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Raisin pudding or balloon at LHC

  1. Jun 10, 2009 #1
    If the LHC discovers energy evaporating to other branes, will the 'raisin pudding' analogy be abandoned in favor of the balloon analogy?
  2. jcsd
  3. Jun 10, 2009 #2


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    Properly understood both analogies illustrate the same reality.

    There is no physical experiment that would give grounds for preferring one over the other.

    To use the balloon analogy correctly you need to concentrate---think of all existence as concentrated on the surface of the balloon. The room inside the balloon does not exist nor does the room outside---only the 2D surface and whatever 2D beings might live there.

    To handle the infinite space case with the balloon is difficult, you have to think of the balloon as so large it is effectively flat, and still expanding.

    To use the raisin pudding analogy correctly you need to imagine that the pudding has no boundary, no edge, no "pudding pan", no top, no bottom. It fills all 3D space. Or for the finite volume case it fills the 3D hypersphere (topologically equivalent to 3D space with a point at infinity added.)

    Either toy model will handle either case---finite or infinite volume space. Neither toy model, correctly understood, has extra dimensions.
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