How many dimensions really exist?

Main Question or Discussion Point

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?

Related Other Physics Topics News on Phys.org
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.

mathman
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.

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

"One thing which struck me recently, and I found it a really disconcerting concept, was that once we accept all that, we get into a very deep set of questions about the nature of physical reality. That's because even in our universe, and certainly in some of the others, there'd be the potential for life to develop far beyond the level it's reached on earth today. We are probably not the culmination of evolution on earth; the time lying ahead for the earth is as long as the time it's elapsed to get from single-celled organisms to us, and so life could spread in a post-human phase far beyond the earth. In other universes there may be an even richer potentiality for life and complexity.

Now life and complexity means information-processing power; the most complex conceivable entities may not be organic life, but some sort of hyper-computers. But once you accept that our universe, or even other universes, may allow the emergence within them of immense complexity, far beyond our human brains, far beyond the kind of computers we can conceive, perhaps almost at the level of the limits that Seth Lloyd discusses for computers—then you get a rather extraordinary conclusion. These super or hyper-computers would have the capacity to simulate not just a simple part of reality, but a large fraction of an entire universe.

And then of course the question arises: if these simulations exist in far larger numbers than the universe themselves, could we be in one of them? Could we ourselves not be part of what we think of as bedrock physical reality? Could we be ideas in the mind of some supreme being, as it were, who's running a simulation? Indeed, if the simulations outnumber the universes, as they would if one universe contained many computers making many simulations, then the likelihood is that we are 'artificial life' in this sense. This concept opens up the possibility of a new kind of 'virtual time travel', because the advanced beings creating the simulation can, in effect, rerun the past. It's not a time-loop in a traditional sense: it's a reconstruction of the past, allowing advanced beings to explore their history."

-Sir Martin Rees
___________________________

/:set\AI transmedia laboratories

http://setai-transmedia.com [Broken]

Last edited by a moderator:
Superstring/M-theory theories indicated that the extra dimension beyond the three that we know of are hidden within the Planck domains ($10^{-33}$ 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.

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.

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.

The_Thinker said:
Dimensions are basically projections of lines.
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?

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.

Poy
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...

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.

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.