String Theory a Disaster for Physics?

BlueCup writes "Mathematician Peter Woit of Columbia University describes string theory in his book Not Even Wrong,. He calls the theory 'a disaster for physics.' Which would have been a fringe opinion a few years ago, but now, after years of string theory books reaching the best sellers list, he has company."

Comments

Before the consensus ...

[aws4y]

Let me point out that this has been well known in physics departments for years. The problem is string theory is nowhere near producing any prediction that can be tested, this means that it is not science, any more than mathematics is physics.

Not so?

[Kawahee]

Michio Kaku in his book Hyperspace describes why we can't actually get very far with this theory, is because "nobody is smart enough to figure it out". Since it was an accidental discovery in the 80's, he describes it as "21st century math that accidently made its way into the 20th century". The problem is to do with phase shifts and perturbation theory:

(Excerpted from Hyperspace: A scientific Odyssey through the 10th dimension)

    To understand this form of tunneling, think of an imaginary Charlie Chaplin film, in which Chaplin is trying to stretch a bed sheet around an oversize bed. The shit is the kind with elastic bands on the corners. But it is too small, so he has to strain to wrap the elastic bands around each corner of the matress, one at a time. He grins with satisfaction once he has stretched the bed sheet smoothly around all four corners of the bed. But the strain is too great; one elastic band pops off another corner. Every time he yanks an elastic band around one corner, another elastic pops off another corner.
    This process is called symmetry breaking. The smoothly strechted bed sheet possess a high degree of symmetry. You can rotate the bed 180 degrees along any axis, and the bed sheet remains the same. This highly symmetrical state is called the false vacuum. Although the false vacuum appears quite symmetrical, it is not stable. The sheet does not want to be in this stretched condition. There is too much tension. The energy is too high. Thus one elastic pops off, and the bed sheet curls up. The symmetry is broken, and the bed sheet has gone to a lower-energy state with less symmetry. By rotating the curled up bed sheet 180 degrees around an axis, we no longer return to the same sheet.
    Now replace the bed sheet with ten-dimensional space-time, the space-time of ultimate esymmetry. At the beginning of time, the universe was perfectly symmetrical. If anyone was around at that time, he could freely pass through any of the ten dimensions without a problem. At that time, gravity and the weak, the strong and the electromagnetic forces were all unified by the superstring. All matter and forces were part of the same string multiplet. However, this symmetry couldn't last. The ten-dimensional universe, although perfectly symmetrical, was unstable, just like the bed sheet, and in a false vacuum. Thus tunneling to a lower-energy state was inevitable. When tunneling finally occurred, a phase transition took place, and symmetry was lost.
    Because the universe begain to split up into a four- and a six-dimensional universe, the universe was no longer symmetrical. Six dimensions have curled up, in the same way that the bed sheet curls up when one elastic pops off first. For the ten-dimensional universe, however, there are apparently millions of ways in which to curl up. To calculate which state the ten-dimensional universe prefers, we need to solve the field theory of strings using the theory of phase transitions, the most difficult problem in quantum theory.

A Physicist's Thoughts

[ichin4]

I am an (ex-) particle theorist. I worked on phenomenology, which is how particle physicists describe people try to work with actual data.

I don't think the rise of string theory has been the cause of the dearth of breakthroughs in particle physics in the last 30 years, but rather the effect. For all that time, nothing unexpected has come out of accelerator experiments -- just more confirmations of the predictions of the standard model developed in the 1970s, and more accurate measurements of its parameters. In an environment like that, it's no surprise that theoreticans turn to highly speculative and mathematically challenging models to keep their work interesting.

There are still some related fields generating new and interesting data for good young theorists to cut their teeth on -- cosmology, for example.

The meaning of "theory"

[mblase]

I think ST is a very interesting and peculiar theory. I'm not sure it's a disaster. Even if ST is proved wrong in some way the math that resulted from ST is still worthwhile.

Think of Newtonian physics. We now know that Newton falls apart when viewed under the lens of Einsteinian relativity. But if you're dealing with relatively small masses, at relatively slow speeds, then Newton's physics works perfectly because relativity is too small a factor to affect the numbers. Likewise with quantum mechanics at the macroscopic level.

Neither of those three "theories" is a complete and accurate view of how the universe works. They are each of them a model for certain situations, and which one you choose depends on which one is most appropriate.

The thing about string "theory" is that it's more of a model than a theory. When physics gets down to this level, it's more mathematics than science. The theory/model that you use is never going to be perfect or complete, but as long as it fits the purposes you want it for, it's good.

Re:The meaning of "theory"

[pVoid]

The reason why ST is different from Newtonian, Maxwell's EM, relativistic or even quantum physics is not that it's more a mathematical model or some such thing...

It's simply because each one of these theories were postulated starting from physical events, a model was conceived and using this model, we were able to predict phenomenons that we had yet not experienced.

Case in hand: back in Newton's time, there were no air hockey tables. There wasn't anything that would make people think that an object would continue in a straight line at the same velocity if not interfered by any outside force. Try telling a medieval man that the mule and ox pulling his cart were only doing so to counter the force of friction on the wheel axle. He would laugh at you. Turns out, pretty much everything from going to the moon to airplanes could be explained if not predicted using newtonian theory.

Maxwell, using nothing but simple equations not only 'found out' that light had a maximum speed, he measured the said speed. He's also the one who came up with e=mc^2, although he didn't quite know what that meant.

Einsteins relativity. No need for an example.

Quantum? As far fetched and sci-fi as quantum is, it explained how tainted glass can possibly be (something which made no sense in classical physics), it also predicted transistors (by the same tunelling principle).

ST on the other hand, is a very very highly indirect 'theory' in which there has been practically no observation, and no verifiable predictions made. It's all underneath the cloak of the "too small to be verified". Which, when you really look at it, means it's on the same level as mysticism: as systematic as it might be inside of its confines, you have to first start by believing in it.

All this being said, I'm not taking sides. I do hope that they eventually find something of relevance from it. I know a few people at least who've put their live's work into this.

Kaku is a self-promoting hack.

[dr. loser]

IAAP (I am a physicist). Out of all the bloviating, often obnoxious high energy physicists who feel compelled to write popular books with pretentious titles (Dreams of a Final Theory (Weinberg); The Quark and the Jaguar (Gell-Man); The God Particle (Lederman); The Cosmic Landscape (Suskind); A Brief History of Time (Hawking)), Kaku has absolutely contributed the least to the actual science. Lisa Randall is 10x the physicist of Kaku, if not moreso.

Re:Man...

[Mike Peel]

That tends to make me think that we do in fact, have a pretty good grasp of the laws of physics. IMO, the only thing we're missing is the "gravity to the rest of it" connection, confounded by the inconvienient fact that gravity appears to be the only force in the universe which is apparently instantainious over galactic distances.

We haven't thought that gravity is instantaneous for about 90 years now - General Relativity shows that the force of gravity moves at the speed of light. Have a read about gravitational radiation sometime.

Go work any celestial orbital mechanics problem, including the orbit of the earth around the sun, and try and make it work if the gravitational attraction vector is assumed to be toward where the sun appears to be now (as opposed to where it is right now instead where it was 8 minutes ago when that light left the suns position then). By adding any delay, the orbit falls apart, and our earth would have spiraled into the sun many billions of years ago.

I'm confused here. The sun is (pretty much) unmoving, and emits a (pretty much) spherically symmetrical gravitational field. So wherever the Earth is, the 'gravitational attraction vector' is going to be pointing to the sun - as that's the direction of the gravitational field. As the mass of the sun is (pretty much) unchanging, there will be no changes to the gravitational field over time, and things continue just as in newtonian physics.

Complications to this probably arise when you've got more bodies in the system, though - so if you include the other major planets, you'll get effects such as you're talking about, but they're on a far smaller scale than you think as the sun's so big in comparison.

(Note that the same does not apply to pulsars, black holes and the like - where there's a lot more mass, and things are a lot more extreme.)

Re:I'd call this a 'debate', but....

[Schraegstrichpunkt]

That's induction, buddy.

It also happens to be philosophy -- possibly mathematics -- rather than science.

The only way (that I know about) to prove "all X have Y" in science is to enumerate all X, which typically isn't possible in the physical world, and even if you do that, you still haven't proved that "all X must necessarily have Y".

... buddy.