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Gravitons in the 5th Dimension

  1. Feb 27, 2004 #1
    Can someone please explain to me or direct me to a website about the theory that there are 4 spacial dimensions, and that gravitons exist in the 4th one. I am now aware of this theory, and that this could explain why gravity is so weak. I find this really interesting, and would appreciate any help.
  2. jcsd
  3. Feb 27, 2004 #2
    I haven't heard of any theory of which you describe, however, it does sound very similar to what current flavor of string theory has to say. In string theory(s) there are many demensions(11 last time I looked) and it is theorized that unlike the 3 other fundamental forces, gravity was not bound to our 4 demensions.

    The explanation of this according to my understanding of string theory is that our 4 dimensions make up of a plane in which strings(the smallest constituent particle of string theory) would attach to, so they were more like loops(with both ends firmly attached to the space occupied by our 4 dimensions) then O-shaped strings. Gravity is unlike the other forces and is a full string(not bound to our dimensional plane) and thus not bound to our dimension. If this is true, it would explain why gravity is so much weaker then other fundamental forces.

    String theory is kinda out there but it does have alot of mathematical evidence that suggests it COULD possibly be on the verge of some pretty amazing scientific break-throughs(or it could also be just one big waste of time, but such is the risk of science)
    Last edited: Feb 28, 2004
  4. Feb 28, 2004 #3
    There was an article on this in the February 2004 edition of the Scientific American. You might be able to check it out at their website at www.sciam.com

    Edit: I just checked the website and it looks like they took it off already. It was a special report called 'Four Keys to the Cosmos'.
    Last edited: Feb 28, 2004
  5. Feb 28, 2004 #4
    Most Kaluza-Klein theories of gravity are 5-dimensional, so that could be one possible candidate of what you're mentioning.

    Alternatively, this could also be a theory of large extra dimensions (LED), which predicts that there are at least 2 extra sub-millimeter dimensions (i.e. not compactified) in which gravitation can travel but not the other forces. This is used to help explain the hierarchy problem between the fundamental forces. If correct, amongst other testable quantities we should expect to see deviations from Newtonian gravity at distance scales of a few micrometers.
  6. Feb 28, 2004 #5
    Stephen Hawkins' book, 'The Universe in a nutshell' covers this topic and is a (fairly!) easy read. You may find it interesting. I certainly did!
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