String Theory in Two Minutes - Page 2 - U.S. Politics Online: A Political Discussion Forum

WarOnIgnorance · #16 (**permalink**) 10-28-2007

Quote:

Originally Posted by WildMan

Emotional reactions to theories - other than perhaps perplexity or wonder - continue to amuse me. Why would we desire to supplant a theory that holds so much promise despite it's absence in experimental science?

I guess beauty is indeed in the eye of the beholder. Granted, to visually behold more than 3 dimensions + time is a challenge with our eyes and senses limited in the 3D + time world. However with some well used and readily understood mathematics (for those who care to wander that path) we can in a fashion extend our senses and draw 2D models (or build 3D models) of the higher dimensions. These models appear visually complex and unreachable from our braneworld - but the math behind them is not.

Now, the development of new math to further extend the string theories can be left to the likes of Witten, and I think that this is what he refers to when lamenting complexity.

Besides 50 years is not that long. 2400 years or so ago Democritus postulated the atom. Aristotle and others rejected it and it took another 2000 years for Dalton to pick it up and try again - this time with the advantage of accurate quantitative measurements when combining chemicals (Lavoisier). It then took another 50 years for the theory to be generally accepted. I'd say we are comfortably ahead of schedule if we are to accept Witten's 50 year wait plus the 90 years since the first postulation of string theory. Interestingly string theory also, like Democritus' atoms, underwent a falling out of favour and revival.

GUT - may be observable from proton decay. The now repaired in 2006 Super-K III may find it.

Supersymmetry - observations possible with current technology in 5-10 years. This may also yield clues to the nature of multidimensional space.

I agree completely. What I found remarkable is that Calabi-Yau shapes are indeed not all that complex mathematically (I expected much worse). For visualization I found it very helpful to imagine three complex dimensions instead of six real ones. From what I read, this is not a travesty as both approaches are mathematically equivalent.
The topology of these shapes is also fascinating. The usual manifold transformations allow them to be viewed under many guises. I think it's too soon to declare the ten current dimensions as final. Since the theory is not really dependent on the exact number, the mathematical model that will -eventually- be found to correspond to nature might actually have more, maybe even a lot more.

USViking · #17 (**permalink**) 10-29-2007

Quote:

Originally Posted by WildMan

Emotional reactions to theories - other than perhaps perplexity or wonder - continue to amuse me. Why would we desire to supplant a theory that holds so much promise despite it's absence in experimental science?

Do you have an attention span of over two minutes?

If so, then why don't you take a looksie at that link
I recommended in post# 14?

If you read it you will see it uses a review of books
by two expert opponents as the framework for extended
criticsm of String Theory. Although they may not
use the word, I think it is safe to say the two experts
"hate" the theory.

I am guessing part of the reason for the emotional
content of their view is the same as mine: aversion
to a final Natural Law which they consider ugly.

Quote:

Originally Posted by WildMan

I guess beauty is indeed in the eye of the beholder. Granted, to visually behold more than 3 dimensions + time is a challenge with our eyes and senses limited in the 3D + time world. However with some well used and readily understood mathematics (for those who care to wander that path) we can in a fashion extend our senses and draw 2D models (or build 3D models) of the higher dimensions However with some well used and readily understood mathematics (for those who care to wander that path) we can in a fashion extend our senses and draw 2D models (or build 3D models) of the higher dimensions. These models appear visually complex and unreachable from our braneworld - but the math behind them is not.

We cannot "visually behold" 3D plus time geometrically.
You are stuck with the three spacial dimensions unless you
mean the word "visual" in a figurative sense. Drawing a
clock in the middle of a box won't do because the picture
of the clock is itself part of the three spacial dimensions.

Quote:

Originally Posted by WildMan

Now, the development of new math to further extend the string theories can be left to the likes of Witten, and I think that this is what he refers to when lamenting complexity.

Even his opponents surely recognize Witten's genius. Part of
my dislike of the ST is that someone as smart as he is can
spend his entire life on something and still admit the answer
is nowhere in sight.

Quote:

Originally Posted by WildMan

Besides 50 years is not that long. 2400 years or so ago Democritus postulated the atom. Aristotle and others rejected it and it took another 2000 years for Dalton to pick it up and try again - this time with the advantage of accurate quantitative measurements when combining chemicals (Lavoisier). It then took another 50 years for the theory to be generally accepted. I'd say we are comfortably ahead of schedule

I have always been the impatient type, and that is
another reason why I hate ST.

I would hate it even more if I thought it might 2000
years to reach fruition!

It took only 11 years to get from Special Relativity
to General Relativity and another three years or so
to extend GR to cosmology, all of which are subject
to experiment and observation.

It took only 25 years to get from Quantum Theory
to Quantum Mechanics. I am aware that QM is an
ongoing area of discovery (ST being a QM theory),
but the significant discoveries since 1925 have all
been fully buttressed by observation, while ST remains
without known hope of such to date.

Quote:

Originally Posted by WildMan

if we are to accept Witten's 50 year wait plus the 90 years (emphasis added-USV) since the first postulation of string theory.

Inaccurate.

ST has not been around for 90 years. The "String"
insight was first attained in the mid to late 1960s.
It was the antecedent of the theory which goes back
about 90 years to I think a 5-dimensional theory by
Kaluga (sp?) and perhaps others.

Quote:

Originally Posted by WildMan

Interestingly string theory also, like Democritus' atoms, underwent a falling out of favour and revival.

String theory has been on the front burner pretty much
from the word go.

Quote:

Originally Posted by WildMan

GUT - may be observable from proton decay.

This statement carries with it the implication that proton
decay is predicted by ST.

Inaccurate.

ST does not predict proton decay.

An early GUT which did predict proton decay was BTW
co-authored (with Georgi) by Nobel Laureate and Harvard
Department Chair Sheldon Glashow, who has been one of
ST's most vociferous critics for decades.

He famously likens it to "medieval scholasticism".

Quote:

Originally Posted by WildMan

The now repaired in 2006 Super-K III may find it.

Unfortuately for this theory, no evidence has been found
for 20-30 years for proton decay, which I am not sure is
amenable to detection by colliders.

Quote:

Originally Posted by WildMan

Supersymmetry - observations possible with current technology in 5-10 years. This may also yield clues to the nature of multidimensional space.

Sounds interesting.

Please elaborate, making sure you have your facts down
more pat than you did with the GUT-proton decay comments.

WildMan · #18 (**permalink**) 11-06-2007

Quote:

Originally Posted by USViking

Do you have an attention span of over two minutes?

If so, then why don't you take a looksie at that link
I recommended in post# 14?

If you read it you will see it uses a review of books
by two expert opponents as the framework for extended
criticsm of String Theory. Although they may not
use the word, I think it is safe to say the two experts
"hate" the theory.

I am guessing part of the reason for the emotional
content of their view is the same as mine: aversion
to a final Natural Law which they consider ugly.

We cannot "visually behold" 3D plus time geometrically.
You are stuck with the three spacial dimensions unless you
mean the word "visual" in a figurative sense. Drawing a
clock in the middle of a box won't do because the picture
of the clock is itself part of the three spacial dimensions.

Even his opponents surely recognize Witten's genius. Part of
my dislike of the ST is that someone as smart as he is can
spend his entire life on something and still admit the answer
is nowhere in sight.

I have always been the impatient type, and that is
another reason why I hate ST.

I would hate it even more if I thought it might 2000
years to reach fruition!

It took only 11 years to get from Special Relativity
to General Relativity and another three years or so
to extend GR to cosmology, all of which are subject
to experiment and observation.

It took only 25 years to get from Quantum Theory
to Quantum Mechanics. I am aware that QM is an
ongoing area of discovery (ST being a QM theory),
but the significant discoveries since 1925 have all
been fully buttressed by observation, while ST remains
without known hope of such to date.

Inaccurate.

ST has not been around for 90 years. The "String"
insight was first attained in the mid to late 1960s.
It was the antecedent of the theory which goes back
about 90 years to I think a 5-dimensional theory by
Kaluga (sp?) and perhaps others.

String theory has been on the front burner pretty much
from the word go.

This statement carries with it the implication that proton
decay is predicted by ST.

Inaccurate.

ST does not predict proton decay.

An early GUT which did predict proton decay was BTW
co-authored (with Georgi) by Nobel Laureate and Harvard
Department Chair Sheldon Glashow, who has been one of
ST's most vociferous critics for decades.

He famously likens it to "medieval scholasticism".

Unfortuately for this theory, no evidence has been found
for 20-30 years for proton decay, which I am not sure is
amenable to detection by colliders.

Sounds interesting.

Please elaborate, making sure you have your facts down
more pat than you did with the GUT-proton decay comments.

Maybe your impatience will be salved --

Raised in another thread:
LHC machine - why?

USViking · #19 (**permalink**) 11-06-2007

Quote:

Originally Posted by WildMan

Maybe your impatience will be salved --

Raised in another thread:
LHC machine - why?

Aha!- a bone from ST to the collider boys and girls!

Here is the appropriate link decscribing CERN attempts
to find evidence of extra dimensions:

Search for Extra Dimensions

According to the link analysis of CERN data from 1992-96
found no evidence of extra dimensions.

The link does not say why only five years of data were
studied; perhaps that was thought to be enough to rule
out the liklihood of detection from the rest of the data
produced by pre-LHC technology.

However, The link goes on to say new evidence of extra
dimensions may arise from gravitational "enhancement"
which a current theory (by Arkani-Hamed, Dimopoulos and
Dvali) predicts will take place if particles collide with enough
energy, and which LHC seems capable of detecting.

This theory hinges on the proposition that some of the extra
dimensions "can be as large as one millimeter".

So keep your fingers crossed ST fans: CERN may in the near
future give a big boost to your pet.

And even if it fails to produce evidence, it will not be ST
as a whole which is in danger of falsification, but only the
"one millimeter" ST version of Messrs Arkani-Hamed, Dimopoulos
and Dvali. Look for them to share a Nobel Prize if test results
are positive.

Incidentally, postitive results will also be strong indirect evidence
for the exisitence of gravitons.

USViking · #20 (**permalink**) 11-09-2007

Here is a square-off via separate interviews between
Sheldon Glashow (in this post), who is one of
String Theory's foremost critics, and Edward Witten
(next post), who is probably ST's foremost theorist:

NOVA | The Elegant Universe | Sheldon Glashow | PBS

(I may have been mistaken when I said in another post
that Glashow was ever the Harvard Department Chair.
He was on the faculty, and did win a Nobel while so)

Quote:

Originally Posted by Sheldon Glashow

I was at the University of California in Berkeley from roughly 1963 to 1966 as a professor, and I remember clearly that the experimenters and the theorists were in very close contact...It was a very intimate relationship.

But oddly there has been a new development, in which a new class of physicists is doing physics, undeniably physics, but physics of a sort that does not relate to anything experimental. This new class is interested in experiment from a cultural but not a scientific point of view, because they have focused on questions that experiment cannot address...

It's called superstring theory and it is, so far as I can see, totally divorced from experiment or observation. If not totally divorced, pretty well divorced. They will deny that, these string theorists. They will say, "We predicted the existence of gravity." Well, I knew a lot about gravity before there were any string theorists, so I don't take that as a prediction...

The string theorists have a theory that appears to be consistent and is very beautiful, very complex, and I don't understand it. It gives a quantum theory of gravity that appears to be consistent but doesn't make any other predictions. That is to say, there ain't no experiment that could be done nor is there any observation that could be made that would say, "You guys are wrong." The theory is safe, permanently safe. I ask you, is that a theory of physics or a philosophy?...

There is today a disconnect in the world of physics. Let me put it bluntly. There are physicists, and there are string theorists. Of course the string theorists are physicists...

we don't listen to them, and they don't listen to us. We can't understand them, and what we do is not of any direct interest to them...

The physics and astronomy enterprises in this country spend a great deal of money to do experiments on Earth and in the heavens. There are orbiting observatories, there are laboratories deep underground, there are accelerators in many countries, and these guys produce a lot of data in order to lead us to construct a better and more useful theory of nature. And it turns out that the best and the brightest young theorists, instead of being concerned about the experimental enterprise, are going off among themselves and doing their thing with the doors closed...

There is a big accelerator, the Large Hadron Collider, which is scheduled to be completed in another five years or so. That should make lots of discoveries. Who will be interested in trying to fit these discoveries into the theory? It will be people like me, except we may be dead by then or if not we'll be rather old. Or it will be the young theoretical physicists, but the young theoretical physicists are doing string theory, and they ain't interested in the results of the experiments. Not now, and not then...

If you read the whole interview you will see that Glashow
does begrudge some favorable comments about ST,
but what he has to say is for the most part scathing.

However, I am confused because I think the "one millimeter"
ST theorists seem to have made falsifiable predictions which
LHC can test. If test results are positive it will not come close
to validating the whole theory. It would still have to be a
great triumph to:

(1) Establish the exisitence of gravitational "enhancement"

(2) Establish the exisitence of five or more dimensions

(3) Provide new indirect evidence of the existence of gravitons.

...and the ST boys and girls must be ready to watch the LHC
experiments very closely.

It may be 1mmST had not made the predictions at the time
of Glashow's interview, although the interview is copyrighted
2003, and I believe 1mmST is older than that.

Anyone here with a physics degree who can fill us in?

USViking · #21 (**permalink**) 11-09-2007

Here is the interview of Edward Witten.

I have about 10-15 hardcover books dealing with
physics dating back to the late 1980s, which I have
read cover them to cover if not come anywhere
close to understanding cover to cover.

A recurring theme of most if not all of these books
has been the towering genius of Edward Witten.
He is on most short lists of the first most brilliant
person alive, both as a physicist and a mathematician.

Even Einstein and Heisenberg needed a lot of help
with the math at times. Apparently not so Witten-
he has always been able to do his own math.

NOVA | The Elegant Universe | Edward Witten | PBS

Quote:

Edward Witten:
String theory is an attempt at a deeper description of nature by thinking of an elementary particle not as a little point but as a little loop of vibrating string. One of the basic things about a string is that it can vibrate in many different shapes or forms, which gives music its beauty. If we listen to a tuning fork, it sounds harsh to the human ear. And that's because you hear a pure tone rather than the higher overtones that you get from a piano or violin that give music its richness and beauty.

So in the case of one of these strings it can oscillate in many different forms—analogously to the overtones of a piano string. And those different forms of vibration are interpreted as different elementary particles: quarks, electrons, photons. All are different forms of vibration of the same basic string. Unity of the different forces and particles is achieved because they all come from different kinds of vibrations of the same basic string. In the case of string theory, with our present understanding, there would be nothing more basic than the string...

It's indeed surprising that replacing the elementary particle with a string leads to such a big change in things. I'm tempted to say that it has to do with the fuzziness it introduces. So the particle is spread out. But it turns out that everything about spacetime is a little bit spread out; it's blurred. You have to start doing some calculations to really see it...

Even before string theory, especially as physics developed in the 20th century, it turned out that the equations that really work in describing nature with the most generality and the greatest simplicity are very elegant and subtle...

Now there must be skeptics out there who will tell you that these beautiful equations might have nothing to do with nature. That's possible, but it's uncanny that they are so graceful and that they capture so much of what we already know about physics while shedding so much light on theories that we already have...

In Einstein's general relativity the structure of space can change but not its topology. Topology is the property of something that doesn't change when you bend it or stretch it as long as you don't break anything. You can imagine a bowling ball and you can imagine a coffee cup that has a handle—the coffee cup is different topologically because there's a handle. Even if you could bend it or stretch it, as long as you don't break it, it's still got that handle, which makes it topologically different.

There was a long history of speculation that in quantum gravity, unlike Einstein's classical theory, it might be possible for the topology of spacetime to change. And it turned out in string theory in the late '80s and early '90s we actually were able to calculate examples where you could really see changes in the topology of spacetime. That was fun because it was very concrete—you could understand it pretty well. And it illustrated how the theory went beyond Einstein's general relativity as understood before in a very nice and down-to-earth way...

Quantum mechanics brought an unexpected fuzziness into physics because of quantum uncertainty, the Heisenberg uncertainty principle. String theory does so again because a point particle is replaced by a string, which is more spread out. And even though it's a naïve statement, it leads in the right direction: when we study it more deeply, we find that in string theory, spacetime becomes fuzzy.

To this point we may sum up Witten's remarks as that
ST has a loopy fuzzy beauty with broken topology.

Quote:

Edward Witten:
Technically you need the extra dimensions. At first people didn't like them too much, but they've got a big benefit, which is that the ability of string theory to describe all the elementary particles and their forces along with gravity depends on using the extra dimensions. You have that one basic string, but it can vibrate in many ways. But we're trying to get a lot of particles because experimental physicists have discovered a lot of particles. The electron and its heavy cousins the neutrinos, the quarks, photons, gravitons, and so on. There is really a big zoo of elementary particles that you're trying to explain. Having those extra dimensions and therefore many ways the string can vibrate in many different directions turns out to be the key to being able to describe all the particles that we see.

Witten repeats the famous "zoo of particles" line recurrent
in the field of physics.

Glashow won his Nobel because his theory correctly predicted
the existence of NEW particles (W and Z gauge bosons),
NEW animals in the particle "zoo" which no one had an inkling
of before.

For 1mmST or any other ST to carry the field of Natural Law
they must match Glashow and all the other theorists in the
history of Science.

They must predict something NEW.

I am really curious to see if LHC does the trick for them.

Quote:

Interviewer: But why do we think that they might actually exist? We certainly can't see them.

Edward Witten: We see light waves with our eyes, but most of the other particles take 20th-century equipment to discover them.

Not OK.

Witten makes a poor comparison here.

We have always been able to see light, but we will never
be able to see radio waves, I don't think, and radio waves,
undreamed of before, were discovered in theory in about
1857, discovered in experiment by about 1890, and put to
practical use before 1900.

Quote:

Edward Witten:
As far as extra dimensions are concerned, very tiny extra dimensions wouldn't be perceived in everyday life, just as atoms aren't:

Not OK.

Witten makes a poor comparison here.

The evidence of atoms has the supporting testimony of
trillions of dollars of practical commerce going back well
over 100 years ago to back it up. The evidence for atoms
is as small as a child's chemistry set to as large as nuclear
weapons, and then some.

Quote:

Edward Witten:
The theory has to be interpreted that extra dimensions beyond the ordinary four dimensions the three spatial dimensions plus time are sufficiently small that they haven't been observed yet.

Again, I am confused. Either 1mmST had not been developed
by the time of this interview, or Witten does not believe 1mmST.

Quote:

Edward Witten:
So we would hope to test the theory, conceivably directly at accelerators. I suspect that's a long shot.

See above.

Quote:

Edward Witten:
More likely we'll do it indirectly by making more precise calculations about elementary particles based on the existence of extra dimensions.

Whaddaya mean?! You've been doing that all your life already,
and all you can offer is more of the same for ever and ever?!
Oh please, ST, give us a scrap or bone of something more.

Pretty please?

Quote:

Edward Witten:
There are a lot of conceivable ways we could get experimental information that would help with string theory. Explorations of cosmology, studying the cosmic background microwave radiation and hopefully finding gravitational waves left over from the big bang and studying their properties are very plausible avenues for eventually testing string theory, although there isn't yet to my thinking a satisfactory theoretical understanding of what to expect.

But it's conceivable that the big bang could have produced a string so large that it would be present in today's universe and visible in telescopes, perhaps discoverable by the satellites that are now mapping out the microwave sky. If that were discovered, it would be a dramatic confirmation of the existence of strings. Still, that's a story that will develop over the next decade or two as the experiments progress and conceivably as the theory progresses.

I did not know that Witten looks to telescopes rather than
colliders as the most promising devices to provide evidence
for ST.

He believes telescopes may yield:

(1) Primordial gravitational waves

and ESPECIALLY (2) a Galactic String.

Make that a Supragalactic String.

OK: (2) is about as big a prediction as you can get.

If the girls and boys with telescopes see THAT
then ST will have its crown in Natural Law.

I would hate for Edward Witten to fail.

I want a man so sterling in intellect to succeed,
and succeed in the greatest measure.

I want him to have a rose in the garden of truth.

gato_callejero · #22 (**permalink**) 11-28-2007

Quote:

Originally Posted by White Rabbit

I love the sound of the 'Eastern European' (Polish or Russian) accent when speaking English as a second language - it sounds very cool and quite distinctive!

I'd say she was dutch.

As to the video, it would be pretty neat if they figured a global model for physics. It would be like discovering the root axiom from which everything else could be "deduced". This would allow to discover everything, top-downwards; it would be like knowing the correct answer before knowing the question even existed.

Speakeasy · #23 (**permalink**) 11-28-2007

I wanna play! She sounded like Bjork, so I'm going to go with Icelandic.

gato_callejero · #24 (**permalink**) 11-30-2007

OK, I watched the video again. I change my guess to nordic (norwegian, swedish or finish).

USViking · #25 (**permalink**) 12-04-2007

I just now, finally, got around to looking at the winning video.

I wish I hadn't.

String Ducky!?

Are you kidding me?

What kind of crap is that?

Messrs gato_gallejero and speakeasy seem to have
lucked onto a runner-up video featuring some
good-looking girl from a Scandinavian country.

Scandinavian girls are exactly what String Theory
needs more of
to make a believer out of me!

PaleoRepublican · #26 (**permalink**) 12-09-2007

If this is an attempt at reductionism, string theory failed.

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