanks for your time.
     
  2. jcsd
  3. Sep 3, 2014 #2
    http://www.physics.princeton.edu/~steinh/dm2004.pdf

    Look over stuff about his cyclic model, it's vaguely along the lines of what you suggest, colliding bouncing branes. It might violate a theorem of Vilenkin, also if the latest data is true, although it may have been just dust it seems, it would perhaps be experimentally have been placed on very shaky ground at the least.
     
  4. Sep 3, 2014 #3

    Drakkith

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    Have you read of the Cyclic Model of the Universe?

    http://en.wikipedia.org/wiki/Cyclic_model

    Current evidence suggests that our universe isn't cyclic, but who knows what we'll find out in the future.

    Also, the universe wouldn't have been a black hole at the time of the big bang. A black hole only exists in near-static situations like we have now. Space was undergoing rapid expansion in the early universe, so a black hole wouldn't have formed. The current state of the universe, our accelerating expansion, means that the universe will not end up being devoured by black holes. In fact, in the far far future black holes will most likely evaporate via the emission of hawking radiation and the universe will gradually cool, approaching a "heat death".
     
    Last edited: Sep 3, 2014
  5. Sep 3, 2014 #4

    phinds

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    Your theory presupposes that the big bang happened at a point in space. It did not, thus your theory fails. That theory is shot down here about once a month. There ARE, as porcupine said, cyclical models, but not the one your propose.
     
  6. Sep 3, 2014 #5

    marcus

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    It's a fairly common model in a branch of cosmology called "Quantum Cosmology" (QC). This is cosmology where quantum effects at extreme energy density around the start of expansion are taken account of.

    QC is increasingly popular in the research community and if you do a search for "quantum cosmology" research papers since 2009 you get results like this. The important one is the first. The other searches provide comparisons I was interested in:

    "quantum cosmology" since 2009, Inspire search:
    http://inspirehep.net/search?ln=en&...search=Search&sf=&so=d&rm=citation&rg=25&sc=0 (721 found as of 3 September 2014)

    "quantum cosmology" and not "loop" since 2009, Inspire search:
    http://inspirehep.net/search?ln=en&...search=Search&sf=&so=d&rm=citation&rg=25&sc=0 (355 as of 3 September)

    "quantum cosmology" 1995-1999, Inspire search:
    http://inspirehep.net/search?ln=en&...search=Search&sf=&so=d&rm=citation&rg=25&sc=0 (395 found as of 3 September)

    "quantum cosmology" and not "loop" 1995-1999, Inspire search:
    http://inspirehep.net/search?ln=en&...search=Search&sf=&so=d&rm=citation&rg=25&sc=0 (368 as of 3 September)

    It's easy to see that before year 2000 quantum cosmology research was almost all non-loop. From 2009 onwards it has been about half non-loop and half loop-related. The highly cited papers (listed first) are mostly Loop.

    The point is that in half or more of the papers the models being studied involves a BOUNCE (Loop QC always does and several other approaches have a bounce as well). What I mean is the model has an ordinary universe that collapses, and at extreme density quantum effects take over and it rebounds, and initiating the expansion that we see.

    Bounce models are fairly simple as cosmic models go (no "colliding branes" , no "higher dimensions", just a conventional crunch that rebounds into a bang)

    I was surprised by the negative character of several responses. There are some fine points of language, and some quibbling matters, where your description diverges from say Loop QC scenario. But the idea is basically just that of bounce cosmology. A finite volume universe, with nothing outside it, that collapses, is very much like a gigantic black hole (except that it is a BH with nothing outside it). So your mental image of a BH collapse is not entirely missing the point! Far from it, I would say.

    So far we don't know whether our universe is spatially finite volume or infinite volume. If it is finite, then the balloon analogy (all existence concentrated on a 3D hypersphere surface, analogous to 2D surface of balloon) is the most common picture. It's hard to imagine a finite volume which is boundary-less, but cosmologists use that model.

    Picture a balloon (with all existence on the 2D surface) slowly shrinking down until everything is very close together and quantum effects are felt, turning the collapse around, and then starting to expand. Stuff getting farther apart again.

    How does that work for you?
     
    Last edited: Sep 4, 2014
  7. Sep 3, 2014 #6

    Drakkith

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    Hmmm. That seems to contradict what I've read about black holes and the state of the early universe. Unless I'm misunderstanding something.
     
  8. Sep 4, 2014 #7

    marcus

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    Hi Drakkith, actually if anybody is interested in current Quantum Cosmology research I would suggest clicking the Inspire search:
    http://inspirehep.net/search?ln=en&...search=Search&sf=&so=d&rm=citation&rg=25&sc=0

    and looking over a representative paper like the one that is most highly cited, by Ashtekar et al.

    The search results are ranked by number of citations so you can see the QC papers that are likely to have been the most useful/influential or characteristic of current direction in the field.

    When they work back in time what they find is that the start of the expansion we see was caused by a rebounding collapse. Gravitational collapse of BH also causes a rebound in some versions of LQG. (See the Planck star thread.) So it is not completely off base as a comparison, as I said. Different yes, but as instances of gravitational collapse (and bounce) they have a substantial amount in common.

    A lot of the current work is in QC phenomenology. trying to determine what traces of the bounce can be looked for in the CMB. Aurelien Barrau and Julien Grain are leaders there.

    So if anybody wants some reading. The Ashtekar link is:
    http://arxiv.org/abs/arXiv:1108.0893 (183 cites)
    A sample Grain, Barrau et al link is:
    http://arxiv.org/abs/arXiv:1011.1811 (29 cites, Physical Review D)

    btw the ESQG (experimental search for QG) meeting at ISAS Trieste is going on this week and Julien Grain is speaking. His slides PDF has been or will be posted. We should check to see what's new in the bounce cosmology observational testing department!
     
  9. Sep 4, 2014 #8

    Drakkith

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    Thanks, Marcus!
     
  10. Sep 4, 2014 #9

    marcus

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    Thanks for asking/raising some interesting questions!

    By good fortune Julien Grain's talk at ISAS was yesterday and the slides PDF is already posted, so we can check it out.
    http://www.sissa.it/app/esqg2014/schedule.php
    Here are the slides:
    http://www.sissa.it/app/esqg2014/slides/GRAINesqg14_sissa.pdf
    Here is the abstract
    Julien Grain (Institut d'Astrophysique Spatiale)
    16:30, Tue 2nd Sep 2014
    A brief overview of loop quantum cosmology and its potential observational signatures
    Loop quantum cosmology (a symmetry-reduced quantum model of the Universe inspired by loop quantum gravity) extends the inflationary paradigm to the Planck era: the big bang singularity is replaced by a quantum bounce naturally followed by inflation. Testing for these models requires to compute the amount of cosmological perturbations produced in this quantum background and subsequently derives their footprints on the cosmic microwave background. I propose to review two theoretical approaches treating for cosmological perturbations in a quantum background (see Barrau et al. 2014 and Agullo et al. 2013), making their respective assumptions and methodology as explicit as possible. I will then show the observational consequences of those treatments focusing on the specific case of the cosmic microwave background anisotropies as a probe of the primordial Universe.
     
  11. Sep 4, 2014 #10

    marcus

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    A related talk was given yesterday at the ESQG (experimental search for quantum gravity) workshop:
    this was about the black hole bounce that is calculated using the Loop approach to quantum GR. The slides are remarkably clear and well-organized, I find, with good graphics. One can almost read the slides as a stand-alone exposition of the ideas.

    (But this is easier when you have already read some of the contributory papers and had a chance to think about it. I'm not sure how well someone coming fresh to the subject would fare, just reading the slides. Worth trying though.) Here is the overall ESQG schedule with links to slides pdf.
    http://www.sissa.it/app/esqg2014/schedule.php

    Here is the link to slides PDF for the talk on BH bounce producing observable GRB explosions
    http://www.sissa.it/app/esqg2014/slides/Vidotto_Trieste_2014.pdf
    and the accompanying summary of the talk:
    Francesca Vidotto (Radboud University Nijmegen)
    14:30, Wed 3rd Sep 2014
    What can we learn from Loop Quantum Cosmology? The case of Planck Stars
    Loop Quantum Cosmology suggests that cosmological singularities are generically resolved by quantum effects. This can be understood at the effective level as the appearance of a repulsive force in the deep quantum-gravity regime. A similar mechanism should take place in the interior of black holes, whose singularity would then be replaced by a core of Planckian energy density. Such Planck Star provides a remnant which can help avoid the information paradox. Furthermore, if the evaporation ends with an explosive event, the Planck star could provide a precise astrophysical signal. Using the current models for primordial black holes and the bounds given by dark-matter abundance, this signal could be compatible with a specific kind of gamma rays, that we have already observed.
     
  12. Sep 4, 2014 #11
    Loops vs Strings Hopefully not entirely OT and merely a fun tangent.... submitted entirely for smiles.
     
  13. Sep 4, 2014 #12
  14. Sep 4, 2014 #13

    Drakkith

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  15. Sep 4, 2014 #14

    PeterDonis

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    To me, this means it is *not* "very much like" a BH, since the whole *point* of a BH is that there is "something outside it", namely, there is a future null infinity that the interior of the BH is not in the causal past of.
     
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