Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

CMB and the big bang

  1. Jul 14, 2013 #1
    Hi all, I'd like to apologise in advance for the layman's terminology in the idea below. I'd be delighted to get any feedback/thoughts on whether CMB observations could be explained in this way.

    Could the universe have started as a giant black hole that reached a critical mass and collapsed in on itself?

    White dwarfs, neutron stars and black holes have all collapsed to a denser state under the effects of gravity. Maybe black holes can collapse too. Imagine a black hole becomes so massive that it can no longer maintain itself against the huge gravitational forces. The black hole might collapse in on itself and then explode with all the predicted effects of the inflationary big bang model. In order for critical mass to be reached material would need to be falling into the black hole and this spiralling disc of material might explain the so-called axis of evil that appears in the CMB. An inflationary model expanding into non-nothingness might also produce the less uniform CMB of experimental observation.

    Best regards

    Aaron Ironmonger
  2. jcsd
  3. Jul 14, 2013 #2


    User Avatar
    Gold Member

    This question has been asked here approximately 4,297 times. Please do a forum search.

    Oh, and the answer is no.
  4. Jul 14, 2013 #3
    Well that told me!
  5. Jul 14, 2013 #4
    the universe did not start from a black hole. the singularity described at the beginning is where we can no longer describe it with mathematics etc. A BH beginning would have different observations than what we see. In the BH the universe would be expanding from a central point. In observations expansion is the same everywhere no matter what coordinate you choose.
  6. Jul 14, 2013 #5


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    Well you introduce this as a layman's question and as such it is a pretty good one! In slightly different terms the essential idea has been floating around since 1992 or so in the quantum gravity community and has at least one wide-audience book written about it (The Life of the Cosmos, by Lee Smolin) as well as a number of scientific papers.

    The original idea is said to go back even earlier to John Archibald Wheeler, a renowned Princeton physicist who was Richard Feynman's PhD advisor.

    So it's not a kook idea, or automatically wrong. It's a strange idea that is hard to get a grip on. But it has a good pedigree.

    But if you are interested in cosmology you had probably start by getting better acquainted with the basic concepts and more or less "known" stuff as widely understood, rather than blue-sky wild ideas (even if they have good pedigree).

    The reason is we don't have a good idea of the MECHANISM at work in the pit of a BH. It may be that there is a threshold mass and if a BH has that mass its center will reach a threshold density at which quantum effects (that only kick in at extreme density) cause gravity to reverse and REPEL instead of attract and then a new expanding region of space-time would form "out the back door" so to speak. A separate expanding region. You might call it a "baby" universe but it might grow up to be what we think of as full size.

    There are some ideas for mechanisms---ideas for how a new universe (invisible to us, out the back door of a black hole that we can't see into) could get all the requisite matter---ideas for how quantum effects would appear at extreme density and cause contraction to rebound and re-expand---ideas for how the new universe could have its own "inflationary" episode similar to ours. But those ideas are what is called "speculation". Not grounded on observation, more what-iffy.

    So if you are just beginning to learn cosmology you probably would not find you could get very far along that line.

    But in case anyone is interested in pursuing it Jorge Pullin just posted a new paper about this.
    It is fairly cautious. In a certain theoretical model of cosmology called Loop Quantum Cosmology the mechanisms exist, so based on that theoretical model, it would work, according to what he finds. I will get the link to Pullin's article.
    Last edited: Jul 14, 2013
  7. Jul 14, 2013 #6


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    Loop quantization of the Schwarzschild black hole
    Rodolfo Gambini, Jorge Pullin
    (Submitted on 21 Feb 2013)
    We quantize spherically symmetric vacuum gravity without gauge fixing the diffeomorphism constraint. Through a rescaling, we make the algebra of Hamiltonian constraints Abelian and therefore the constraint algebra is a true Lie algebra. This allows the completion of the Dirac quantization procedure using loop quantum gravity techniques. We can construct explicitly the exact solutions of the physical Hilbert space annihilated by all constraints. New observables living in the bulk appear at the quantum level (analogous to spin in quantum mechanics) that are not present at the classical level and are associated with the discrete nature of the spin network states of loop quantum gravity. The resulting quantum space-times resolve the singularity present in the classical theory inside black holes.
    4 pages. To appear in Physical Review Letters (2013)

    Jorge presented the finding last week at a major international conference in Europe: the triennial GR20. Here is the summary of his talk:

    ==http://gr20-amaldi10.edu.pl/userfiles/book_05_07_2013.pdf [Broken]==
    Complete quantization of vacuum spherically symmetric gravity
    Pullin J
    We find a rescaling of the Hamiltonian constraint for vacuum spherically symmetric gravity that makes the constraint algebra a true Lie algebra. We can implement the Dirac quantization procedure finding in closed form the space of physical states. New observables without classical counterpart arise. The metric can be understood as an evolving constant of the motion defined as a quantum operator on the space of physical states. For it to be self adjoint its range needs to be restricted, which in turn implies that the singularity is eliminated. One is left with a region of high curvature that tunnels into another portion of space-time. ...
    Last edited by a moderator: May 6, 2017
  8. Jul 14, 2013 #7
    This article is a good, non pop media, review of observational cosmology. There is no math in it, however it explains many of the key details on todays cosmology.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook