Why exacly 11 dimensions? [Archive]

Tom McCurdy

Sep5-04, 11:35 AM

Well i assume than you are talking about M-theory which says there must be 11 dimensions according to the approximate equations worked about by witten when he combined previous 5 theories into one theory

I think you might like to use one of the folliwng resources

http://www.quantumninja.com/toe/StringIntroLecture.mp3

It is about 35 minutes of a lecture I wrote with help from some members here including selfAdjoint

I also have a powerpoint that goes with it
but this lecture was meant to be stand alone if you would like to kind of follow along with the powerpoint
the powerpoint is here

http://www.quantumninja.com/toe/powerpoint.ppt

also a transcript of the speech itself is avaliable here

http://www.quantumninja.com/toe/Speech.doc

If you just want a quick answer just keep reading

http://www-th.phys.rug.nl/~schaar/h...ort/node12.html

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.

if you need more information
one ask me
two go to the string forum
three read the elegant universe

veryyoung

Sep5-04, 10:31 PM

i believe tom has summed it up rather nicely but really more than 11 dimensions COULD exist although as of now they arent needed and therefore we dont add them. really i would just wait until m theory's full calculations have been done before i said that only 11 can exist.

ШЇSЭЯ

Sep9-04, 01:29 AM

wow very interesting,,

sifeddin

Sep11-04, 10:55 PM

So what would you say if there is a theory that can explain ALL the forces of nature as only the consequences of ONE property of VERY LIMITED number of fundamental particles and consistently predicts quantization of electron energy inside an atom, radiation interaction with material, the existance of other particles and their "binding energy", the wiglling of star motion and includes the gravity forces together on equal footage interpreting with few postulates why there is no repultion of masses and there is an static electomagnetic field around our earth using only three dimensions of the "natural" space and the universal time and give "relativistic-like" conclusions only within "classical-like" mechanics and give all physics the unity it deserves?
I DO NOT mean www.thefinaltheory.com but I mean the Unity Theory of Amr M. Morsi who was one of my students in EM theory at Ain Shams Univ. (where I'm an LA) and then an electronics eng. colleague and finally a personal physics tutor and friend.
However there is another Egyptian Prof. Mohammed-Saladdin ElNashaei (I don't know how his name appears in literature) who I met in Cairo Univ. open lecture and talked about his infinite dimension theory where time is just like anyone of them out of his study of the deterministic chaos. but I did not read anything he wrote (because I cannot spell his english name and my tight time. so if anyone can guide me on his theory my mail is open to receive documents at sifeddinpapers@yahoo.com)
There are still this John Carolle of Camdridge Univ. who claims there are three time dimensions as well asa the three space dimensions that allow to give space-time vortices that explains why there is no isolated magnetic charge.
So how many dimensions do think live in? Would you like to be Mr. Square or Lady Sphere or may be Mr. 4WD!

The Undergraduate

Jan27-05, 04:10 PM

VincentS

Jan28-05, 07:57 AM

"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?"

Well acording to the M-Theory, the extra dimensions are claimed to be extremly small, Where every object exists in all the extra dimensions its just to small for us to even notice. These extra dimensions are just curled up into the 3 standed height, length and width ones.

selfAdjoint

Jan28-05, 09:04 AM

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?

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.

Enos

Jan28-05, 10:01 PM

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.

selfAdjoint

Jan29-05, 10:28 AM

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.

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.

Haelfix

Jan30-05, 01:47 AM

Why 10 dimensions? Well, 4 usual space/time dimensions and 6 compactified ones. Plus an extra M theory one that is kinda taken to be fuzzy (hard to define a length on it).

So why 10 dimensions? Well it turns out, this number is fixed. You can't deviate from it at all in order for the theory to be consistent. If someone in 10 years says "well we really need 14 dimensions to describe nature', then that something is not string theory. In conformal field theory, much of the mathematics of string theory, quantum anomaly conditions must match precisely and this number outputs 10 dimensions. No more, no less.

Louis Cypher

Feb1-05, 04:23 AM

Enos

Feb1-05, 01:51 PM

I prefer the 4 dimensional universe over the 10 or 11. But we shouldn't cut the strings just yet.

tardis

Aug28-05, 10:31 PM

Assuming we accept the 11 dimensional calabi-yau model, does this model REQUIRE that the other three dimensions be very large or is this just a bonus?

Either way, is there a minimum size needed for the 4 large dimensions to make this model work?

lalbatros

Aug29-05, 01:05 AM

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?

εllipse

Aug29-05, 01:46 AM

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?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

Aug30-05, 01:59 AM

εllipse,

I totally agree that 3D is a direct experimental evidence.

But, I was wondering if some people had come with temptative explanations / interpretations about the number of 3 'obvious' dimensions.

Of course, if the 11 dimensions are definitively proved, and if -indeed- a bunch of these are microscopic dimension, then it is factual reasons that lead us to 3 dimensions in our daily lifes. By the way, are the reasons for 11 dimensions factual or more fundamental? Does a 11D space have special properties as compared to other spaces?

Finally, let me note that if I had to choose -by myself- an hypothetical dimension for the scene of physics, I would choose the infinite. I have the feeling that this would open a lot of possibilities ...

Fallaciousmiles

Aug31-05, 01:03 AM

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 :wink:

String theory too could be just an imagined nonsense :wink:

Let's maintain some sort of scientific approach to these mathematical sophistries at least until the evidence for them is there :smile:

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 :biggrin:

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 :smile:

Well, from calculations, more specifically, equations they have actually found out that using the curved model of the fifth dimension. The resulting equations would be somewhat similiar to those of electromagnetism.

For clarifications, their model of curved dimensions actually only has the fourth dimension large enough to be felt, straight in the face right?
With the speculations that the fifth and above dimensions would be smaller then planck's constant, thus it being almost impossible to be detected :confused:

0zyzzyz0

Jul4-08, 10:26 AM

I see that this thread has lain dormant for about three years now, but i'm chipping in with my small change on this because it seems to end right about where my thoughts have been wandering lately. If a moderator prefers to turn this into a new thread, that's ok by me.

Fallaciousmiles mentions that there has been speculation that the dimensions beyond the familiar spacial three are somehow smaller than the Planck length. When hearing that these dimensions are curled up (or wound up? -- another speculation of mine) so that they are too small to be detected, i've wondered how small that might be. Specifically, what i am most curious about is whether there has been any serious speculation that anything other dimensionally could be going on at sub-Planck lenths. [Don't throw anything!] Yes... I do appreciate that the Planck length represents a limit beyond which we can't calculate, [Right?] but i've always had difficulty reconciling that with a lot of other thinking cluttering up my mind. I suspect any serious speculation along such lines could only be going on amongst those with greater maths knowledge than i possess (with my historian/librarian + curiousity background), so i bring my quandary up here.
My thinking along these lines connects with my suspicions that 'existence' must extend by infinite scales of magnitude both towards smaller and larger -- a suspicion i base mostly on the philosophical rationale that either 'all' has ultimately had some sort of beginning ex nihilo [defying our common experience], or there must be an infinite regress of cause and effect [defying nothing in our experience, but challenging our ability to imagine anything as actually infinite].

BigFairy

Jul4-08, 07:15 PM

turtles all the way up, turtles all the way down lol

Phrak

Jul5-08, 12:40 AM

There are any connection between D=11
and alfa(Fsc)=137;1+3+7=11?

That depends. What do you get in base 7?

arivero

Jul6-08, 09:47 AM

This part of the thread stresses an interesting question. If the extra dimensions were Kaluza Klein dimension, whose symmetry generators are gauge bosons, the answer would be an easy one, and to do a good debate about "principia".

I still believe such is the case, and that there is some reason forbidding the symmetry of W and Z "translations" (or rotations) to get a massless mode, the next available being then of the order of the mass of the top (and probably the "size" of such dimension).
Remember that 7 extra dimensions is the quantity you need to fit independent actions of SU(3) times SU(2) time U(1): a product of three manifolds of respective dimensions 4, 2 and 1.

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?

Freezeezy

Jul6-08, 02:47 PM

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.
http://www.physicsforums.com/showthread.php?t=220894

I read this... Are you on the "Hippy-Lettuce"?????????

To be honest you need to now find three intelligent ideas in that bong-ridden head of yours to balance out that one very bad one... oh wait... 3:1... Nevermind... You are just making very vague comparisions to try and explain a very complex universe. The numbers 1, 2, 3, 5, 7, 11, ect are all very common, universally-associated numbers. This is likely due to them being prime numbers... but you didn't know that, right?

The real answer is that the 7 other dimensions are, yet again, just another tiny measument of the universe. Too small for us to accurately observe so we don't know the implecations other than those on paper. Interesting?

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.

arivero

Jul6-08, 04:55 PM

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.

Yep, and while it is OT, and I guess it has been threaded in the general subforums a 1000nd of times, I keep wondering why people can be at the same time interested and uninterested in a topic. (as I say, it is OT... please link to other subforum thread if answering this ;-)

gorgos

Jul6-08, 06:50 PM

Can anyone explaine to me why there is exacly 11 dimensions :bugeye: , why not 13 or 7? I have searched a lot but I have not found it anywhere.

Thanks,
Stamba

To my opinion best answer you can read on
http://arxiv.org/abs/hep-th/0205309

humanino

Jul6-08, 07:09 PM

To my opinion best answer you can read on
http://arxiv.org/abs/hep-th/0205309

Very interesting paper. Townsend is certainly a major figure in this business. However, as pleasant as this paper is, I find it technical for the level of the discussion here, so can you please point us exactly where is the question addressed ?

I tend to think that Note that ﬁxing the position in {\cal M}_{8-k} 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.for instance, will confuse anybody who does not already know how to calculate the numbers 26 or 10.

robheus

Jul9-08, 08:21 PM

arivero

Jul19-08, 08:50 PM

Stable planetary orbits and atoms exist only in 3d.
And a curiosity is also that knots only exist in 3d space.

I think that the point about knots is a low-dimensional effect, as the existence of regular n-poligons. But the one on stability and properties of 1/r^n interactions is a good point, and one wonders why it is not exploited in actual theories.

Demystifier

Jul21-08, 09:58 AM

That depends. What do you get in base 7?
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:

DaveC426913

Jul21-08, 10:28 AM

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:

Durr. That's where that number came from. I brought this up (a theory with 26 dimensions) in a thread months ago but could not name it or its source. I got trounced.

DaveC426913

Jul22-08, 04:18 PM

Why three dimensions ?

Because 3 to binary 11. No more minimal and simple symmetry.
Don't forget Jonn Wheeler's "It from bit"
I'm afraid to ask. So I won't.

Sounds like we're back on the numerology train.
All aboard! Woo woooooooo!! :biggrin:

azzkika

Jul26-08, 08:53 AM

arivero

Jul26-08, 04:17 PM

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??

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.

Jul26-08, 04:50 PM

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.
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

Jul26-08, 09:23 PM

If you say it that way, why wouldn't mass be a dimension, added on to x,y,z, and t, or anything else?

Can you see mass? Or do you infer it from all measurements of x,y,z,t, V(x,y,z,t)? It seems more reasonable to think that the extra dimension is the potential energy, and not the mass. In this way you can keep adding dimensions simply by adding new force fields.

But note that Kaluza Klein theories, in origin. were near of this idea of mass coming from extra dimensions. They compared the massless equation for relativistic energy in five dimensions with the massive equation in four dimensions.

trinity_81

Nov5-09, 04:56 AM

Any one contemplated the idea of infinite dimensions?

History has shown us that we once believed the universe was a finite size only to discover its size is infinite. We once believed there to only be one universe to now believe there, according to m-theory, to be infinite parallel universes. So why stop there. After all 11 does seem to be an arbitrary number as would any defined number. I wonder how the maths would hold up to this idea.

On another point, physicists tend to put a limit to how small the universe is. Hawking did it now string theorist believe it to be in the ball park of 10-34m(the size of a string). Well I say if the universe is infinitely large then by definition the universe should infinitely small. It’s all relative isn't it?

In closing… Infinity on everything.

SimonA

Nov5-09, 06:34 PM

To go back to the original (and simple) question, the reason it comes down to 11 dimensions in M Theory is this;

Theorists took the formulas that our research into understanding the nature of the universe found, and used the laws of algebra to merge them together. Out of that came 5 different theories suggesting a solution. All of them suggested 10 dimensions. Then some bright spark tried imposing 11 dimensions on the different theories, and suddenly they all appeared to be the same theory seen from different perspectives.

This of course made those who follow Madonna in Kabbalah happy - their mystics proposed 10 dimensions and a hidden eleventh centuries ago.

But to give them credit for that would be to assume that there is an equivalence between spacial calculations and spiritual perception. We must be very careful about that - it may well be that new evidence suggests just 6 dimensions, and then the people in China will say - we told you so.

In the meantime, it seems as if reality is composed of 3 spacial dimensions, 1 temporal dimension, and several other dimensions of which we understand little. And we can be confident that there is more hard evidence for extra dimensions, than there is for extra universes.

arivero

Nov5-09, 09:42 PM

Well, you should also check that these people of the China or Kabbalah or whatever have actually said it. Most times, it is interpolation. There is a very famous one in Indian poetry, about the speed of the light, in a old poem... that happened to be copied about ten or fifteen years after the actual measurement of the speed of the light, so the copist did the interpolation probably to show that he was a learned men, aware of modern advancement.

About 11 dimensions, it is wrong to say that they come from M Theory because then it seems to date in the mid nineties, while the supergravity papers come from the seventies. Particularly Cremmer Julia Scherk (D=11) is from 1978, and the research linking strings with supergravity in D=10 predates it a couple years, 1976 or so.

Kaluza Klein extra dimensions were ocassionally examined before, but it was impossible to link them to D=11 without the discovery of SU(3) colour and the SU(2)xU(1) electroweak model.

To go back to the original (and simple) question, the reason it comes down to 11 dimensions in M Theory is this;

Theorists took the formulas that our research into understanding the nature of the universe found, and used the laws of algebra to merge them together. Out of that came 5 different theories suggesting a solution. All of them suggested 10 dimensions. Then some bright spark tried imposing 11 dimensions on the different theories, and suddenly they all appeared to be the same theory seen from different perspectives.

This of course made those who follow Madonna in Kabbalah happy - their mystics proposed 10 dimensions and a hidden eleventh centuries ago.

But to give them credit for that would be to assume that there is an equivalence between spacial calculations and spiritual perception. We must be very careful about that - it may well be that new evidence suggests just 6 dimensions, and then the people in China will say - we told you so.

In the meantime, it seems as if reality is composed of 3 spacial dimensions, 1 temporal dimension, and several other dimensions of which we understand little. And we can be confident that there is more hard evidence for extra dimensions, than there is for extra universes.

SimonA

Nov7-09, 04:11 AM

About 11 dimensions, it is wrong to say that they come from M Theory because then it seems to date in the mid nineties, while the supergravity papers come from the seventies. Particularly Cremmer Julia Scherk (D=11) is from 1978, and the research linking strings with supergravity in D=10 predates it a couple years, 1976

This quote from Madhusree Mukerjee of Scientific American is the contex I was coming from, before then there was little consensus;

"Today's excitement has grown from the finding that if we postulate the existence of a mysterious M-theory in 11 dimensions we can show that the five competing string theories are actually different versions of the same thing. Like a Roman general surveying the battlefield from the third dimension [on top of a hill], physicists today stand on the hilltop of the 11th dimension and see the five superstring theories below, unified into a simple, coherent picture, representing different aspects of the same thing."

tom.stoer

Nov7-09, 11:33 AM

As far as I know the 11th dimension was hidden in string theory (old 10d version) because this was just a limiting case of the full 11d theory. I do not understand the following:
- how can we be sure about 11d in M-theory if we do know its basic equations (Lagrangian?)
- could it be that M-theory is again an approximation to some deeper theory?

Saul

Nov7-09, 12:05 PM

What is a “dimension”?

It is possible to create very complicated mathematical models that have no relationship with the physical world, with electrons, protons, and physical space. John Hogan coined the term “Ironic Science” for the creation of very complicated mathematical models that make no predictions that may have no connection with physical science. “Ironic Science” seems scientific. Intelligent people in the last 20 years have written over a 100,000 “scientific papers” concerning “String Theory”, attended conferences, got advanced degrees, however, after 20 years work the string theorists do not have a “theory”, something that can make predictions.

"String Theory" is a methodology. There is no "String Theory".

The "String theory methodology" may be the end of the mathematical theoretical physics methodology as a means to solve practical physical problems, to advance science. Why do we believe that the "String Theory" Methodology will be successful? Why do we believe practicing the "String Theory" methodology is science?

If we met an advanced alien society that had an answer to what is physical space and what is the relationship of physical space to protons and electrons, it would be possible to know whether “String Theory” is science. “String Theory” could be a kin to alchemy. It is obvious now that we have atomic physics and physic chemistry that the alchemists’ methodology would never have produced a viable practical scientific model.

Mathematical theoretical physics started with the creation of the theoretical entity “space-time”. Prior to the coining of the term “space-time”, physical space, electrons, protons, and so on were the only primitives and time was a term that described how the primitives changed. It is the prior success of mathematical theoretical physics over the competing physical methodology that explains the popularity of the "String Theory" methodology. From a practical standpoint, if a 100,000 papers can be written there is no end to the process, as there are more possible "string models" than there are atoms in the universe, there is no reason for the "String Theory" paper writing to cease.

The analysis technique of constraining the model and then trying to develop a model that matches the physical observations is the physical approach of constructing a model. That methodology would be effective if the correct solution is a model that was constrained to 3 dimensions.

The physical approach is misunderstood and incorrectly believed to naïve. The physical approach is simply a different methodology. The model produced by a physical methodology will likely also be mathematically complicated and may have some mathematical similarities to “string models”, however it is the constraint of the set of all possible models by the physical observations that enables the correct model to be found.

From the “Trouble with Physics” by Lee Smolin Introduction page 15.

“David Gross, a Nobel laureate for his work on the standard model, has since become one of the most aggressive and formidable champions of string theory. Yet he closed a recent conference to celebrate the theory’s progress by saying, “We don’t know what we are talking about…The state of physics today is like it was when we were mystified by radioactivity…They were missing something fundamental. We are missing perhaps something as profound as they were back then.”

On the other hand, if string theorists are wrong, they can’t be just a little wrong. If the new dimensions and symmetries do not exist, then we will count string theorists among science’s greatest failures, like those who continued to work on Ptolemaic epicycles while Kepler and Galileo forged ahead. Theirs will be a cautionary tale of how not to do science, how not to let theoretical conjecture get so far beyond the limits of what can be argued that one starts engaging in fantasy.

From "Not Even Wrong" by Peter Woit page 244
"In his recent book, Susskind admits that he has no plausible idea about how one might be able to derive any predictions from string theory. The surprising thing is that he and other prominent theorists don't see this as a reason to give up on the theory (my comment what theory), but instead choose to believe that the theory must be true (my comment again, what theory), even though it can't predict anything.

SimonA

Nov7-09, 01:43 PM

Saul

Nov7-09, 04:17 PM

Yes some good points, and I have read "the trouble with physics". I don't think we can ignore the maths behind string theory, but the trouble is that we are so far away from understanding the most basic elements of space, time and quantum particles at an epistemological level, and so all the maths is hollow.

I agree.

One of the last people to make progress using deep fundamental analysis was Faraday. I started researching the origin of modern Field Theory and Relativity starting with Faraday's work. I was quite surprised that Faraday's models do not agree with Maxwell's mathematical representation. Maxwell has aware of the discrepancy and noted that he lacked the mathematical modeling tools to model Faraday's model of matter and space.

Faraday analyzed the physical observations using deep logical parsing, looking at the observations as logical clues as to what was the true/fundamental nature of matter and space. He retained competing models and would come up with new experiments to help reduce the number of fundamental models and to refine the fundamental models he would carrying through the process.

For example. The fact that electrons move at right angles to the "magnetic field" was Faraday's discovery. Ampere and others worked on the problem from a mathematical standpoint and assumed that as electrostatic force and gravity were center based forces that the magnetic force should also be center based.

Why electrons move at right angles to the magnetic field or why electrons move at all is not known. Faraday looked at the complete set of observations as hints as to what is the true nature of matter and space.

Faraday thought of matter as a field of force, rather than an entity that projected force or carried force.

He thought of conservation of force, rather than conservation of matter and energy, as he believe observational evidence indicated that energy and matter where not separate entities. Likewise he believed matter to be part of space rather than separate from space. Curiously the experiments at the beginning of the last century show that to be true but somehow the experiments are incorrectly interpreted that space is empty. Faraday would avoid the fatal mistake (if the objective is to solve a problem that has a unique solution) of picking an incorrect interpretation as he carried all reasonable interpretations (models) through the process, including flawed models.

It seems odd that we will logically accept the "String Theory" methodology that has as many possible models as there are atoms in the universe but decide that it is irrational to consider models where space is full rather than empty and to investigate constrained models.

Faraday experimented with the conversion of one "force" to another which he believed was possible if matter was a collection of force rather than a force center and electricity was movement of the dynamic force (matter). The conversion of matter to energy and energy to matter is consistent with Faraday's model.

Faraday thought matter was dynamic not static which is the essence of the quantum theory and modern atomic theory. The atom cycles through a complex time varying pattern. Depending on where it is in that pattern determines how it reacts which explains why the probabilistic addition is required to correct for an assumed static model of matter. Chemical and atomic bonding are determined by how the time varying entities interact.

Faraday's method is by experiments to come up with a set of possible fundamental models or basis for the new model. The mathematical model would then follow rather than lead. The ultimate mathematical model is likely quite complicate, however, it is fundamentally connected or correct when compared to physical space and matter.

It is interesting to compare Faraday's method to the "String Methodology". The String theorists are approaching the problem from a mathematical standpoint. The addition of extra entities or dimensions would make the problem very, very difficult to solve, if the extra entities and dimensions do not exist physically.

As it is a fact that the "String Theory" methodology has not led to a single theory in 20 years, it seems it would be logical to consider approaching the problem using an alternative methodology.

SimonA

Nov7-09, 04:50 PM

Saul

Nov8-09, 12:01 PM

I agree with the extra entities being unnecesary, certainly in terms of "dark" theories.

However, I don't see any evidence of a desire to understand. Just an aversion to string theory. Is that fair ?

It is not possible to prove the "String Theory" methodology will not lead to a theory. It has not as of yet, there is no "String Theory". We use the words dimension and string, however, the methodology is the construction of an astronomically large set of mathematical models, that may have absolutely no connection with the physical world.

Is it possible that the development of the "Set of all String models" (there are no string theories, as of yet) is Ironic Science a kin to alchemy, in that the string methodology will never lead to the correct solution? I believe it is possible. My question is there another methodology to approach the problem? And if there is why has it not been applied? Is there a logical barrier or an aversion which is blocking its application?

From the “Trouble with Physics” by Lee Smolin Introduction page 15.

On the other hand, if string theorists are wrong, they can’t be just a little wrong. If the new dimensions and symmetries do not exist, then we will count string theorists among science’s greatest failures, like those who continued to work on Ptolemaic epicycles while Kepler and Galileo forged ahead. Theirs will be a cautionary tale of how not to do science, how not to let theoretical conjecture get so far beyond the limits of what can be argued that one starts engaging in fantasy.

From "Not Even Wrong" by Peter Woit page 244

"In his recent book, Susskind admits that he has no plausible idea about how one might be able to derive any predictions from string theory. The surprising thing is that he and other prominent theorists don't see this as a reason to give up on the theory (my comment what theory), but instead choose to believe that the theory must be true (my comment again, what theory), even though it can't predict anything.

I am criticizing the "String" methodology because its acceptance has stopped the alternative physical approach.

The aversion is to the discussion and the analysis of the observations using constrained models which is the essence of the physical methodology. People incorrectly believe the physical methodology is naive, because of the failures at the turn of the century and the success of the theoretical approach. The word "aversion" is an emotional rather than a logical decision.

In all other fields of science, new models are constructed using a physical methodology. For example, in biology or paleoclimatology one does not change the "laws of physics" when there is new unexplained phenomena. The phenomena must be explained by a constrained model.

The problem situation in physics is there is no fundamental model. There are a set of incompatible very complex curve fitting models and there are phenomena such as the galactic rotational anomaly or the "quantum" anomalies that do not have an explanation. There are place holder theories but they have emerged ad hoc.

SimonA

Nov11-09, 03:33 AM

It would be great if more people stepped back more like you do. We have too many highly specialised theories in modern physics, often with little rational basis, and often contradictory. Because they are so far away from a rationed basis (as opposed to mathematical speculation around imagined variables), it's impossible to verify one over another. It's not just testability that's missing - it's a lack of fundamental explanatory powers.

Like you mentioned, faraday is a great example of someone who rationalised the basics. The only question I have is whether it's possible to rationalise all the branches of physics that now exist, and all the reams of evidence and pseudo evidence, into something more fundamental ? Or are we now condemed to delve deeper and deeper into string theory and loop gravity etc, until at the far end of one a few pieces fit together and allow us to deconstruct the theory backwards into a coherent rational basis. It seems the wrong way around, but the way peer review etc works nowadays, I suspect it's the only way that has a chance.

arivero

Nov11-09, 04:02 AM

I am criticizing the "String" methodology because its acceptance has stopped the alternative physical approach.

In your support, it could be argued that most of the important results of string theory were done in the seventies, before the so-called "string revolutions". At that time, string theory still was keeping a physical approach, from its roots in the theory of strong interactions.

Mgt3

Nov12-09, 10:20 AM

The more you learn about this stuff, the more it appears as though theoretical physicists have been making ad hoc equations and justifications for string theory over the past 20 years without any empirical verification. More frightening is that these bodies of speculation - they cannot be called theories - are presented to the general public as if they are supported by observation.

DaveC426913

Nov12-09, 11:28 AM

More frightening is that these bodies of speculation - they cannot be called theories - are presented to the general public as if they are supported by observation.
I guess that depends on your idea of "...presented to the general public..."

I am not a scientist; I am merely a science enthusiast. I read layperson books on string theory. I have never gotten the impression that anyone thinks they are truly theories, born out by observation. My reading always talks about how unprovable or unfalsifiable string theory is. Any amount of due diligence into the subject will reveal this, IMO.

I'm not sure it is even meaningful to talk about how string theory is "...presented to the general public..." at any farther arm's-distance than these lay-person's books. Any farther removed (newspaper articles? TV shows?) and you lose any meaningful learning.

Naty1

Nov12-09, 11:47 AM

ok so maybe "string hypothesis" would have been a better name but even cursory reading reveals string theory is based on perturbative (approximate) math, is incomplete even by string theorists standards themselves, and the basic underlying principles, which we assume are there, remain obscured. So far it has no proven to be the magic bullet once envisioned, er, twice, counting the frist and sec ond "revolutions"....

Naty1

Nov12-09, 12:02 PM

Post 38 mentions: ... All of them suggested 10 dimensions. Then some bright spark tried imposing 11 dimensions on the different theories, and suddenly they all appeared to be the same theory seen from different perspectives.

The "bright spark" was Ed Witten (Princeton) who was able to go beyond the approximations of the five basic string theory approximations and show that an additional, or tenth, space dimension had been missed in earlier approximations...so what appeared to be five different string theories could be "unified" with an additional space dimension.....and to add to the complexity it was discovered that p dimenisonal objects or p-branes were also embedded in the theory and that the tenth space dimension does not have to necessarily be much smaller than the others. Lisa Randall (Harvard) and collaborators have interesting theories on large size dimensions. (described in non mathematical tems in her book WARPED PASSAGES).

twofish-quant

Nov12-09, 03:34 PM

I think of string theory as something like medieval theologians trying to logically prove the existence of God. Yes it turns out that you can't logically prove the existence of God, but you don't know that until you spend a lot of time and effort trying and not getting anywhere.

DaveC426913

Nov12-09, 04:47 PM

I think of string theory as something like medieval theologians trying to logically prove the existence of God.Well, string theory had once been described by some as a piece of 21st century mathematics that fell into the hands of 20th century mathematicians....

Mgt3

Nov12-09, 05:42 PM

Well, string theory had once been described by some as a piece of 21st century mathematics that fell into the hands of 20th century mathematicians....

My hunch is that physicists are going to continue spinning their wheels as long as they keep trying to find a theory of everything that attempts to explain a finite universe. It's not going to happen. The universe (or multiverse if you prefer) has to be infinite.

twofish-quant

Nov12-09, 07:53 PM

I can explain why 11 dimensions.

Let's go back to the standard model. You have three matrices that describe the forces in the universe. A one dimensional matrix that describes EM. A two dimensional matrix that describes the weak force. A three dimensional matrix that describes the strong force. Now you are a theorist, and you see that gravity is described by a four dimensional matrix. So the logical thing to do is to lump all of these matrices together and get a 10 dimensional matrix. And you argue that the extra six dimensions that describe all of the forces are just tiny little dimensions so 1+2+3+4 = 10. And you end up with a nice elegant theory that quite nicely seems to describe all of the forces in nature.

Except for one little detail.....

You have all of the forces in your 10 dimension matrix, but you don't have any matter..... Hmm.... it turns out that you can try to fix this problem by adding one more dimension which turns a force into matter and matter into forces. So this is where you get 11. Now the only problem is to then look at the big matrix and then take a sledge hammer to it until you get back the standard model.

Now in 1980, it wasn't obvious that if you think about it long enough you'll come up with neat math trick for getting the standard model out of this 11 dimensional theory. But people have been trying for a lot of years, and no one has getting it to work.........

SimonA

Nov13-09, 04:00 PM

Mgt3

Nov13-09, 05:14 PM

The funny thing is that string theory posits billions of possible realities, and theorists tune it based on the standard model. And then all theorists seem to invent multiple universes to explain the strange fact that goldilocks porridge is perfectly warm.

I don't like the term multiple universes, the "multiverse" should be the Universe, and each little "universe" should be considered spatial regions. Let's face it, in an infinite universe an infinite amount of events will occur. Nobody is inventing universes.

SimonA

Nov13-09, 06:01 PM

I don't like the term multiple universes, the "multiverse" should be the Universe, and each little "universe" should be considered spatial regions. Let's face it, in an infinite universe an infinite amount of events will occur. Nobody is inventing universes.

give me one single piece of evidence that there is more than one universe. "spacial regions" is nonsense in terms of dimensionality.

DaveC426913

Nov14-09, 11:05 PM

give me one single piece of evidence that there is more than one universe. "spacial regions" is nonsense in terms of dimensionality.
It is a hypothesis. No one is suggesting there is evidence that there is more than one universe. The MWI is another such hypothesis.

SimonA

Nov20-09, 09:02 PM

It is a hypothesis. No one is suggesting there is evidence that there is more than one universe. The MWI is another such hypothesis.

But is it reasonable to accept that every sub atomic interaction divides reality such that every possibility did occur? I'd suggest that all our evidence suggests that once a decision is made, it's final.

It's just that in the macro world, the decision is made Very quickly. Decoherence seems to me to be exponentialy related to the plank length, and yet there is an almost quantum nature to the border where the decisions get made - in effect - instantly.

And yet the uncertainty remains in the macro world because firstly there are too many variables for us to be capable of making sense of their interactions, and secondly because at some fundamental level our consciousness lives in the place where quantum uncertainty is normal.

I'm not suggesting
anything like indecision etc. I'm proposing that human will is non deterministic. And I'm certainly not suggesting that consciousness and quantum uncertainty are directly connected. But it is a fact that we are a long way from starting to understand either.

I feel sorry for all the people that have no intellectual curiosity because they believe people far more intelligent than themselves are close to understanding everything. It's cruel that science nowadays is constructed to give that false impression, when the reality would stir and exite so many more to hunger to understand the great mysteries that stand before us all.

If science was more honest about the fact that most of it's current "facts" will be at least partially modified in a decade or two, the crazies that reject reason altogether would have the rug taken from under their feet. And maybe more would hunger for truth.