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Big Bang modeled as a phase-change

  1. Aug 22, 2012 #1
    I like this idea guys:


    It just makes sense to me since so much of Nature involves phase-changes. What do you guys think? Is this consistent with the current work in LQG?
  2. jcsd
  3. Aug 22, 2012 #2

    Simon Bridge

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    "So much of Nature involves X, therefore it makes sense that the Big Bang was a kind of X."

    Do not trust science journalism.
    One team of physicists says the Big Bang should be the thought of not as a hot blast but like liquid water cooling and crystallizing...Well, no, a hot blast would imply a pre-existing space to have a blast into so there is trouble with the description there.

    You need to see the paper to make sense of it.
  4. Aug 22, 2012 #3
    Actually, I do believe that. That's why I was happy to see a team considering this possibility.

    Afraid I probably wouldn't understand the technical details Simon. Is Loop Quantum Gravity proposing a phase-change as the cause of the Big Bang?
  5. Aug 22, 2012 #4

    Simon Bridge

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  6. Aug 22, 2012 #5
  7. Aug 22, 2012 #6
    that model is challeging the big bang and is called the big chill and it comes from Quantum Graphity Model (another background independent physics model like; causal dynamical triangulations CDT, spin foams models, loop quantum gravity LQG etc)

    Domain structures in quantum graphity
    James Q. Quach, Chun-Hsu Su, Andrew M. Martin, Andrew D. Greentree.

    big bang was very small and very, very hot and dense, unlike of the presented model.
    Last edited by a moderator: May 6, 2017
  8. Aug 23, 2012 #7
    I don't think it's challenging the big bang. More like explaining how you can what happened at time zero.

    The big bang was not very small. It was very dense.

    As far as heat goes, that's pretty easy to add. After the universe undergoes inflation, you have to have a period of reheating so it's pretty straight forward to take the reheating models and heat up the universe.

    Also starting from a "cold universe" can nicely explain why the entropy of the universe started out so low. The universe started as a cold dense crystal, and then you add the heat from quantum effects after inflation.
  9. Aug 23, 2012 #8

    Simon Bridge

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    That's my take.

    When I hear stuff like this touted like this I go into damage limiting mode: what a whole lot of creationists are going to hear is "science says big bang theory may be false". So I'm bracing myself for the selective hearing.
  10. Aug 23, 2012 #9
    It just has to be that way guys: it precipitated into existence by virtue of a phase-change caused by the pre-existence trajecting through a critical point of its dynamics.

    Now don't you guys like the sound of that or what? I mean what else could possibly make more sense? I'd like to know.
  11. Aug 23, 2012 #10

    Simon Bridge

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    You forgot to include perturbations on the Kimberly-Bennet Field. If you filter that through the Kopfhurtz equations you get an antisymmetric isogrid that has positive definite huris!
  12. Aug 23, 2012 #11
    That's ok. You guys can make fun of me. I tend to think of myself as in a long line of great Astronomers like Ptolemy, Kepler, Copernicus, and Galilei -- they made fun of some of them -- and Jackmell, the first person to propose a generalized mechanism for creating Universes. :)
    Last edited: Aug 23, 2012
  13. Aug 23, 2012 #12
    "The biggest problem with the big bang model is the bang itself," Mr Quach said.
    "At the bang, physics breaks down".
    "The model cannot make any predictions at what occurs at the big bang. You can't use any of the mathematics [or] any of the theories."

    ....sorry, was very big
    Last edited: Aug 23, 2012
  14. Aug 24, 2012 #13
    There's a definitional problem here for defining what the big bang is.

    What I call the "big bang" was a series of events that happened roughly 13.9 billion years ago. It lasted for about 300,000 years, and we know it happened, because we see it.

    There's also what happened at "event zero." We don't know what happened at "event zero". We don't even know if there was an "event zero." What Quach is calling the "big bang" is what I call "event zero".

    It's very important to make a clear distinction between "the big bang" and "event zero." We can see the big bang and the physics isn't too complicated.
  15. Aug 24, 2012 #14
    irrelevant confusion on your part because the big bang (Friedmann Lemaitre
    equations - Walker-Robertson metric) includes the beggining and evolution of the universe.
    the big bang singularity but quantum mechanics and general relativity breaks down at that level.
    Last edited: Aug 24, 2012
  16. Aug 27, 2012 #15
    On the other hand, the FRLW describes the universe *now* and we normally doesn't include that in the term the big bang.

    I do think that it is very important to make a distinction between the "singularity" at which we are all just guessing about, and the stuff that happened in the hot dense early universe of which there is a great deal of evidence. Personally, I would label as the "big bang" everything that happened before recombination, and most of that stuff is pretty well known until you get to inflation.
  17. Aug 27, 2012 #16
    FRLW describes the universe time dependent, Einstein's field equations derive the scale factor of the universe as a function of time.
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