String Theory, at 20, Explains It All (Are There 10 Dimensions Of Space and Time?)

NY Times ^ | 7 December 2004 | By DENNIS OVERBYE

[shrinkermd]

ASPEN, Colo. - They all laughed 20 years ago.

It was then that a physicist named John Schwarz jumped up on the stage during a cabaret at the physics center here and began babbling about having discovered a theory that could explain everything. By prearrangement men in white suits swooped in and carried away Dr. Schwarz, then a little-known researcher at the California Institute of Technology.

Only a few of the laughing audience members knew that Dr. Schwarz was not entirely joking. He and his collaborator, Dr. Michael Green, now at Cambridge University, had just finished a calculation that would change the way physics was done. They had shown that it was possible for the first time to write down a single equation that could explain all the laws of physics, all the forces of nature - the proverbial "theory of everything" that could be written on a T-shirt.

And so emerged into the limelight a strange new concept of nature, called string theory, so named because it depicts the basic constituents of the universe as tiny wriggling strings, not point particles.

"That was our first public announcement," Dr. Schwarz said recently.

By uniting all the forces, string theory had the potential of achieving the goal that Einstein sought without success for half his life and that has embodied the dreams of every physicist since then. If true, it could be used like a searchlight to illuminate some of the deepest mysteries physicists can imagine, like the origin of space and time in the Big Bang and the putative death of space and time at the infinitely dense centers of black holes.

[dartuser]

You can't detect dark anyway so assign its speed arbitrarily ...

[palmer]

My theory is that any N theories can be "unified" by postulating a new universal theory with N + 1 dimensions.

[The_Reader_David]

Yup.

The perverse thing is that there are approaches to construct other models which get no press time in the U.S. and precious little grant funding (thanks to the string theorists dominating all the review panels):
loop quantum gravity, Alain Connes' almost miraculous
construction of the Standard Model (I think plus the Higgs boson, if I'm not mistaken) from the simplest
non-commutative geometry whose underlying commutative geometry looks like Minkowski space (on 10 or 11 dimensions, just 4 and some fancy algebra), the Barrett-Crane state-sum model, . . .

Basically if string theory is wrong (or useless--see my last post) the NSF has been throwing almost its entire theoretical physics budge down a rat-hole for 20 years.

[The_Reader_David]

Actually you're very close to the latest two iterations of string theory: "M-theory" (M could stand for matrix, the next to last iteration, or membrane). The string theorists argue that because four or five of their attempts approximate each other in certain limits, they must be aspects of a single as yet undiscovered theory. (The limiting arguments are non-rigorous, not usually a consideration in physics if experiments can be appealed to, but they can't in this case, and the overarching argument is completely bogus: quantum mechanics approximates classical mechanics in a certain kind of limit, and this is not evidence of a missing theory which both approximate which is the 'real theory'>)

[The_Reader_David]

Same as the speed of light, but only when it's retreating.

[palmer]

The key my theory is orthogonality, as long as forces are orthogonal to each other in the new theory then there's no unification, just aggregation. Shortly I will present 4 or 5 variants of my theory as proof.

[The_Reader_David]

Physicists (since Feynman) have computed things by defining certain infinite sums which (unlike ones you might have met in Calc II) always diverge when interpretted in an ordinary mathematical sense, then finding a way to interpret them differently ('regularize' them) to get finite quantities.

The best one used outside of string theory--in the context of Feynman diagrams, where one's sums depend on all embeddings of graphs (finite bunched of paths that can branch and rejoin)--is to realize that the dimension of the space-time shows up in the sum, turn the dimension into a variable, d, write the sum as a sum ofmultiples of powers of (d-4). It is infinite when d = 4 because you get some negative powers. Just throw away all the terms with negative powers of (d-4) and add up the rest (as in Calc II). Mirable dictu the result agrees with experiment to 14 places after the decimal.

There is no correponding procedure in string theory, where the sums depend on embedding Riemann surfaces (surfaces glued together out of copies disks from the complex plane so that you can tell which complex-valued functions on them have derivatives in the complex sense).

[Getready]

I always wanted to know about newer modern physics, so I
got Hawkings books, including "universe in a nutshell",
and Greens book, The elegant universe. These concepts are
very difficult for nonmathematicians or maths which don't
specify "topology'...

What is fascinating to me is that strings are suppposedly
these tiny (like 10 to the minus 33) meters size vibrating
loops of energy...but can't there be 1/2 strings, or left
strings, right string? substring areas???..and by the way,
what is energy? Can it be detected by what it does, or
does it exist without our ability to dectect it?
Does energy move material objects? Since material objects
according to string theory are only manifestations of the
vibrational patterns of strings, does that mean energy is
what moves its own species??? It sounds very reminiscent
of it being self-existing on its own without beginning and
without end.....but it is impersonal...hmmmmm....

Finally, some of the maths used to explain these subatomic
physical oddities are accessible only to mathematicians.
They incorporate ideas such as "imaginary time", the
sum of paths mentioned earlier, things existing only because
they are "detected" , fabric of space changing or opening and
closing, multiple universes undetectable by us (as our
physics is different)...and somethings (is that a good wor
to describe it?) called Calabi-Yau spaces which explain in a
spatial way how the extra 7-8 dimension curl up. Like I
said, you gotta he heavy into math to even understand what
they be talk'n 'bout, never mind prove or disprove it...

It is interesting however. We may find that we are trying
to make up "just so" stories to explain that we cannot
really "get at" the core bits of matter/strings cause the
energy requirements to control them or blast them out of
their "comfy" homes are too great. Example, it may take
a supercollider the size of our solar system to generate the
energy to accelerate these "particles" very close to the
speed of light....

Alright, enough of this. Time to watch the 3 stooges.Nyuk,
Nyuk, Nyuk.

[Paradox]

I dont know enough to say for sure, but it seems to me that this string theory may be a bunch of mental mathematical m*sterb*ation. The proof is in the pudding, and as of yet, as you say, there is no unique pudding!

BTW, for some TOE technobabble BS fun in a sci-fi way, read the book called "Distress", by Greg Egan. Takes this stuff and twists it around into ultimately a silly conclusion, but it was kinda fun reading it.. (the person who "discovers" or first interprets the TOE becomes the "keystone", or something like the creator of the Universe....)

[steve8714]

In which dimension?

[RobRoy]

I've believed in string theory for some time. I read a book that talked about it a LONG time ago.

It's called the Bible...

[Edgerunner]

So THAT's IT!!!

[bmwcyle]

I always thought there was seven.

[Allan]

Bump

[Graymatter]

Book rec's much appreciated. :)

[Paradox]

My kind of String theory:

[Dogrobber]

Physicists (since Feynman) have computed things by defining certain infinite sums which (unlike ones you might have met in Calc II) .... (snip) .... together out of copies disks from the complex plane so that you can tell which complex-valued functions on them have derivatives in the complex sense).

Huh?

I really appreciate the attempt to educate me, and if I had the time to put the brainpower to it I think I could absorb it ok, ... but - D@mn that just hurts too much to think about it.

[beef]

I do not pretend to understand string theory beyond the popular descriptions of it, and even those I don't have a good feeling for. But there is no doubt that every explanation posts up a whole new bunch of questions. Strings, I guess, are made of energy. What is the energy made of? What is stuff that energy is made of made of? And so on. When do we know that we have the final theory? When it explains everything except itself? Or including itself (a recursive definition, I guess)? Or equals 42?

[spunkets]

Those are tarts. Share?

[Truthsayer20]

"Physicists (since Feynman) have computed things by defining certain infinite sums which (unlike ones you might have met in Calc II) always diverge when interpretted in an ordinary mathematical sense, then finding a way to interpret them differently ('regularize' them) to get finite quantities."

Renormalization used in quantum field fiels theories is an incredibly clever trick.