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stamba
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Can anyone explaine to me why there is exacly 11 dimensions , why not 13 or 7? I have searched a lot but I have not found it anywhere.
Thanks,
Stamba
Thanks,
Stamba
http://www-th.phys.rug.nl/~schaar/h...ort/node12.html [Broken]
Well added dimensions wasn't something completely unique to string theory it actually started with Kaluza Klein theory in 1919 which postulated the existence of an extra spatial dimension that was currled up. You see mathmatically you have a lot more freedom than you do in what you view as reality. For example let's say you calculate the volume of a 4-d object, it would simply be LaTeX graphic is being generated. Reload this page in a moment. So dimensions were added because it allows more freedom mathmatically and allowed the physicsts do do additonal calculations to unify EM with GR. It went from there to 10 dimensions with string theory. The strings needed the extra degrees of freedom to viberate. Since the particular viberation of a string determines what properties it has it needed to be able to viberate in more than just 3 extended dimensions, so again mathmatically they added the dimensions. (here is a good link on history of dimensions in relation to string theory http://www.pbs.org/wgbh/nova/elegant/dimensions.html )
Now if you get why there needs to be extra dimensions (to allow for more freedom for strings) it becomes apparent that the extra dimensions must be in very specific shapes to get particular viberations. This is where the term calabi yau manifold comes from. It is the predicted shape of the curled up dimensions. However there are thousands of calabi yau shapes so they must be limited down further based on how they would create viberations. And I believe currently we need a calabi yau manifold with 3 holes which allows for the extended dimensions we are familar with today.
However the 10 dimensional model of string theory caused a problem for most people becaue it produced 5 different string theories which a man named Ed Witten was able to combine into one theory known as M-theory which basically said the old theories were merely reflections of each other. (Also keep in mind string theory math is approximate at this stage which is why they added a dimension when they learned it needed an extra one)
So they basically came up with the idea for extra dimensions by mathmatically recoginzeing what they could do with extra dimensions in accordance with a particular theory.
The Undergraduate said:My question is, are these extra dimensions in any particular "order" or would they be of different "classes"? For instance, it seems to me that the dimensions "length", "width", and "height" exist in relation to each other and would therefore be of one "class" of dimensions (spatial). Then we have "time", which seems to be its own kind of dimension. Then we have these "extra" spatial dimensions. Could an object theoretically exist in some dimensions but not others? Could there be a one-dimensional object (using the term "object" loosely) that only exists in, say, time, or one of the unknown dimensions?
Enos said:Ain't 11 dimensions used for the strong & weak forces and electromagnetism to be along the same strenth at one point in time. I'm sure I read something like that somewhere.
We started with three because we only directly experience three. The other spatial dimensions are too small for even the atoms of our bodies to move in and out of. We've only recently discovered more than three because we've only recently started studying things small enough to have some free movement in the other dimensions.lalbatros said:Would there be any reason why three spatial dimensions is such a good start in physics?
It is well known that 2 dimensions would be quite difficult to live in.
But why are we so happy with 3?
Louis Cypher said:Hey guys have you ever thought though that m theory and supersymetry are the deluded ravings of mathemeticians who are being driven slowly insane by the wierdness of qm
String theory too could be just an imagined nonsense
Let's maintain some sort of scientific approach to these mathematical sophistries at least until the evidence for them is there
I think we should be wary of claiming that there are any more than 4 dimensions unless we can prove the existence of them we're in danger of dissapearing up our own backsides with this sophistry.
Fantasticaly interesting and clever theories and to be praised and encouraged, but let's not forget that's all they are: theories; actually thinking about it there not even theories there hypothesis since there is no evidence for any of them
I love mathemeticians kinda like ufo nuts with too much spare time and too little scientific experimentation.
Step outside of the envelope people after all the answers in the post
Me just then, A.Smartarse feb 2005
gorgos said:There are any connection between D=11
and alfa(Fsc)=137;1+3+7=11?
The Undergraduate said:My question is, are these extra dimensions in any particular "order" or would they be of different "classes"? For instance, it seems to me that the dimensions "length", "width", and "height" exist in relation to each other and would therefore be of one "class" of dimensions (spatial). Then we have "time", which seems to be its own kind of dimension. Then we have these "extra" spatial dimensions. Could an object theoretically exist in some dimensions but not others? Could there be a one-dimensional object (using the term "object" loosely) that only exists in, say, time, or one of the unknown dimensions?
gorgos said:That depends. What do you get in base 7?
I don't care about 7.For me interesting base 2.
11 to binary is 1011. This is reminding my Metasymmetry idea.
https://www.physicsforums.com/showthread.php?t=220894
Freezeezy said:The real interesting thing is that none of you (Other than Arivero and OzyzzyzO, thanks for your contributions) seem to sound like you haven't done any research...
HERE:
http://www.sukidog.com/jpierre/strings/
Read all of this... then post again. Thanks.
stamba said:Can anyone explaine to me why there is exacly 11 dimensions , why not 13 or 7? I have searched a lot but I have not found it anywhere.
Thanks,
Stamba
gorgos said:To my opinion best answer you can read on
http://arxiv.org/abs/hep-th/0205309
for instance, will confuse anybody who does not already know how to calculate the numbers 26 or 10.Note that fixing the position in [tex]{\cal M}_{8-k}[/tex] yields a supermembrane in a Minkowski spacetime of dimension D = 4, 5 or 7, according to whether k = 1, 2 or 4, respectively; as it happens, these are precisely the other dimensions for which the supermembrane action is classically consistent, so the existence of these lower-dimensional supermembrane actions is explained by the existence of the 11-dimensional supermembrane.
lalbatros said:Would there be any reason why three spatial dimensions is such a good start in physics?
It is well known that 2 dimensions would be quite difficult to live in.
But why are we so happy with 3?
robheus said:Stable planetary orbits and atoms exist only in 3d.
And a curiosity is also that knots only exist in 3d space.
But the base is not arbitrary. The base is the number of dimensions of perturbative superstring theory = 10. The number of physical degrees of freedom is 10-2=8, which givesPhrak said:That depends. What do you get in base 7?
Demystifier said:But the base is not arbitrary. The base is the number of dimensions of perturbative superstring theory = 10. The number of physical degrees of freedom is 10-2=8, which gives
2 X 8 + 10 = 26, which is the number of dimensions of bosonic string theory.
Everything fits. :rofl:
I'm afraid to ask. So I won't.gorgos said:Why three dimensions ?
Because 3 to binary 11. No more minimal and simple symmetry.
Don't forget Jonn Wheeler's "It from bit"
azzkika said:there seems to be little agreement of how many extra dimensions exist, even if they do at all from some posts. has anyone actually drew a picture, i mean we have 3d drawing. if 11 dimensions exist, then can we not make an 11d drawing??
If you say it that way, why wouldn't mass be a dimension, added on to x,y,z, and t, or anything else?arivero said:Hmm. For instance, a TV screen or a computer screen is usually 6+1 dimensional. It sends to the human receiver information of time (so the +1) and information of six different quantities: R,G,B,luminance,xpos,ypos. And we can perceive all of the six.