11 dimensions

[quick silver]

can anyone tell me what the 11 dimensions that the String Theory talks about? or have they not been discovered yet?

 

a new project.

[Ollie]

They aren't dimensions like various sci-fi shows would have you believe. The easiest way to think of them is as extra degrees of freedom. Everyday experience of a dimension can be summed up by, for instance, making a delivery to to Room 218, Big Building, Townsville. An address tells us a rooms position in 3 dimensions. If you wanted to send lots of packages, but didn't want them to all arrive at once (swamping the confused receiver), you would send each one with a different delivery time (spacing them out in a fourth dimension). If you still needed to send more parcels, you could attach properties such as "colour", "smell", "taste", "texture", "monkiness" etc to them, so that no 2 parcels with the same colour, smell, taste, texture and monkiness can be delivered to teh same place at the same time, but an entire spectrum of parcels, or a 4-course meal of them, could be received.

 

The 11-dimensions (actually, they include our everyday 4, so there are fewer) are so small that they cant really have any meaning attatched to them, other than as mathematical properties that allow strings to oscillate in the variety of complex ways they need to in order to create the physics we observe.

[bascule]

There's...

 

1 time dimension

 

and

 

10 spatial dimensions which break down as follows:

 

3 dimensions are the normal dimensions of space we are familar with

 

6 dimensions are closed and very tightly curved. String theory usually refers to them as being "compactified". Since the normal 3 dimensions of space we are familiar with appear to be very flat, in comparison the other 6 don't seem to exist in our normal day-to-day experience since they are so very small and tightly curved.

 

The final dimension was illuminated through the dualities between the 5 string theories, which paint a picture of a higher dimension in which structures called p-branes and d-branes exist. What we originally thought of as 1 dimensional strings actually appear to be 2 dimensional slices of higher dimensional membranes.

[quick silver]

thnk you that was a real help:)

[Guest raul]

I am new to this forum. Was reading a article about the 11 dimensions got confused.

Can some one please explain me this using a diagram.

 

Also as per the enstein theory of relativity there was not time before big bang..Whereas as per this 11 dimensions there was universe before big bang also. does this implies that time can be negative.

 

I read following somewhere

"our Universe is just one bubble among an infinite number of membranous bubbles which ripple as they wobble through the eleventh dimension."

[Johnny5]

Raul,

 

There are three spatial dimensions, no more no less.

 

Regards

[Tom Mattson]

I am new to this forum. Was reading a article about the 11 dimensions got confused.

Can some one please explain me this using a diagram.

 

Unfortunately' date=' no. 11 dimensional pictures cannot be represented on a 2 dimensional surface (like a piece of paper or a computer screen). It can be hard enough to represent 3 dimensions on a piece of paper!

 

Also as per the enstein theory of relativity there was not time before big bang..Whereas as per this 11 dimensions there was universe before big bang also. does this implies that time can be negative.

 

It's not yet clear that a quantum theory of gravity will insist that time began at the big bang. That inference (I think) is an extrapolation back to the Big Bang singularity, under the assumption that GR is rigorously correct in all its particulars. But GR is a classical field theory, so there is substantial doubt that that is the case.

 

There are three spatial dimensions' date=' no more no less.

[/quote']

 

Wow! Stop the presses! I guess all those string theorists can stop working now, because Johnny5 has the answer!

[bascule]

Raul' date='

 

There are three spatial dimensions, no more no less.

 

Regards[/quote']

 

Then what is the origin of the disparity between small (quantum) scale and large (GR) scale behaviour, if not extra (non-inflated) spatial dimensions having an increasing impact upon behaviour as their scale is approached?

[Crash]

The 11-dimensions (actually' date=' they include our everyday 4, so there are fewer) are so small that they cant really have any meaning attatched to them, other than as mathematical properties that allow strings to oscillate in the variety of complex ways they need to in order to create the physics we observe.[/quote']

I highly disagree with that, have you any evidence to back up the claim that they have no meaning but to mathmatically allow strings to vibrate in a miriad of ways? I would say they are of huge consequence,

To try and picture these 7 extra dimensions its like looking at a piece of paper, it looks 2D but as you get closer to it you notice that its alot more than 2D,

the real queation is why are the other 7 dimensions so small when 4 of them are so large?....cant wait till im like 50 when string theory is broken or hailed and all the math is there to prove it

[Severian]

It is interesting that various people on this thread categarically state that there are 11 dimensions as if it is fact, and no-one objects. But when Johnny5 says there are 4 (well 3 spacial) everyone jumps down his throat. Since we have no experimental evidence at all suggesting that there are more than 4 dimensions (in fact the experimental evidence means that introducing extra dimensions is difficult to do without mucking things up), both points of view are equally valid.

 

My second point is about compactification. It is not strictly necessary to 'roll-up' the extra dimensions tightly. Randall-Sundrum models for example have extra dimesnions which are not compactified, but restrict Standard Model particles and surfaces to lie on a surface in the extended space (a brane). So Standard Model physics would appear 4-dimensional (as it should to match experiment). However, gravity is allowed to flow through the entire space (the bulk): this dilutes it and makes gravity weak, as observed. (More technically, there is a SM brane and a Planck brane, and it is the exponential decay of the strength of gravity in the bulk between the two branes which makes gravity weak on the SM brane.)

[Ollie]

I highly disagree with that' date=' have you any evidence to back up the claim that they have no meaning but to mathmatically allow strings to vibrate in a miriad of ways? I would say they are of huge consequence,

To try and picture these 7 extra dimensions its like looking at a piece of paper, it looks 2D but as you get closer to it you notice that its alot more than 2D,

[/quote']

 

Sorry, I should have been clearer. I meant they have no every-day meaning, like our 3+1 that we experience every day do. Of course, they are very important. If string theory's right then the world would be a much more boring place without them. But as far as every-day experience goes, they might as well not even exist. It's only at energies to be approached in particle colliders being built and designed at the moment that they might be probed.

[Tom Mattson]

It is interesting that various people on this thread categarically state that there are 11 dimensions as if it is fact' date=' and no-one objects.

[/quote']

 

No one did that. The opening post asked about the 11 dimensions that string theory talks about.

[Johnny5]

Wow! Stop the presses! I guess all those string theorists can stop working now' date=' because Johnny5 has the answer![/quote']

 

When you know the answer just shout it out, like in 3rd grade.

[mattd]

i am really confused about the whole notion that the dimensions above the fourth are "really small". i find it a very third dimensional way of looking at it. plus, the idea that the fourth dimension of time isn't a spatial dimension depends upon how you look at it.

 

we only perceive time the way it is because our consciousness travels along it in one direction. cubes become hypercubes from one frame to another. it's just a different way of looking at things instead of how we are used to.

 

is there any resources on the web concerning this topic? i've searched and found very little that explains this well.

[brad89]

I think that there are 11 dimensions, yet the only thing that has access to the others is gravity. Gravity is considered a weak force, but that is because it is often in the other dimensions. Gravity of a black hole, for instance, is well into the 11th dimension.

[Rebel.esd]

The four dimensions (three of space, 1 of time) that we experience are very large. The remaining dimensions are required in order to make string theory 'work' as it were. They allow strings to curl up and to expand, and are used to define the movements of subatomic particles.

 

Various other variants of string theory have higher numbers of dimensions.

 

The question is whether string-theory is reality, or if it is just a clever mathematical device which just happens to come up with real results.

 

For semantics sake, its equivilant to you recieving two apples. Now, you could simply say "I had zero apples, and i recieved two, which is why i have two apples, the result", or you could say "I had zero apples, then, after a large exchange of apples, i ended up with two". The math leads to realistic results, but, since we can't actually experience the scale of strings, we don't know if newer theories are accurate. The ultimate test of any frame in physics is whether it accurately describes extremes. Classical physics breaks down at extreme scales and extreme speeds, reltativistic physics breaks down at small scales, quantum physics becomes completely impractical at large scales.