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The Multiverse

  1. Jan 5, 2015 #1
    People say that Multiverse doesn't exist, But as per #TheGrandDesign by Stephen Hawking,
    Quantum Fluctuations led to the creation of tiny universes out of nothing. A few of these reached a critical size, then expand in an inflationary manner, formed galaxies, stars and, in at least one case, beings like us.
    So, in that case, how did the quantum fluctuations take place? And how is Big Bang related to the Creation of Multiverse?
     
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  3. Jan 5, 2015 #2

    Doug Huffman

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    The multi/mega verse is not causally connected to our singular universe and so is not falsifiable and falls on the non-science side of the demarcation boundary.
     
  4. Jan 5, 2015 #3

    phinds

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    HOW the universe was created is pure speculation. We don't know. Our model (the big bang theory) only holds good back to about one Plank Time after the singularit and describes the evolution from that time forward.
     
  5. Jan 5, 2015 #4
    Sir, Thank you for your answer but can you please explain it briefly? I didn't get you... :D
     
  6. Jan 5, 2015 #5

    phinds

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    I can't really think of any way to say it differently, but I'll try.

    We do not know how the universe was formed. We only know how it acted AFTER it was formed. The big bang theory is what describes how the universe acted after it was formed. The big bang theory says nothing about how the universe is formed. All statements about how the universe was formed are speculation / guesses.
     
  7. Jan 5, 2015 #6
    But as per Classical Physics, Big Bang is the only theory that holds water.
    As per you, how can you define Universe's Creation?
     
  8. Jan 5, 2015 #7

    phinds

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    that is correct
    Again, neither I nor anyone else knows how the universe was created. People have theories but so far they are not falsifiable and therefore are not science, just speculation.
     
  9. Jan 5, 2015 #8

    Doug Huffman

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    In terms of causality, how might Priyank define universe? Can you effect beyond the universe or can beyond the universe effect you?

    Read Karl Poppers The Logic of Scientific Discovery for falsifiability criteria.
     
  10. Jan 5, 2015 #9
    Humans are curious species, they seek answers, but very few of those have a valid proof/history... I too am confused and don't know the mystery behind its Creation...
     
  11. Jan 5, 2015 #10
    I think the Creation of Universe hides behind the Creation of Multiverse...
    If Multiverse is there, then Universe came into existence by Quantum Fluctuation, as I earlier said...
     
  12. Jan 5, 2015 #11
    It's rather like some people say that multiverse is a viable hypothesis, while others disagree. Furthermore, there are different multiverse hypotheses. See also e.g. the paper "Multiversality" (Frank Wilczek), abstract:

    and there is also a 7 pages long thread with inputs and links from many members here:
    https://www.physicsforums.com/threads/multiverse-evidence-explanation.697051/

    It's an open question. See e.g. http://math.ucr.edu/home/baez/physics/General/open_questions.html#cosmology
     
  13. Jan 5, 2015 #12
    If Multiverse doesn't exist, then it what is The Universe expanding? It is nothing but the Multiverse
     
  14. Jan 5, 2015 #13
    I don't understand this question. Can you please rephrase it?
     
  15. Jan 5, 2015 #14
    If there is no Multiverse, then in what is the Universe expanding? Its possibly the Multiverse...
     
  16. Jan 5, 2015 #15
  17. Jan 5, 2015 #16

    phinds

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    No, the universe it not expanding INTO anything. The universe is everything there is. If there IS a multiverse (and I am one who believes there is not) then it does not matter at all since it is totally disconnected from our universe and has nothing to do with our universe. There is no edge to our universe, there is no center to our universe, our universe is all there is, it is not expanding into anything.
     
  18. Jan 5, 2015 #17

    PeterDonis

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    But in your OP, you mentioned quantum fluctuations, which aren't modeled by classical physics. Which do you want to ask about, classical physics or quantum physics?

    As for what you mentioned Hawking as saying, about quantum fluctuations creating tiny universes, that is a speculative hypothesis; it is not established. Not everybody agrees with that hypothesis, which is why you find people saying that the multiverse does not exist.

    Also, The Grand Design is a popular science book; it is not a textbook or a peer-reviewed paper. So it is not really an acceptable reference here on PF. Popular science books are not good sources to use if you actually want to learn the science, as opposed to just getting a brief description of it. You should be looking at textbooks and papers on relativity, quantum physics, and cosmology.
     
  19. Jan 5, 2015 #18
    If Multiverse exists, then we can clearly come to the conclusion that Universe came into existence by quantum fluctuation... As a result, the Big Bang will fail to hold water, which you consider a speculation...
    I've some clips of some pages of The Grand Design by Stephen Hawking, please consult them after I post them.
     
  20. Jan 5, 2015 #19

    PeterDonis

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    No, it isn't. Even if some version of the multiverse hypothesis is true, our universe is not expanding into the multiverse, because the multiverse is not a pre-existing space into which the tiny universes expand. Each universe is its own self-contained spacetime; the multiverse is just an abstract term for the underlying quantum field in which the fluctuations take place, but that field has no space or time.

    Yes, if the multiverse exists. But, as I said in my previous post, the multiverse is a speculative hypothesis; it is not established. So you can't treat it as if it were established fact, because it isn't.

    This is not correct. The Big Bang theory does not claim that there was an initial singularity; it only claims that our universe, at early times, was in a hot, dense state and was expanding very fast. That is compatible with a number of different hypotheses about what came before the hot, dense state; the multiverse is just one such hypothesis.

    As I said in my previous post, The Grand Design is not an acceptable reference. If you want to talk further about the multiverse hypothesis, you need to find acceptable references.
     
  21. Jan 5, 2015 #20
    This was the clip I was thinking about: "Misconceptions About the Universe", .
     
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