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Universe cyclic model and energy loss

  1. Jul 6, 2008 #1
    I'm "aware" of current theories about the cyclic model but what's wrong with this hypothesis?

    The universe starts crunching forming a big black hole
    All the energy is sucked back into this big black hole
    The big bang starts again with all the matter and energy as the previous big bang

    Assuming this is possible, there would be no difference in each cycle and would not be getting longer and larger.

    Feel free to destroy my argument (nicely)
  2. jcsd
  3. Jul 6, 2008 #2


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    I think you want some criticism of this crunch --> bang (also called "bounce") scenario. You say "what's wrong with this hypothesis?" and
    "feel free to destroy...(nicely)"

    Hopefully you will get some feedback of the kind you want. Personally I think you are right to call it an HYPOTHESIS----that is, something that needs testing. A scheme or model which we don't know if it is right and has to be developed to where it makes observable predictions.

    Basically I think it is a good hypothesis. So I'm not one of those people who will criticize it for you.

    It is currently the leading concept in Quantum Cosmology (research area devoted to understanding the big bang using quantized versions of general relativity rather than the classical version). Leading in the sense of more scholarly research publication and more citations than the alternatives (such Steinhardt's cyclic, or ekpyrotic, or clashing branes hypothesis).

    If you do a keyword literature search, ranked by citations, like this
    http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=DK+quantum+cosmology+and+date+%3E+2005&FORMAT=WWW&SEQUENCE=citecount%28d%29 [Broken]
    what comes up is mostly bounce approach papers, investigating the crunch-->bang idea you are asking about
    that is, sticking with recent papers (since 2005) and ranking by how often the papers have been cited in other research, to get a rough idea of relative importance

    Some of the authors involved with this are Ashtekar, Bojowald, Param Singh, Corichi, Vandersloot,...there are about twenty names I think of, won't list them all.

    You mentioned energy loss, in your title. It don't think that is a problem. These people run computer models of lots of different cases and the bounce result is pretty robust. It tends to happen in whatever case. Quantizing the theory of gravity leads to quantum correction terms that these people have found make gravity repellent at very high density. There is no dissiption of energy. The problem is finding some obscure observable effect of the bounce which one could use to TEST the idea----which, for example, would prove that it didn't happen if you didn't see the effect. Some feature of the Cosmic Microwave Background perhaps. that is the kicker. A theory that you can't test remains half-baked.

    Somebody named Zygmunt Lalak in Warsaw Poland just posted a paper with an idea for testing. Param Singh has presented some ideas. there's hope, but it's tough.

    the same would apply to any ideas you might have about a bounce cosmology scenario. there has to be something that makes it testable

    the Steinhardt cyclic, or ekpyrotic scenario had gotten quite a bit of publicity and a lot of people have heard about it--for whatever that's worth. There is not as much current professional research about it and it seems even farther from being testable---but that could change

    nobody can say what the quantum cosmology research picture is going to look like even two years out (in my humble view)
    Last edited by a moderator: May 3, 2017
  4. Jul 7, 2008 #3


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    I second marcus's position. No definitive test for a bouncing model yet exists. It remains speculative until then.
  5. Oct 22, 2011 #4
    Zombie thread warning!

    ok, so I had this whacky idea that the galaxies are one day going to be swallowed up by their ever-gorging blackholes, which also given enough time coalesce into one incomprehensibly massive blackhole/singularity, beginning a new cycle of the universe.
    Trying to find answers I came across this thread. It was comforting to learn that i'm not the only loon out there (sorry OP :smile: )

    my problem resolving this concept though is what happens to the radiation leaked from the poles of the blackholes?
    If space doesn't exist prior to the big bang, then where would this energy be emitted to?
    If energy can be lost like this, would a universe governed by a cyclic model move to a lower entropy with each cycle until it fizzles out to nothingness?
  6. Oct 22, 2011 #5
    Speculating I would say there is a difference between blackholes as we think we know them and the final blackhole made from all the other blackholes. The difference being that the final blackhole/singularity (maybe it should be called "The Singularity") would not have anymore matter to accumilate. At that point everything in the universe will have already been pushed into the singularity. There would not be excessive amounts of matter bottle necking at the event horizon and shooting out the polls anymore. The finale singularity should be quite calm.

    In a cyclical universe space did exist before the bounce but it too would have completely condensed along with everything else back into The Singularity.

    I can imagine The Singularity made of every single quanta in the universe packed so dense that it becomes basicly one particle with no moving parts and cold.
    The entropy at the singularity would be back to almost zero and ready for its next round of inflation.
    Last edited: Oct 22, 2011
  7. Oct 22, 2011 #6
    i think i can accept that The Singularity could be that immense that it would alter the fabric of space and time, or even maybe that the emissions from the poles reaches a point that it is contained by this warping/contraction of space to the point that it creates a feedback loop that possibly even triggers the next cycle.

    but why cold though? i would think that it needs to be incredibly hot for something to trigger the next cycle. if it's cold it lacks all energy and is unlikely to change from that state.
    or am i misinterpreting what you mean by cold?
  8. Oct 24, 2011 #7

    If nothing could move inside the singularity where would the heat come from other than on the surface were the last remnants of quanta were still acumilating. Why would the cycle need heat to trigger it?
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