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Tuesday, Jun 29, 2010
 
Dirac had Einstein's disease
Scientific American magazine has temporarily reprinted The Evolution of the Physicist's Picture of Nature by Paul Dirac in 1963:
In this article I should like to discuss the development of general physical theory: how it developed in the past and how one may expect it to develop in the future. One can look on this continual development as a process of evolution, a process that has been going on for several centuries.

The first main step in this process of evolution was brought about by Newton. Before Newton, people looked on the world as being essentially two-dimensional-the two dimensions in which one can walk about-and the up-and-down dimension seemed to be something essentially different. Newton showed how one can look on the up-and-down direction as being symmetrical with the other two directions, by bringing in gravitational forces and showing how they take their place in physical theory. One can say that Newton enabled us to pass from a picture with two-dimensional symmetry to a picture with three-dimensional symmetry.

Einstein made another step in the same direction, showing how one can pass from a picture with three-dimensional symmetry to a picture with four dimensional symmetry. Einstein brought in time and showed how it plays a role that is in many ways symmetrical with the three space dimensions. ...

The special theory of relativity, which Einstein introduced, requires us to put all the laws of physics into a form that displays four-dimensional symmetry.

I am not sure which is goofier -- the Newton step or Einstein's.

Einstein missed the idea of a 4-dimensional symmetry. He used the Lorentz transformation, just like Lorentz and others years before, but he did not have the idea of a 4-dimensional spacetime or a symmetry group in 1905. He did not even understand these ideas when Poincare and Minkowski published them, and did not appreciate them until at least 1908 when lots of physicists did.

Dirac had Einstein's disease, and searched for grand top-down theories without paying much attention to experiment or the work of others:

This view provides us with another way in which we can hope to make advances in our theories. Just by studying mathematics we can hope to make a guess at the kind of mathematics that will come into the physics of the future. A good many people are working on the mathematical basis of quantum theory, trying to understand the theory better and to make it more powerful and more beautiful. If someone can hit on the right lines along which to make this development, it may lead to a future advance in which people will first discover the equations and then, after examining them, gradually learn how to apply them. It may well be that the next advance in physics will come about along these lines: people first discovering the equations and then needing a few years of development in order to find the physical ideas behind the equations. My own belief is that this is a more likely line of progress than trying to guess at physical pictures.

Of course, it may be that even this line of progress will fail, and then the only line left is the experimental one. Experimental physicists are continuing their work quite independently of theory, collecting a vast storehouse of information.

Dirac is famous for his early work, before he developed this attitude. Like Einstein, he wasted the later part of his life on dead-end ideas.

SciAm has podcasts on Dirac here and here.

Here is an amusing 1929 Dirac interview:

"What do you like best in America?", says I.

"Potatoes," says he.

"Same here," says I. "What is your favorite sport?"

"Chinese chess," says he. ...

"This is the most important thing yet, doctor," says I. "It shows that me and you are more alike than I thought. And now I want to ask you something more: They tell me that you and Einstein are the only two real sure-enough high-brows and the only ones who can really understand each other. I wont ask you if this is straight stuff for I know you are too modest to admit it. But I want to know this --- Do you ever run across a fellow that even you can't understand?"

"Yes," says he.

"This well make a great reading for the boys down at the office," says I. "Do you mind releasing to me who he is?"

"Weyl," says he.

Hermann Weyl may well have been the greatest genius actively working at the time. He produced at a higher level than Dirac or Einstein. He was primarily a mathematician but he wrote seminal books on relativity and quanturm mechanics. I will post some of his funny ideas on relativity.

Sunday, Jun 27, 2010
 
Bogus arguments for supersymmetry
Czech string theorist Lubos Motl writes:
By far the most important argument in favor of supersymmetry is the fact that it seems to be implied by string theory, the only known - and, most likely, the only mathematically possible - consistent unifying theory of fundamental forces including gravity.
No, string theory does not unify any of the forces, and has not been shown to be consistent. If that is not wacky enough, here is his second most important argument for supersymmetry:
The cosmological constant problem has often been presented as the greatest mystery of the contemporary high-energy physics. However, the role of supersymmetry has often been obscured.

In the Planck units, the observed cosmological constant is very tiny, something like 10^{-123}. An easy way to cancel the cosmological constant would be to have an exact supersymmetry. In that case, arguments showing that the C.C. is still equal to zero can work. The vacuum graphs (loops) with bosons would cancel against their superpartners.

However, SUSY is broken and the SUSY breaking scale is at least 300 GeV or so. Is that enough to make the cosmological constant tiny?

Well, it's not. The most natural value of the cosmological constant is something like 10^{-60} times the natural value that you would predict from the SUSY breaking at 300 GeV. And SUSY breaking can't be much lower than 300 GeV because the superpartners would otherwise be easily seen without big colliders - but they're not seen.

So with SUSY, the numerical problem survives. In fact, SUSY makes things more controllable so the statement that the natural value of the C.C. is different than the observed one becomes even more justifiable by mathematics.

Nevertheless, there is one point that pretty much everyone overlooks: 10^{-60} is less unnatural than 10^{-123}. By requiring low-energy SUSY, the fine-tuning problem for the cosmological constant has been reduced by 63 orders of magnitude or so. So much (10^{63} times) higher a fraction of the vacua with low-energy SUSY have a chance to predict a tiny enough vacuum energy so that it agrees with the observations.

Only a string theorist would brag about an experimental prediction that is only wrong by 63 orders of magnitude.

The Asymtotia string theorist blogger writes:

Here’s the really odd thing about all this (and an explanation of the post title): While this is a school on Quantum Gravity, after talking with the students for a while one learns that in most cases the little they’ve heard about string theory is often essentially over 20 years out of date and almost always totally skewed to the negative, to the extent that many of them are under the impression that string theory has nothing to do with quantum gravity at all! It is totally bizarre,
They are right. String theory has nothing to do with quantum gravity. I challenged him to cite the scientific paper that shows some connection, and he ignored it. There are string theorists who speculate that they may someday solve the problem of quantum gravity, but they have almost nothing so far, unless you want to count being wrong by 63 decimal places.

Friday, Jun 25, 2010
 
Stein on Poincare
Howard Stein wrote an unpublished essay on Physics and Philosophy Meet: the Strange Case of Poincaré:
Let me begin with a remark about the culminating event, Poincaré’s memoir of 1905/6 on the dynamics of the electron. I am by no means the first one to comment on that paper: there is a well known controversy over the question whether or not it de- serves to be considered as containing a statement of the special theory of relativity -- and if not, why not? -- i.e., the question, how does Poincaré’s theory differ from Einstein’s? That such a controversy should be possible at all is certainly a little odd; so prima facie, the case is strange. But I have not seen it pointed out just how strange; I know of nothing like it in the entire history of physics. There have been many instances of work inade- quately appreciated at first, on account of what might be called philosophical precon- ceptions or prejudices; but here we have to deal with a great work by a great scientist and philosopher of science whose own author failed to appreciate its true worth.
I think Stein is correct that there is no other example in the history of science like Poincare and relativity. There are lots of examples of geniuses who did get credit because their work was ignored. But Poincare was not ignored, he published more of the theory than Einstein, and he continues to be downplayed by physicists and historians to this day.

Stein goes on to discuss Poincare's physics and philosophy, and why the Poincare story is puzzling. He says Poincare did not believe in the aether, and objected to any argument depending on the aether. But "he does not suggest (explicitly, at any rate) that an electromagnetic theory of light can be formulated without an ether altogether." Stein attributes this to "Poincaré’s philosophical mistake", and explains:

And this is the crucial difference, as I see it, between Poincaré’s relation to the special theory of relativity and Einstein’s. Both of them discovered this theory -- and did so independently. So far as its mathematical structure is concerned, Poincaré’s grasp of the theory was in some important respects superior to Einstein’s. But Einstein “took the theory seriously” in the sense that he looked to it for NEW INFORMATION about the physical world -- that is, in Poincaré’s language, he regarded it as “fertile”: as a source of new “real generalizations” -- of empirically testable consequences. And in doing so, Einstein attributed physical significance to the basic notions of the theory itself in a way that Poincaré did not.
If Stein were correct, then it would indeed be puzzling that Poincare could discover relativity and not understand it. Stein justifies his conclusion by saying that Einstein found in 1915 that relativity affects the Mercury perihelion, and that Einstein badmouthed Poincare in 1911.

Stein has many references to Poincare's 1908 book, but obviously did not notice that it proposes using relativity to explain that Mercury perihelion deviation. Poincare was 7 years ahead of Einstein, even on Stein's best example.

It is absurd to suggest that Einstein took the physical applications of relativity more seriously. The best relativity experiments of the time were those of Kaufmann and others on relativistic mass. Those started in 1901, before Einstein said anything on the subject. Poincare considers them carefully in his 1905 paper, and admits that they might prove the theory wrong. Einstein ignores such matters.

Einstein badmouthing Poincare says more about Einstein than Poincare. Einstein obviously felt very threatened by Poincare, because recognition of Poincare's originality would be very damaging to his own reputation. It is bizarre for Stein to cite this Einstein remark as evidence that Einstein had some better understanding than Poincare. Stein could only say something so silly if he had a basic premise that Einstein was omniscient.

It seems to me that Stein is just applying his own philosophical prejudices. Even if he were right, he is still just saying that Poincare should be denied credit for relativity because of some obscure philosophical issues.

Much as these folks try, they are unable to give a coherent argument for crediting Einstein. Stein even has to add a footnote at the end of his essay admitting that he has had trouble convincing people that Poincare made a mistake, because there is no clear explanation of just what the mistake was.

Why would anyone be convinced by Stein's argument? Stein is essentially saying that Poincare independently discovered relativity theory and had a superior grasp of the theory, but Einstein should get the credit because of some philosphical argument that takes 24 pages to explain. Regardless of what that argument is, it would make more sense to credit Poincare with relativity, and credit Einstein with that philosophical argument, if indeed Einstein had some sort of superior philosophical view. But then Einstein would not be the world's greatest genius if all he did was to take Poincare's theory more seriously and to attribute physical significance to it.


Wednesday, Jun 23, 2010
 
The hunt for the God particle
The UK Guardian reports:
The idea of a hidden world might sound absurd, but physicists have good reason to believe it exists. Even with today's most advanced telescopes, astronomers can see only 4% of what makes up our cosmic neighbourhood. The rest is invisible to us, revealing itself only by the effects it has on the galaxies we can see. Around 70% of the unseen universe is labelled as "dark energy", a mysterious force that drives the expansion of the universe, making galaxies race away from us. The remaining quarter is chalked up as "dark matter", an obscure substance that clings to galaxies and exerts an unmistakable gravitational pull on them. The word "dark" means we cannot see it, but it also means scientists haven't the faintest clue what it is. ...

"Once you start considering these ideas actively, there's no theoretical reason to rule out a very interesting, dynamic and diverse dark or hidden world," says Neal Weiner, a physicist at New York University. "It leads to all sorts of conversations about the possibilities of dark people and dark planets. Now that is extremely unlikely, but it's something to think about. Once you open the box, it's not obvious where it will end." ...

The uncertainty over what exists in the hidden world has done nothing to dampen physicists' enthusiasm for the idea. John March-Russell, a theoretical physicist at Oxford University, says proof of a hidden world could become the central plank of a scientific revolution that rivals any in history. When Copernicus put the sun at the centre of the solar system in the 16th century, and when Charles Darwin described evolution in the 19th century, they both knocked humans down a peg or two. The discovery of a hidden world would force us to reassess our place once more. The cosmos as we know it – with all its stars and planets – might turn out to be nothing more than a mediocre microcosm of a far richer and more complicated universe.

"Just as the Copernican revolution told us that the Earth isn't special, the same could be true for everything that we've so far discovered," says March-Russell. "All of this stuff around us, the stuff of our reality, is it the dominant and most complex part of the universe? It might not be."

This nonsense about knocking human down a peg comes up a lot. I call it the Copernican-Freudian-Gouldian pedestal principle. I posted about it here, here, and here. Dark energy is probably the quantum vacuum, or what used to be called the aether. Dark matter is probably some sort of heavy neutrino. Finding these will not knock man off the pedestal.

There is an embarrassing correction at the end. The original said:

When Copernicus put the Earth at the center of the solar system in the 16th century, and when Charles Darwin described evolution in the 19th century, they both knocked humans down a peg or two.
The correction is still not right. Copernicus put the Sun near the center of the universe, but not at the center.

Tuesday, Jun 22, 2010
 
Latest Superstring Revolution
The June 2010 Scientific American Magazine reports:
"Twistor" Theory Reignites the Latest Superstring Revolution
A simple twist of fate: An old idea from Roger Penrose excites string theorists

In the late 1960s the renowned University of Oxford physicist and mathematician Roger Penrose came up with a radically new way to develop a unified theory of physics. Instead of seeking to explain how particles move and interact within space and time, he proposed that space and time themselves are secondary constructs that emerge out of a deeper level of reality. But his so-called twistor theory never caught on, and conceptual problems stymied its few proponents. Like so many other attempts to unify physics, twistors were left for dead.

In October 2003 Penrose dropped by the Institute for Advanced Study in Princeton, N.J., to visit Edward Witten, the doyen of today’s leading approach to unification, string theory. Expecting Witten to chastise him for having criticized string theory as a fad, Penrose was surprised to find that Witten wanted to talk about his forgotten brainchild.

A few months later Witten posted a dense 97-page paper that tied together twistors and strings—bringing twistors back to life and impressing even the harshest critics of string theory. In the past few years theorists have built on Witten’s work and rethought what space and time are. They have already spun off calculational techniques that make child’s play of the toughest problems in ordinary particle physics. “I have never been more excited about physics in my life,” says string theorist Nima Arkani-Hamed, who recently moved to the institute from Harvard University to immerse himself in the emerging field. “It is developing at a blistering pace right now, with a group of roughly 15 people in the world working on it day and night.”

The history of string theory is marked by revolutions. There is never any progress in relating string theory to the real world or in making testable predictions. Just revolutions. I thought that the landscape was the third string theory revolution, but maybe it is twistor duality.

You know a subject is bogus when its leaders are always talking about revolutions and paradigm shifts.

One reader comments:

This is yet another instance where nonsensical speculations promoted by influential theorists fail to make connection with physical reality. There is no shred of observational evidence that what this article tries to sell has any merit whatsoever. Hypotheses that cannot be falsified belong to pseudo-science.
Another comment:
One suggestion: I would recommend referring to these various concepts which have not yet been experimentally tested as "hypotheses" or "concepts" rather than "theories", at least in public.

We already have enough trouble in the schools, with people of a certain persuasion claiming that evolution is "just a theory", and creationism is "creation science". As I said, just a suggestion.

No, it is a mistake to describe string theory as something that has not yet been experimentally tested. It has no hypotheses waiting to be tested. If this commenter is so concerned about creationism masquerading as science, why isn't he similarly concerned about string theory? The answer is that the string theorists are all atheists.

There are things that string theorists argue about, as you can see in this 2004 Smolin-Susskind debate.

For the most part, string theorists refuse to debate their critics. The popular physics preprint server has even been configured to show trackbacks to blogs supporting string, but not to the Not Even Wrong blog.


Monday, Jun 21, 2010
 
Only 20k human genes
I have commented before that the Human Genome Project vastly overestimated the number of human genes. Now Hawks explains:
While doing some other research, I ran across a remarkable short paper by James Spuhler, "On the number of genes in man," printed in Science in 1948.

We've been hearing for the last ten years how the low gene count in humans -- only 20,000 or so genes -- is "surprising" to scientists who had previously imagined that humans would have many more genes than this.

So here's the next to the last line of Spuhler's article:

On the basis of these speculations there are then some 19,890-30,420 gene loci in man.
Wow. 50 years of research, billions of dollars, many Nobel prizes, stunning technological advances, and a worse human gene count than a 1948 estimate. The project leaders should have just admitted that they were not really finding the genes.

Thursday, Jun 17, 2010
 
Wisdom of Feynman
From another blog:
"I do not understand why journalists and others want to know about the latest discoveries in physics even when they know nothing about the earlier discoveries that give meaning to the latest discoveries"

Richard Feynman (quoted by G.F.Giudice, "A Zeptospace Odyssey", Oxford University Press 2010)


Monday, Jun 14, 2010
 
No medical cures from human genome project
The popular leftist-atheist-evolutionist blog Pharyngula writes:
Nicholas Wade of the NY Times has written one of those stories that make biologists cringe — it just gets so much wrong. It's a look back at the human genome project, and I was turned off at the first paragraph. ... he makes this error-filled statement:>
The barely visible roundworm needs 20,000 genes that make proteins, the working parts of cells, whereas humans, apparently so much higher on the evolutionary scale, seem to have only 21,000 protein-coding genes.
Humans aren't high on the evolutionary scale…there is no evolutionary scale. We aren't the pinnacle of anything. It's also weird to see people still expressing astonishment that we "only" have about 20,000 genes.
What is astonishing is that evolutionist professors can deny that humans are high on the evolutionary scale.

Wade also says:

… despite all the hype, the contribution of the genome to human health has been pretty negligible. In other words, from a purely medical point of view, there isn’t much to celebrate.
The human genome project is loved and hated for the same reason -- it is a reductionist approach to the never-ending nature-nuture debate.

Sunday, Jun 13, 2010
 
Naming denialists
Megan Scudellari writes in the British journal Nature:
Scientists regularly debate hypotheses and interpretations, sometimes feverishly. But in the public sphere, a different type of dissension is spreading through media outlets and online in an unprecedented way—one that challenges basic concepts held as undeniable truths by most researchers. 'Science denialism' is the rejection of the scientific consensus, often in favor of a radical and controversial point of view. Here, we list what we see as a few of today's most vocal denialists spreading ideas that counter the consensus in health fields.
This is a scurrilous approach for a scientific journal. Some of those listed back up what they say with cites to scientific articles. They have legitimate opinions based on the research they cite. If they are wrong, then Nature could publish an article demonstrating their error. But it is not scientific to just publish an article with name-calling about how they are in a minority.

See Michael Fumento's reply.

It is true that the BMI of people who live the longest is in the overweight range, that swine flu was declared a pandemic only by changing the definitions, and the optimistic mainstream predictions for embryonic stem cell therapies have failed. We need people pointing these things out, without the science establishment branding them denialists.


Saturday, Jun 12, 2010
 
Vladimir I. Arnold dies
From Arnold's obituary:
A similar approach can also be applied to the motion of planets. If Earth were the only planet to circle the Sun, its orbit would follow a precise elliptical path, but the gravity of the other planets disturbs the motion. Scientists found that it impossible to calculate the precise motion of the planets over very long periods of time or even prove that Earth will not one day be flung out of the solar system.
Henri Poincare was the first to show the possibility of planetary orbits being chaotic.

Poincare and Arnold were geniuses. Einstein never did any mathematical physics with this depth.


Friday, Jun 11, 2010
 
String theory predictions
The June 2010 Scientific American magazine describes 12 Events That Will Change Everything. One of the 12 is possibility that the new Swiss particle collider will discover the extra dimensions of string theory. The author gives it a 50-50 chance. The online reader poll is similarly split.

But the string theory gurus are now less optimistic:

John Hockenberry, the panel’s moderator, asked Greene if he thought experimental evidence would come during his lifetime.

“I’d be surprised,” said Greene.

“And in your lifetime?” Hockenberry asked Kachru.

“…I’d be surprised,” conceded the young physicist reluctantly.

I think that the possibility is zero, as the theory has already been determined to be a big washout. But whether that is true or not, I don't see how the 6 or 7 extra dimensions could "change everything". A nuclear war or a global pandemic are 2 of the 12 things that might change everything. Those effects will be obvious to everyone. But how will anything be changed by someone saying that extra dimensions could help explain some particle collision? It is likely that someone else will find an explanation that is just as good, but does not use the extra dimensions.

The discover of quantum mechanics in the 1920s really did change everything, but most of the philosophical implications are fallacious. There are many interpretations of quantum mechanics, and not all of them are probabilistic or observer-dependent.