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Origin of Universe - Hole with no bottom?

  1. Jul 26, 2011 #1
    So i have jut finish watching BBC Horizon Documentary about What happen before big bang. Documentary raises more question then answers. So i suppose main theory goes like this: there was nothing and then at some moment, for what ever reasons, there is a huge explosion and universe comes to existence and continues expanding. Am i right? Anyway, then comes along some scientis and says "No, No that is impossible how can something be created from nothing". So they think of brane, universes form black holes and so on. So lets assume that they are right about brane and that big bang was actually collision of two branes. Ok but this raises question where are branes located and how they come to existence. So for example :

    my house-->city-->country-->continent-->earth-->solar system-->our galaxy-->universe-->brane-->>x-->y-->z--> and so on and so on.

    So my question on is is origin of universe(branes or what ever) hole with no bottom?
    Any thoughts?
     
  2. jcsd
  3. Jul 26, 2011 #2

    marcus

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    I watched the BBC program "What happened before the BB?"

    It presented various alternative ideas, some with more or less clear models, about what was happening before the start of expansion.

    The Colliding "Branes" idea presented by Neil Turok was only one of the alternatives, and not the most convincing one I think. Nor the simplest, nor the easiest to check by astro observation. It was the only one that mentioned "branes".

    Most of the ideas presented there are already fairly old. Turok's "branes" one goes back 10 years. Some go back to the 1990s.

    The main thing is they are alternatives. We have to do some work to decide which if any of them fits the real universe we see.

    ===================

    I think you are right about bottomless hole, as I understand your idea.
    I would say that human explanations are an INFINITE REGRESS. Behind every explanation no matter how good and clear and checkable, there must be an explanation of how that one got set up.

    I do not see how there can be an end to explanation. Which is fine. It is a great adventure. There will never be an end to the excitment.
    Just my two cents.
     
    Last edited: Jul 26, 2011
  4. Jul 26, 2011 #3

    DaveC426913

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    The question of what started everything is distinct from what started the universe.

    The colliding branes hypothesis is a good attempt to answer the latter, though not the former, but it's still nothing to sneeze at.
     
  5. Jul 27, 2011 #4

    Chalnoth

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    Well, that sort of depends upon what you mean by "universe". Unfortunately, many people, even cosmologists, rather sloppily exchange different meanings for the word. I'm pretty sure you mean our observable universe here, but you could just as well mean everything when you use the word universe.

    Anyway, my favorite idea for why anything at all exists is Tegmark's mathiverse. My favorite idea for why our particular region of space-time exists is something akin to vacuum fluctuations producing new regions of space-time.
     
  6. Jul 27, 2011 #5

    Chronos

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    Caveats, there are always caveats. I like the quantum fluctuation thing, but, assuming there was no 'spacetime' for the fluctuation to occur within makes it sound like 'turtles all the way down'.
     
  7. Jul 27, 2011 #6

    Chalnoth

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    Well, this model is that of a sort of equilibrium universe out of which the occasional fluctuation produces a new region, some fraction of which are habitable. I don't see that there is a problem with this proposal (I think the "turtles all the way down" description is overly-simplistic).
     
  8. Jul 27, 2011 #7

    DaveC426913

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    What I mean by the universe is everything that came out of the Big Bang. That includes both the observable universe and the unobservable universe.

    We do not have a commonly accepted name for what occurred before the Big Bang.

    For this reason, I use the word universe without need of qualification.
     
  9. Jul 27, 2011 #8
    The idea of a quantum fluctuation creating a universe seems farfetched to me. Some have asked the question, "a quantum fluctuation of what?" which seems a reasonable thing to ask. On the other hand, if it is a quantum fluctuation within an existing universe -- well, we are IN an existing universe and I haven't heard of any fluctuations creating more than a virtual particle. That's a long way from creating a universe.

    So I suppose some questions might be:

    1) Do scientists believe a quantum fluctuation can appear out of nothing?
    2) If fluctuations have to appear from something, should we be seeing them in our universe?
    3) Or is it theorized that we would be unaware if another universe fluctuated from ours?
    4) Or perhaps that we would be aware, but it is such a rare event that it hasn't happened recently in our observable universe?
     
  10. Jul 27, 2011 #9

    phinds

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    Just FYI, this concept is generally referred to as "turtles all the way down"
     
  11. Jul 27, 2011 #10

    Chalnoth

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    Well, there are some very simple, well-known cases where quantum fluctuations do indeed produce real particles. Specifically, quantum vacuum fluctuations near the horizon of a black hole produce real particles that make up Hawking radiation.

    But in this case, the fluctuation would look, to us, like a microscopic black hole which pops into existence and then rapidly evaporates. It would behave, to us, very much like a virtual particle. But it could easily spawn a whole new universe.

    One sort of visual representation of this would be to imagine our space-time as being a sheet, and vacuum fluctuations as being ripples on the sheet. These ripples are randomized, with some larger and some smaller. Every once in a great while, one ripple gets so big that a bubble pinches off from the sheet. This bubble becomes its own universe, while the original sheet continues on as if nothing ever happened.

    I'm not entirely sure that something appearing out of nothing is sensible. Certainly nobody knows how such a thing would be described mathematically. But just because we don't know how to describe it now doesn't necessarily mean it isn't possible: perhaps the correct theory of quantum gravity will explain how this can happen.

    I'm pretty sure that the fluctuations that would produce new universes would be exceedingly hard to detect. The exception would be a fluctuation into a lower-energy vacuum state, which would destroy our entire universe.

    This is also possible.
     
  12. Jul 27, 2011 #11
    From the National Science Teachers Association (NSTA):

    About NSTA
    The Executive Summary
    Headquartered in Arlington, Virginia, the National Science Teachers Association is a member-driven organization, 60,000-strong. We publish books and journals for science teachers from kindergarten through college. Each year we hold four conferences on science education: three regional events in the fall and a national gathering in the spring. We provide ways for science teachers to connect with one another. We inform Congress and the public on vital questions affecting science literacy and a well-educated workforce. And with your help, we can do even more.
    http://www.nsta.org/about/?lid=tnavhp
     
  13. Jul 27, 2011 #12
    Hi Chalnoth,

    Thank you for the replies. These are difficult things to grasp -- that a microscopic black hole can "easily" spawn a new universe -- which we would likely not notice. I did find a paper by Poplawski, "The universe as a black hole in isotropic coordinates", which theorizes that our universe may exist inside an Einstein-Rosen black hole:

    http://xxx.lanl.gov/PS_cache/arxiv/pdf/0901/0901.0215v1.pdf

    But this seems to be a relatively new idea and I don't know what level of acceptance it has in the physics community. Of course, your comments may be based on a different concept -- if so, I would love to read about it if references exist.

    If a white hole results from certain types of black holes, does the resulting universe contain only the amount of matter contained in the original black hole?
     
  14. Jul 27, 2011 #13

    Chalnoth

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    Nah, that's a somewhat different idea. Here's a rather detailed description of the idea:
    http://arxiv.org/pdf/gr-qc/0512034v3
    It looks like this is the original work regarding new universes that look like black holes on the outside, but it requires a subscription:
    http://www.sciencedirect.com/science/article/pii/055032139090357J

    Well, a white hole is a time reversal of a black hole, which means it is decreasing in entropy with time, which means that you got the arrow of time wrong. In other words, white holes are unphysical.
     
  15. Jul 28, 2011 #14

    Chronos

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    This is why math is a dangerous master, it produces many unphysical 'solutions'. I'm not suggesting math is wrong, merely indicting the usual suspects [assumptions].
     
  16. Jul 29, 2011 #15
    Actualy,you aren't,there was no explosion,the universe was once in an extremely hot and dense state that expanded rapidly and that is called Big Bang
     
  17. Jul 29, 2011 #16
    I thought it important to bring forth Cosmic Microwave Background Radiation Anisotropies: their Discovery and Utilization, Nobel Lecture, December 8, 2006 by George F. Smoot. I present only two snippets from the his lecture though encourage people to read it in its entirety:

    1. "The Cosmic Background Radiation Observations of the Cosmic Microwave Background (CMB) temperature anisotropies have revolutionized and continue to revolutionize our understanding of the Universe. The observation of the CMB anisotropies angular power spectrum with its plateau, acoustic peaks, and high frequency damping tail have established a standard cosmological model consisting of a flat (critical density) geometry, with contents being mainly dark energy and dark matter and a small amount of ordinary matter. In this successful model the dark and ordinary matter formed its structure through gravitational instability acting on the quantum fluctuations generated during the very early Inflationary epoch. Current and future observations will test this model and determine its key cosmological parameters with spectacular precision and confidence."

    2. "According to Big Bang theory, our universe began in a nearly perfect thermal equilibrium state with very high temperature. The universe is dynamic and has been ever expanding and cooling since its birth. When the temperature of the universe dropped to 3,000 K there were insufficient energetic CMB photons to keep hydrogen or helium atoms ionized. Thus, the primeval plasma of charged nuclei electrons and photons changed into neutral atoms plus background radiation. The background radiation could then propagate through space freely, though being stretched by the continuing expansion of the universe, while baryonic matter (mostly hydrogen and helium atoms) could cluster by gravitational attraction to form stars, galaxies and even larger structures. For these structures to form there must have been primordial perturbations in the early matter and energy distributions. The primordial fluctuations of matter density that will later form large scale structures leave imprints in the form of temperature anisotropies in the CMB.”


    Big Bang: Cosmic Microwave Background Radiation Anisotropies: their Discovery and Utilization, Nobel Lecture, December 8, 2006 by George F. Smoot.

    http://nobelprize.org/nobel_prizes/physics/laureates/2006/smoot_lecture.pdf
     
  18. Jul 30, 2011 #17
    you could ask this question and from different people get a different responces, for example, a priest or religious teacher would say that the universe was nothing and God (Who has been around for all eternity) started the universe from nothing, on ideas like these you could look up aquinas's theory of cause and affect. an agnostic would say that they dont know and are open to all beliefs
    Another example is that there is an infinate time or a "cyclic universe" where the universe has always been there and there is no idea of beggining or end. Another idea is that there was no concept of time before that big bang, just a singularity of super dense hot particles fitted in a space that was infinatlely small, that for some reason from a gravitational brane almost borrowed energy from gravity that started the cosmic expansion. Although it is only speculative, i like to think that the our universe started by when two brane universes collided it caused a super expansion of space made from the two branes :D
     
  19. Jul 30, 2011 #18

    phinds

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    Comforting to you perhaps, but doesn't answer anything at all. Where did the branes come from ? That's still turtles all the way down.
     
  20. Jul 30, 2011 #19
    What is wrong with turtles all the way down? Sticking with the turtles analogy there are 3 options that I can see...

    Turtles all they way down
    The turtle is self contained and "under the turtle" has no meaning
    Turtle is standing on a hippo, hippo standing on a rock, pick some number of layers beyond which you cannot formulate a theory.

    I'm not sure if it's scientifically possible to determine which turtle analogy best fits the universe, I think it lies more in the realm of philosophy and personal preference.

    Personally I find turtles all the way down to be the most beautiful and elegant of the 3 possibilities.
     
  21. Jul 30, 2011 #20

    bcrowell

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    Let's confine the discussion to physics. PF has a separate philosophy forum. If there is nothing left to say in this thread that is actual physics, then it's time to close the thread.
     
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