Main Question or Discussion Point
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.
if you need more informationhttp://www-th.phys.rug.nl/~schaar/h...ort/node12.html [Broken]
Well added dimensions wasn't something completly unique to string theory it actually started with Kaluza Klein theory in 1919 which postulated the existance of an extra spacial 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 lets 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 dimensions are in two classes; time, and space. One dimension is time, and all the others are space dimensions. As such they would be interchangeable (as length, width, and height are, really; you can mark those on the edges of a box and then rotate the box any way you want). The thing that breaks the interchangeability symmetry is that seven of the space dimensions are compacted (curled up small). But there isn't any special way to choose which space dimensions become small, it's just a fact of life which are.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?
I think that's ten dimensions; supersymmetric GUTs that unify those three forces (without strings) require ten dimensions, and tend to compact them just as string theorists do.Enos said:Ain't 11 dimensions used for the strong & weak forces and electromagetism 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 spacial 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 lets 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
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?
I read this... Are you on the "Hippy-Lettuce"?????????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.
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...
Read all of this... then post again. Thanks.