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How many dimensions really exist?

  1. Jun 16, 2004 #1
    i've seen talk of 4d, 5d, 10d, and even 26d space. Have any experiments been conducted in these extra dimensions, or have any experiments been conducted in 3d to show these dimensions exist? Or, are these extra dimensions just the best existing explaination for the quantum force of gravity?
  2. jcsd
  3. Jun 16, 2004 #2
    if you were looking at different theories, then all the dimensions are there to support the specified theory...........e.g. The M theory which needs 11d to support it.
  4. Jun 16, 2004 #3


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    As far as experimental evidence is concerned, there is none (yet) to indicate there are more than the known 3 space + 1 time. However there is no proof that they don't exist either.
  5. Jun 16, 2004 #4
    copied from duplicate thread at SB+LQG

    probably infinite- [but it must be understood that space's dimension is-as-it-is and is not quantized into integers of axes- although “larger” <unquantized> dimensions are possible- the concepts of fractal dimensionality seem to be closer to nature ]

    and I think that it is reasonable to say that extra dimensional spaces are proven becasue there are many discovered/invented "stable" universe simulations in higher dimensions- therefore it is possible to build virtual/artificial/digital universes with higher dimensionality- if a viable hyperdimensional space can be programed- then complex natural process somewhere in the universe should have already allowed such universes to emerge- also if something is created by an intelligence ultimately it is just as natural as anything else that forms- the only difference is that part of the emergent dynamics includes the operation of intelligent systems- a nest is a natural thing built by birds .'. an hyperdimensional continuum is a natural thing built by sophonts

    in fact there is an argument that it is more likely that our universe is an alien artifact/simulation than natural based on anthropic reasoning/ Bekenstein's ideas/ and the seemingly digital discreteness of the Planck-scale


    /:set\AI transmedia laboratories

    Last edited: Jun 16, 2004
  6. Jun 16, 2004 #5
    Superstring/M-theory theories indicated that the extra dimension beyond the three that we know of are hidden within the Planck domains ([itex] 10^{-33} [/itex] cm).

    Theorists said that the Newtonian inverse square law of distance of gravity force is a proof that the world is three dimensional. And this inverse square law is experimentally proved correct down to a tenth of a millimeter. And that 2-dimensionality can be proved by inverse distance law of force. And that 1-dimensionality can be proved by a constant force law. And that inverse cube law of force will provide a proof for 4 dimensional space. And that inverse 4th power law of force will provide a proof for 5 dimensional space, etc.
  7. Jun 16, 2004 #6
    Your question is like asking if God exists. Because we can only be sure of the dimensions that we can see(or experiment) in the material Univers. But a dimension does not need to be influencing the world that we know. So it is impossible to know, we can only try to understand as best as we can the few dimensions that are accessible to us.
  8. Jun 17, 2004 #7
    Frankly, i think that the number of dimensions are limitless. But finding, dimensions, which are mutually perpendicular to each other, other than the already known three is impossible. Dimensions are basically projections of lines. So one can go to infinity, by extending the projections of of a diagram. present. For example take a look at the below link, i have drawn a 4 d diagram. And can go on. The funny thing is that as i seem to extend these diagrams to more dimenions, they seem to eventually form a sort of string. There is no mystery of the 4th dimension, nor is there is anything hidden when we look at the fourth dimension.

  9. Jun 18, 2004 #8
    If dimension is a projection of line, then it should not have any property of size and shape as the string theorists want us to believe. I think branes theories are theory of projections.

    Can you, the thinker, give me the maximum number of orthogonal lines that are mutually connected and can be attached to a spacetime point? I think there is only three? Do you think I am right?
  10. Jun 18, 2004 #9
    in a book im reading it discusses such a thing as the fourth dimensional spacetime. the guy helps to understand a fourth dimension by the analogy of 2d people living in a curved 2d universe (there is a picture of a bowl with a flat top; looks like you cut a hole in a piece of paper and put it to the opening of a bowl). they see things as two dimensional. the only hint they get of a new dimension is that when they draw two parallel lines that go down into the bowl and back out is that they cross at the bottom of the bowl. he gives rise to the possibility of more dimensions but that comprehending them would be nearly impossible.
  11. Jun 18, 2004 #10


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    Doesn't it also depend on what means by a dimension? The dimensions of space and time (as far as I understand them) are very diffrent, so one could argue other 'things' define a dimension...
  12. Jun 18, 2004 #11
    I think the string theorists would attract much more interest if a word other than "dimension" had been used. Such as, sub-sets or mathamatical coordinate variances (mcv). Just by using another phase, my mind would find it easier to comprehend. Of course, thats just me.
  13. Jun 18, 2004 #12
    Like i said earlier. I think it would be impossible to find another dimension that is perpendicular to all the three already known in time. Irrespective of how small people claim it is.
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