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Why universe is not symmetrical

  1. Dec 11, 2014 #1
    Did scientist ever tried to explain the reason for the non symmetrical nature of the universe?

    If we accept that scientific laws are same everywhere;
    and there was nothing in the beginning ;
    (thus symmetry of nothing, until matter is created by some sort of physics law and bigbang)

    How could every angle and radius from initial beginning point today can have different particles?
     
  2. jcsd
  3. Dec 11, 2014 #2
    What makes you think it isn't? The cosmological principle basically states that on a sufficiently large scale, the universe is homogeneous and isotropic.
     
  4. Dec 11, 2014 #3
    I guess we mean different symmetries.

    If everything were initially same in every direction, than universe should have been like a sphere, that's what I mean. If there is a hydrogen atom at the angle 0, radius 1km from the point where bigbang happened, then there should also be a hydrogen atom at the angle 1, angle 2, ... given that they have the same distance, 1km with respect to the initial condition.

    I don't know about large scales but as far as I see, nothing is symmetrical, which is pretty weird since physics laws applies the same everywhere.
     
  5. Dec 11, 2014 #4

    phinds

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    There were, for reasons that are unknown as far as I am aware, very minor differences in the early universe and they became exaggerated over time, giving rise to galaxies and all the rest.

    The most obvious non-symmetry is between matter and anti-matter. Had there been perfect symmetry, we would not be here.
     
  6. Dec 11, 2014 #5
    I think they work on it.
     
  7. Dec 11, 2014 #6
    I think you do mean homogeneity and isotropy. I believe the current model assumes it at early stages of the universe. However, as they become further apart from each other, the homogeneous phase become unstable, and phase transition leads to spontaneous broken symmetry. The broken symmetry is widely observed in physics, in phase transitions, in Higgs mechanism for example.

    In my perspective, the Friedman-Robertson-Walker metric based on cosmological principle is describing the universe with non interacting cosmic fluid (dust-like). But when interacting matter is introduced, there is locally broken symmetry as stated, and the gravitational effect of clustering phases decouples the surrounding from the F-R-W metric.
     
  8. Dec 11, 2014 #7
    In any case, can we deduce that if there is no symmetry, there must be different physics laws on different directions. Otherwise, lets say universe was to become unstable by "introducing an interacting matter", or in any other way without breaking the physics laws as we know them (or will discover them). Then, if physics laws were the same everywhere, we wouldn't get a different kind of unstability on two different points.
     
  9. Dec 11, 2014 #8

    Bandersnatch

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    Not at all. The case here is the same as with a needle pefectly balanced on its tip. The laws of physics govering the needle and its surroundings are the same everywhere, yet it will not stay in its perfectly balanced state but fall to one side.
     
  10. Dec 11, 2014 #9

    Vanadium 50

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    Ozgren, you are getting very close to a personal theory.

    On large scales, the universe is homogeneous and isotropic - the technical terms for what you call "symmetry". On smaller scales, it is no longer the case because of initial fluctuations and the subsequent evolution, which includes interactions among the matter at these scales.
     
  11. Dec 11, 2014 #10
    In reality no, there is always something that makes it fall on some particular direction, whether an air current, or maybe even the gravitational attraction of my own mass, or something like that. Because the universe is already is not symmetrical. But if you consider a symmetrical needle in very beginning, it must stay as it is depending on the physics laws we currently have.

    That is why Im asking if anyone had a good answer for that before. Just large scales being homogeneous and isotropic is not enough to answer that question, because we were suppose to have a perfect symmetry. Im just saying those initial fluctuations or whatever you call them, they must be non symmetrical, since they are in general, called the physics laws, physics laws have to depend on direction. Otherwise universe would be just the same everywhere.
     
  12. Dec 11, 2014 #11

    Bandersnatch

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    But it's not true! If you had the needle surrounded by a perfectly symmetrical distribution of molecules, in a short time the random motion of these molecules would break the symmetry and push the needle to one side. It's the same with gravitational interaction on cosmological scales.
     
  13. Dec 11, 2014 #12
    Do you mean the quantum sense of randomness? Like any of its atoms not having a defined position, appearing here and there, sort of thing?
     
  14. Dec 11, 2014 #13

    Bandersnatch

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    That's a large part of it. You need only the tiniest divergence from the equilibrium state to cascade into full-blown symmetry breaking, and the quantum nature of the world on the smallest scales is always going to supply such tiny nudges.
    But also, you need to consider the processes that you think preceeded the equilibrium phase. Is there any reason why they ought to output a perfectly balanced setup, and not one with inherent deviations from symmetry? On the large scale, it may look homogenous and isotropic, but it's just a statistical effect. Why would it need to be so on the smallest of scales as well?
     
  15. Dec 11, 2014 #14
    Because I assume there is some causation in physics rules, I don't think nature is random even in the tiniest scales. (Saying it is random is easy, but in any case there is this possibility that we just can't see the connection. If someday, someone really proves it to be random, then we can just throw away all equations and live with a huge statistical data. )

    I guess even in quantum physics, Bohmian Mechanics suggest causation by breaking locality.

    And if there is causation, that means laws are local, directional, not universal.
     
  16. Dec 11, 2014 #15

    Doug Huffman

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    Ahh, predestination and determinism! Read Popper (no historicist prophesy for freewill) and Smolin (no determinism for randomness). The root is in the fallacy of the dialectic, thanks Plato - NOT!
     
  17. Dec 11, 2014 #16
    As the physical laws go, we have to assume they are consistent to get "way back when" all the matter formed after the big bang. You can't cut off your nose to spite your face. The laws worked backwards from now is what lead to the HBB theory in the first place. You can't then take a theory based on an assumption and "start over" from the big bang and try to change the rules... You'd have to work backwards from now with variable laws and try to work back to see what the start would look like, and perhaps the picture would look very different.
     
  18. Dec 11, 2014 #17

    Vanadium 50

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    Well, you're just wrong then. Nature is fundamentally probabilistic.
     
  19. Dec 11, 2014 #18
    Me either but quantum physics convincingly predicts it could be.
     
  20. Dec 11, 2014 #19

    Doug Huffman

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    There is a nice paper by Andreas Albrecht of UC Davis demonstrating frequentist statistics as a sub-set of QM.
     
  21. Dec 11, 2014 #20
    We can't say there was nothing in the beginning. We don't know.
     
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