Membrane theory and the 11th Dimenson

Discussion in 'Physics & Math' started by machiaventa, Jan 21, 2010.

  1. machiaventa Registered Senior Member

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    Dear Fellows:
    Recently I viewed a program on the sci-channel discussed in great depth the fact that there are 10 dimensions and then there is the 11th dimension in which we exist. It said the 11th dimension was the capable of supporting space and time, as well as gravity.They went so far as to explain the big bang and all the matter produced subsequent to it was caused by one membrane dimension bumping in to another therefore creating our universe. It has even been proven by mathematical calculation. I found this to an alot to digest,but in a way it made sense. Did anyone else see this show and what do you think of this theory? Supposedly the other 10 dimension and branes could include opposite charged particles than ours and may only be 1 billionth of a millimeter wide, therefore being right next to us without our knowing or seeing. I welcome your input in this matter.:shrug:

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    Paul/Machiaventa
     
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  3. AlphaNumeric Fully ionized Registered Senior Member

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    You're talking about two different things.

    M theory is the eleven dimensional extension of the different ten dimensional supersymmetric string theories into a single framework. Its fundamental objects are 2 dimensional things known as membranes. If you wrap up these membranes into cylinders and make the cylinder have a very very small radius compared to its length then it looks like a string, hence how you get string theory from it. M theory is heavily constrained due to symmetries and is UV complete but the actual completion isn't currently known.

    The second thing you talk about is known as a brane-world scenario. Our universe appears to have 3 large spacial dimensions but string theory needs 10. To reconcile these two points of view you can have all the matter in our universe stuck to a 3 dimensional object, a 3-brane. Other 3 branes might be elsewhere in the 10 dimensional universe but since their matter is stuck to them too we can't detect them other than perhaps by gravitational interactions, which are not stuck to any of the branes.
     
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  5. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Another point is that presently there is no physical evidence which shows there are additional dimensions. These are mathematical constructs that have been developing for 40+ years.
     
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  7. AlphaNumeric Fully ionized Registered Senior Member

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    Ah Walter. Surely you have been arguing about the possibilities of extra dimensions because they are an essential component in any model which says the LHC can form micro black holes. Are you now turning around and saying its a silly prediction of string theory to say there are extra dimensions?

    Either you accept extra dimensions as a viable notion, which you require in order to motivate your claims the LHC could be dangerous, or you reject extra dimensions and accept the LHC is safe.

    So which is it? You can't have your cake and eat it.
     
  8. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Sorry Walter, but...

    :roflmao:
     
  9. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    What? Why does one have to either accept or reject that theory to point out that it's not established? I never said it's not correct. I said it's not established as correct by physics experiments. But maybe you Einsteins can assert it's correct even if it's not.
     
  10. AlphaNumeric Fully ionized Registered Senior Member

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    It seems odd to us that you have spent so much time and effort whining about micro black holes at the LHC, a point which has no experimental justification and the only theoretical justification comes from fringe ideas and requires large extra dimensions, to then turn around and take a pot shot at string theory for postulating extra dimensions.

    Any negative comment you make about string theory's notion of extra dimensions immediately falls back on your own claims about the danger of the LHC. Extra dimensions are essential to all models which suggest micro black holes might be made so if you are arguing about the LHC posing a real clear and present danger than you must be accepting that extra dimensions are sufficiently likely and thus string theory is not hurt by such predictions.
     
  11. machiaventa Registered Senior Member

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    String Theory

    String theory presents as interesting postulation,that all things vibrate at a varied harmonic tone, could this be why we like music so much especially the lower frequencies.I believe even our bodies put out a harmonic frequency which varies with age and health.That may explain why some animals can sense disease as well as disharmony within us.:grumble::roflmao:
     
  12. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    In what manner did I take a pot shot at string theory, or make a negative comment? I simply asserted that it is not proven by experimentation. It might very well provide a more accurate description of sub-nuclear physics.

    Your ability to jump to erroneous conclusions is amazing.
     
  13. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    this is not physics.
     
  14. AlphaNumeric Fully ionized Registered Senior Member

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    Are you saying you mentioned the non-experimentally justified prediction of string theory is something you mentioned as a positive?

    Well there was a 50% change I was right, eh Walter

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  15. Pete It's not rocket surgery Registered Senior Member

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  16. Fraggle Rocker Staff Member

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    This illustrates my assertion that cosmology--microcosmology in this case--is an awkward combination of physics, math and philosophy. When we finally devise an elegant model of the universe that resolves the remaining problems in our current model, it may be a pure abstraction with no physical evidence.

    This is just as true in macrocosmology. How can we ever know what is "outside the Hubble volume" or what came "before the Big Bang," or even whether those are meaningful questions?
     
  17. prometheus viva voce! Registered Senior Member

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    That doesn't mean that cosmology is "awkward." Current models of cosmology have revolutionised our understanding of what the universe actually is and how we came to the point we find ourselves at. Just because you can't ask sensible questions doesn't mean there's anything wrong with cosmology as it is.
     
  18. AlphaNumeric Fully ionized Registered Senior Member

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    The reason for not looking for a twelve or higher dimensional theory is that the requirement of supersymmetry relates the dimensionality of space-time to the field content of the theory. Even the least restrictive case of N=1 supersymmetry in twelve dimensions requires the existence of a particle with spin 5/2. Such spin particles do not lead to consistent interactions and thus a meaningless theory. Hence the highest space-time dimensionality you can have for a supersymmetric theory is eleven. In eleven dimensions the N=1 supermultiplet construction is the only possible one and hence is unique. Its supergravity limit is the eleven dimensional supergravity.
     
  19. LIGHTBEING Registered Senior Member

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    Machiaventa -

    I just saw this one a few days ago. I'm just at the very early stages of studying physics so it's hard for me to even explain what it was clearly about.

    But I do recall them speaking on String Theory and different versions of the ST started to pop up - A total of five I believe. You could imagine it took a huge step back in the world of physics at this point. Then it mentioned something about Supergravity theory which I think proposed the concept of 11 demensions first.....but was frowned upon once ST entered into the equation. Then at a conference Ed Witten proposed the 11 demensions again and all 5 versions of the ST were the exact same answer....something to that effect.

    I thought this evolved into M-theory and the Membrane concept? That's atleast what I got from the program.

    **disclaimer** don't quote me on anything ....it could have very well been that a got caught on the very first thought in the program and the rest of it went over my head.
     
  20. AlphaNumeric Fully ionized Registered Senior Member

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    You're right, Witten in ~1995 demonstrated you can view 6 different 10 or 11 dimensional theories which had been constructed individually as the limits of a single more general theory, M theory.

    If you take only the lightest fields in M theory you get 11 dimensional supergravity. If you make one of the dimensions of 11 dimensional space-time a circle then if you shrink that circle to a point you get Type IIA string theory. If you make one of the dimensions into an interval rather than a circle and shrink it to a point you get E8xE8 heterotic string theory. These are then related to the other string theories via T and S dualities which are a little technical for me to go into, I suggest checking out the Wikipedia pages on them.
     
  21. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Those are not sensible questions, in the sense that they can never really be tested. One may be able to see some evidence of this in, for example, the CMB spectrum. But that's about it, I think. The best you can do is make statements about what might exist, with the full realization that those statements can only really be falsified by God.
     
  22. LIGHTBEING Registered Senior Member

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    Alpha -

    Thanks, any other learning materials you would suggest? Books, audio books, DVDs etc (for a beginner) ?
     

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