 
I made some poorly substantiated complaints about string theory in a recent post. Roger Penrose, who might be the most famous mathematician alive, has some complaints too, which carry just a little bit more weight than mine! There is a series of his lectures -- Fashion, Faith and Fantasy in the New Physics of the Universe -- available free online at www.princeton.edu/WebMedia/lectures/ [many many thanks to Marc Ngui for the tip].
String theory relies on the theory of supersymmetry as a "central ingredient." Supersymmetry calls for each particle to have a supersymmetric particle. But discovering these particles is proving very difficult. Says Penrose:If you haven't seen the supersymmetric partner that's because we haven't built a powerful enough accelerator yet. As long as you don't find these things you just say "Well, we've got to build a more powerful machine," and it doesn't get disproved.
Another famous fact about string theory is that it requires extra dimensions. Penrose says:
When I first heard about string theory I really thought it was a fantastic idea, I must say. It looked very beautiful...But then I learned it doesn't work unless space/time has 26 dimensions. Some people might say, "Oh well, space/time doesn't have 26 dimensions, so that's the end of that." But that wasn't the reaction of some people. They say, "Well, if it doesn't have 26 dimensions, we'll make it have 26 dimensions.
But Penrose is far from dismissive of the theory. He recognises that it is compelling. In doing research he talked to Richard Thomas, a pure mathematician, who had the following to say:
Everytime there is a prediction made [by string theorists], and suitably interpreted mathematically, they turn out to be true. We have no idea why they're true, they must come from a higher reason.
Penrose asks, how much of the current interest in string theory comes from fashion, and how much from physical motivations? He feels that it is not the latter, that string theory does not hold together, and is not a theory of quantum gravity. But, it's not just fashion either. Says Penrose:I'm jolly glad that people are doing it, and something deep about physics is being revealed by these ideas.
I've only watched the first lecture in the series so far, and it was excellent. The math and a lot of the concepts are beyond my grasp, but an untrained person like me can certainly follow the basic ideas, and the overhead projector diagrams and careful logic are a welcome antidote to the whizz-bang graphics of Brian Greene's Elegant Universe series.
If only Brian Greene had wirtten a book called the Elegant Universe, that (being a book) was less wizz-bang than the series. Oh well, such a book would probably be imposible to find.
hah hah. in-joke-joester. I have the book. I've read some of it, and you're right! There weren't any pictures.
Yes, and to be fair it was "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" that I gave you for your birthday, and not "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory" as I was insinuating.
Okay, no more in jokes, sorry. I've broken one of my New Years resolutions already. Still, it's been six days and I've yet to tell Tom to buy a mac, (although that's not so impressive because I got a pretty good shot in over the xms break).
Roger Penrose rocks. I'm managed to make through to chapter 3 of the The Emperors New Mind. Too bad there aren't more pictures!
Sibling quiblling aside, the first chapter of "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" is an elegant, accessible, and inspiring summary of the history of science. I've read it several times over since recieving it as a very thoughtful and appropriate birthday gift and it gives great context. Greene's writing gets a little florid as he introduces string theory, but everyone is entitled to their enthusiasms, n'est-ce pas? some quotes:
The classical Newtonian worlrdview was pleasing. Not only did it describe natural phenomena with striking accuracy, but the details of the description--the mathematics--aligned tightly with the experience. If you push something, it speeds up. The harder you throw a ball, the more impact it has when it smacks into a wall. If you press against something, you feel it pressing back against you. The more massive something is, the stronger its gravitational pull. These are among the most basic properties of the natural world, and when you learn Newton's framework, you see them represented in his equations, clear as day. Unlike a crystal ball's inscrutable hocus-pocus, the workings of Newton's laws were on display for all with minimal mathematical training to take in fully. Classical physics provided a rigorous grounding for human intuition.
[...]
Whereas human intuition, and its embodiement in classical physics , envision a reality in which things are definitely one way or another, quantum mechanics describes a reality in which things sometimes hover in a haze of being partly one way and partly another. Things become definite only when a suitable observation forces them to relinquish quantum possibilities and settle on a specific outcome.
[...]
A conflict in the known laws of physics means a failure to grasp a deep truth and that was enough to keep these scientists from resting easy. Those who plunged in, though, found the waters deep and the currents rough. For long stretches of time, research made little progress; things looked bleak. Even so, the tenacity of those who had the determination to stay the course and keep alive the dream of uniting general relativity and quantum mechanics is being rewarded. Scientists are now charging down paths blazed by those explorers and are closing in on a harmonious merger of the laws of the large and small. The approach that many agree is a leading contender is superstring theory.
The gung-ho attitude comes across much better in book form than it did on TV. And what's wrong with enthusiasm? But somehow, and I'm not qualified to say this, I just don't think string theory, as it is currently described, is going to turn out to be the unified theory of everything. Furthermore, and I'm REALLY NOT qualified to say this--its just a hunch--I suspect that string theory, if pursued, might show that the dogged desperate search for a theory that brings classical physics and quantum physics under one mathematical umbrella is in fact a red herring. This is where I like what Penrose was saying, in that I think the application of the model can be fruitful, even if the model is dead wrong. But if the use-value of string theory is embedded in its function as an analogy, then the over-abundance of imagery and visual analogy in that tv show obscures the point. Either way, it reads as slightyly cheesey promotion for a not-so-new-anymore cool idea that needs to stay in the popular spotlight in order to survive.
And joester, I'm pretty sure that if you saw that NOVA series you'd agree with me.
and leslie - yeah! Penrose is good with pictures. The overhead diagrams in his lectures are great and of course there's the famous pretty tiling.
I watched all of this including the first Penrose lecture and now my brane hurts!
I liked what you quoted about models, and what you had to say about models.
Relativity was so very non-intuitive when I was first exposed to it and the visualizations that people use to explain it. I had to internalize a model rather than wrap Gallileo's quadratic equations or Newton's calculus around an already intuitive model.
The search for a grand unifying theory has a certain "Holy Grail" air to it. (Not necessarily the movie.) Each new model removes a veil, but perhaps there's always another veil.
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I made some poorly substantiated complaints about string theory in a recent post. Roger Penrose, who might be the most famous mathematician alive, has some complaints too, which carry just a little bit more weight than mine! There is a series of his lectures -- Fashion, Faith and Fantasy in the New Physics of the Universe -- available free online at www.princeton.edu/WebMedia/lectures/ [many many thanks to Marc Ngui for the tip].
String theory relies on the theory of supersymmetry as a "central ingredient." Supersymmetry calls for each particle to have a supersymmetric particle. But discovering these particles is proving very difficult. Says Penrose: Another famous fact about string theory is that it requires extra dimensions. Penrose says: But Penrose is far from dismissive of the theory. He recognises that it is compelling. In doing research he talked to Richard Thomas, a pure mathematician, who had the following to say: Penrose asks, how much of the current interest in string theory comes from fashion, and how much from physical motivations? He feels that it is not the latter, that string theory does not hold together, and is not a theory of quantum gravity. But, it's not just fashion either. Says Penrose: I've only watched the first lecture in the series so far, and it was excellent. The math and a lot of the concepts are beyond my grasp, but an untrained person like me can certainly follow the basic ideas, and the overhead projector diagrams and careful logic are a welcome antidote to the whizz-bang graphics of Brian Greene's Elegant Universe series.
- sally mckay 1-06-2005 6:15 pm
If only Brian Greene had wirtten a book called the Elegant Universe, that (being a book) was less wizz-bang than the series. Oh well, such a book would probably be imposible to find.
- joester 1-07-2005 1:08 am
hah hah. in-joke-joester. I have the book. I've read some of it, and you're right! There weren't any pictures.
- sally mckay 1-07-2005 1:33 am
Yes, and to be fair it was "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" that I gave you for your birthday, and not "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory" as I was insinuating.
Okay, no more in jokes, sorry. I've broken one of my New Years resolutions already. Still, it's been six days and I've yet to tell Tom to buy a mac, (although that's not so impressive because I got a pretty good shot in over the xms break).
- joester 1-07-2005 5:06 am
Roger Penrose rocks. I'm managed to make through to chapter 3 of the The Emperors New Mind. Too bad there aren't more pictures!
- leslie (guest) 1-07-2005 5:42 am
Sibling quiblling aside, the first chapter of "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" is an elegant, accessible, and inspiring summary of the history of science. I've read it several times over since recieving it as a very thoughtful and appropriate birthday gift and it gives great context. Greene's writing gets a little florid as he introduces string theory, but everyone is entitled to their enthusiasms, n'est-ce pas? some quotes:
The gung-ho attitude comes across much better in book form than it did on TV. And what's wrong with enthusiasm? But somehow, and I'm not qualified to say this, I just don't think string theory, as it is currently described, is going to turn out to be the unified theory of everything. Furthermore, and I'm REALLY NOT qualified to say this--its just a hunch--I suspect that string theory, if pursued, might show that the dogged desperate search for a theory that brings classical physics and quantum physics under one mathematical umbrella is in fact a red herring. This is where I like what Penrose was saying, in that I think the application of the model can be fruitful, even if the model is dead wrong. But if the use-value of string theory is embedded in its function as an analogy, then the over-abundance of imagery and visual analogy in that tv show obscures the point. Either way, it reads as slightyly cheesey promotion for a not-so-new-anymore cool idea that needs to stay in the popular spotlight in order to survive.And joester, I'm pretty sure that if you saw that NOVA series you'd agree with me.
- sally mckay 1-08-2005 1:19 am
and leslie - yeah! Penrose is good with pictures. The overhead diagrams in his lectures are great and of course there's the famous pretty tiling.
- sally mckay 1-08-2005 1:34 am
I watched all of this including the first Penrose lecture and now my brane hurts!
- Tino (guest) 1-10-2005 5:53 pm
I liked what you quoted about models, and what you had to say about models.
Relativity was so very non-intuitive when I was first exposed to it and the visualizations that people use to explain it. I had to internalize a model rather than wrap Gallileo's quadratic equations or Newton's calculus around an already intuitive model.
The search for a grand unifying theory has a certain "Holy Grail" air to it. (Not necessarily the movie.) Each new model removes a veil, but perhaps there's always another veil.
- mark 3-28-2005 12:12 am