Superheating: fun in a microwave oven

Superheating (Wikipedia) may be fun but it may also be dangerous.

U.S. poll: Global warming 8th environmental problem

Some social scientists in Missouri made

a survey (UPI report)

in which people located environmental issues that deserve, in their opinion, more effort from the government. Despite the intense media hysteria, CO2 emissions do not belong among the top environmental issues. The most important issues (some of them written positively, some of them negatively, the context makes it clear) according to the U.S. citizens are

1. drinking water
2. pollution of rivers, lakes, and ecosystems
3. smog
   
4. forest preservation
5. acid rain
6. tropical rain forests
7. national parks
8. greenhouse emissions
9. ozone layer
10. nature around "my" home
11. urban sprawl
12. extinction.

Well, I would surely put greenhouse emissions at the last place here (and below many other environmental topics) but the 8th place is what the U.S. citizens think. If the governments planned to spend 1% of the GDP for the 8th environmental problem, it is not hard to see that the governments would probably need more than 100% of the GDP for all environmental issues combined. And how would you pay for the other sectors?

Because people are still not buying this weird fashionable propaganda about a dangerous global warming, it is not too surprising that Al Gore, the de facto leader of the IPCC and similar disgraceful institutions, is planning to strengthen his attempts to brainwash the people. His new threat is that he wants to waste USD 300 million for pure propaganda.

His commercials will create unlikely bedfellows - for example, Pat Robertson will sleep with Al Sharpton; see NewsBusters' comments. I suppose that Al Gore assumes that he will cover the "whole" political spectrum. Well, I guess that the spectrum is not wide enough for me. Most likely, some dimensions such as intelligence (and uncorruptability by rich quasireligious zealots) might be absent on the Sharpton-Robertson axis. But frankly speaking, it is likely that millions of Americans will perceive themselves as a certain linear combination of these two Gentlemen - as Sharpertsons and Roberptons of various kinds. ;-/

LHC alarmists ask judge to save the world

Dennis Overbye has an entertaining - or stunning, depending on your perspective - article in

The New York Times,

the most e-mailed article of the Times today. See also MSNBC's Alan Boyle. Nima, Lisa, and a few others are among the serious sources. Overbye follows physics and certainly its sociological structure.

A poor judge in Honolulu was ordered by two alternative physicists who have visited this blog several times and who have written some inappropriate and impolite comments, namely Walter Wagner (left, click) and Luis Sancho, to prevent the CERN - an institution at a completely different continent :-) - from launching the LHC collider which is expected to begin operations at 10 TeV in July.

A short time ago, I discussed the topic about the LHC alarmists and won't repeat myself. But let me say that I have recently seen so much monstrous stupidity among ordinary people and even not-so-ordinary people that I wouldn't really be shocked if the two loons mentioned above were able and allowed to kill the USD 6 billion experiment or at least delay it by 4 months, as they plan now. More precisely, I would be shocked but rationally speaking, I wouldn't be completely surprised. ;-)

What can the poor judge do if he can't go through the scientific arguments and the hypothetical catastrophic Lorentz violation effects himself? He must trust other people. One half of them, including the blog "Freedom of Science" (where it is claimed that physicists have taken the absurd so far into the twilight zone so that their claims can't be trusted by the courts), tell him that our planet may be destroyed. He simply has to act! :-)



Luis Sancho's unification theory based on superorganisms looks much like Lee Smolin's octopi theory. Click the image for more details of read a "preprint". While LS (U.S. edition) has only thought about the cosmic natural selection and reproduction through black holes, his LS (Spain) counterpart has also discovered star nurseries and reproductive curves of galactic herds. ;-)

We live in a world that respects an obsessed megalomaniac and a frequent prophet of doom, Al Gore, as a prominent climate scientist and that copies the opinions of Lee Smolin and similar cranks about high-energy physics. If you combine the two examples from the previous sentence, it shouldn't be excessively surprising if a federal judge decided that the Mr Wagner and Mr Sancho have a point and that we face a catastrophic threat that should be avoided. ;-)

According to a Discover Magazine blogger, Wagner's greatest achievement is that he has appeared on the paranormal-matters talk show "Coast to Coast" in which he claimed a discovery of magnetic monopoles in his balloon. Wagner has apparently worked in nuclear medicine and is currently accused (together with his wife) of an identity theft designed to steal pieces of the World Botanical Gardens.

Sancho, who has no degrees either, is a "time theory expert" who used to live in Barcelona, Spain (see rafa's comments). It seems that he has moved to Hawaii as well, to learn some surfing in order to be accepted as a new Albert Einstein or even a new Garrett Lisi by the world. ;-) FoxNews says that Sancho's presence makes the entire case a bit quixotic. :-)

The judges could also approve the opinion of another commenter on this blog, Lawrence Krauss, that the astronomers are ruining the Universe by looking at it and ban cosmology. Incidentally, Krauss recently wrote an article in Nude Socialist about the destruction of the Universe and Boltzmann's brains in particular and called it "String theory's latest folly" (update: in the slow comments, he argues that the title was chosen by the editors) even though string theorists are pretty much the only group of theoretical physicists who - unlike Sean Carroll or Don Page - doesn't collectively study this 19th century extremely speculative topic.

The only major exception (of a string theorist who likes to write about Boltzmann's brains) I know of is Lenny Susskind (and a small number of his very young collaborators) and Susskind surely enjoys freedom for his occasionally idiosyncratic opinions, without losing his exceptional name. However, the key point that should be obvious is that Boltzmann's brains have nothing to do with two-dimensional conformal field theory coupled to gravity or any other technical aspect connected with string theory.

Because of these simple reasons, "String Theory's Latest Folly" is what I call a dishonest title for an article criticizing speculative papers about cosmology - something that Krauss likes to write himself (besides neverending preprint conversations about fractal analyses of paintings of Jackson Pollock whose details resemble Luis Sancho's fractal argument from the image above where the longest distance scale i=9 agrees with i=1).

Hat tip (LHC): Steve Heston

P.S.: Let me say something about the titles. Of course, I do know that the title is routinely chosen by the editor or the publisher. That was the case of "The Bogdanov Equation", too. On the other hand, I am convinced that the author always has to approve it. Although it was a bit of a shock to see the cover of the book for the first time, I of course fully confess that I approved it after a little thought accompanied by mixed feelings even though this title is arguably not the most accurate description of the content of the book. Whether someone including myself likes it or not, I am responsible for the title. In the very same way, I am convinced that the titles such as "The Trouble With Physics" and "String Theory's Latest Folly" were approved by the authors, too. Trying to get rid of the responsibility - whenever the title becomes inconvenient - is an unfair game.

Earth Hour: turn your lights on at 8 p.m.

Tonight, at 8 p.m. local time, you should turn on all the light bulbs you have for 60 minutes (it will only cost you 3 cents per light bulb in average for the whole hour) to fight global obscurantism. You should look how many lights are on around. Every light bulb you see will be a sign of the audacity of hope, as Jeremiah Wright would say.

An article about the event.
Official U.S. page.

The World Wildlife Fund (WWF), a group of wild animals pretending to be humans, is trying to return our civilization to the Dark Ages. They urge everyone to turn their lights off. But as Financial Post recommends: don't have a sexual intercourse with pandas.



The event was tried in Sydney a year ago and now it goes global. A month ago, a similar event in the U.K. saved statistically insignificant 0.1% of the energy, despite loud and hysterical threats by the London bishop, Richard Anti-Christ Chartres.

Tonight, the officials in many cities, including Atlanta, Phoenix, San Francisco, Montreal, Toronto, Bangkok, Dubai, Tel Aviv, Bogota, Buenos Aires, Caracas, Mexico City, Ottawa, Warsaw, Copenhagen, and Dublin, joined the activists. The Chicago skyline will probably disappear, too. All Czech cities, towns, and villages unanimously rejected the idea. TVs will likely be on, too: Sexy Pistols are on TV NOVA since 8 p.m. ;-) India won't join, either.



Incidentally, the believers who will replace light bulbs by candles should know that a candle produces as much CO2 as a 20W light bulb powered by average energy sources during the same time. Five candles replace the CO2 output of a 100W light bulb.

Last February, Jiří Hájek, the spokesman for the Prague Castle described a similar 5-minute event well:

You talk in categories of holocaust deniers which is clearly absolute nonsense. If you were right, we could return to the trees and deny the whole civilization. The 'five minutes without power' campaign is a ridiculous political event and people who believe these warnings are naive. We can't see obscurantism [in Czech: darkism] in natura frequently but this is an example.

Alexander Grothendieck: 80th birthday

Today, Alexander Grothendieck probably and hopefully celebrates his 80th birthday.

Congratulations to his cabin in the Pyrenees.

The romantic home doesn't prevent him from doing some great mathematics. For example, in Fall 2007, Chien-Hao Liu and Shing-Tung Yau clarified the new Polchinski-Grothendieck D-brane Ansatz on page 17 (19 of 59). ;-)

How did the Polchinski-Grothendieck collaboration work? Well, Grothendieck was having fun with his garden in the mountains while Joe listened to a Grothendieck-related talk and this is what he, not to be confused with Ginger, heard. :-)

Superdelegates

Bolshevik guerilla groups such as MoveOn.ORG and other fans of a particular presidential candidate are trying to intimidate the whole Democratic Party into disregarding its own rules.

In 1982, a commission chaired by North Carolina governor Jim Hunt analyzed the reasons behind humiliating losses of McGovern against Nixon (1972) and Carter against Reagan (1980) and they determined that an important reason was that the party leaders who actually have some political skills have lost the influence over the Democratic Party.

Hunt et al. invented the superdelegates. Their intended share was 30%, the figure dropped to 14% instantly, but grew to roughly 20% today.

One could probably live without these rules but there certainly exists a rational justification of these new rules: without such an explicit influence of the party officials, the whole primaries reduce to a new round of general elections. The party would effectively disappear. More importantly, they are the current rules of the game. A certain fraction of the delegates are unpledged and they vote independently of the popular vote.

I find it kind of amazing that so many people are ready to question these rules in the middle of the game - just because they suddenly find superdelegates inconvenient. When rules are ignored but no one is hurt, one can sometimes understand such a careless approach. But that's certainly not the case right now.

If the Democratic Party thought that the superdelegates were such a bad policy, they should have abolished them - for example, after 2000, when the Democratic nutjobs promoted the popular vote into a holy principle by ad hoc and ridiculous claims that their Gore should have won the 2000 elections that he lost. But they didn't abolish them which makes a difference.

I have no idea how they want to justify such a position and I have no clue how they actually want to guarantee that the rules will be pissed upon because it is not such a trivial thing to do something that blatantly contradicts their own law. Will they blackmail or assassinate the superdelegates? What they want to do is nothing less than a coup or a new October Revolution.

Needless to say, the potential inability of the Democratic Party to obey its own rules will eventually lead to a backlash. Sponsors might be lost and the 2008 Democratic nominee may easily repeat the fate of McGovern and Carter in the general elections.

And that's the memo.

Al Gore, the flat Earth, and a tiny, tiny minority

On Sunday, 7 p.m. ET/PT, CBS will broadcast

Al Gore's message (CBS)

to us, a "tiny, tiny minority" of climate realists. We are so tiny, in fact, that we are almost like those who believe that the Moon landing was shot in Arizona and the world is flat, this monster mind tells us.



Thank you so much for your revealing message, Mr Gore, even though you are not exactly the only person at your intellectual level who is sending me similar messages.



When you listen to him, you can see that this guy must genuinely believe that it is possible to learn how Nature works or settle an argument by sticking with a majority. That's the scientific method, Gore edition.

For example, if you want to know whether the mankind or the German nation can survive without exterminating the Jews, you listen to the leader and to the majority who says "It can't" and to be really sure that you are right, you send the tiny, tiny minority to the same camps as the Jews.

But are those who disagree with Gore a minority? Read the comments at the CBS link above or below a similar article in

USA TODAY.

An overwhelming majority of the commenters criticize Al Gore, the scientists who follow him, Gore's hypocrisy, Gore's politicization of science, and they offer link to skeptical resources. Some of their wise comments and jokes are pretty good:

Following scientists who back Al Gore is like following the lead lemming to the see, glub glub glub. He didn't run for the president because he didn't want to take the pay cut. Who believes Al Gore's climate science must also believe that he invented the Internet. Al Gore is a moron who has never contributed anything worthwhile when he had a chance. Now he's jumping on any bandwagon that will give him the time to utter his mindless drivel. There is so much in common with religion. The earth has been warming since 1847. Hey Al, greetings from the "tiny" minority that whipped you and Kerry like red headed stepchildren. In reality, after you peel the left wing liberal Hollywood cretins from his bandwagon, the "tiny" group is actually Al's.



Al Gore should be finally "realized" that his 15 minutes of fame are up.

2008 Abel Prize: Thompson and Tits

The 2008 Abel Prize for mathematics

is shared by John Griggs Thompson (Florida) and Jacques Tits (France). It is a great victory for group theory and symmetries.



Both mathematicians have played a key role in the multi-decadal project of the classification of all finite groups.

John Griggs Thompson (*1932) has also solved the problem of the nilpotency of Frobenius kernels. He proved the even parity of the order of simple non-Abelian groups, classified various groups satisfying constraints on various normalizers. The Thompson group is one of the sporadic groups. It may be obtained from a centralizer of a type 3C element of the monster group or as a subgroup of the Chevalley group E8(F3), a reason why the Thompson group has a 248-dimensional representation.

You might think that giving an Abel prize for non-Abelian groups is paradoxical but believe me, giving USD 1.2 million for Abelian groups would be even more crazy. ;-)

Jacques Tits (*1930), a Belgian mathematician, was an honorary member of the infamous ultra-rigorous Nicolas Bourbaki group. However, not everything is an excrement if it looks dark. ;-) Tits is the guy who has coined the terms such as "Coxeter number", "Coxeter group", and "Coxeter graph". You may have heard of the Tits group, the "simplest" or "most classical" among the sporadic groups (occasionally included among groups of Lie type): it is the derived subgroup of the twisted Chevalley group 2F4(2).

BMW 520d: more efficient than Toyota Prius

Many celebrities and folks who want to look green like to buy Toyota Prius these days.



The Sunday Times organized a test and it seems to imply that Prius is just what it seems to be - a fashionable symbolic bubble for hypocrites that actually consumes more fuel than ordinary big cars and enjoys undeserved special rights on the superhighways.



On their trip from London to Geneva (plus 100 urban miles), the BMW pictured above played music and ran air-conditioning while the Prius driver turned off both as he tried to drive very carefully. Nevertheless, the BMW consumed 4.7 liters per 100 km (41.9 mpg) while the Prius has burned 4.9 liters per 100 km in average (40.1 mpg). Subtle BMW gadgets to save fuel seem to be more important than the hybrid core of the Prius as well as its 500 missing pounds.

The Prius driver was disappointed and plans to buy a V8 Range Rover and to open his own oil well in protest against the would-be environmentalist silliness that began to influence the car industry and traffic rules.

See also TechnoRide, Autoblog.

D2-branes from M2-branes, three-algebras, and associators

Today, I certainly recommend you the hep-th paper by

Sunil Mukhi, Constantinos Papageorgakis

who investigate a new type of a Higgs mechanism in a new type of theory relevant for M-theory membranes. A condensate of a 3-algebra-valued eighth scalar is claimed to convert a topological field theory from M2-branes to the conventional Yang-Mills theory defined on D2-branes.

The authors wisely posted the paper as the first paper on the hep-th archive. They did the right thing because the paper is arguably the most important one.

Review

Because I haven't yet written about these cool things, let me say a few words. The main resource I recommend you about this new theory is a paper by

Jonathan Bagger and Neil Lambert

that defines a very promising candidate for a theory describing N M2-branes because it has the required supersymmetries, conformal symmetry, SO(8) R-symmetry, and - according to the Mukhi & Papageorgakis paper - also the correct Yang-Mills correct limit after the Higgsing. That looks like a really non-trivial body of evidence for such an unusual theory.

For the sake of order, I won't link to the papers by Basu and Harvey (2004), Bagger and Lambert (2006), and Gustavsson (2007) who, especially in the latter case, also deserve credit. Instead, I will only discuss the story as presented by Bagger and Lambert (2007) mentioned above. David Berman has been playing with similar things. So was I. And Shiraz Minwalla was very helpful for the Mukhi & Papageorgakis new paper.

Mysterious triple structures of M-theory

Conventional physics uses quadratic Lagrangians, two-dimensional worldsheets, second-rank tensors under Yang-Mills groups, commutators between two objects, and similar structures based on the number "2" all the time. We know them quite well.

Still, it looks likely that there exists a whole realm of wisdom that remains mostly hidden in a cloud of mystery. Even though a great deal of the physics is known, we don't know of any simple covariant descriptions of M-theory in 11 dimensions, multiple M2-branes, and multiple M5-branes. We know how to study many physical phenomena in their context but our degree of understanding simply doesn't seem to match the Yang-Mills, worldsheet, free theories discussed in the previous paragraph.

There exist hints that these largely unknown structures might be based on the number "3" in a similar way as the known theories are based on the number "2". This comment looks extremely vague but there are many reasons to see this prophesy. Exceptional groups frequently appearing in M-theory have cubic invariants. Membrane worldvolumes have three, not two dimensions. The number of degrees of freedom of an M5-brane seems to scale with the third, not second power of N. And all these insights could be relevant for the third superstring revolution just like D-branes and Yang-Mills theories were for the second. ;-)

We understand the low-energy limit of a single M2-brane and a single M5-brane. In the former case, the theory has 8 transverse dimensions (2+1 + 8 = 11 as in M-theory). One of the dimensions can be electromagnetically dualized to a gauge field in 2+1 dimensions, obtainining a gauge theory in 2+1 dimensions with 7 additional transverse scalars, a description of D2-branes in type IIA string theory. That's how the Yang-Mills terms for the D2-brane gauge field is generating from the eleventh dimension of M-theory that gets compactified.

The non-Abelian case generalizing the simple construction above to the case of multiple M2-branes or D2-branes is not understood. Or at least, it wasn't understood until recently, until the end of 2007. ;-)

You might think of many ways how the number "2" in the well-known theories should be replaced by "3". Certain people keep on constructing 2-groups, gerbes, and similar superconstructions that never work at all. The Bagger-Lambert-Gustavsson construction is different because it actually seems to have all the required symmetries and the correct Yang-Mills limit after the Higgsing!

So how does the Bagger-Lambert-Gustavsson construction work? It will sound as a sort of kindergarten game but believe me, I am serious. ;-)

Well, the commutator [A,B] uses two letters. It vanishes if A,B commute with one another. The generalization to three objects must clearly be [A,B,C]. It vanishes if the associativity holds, so choose

< A,B,C > = (A.B).C - A.(B.C)

That's the associator, extending the commutator. ;-) For certain reasons, it is more useful to use the completely antisymmetrized associator

[A,B,C] = < A,B,C > +- 5 other terms

A trace form (behaving "democratically" with respect to three objects in a product) and a Hermitean conjugation must exist. The trace of A and the antisymmetrized associator [B,C,D] gives you an antisymmetrized object with four indices. Now you can write down a lot of mutated versions of well-known equations with an additional index, including the mutated Jacobi identity.

Mutated Lie rules and actions

The parameter Lambda of gauge transformation in this three-algebra realm have two "adjoint" indices instead of one. The mutated gauge fields and mutated gauge transformations look pretty much identical as in the Yang-Mills case if you write them in terms of two indices attached to every gauge field. The three-algebras are "more powerful" than the normal Lie algebras but one can construct a Lie algebra "imprint" of every three-algebras - a potential Lie algebras that can occur in D-brane Yang-Mills limits of it.

An expert could think that all of these games are childish and probably won't lead to sensible theories. The first shock occurs on page 7 of Bagger & Lambert where a supersymmetric action based on these things is found. It literally looks like the three-generalizations of the usual formulae. For example, the supersymmetry variation of a fermion has the normal term proportional to "X" but also an additional non-linear term proportional to the associator [X_I, X_J, X_K]. Wow. The 4-index mutated structure constant tensors appear elsewhere.

The final Lagrangian looks as expected. There is no kinetic term for the gauge field, normal kinetic terms for the scalars and fermions, a mutated Yukawa term with Psi.X.X.Psi replacing the usual Yukawa Psi.X.Psi term, and a Chern-Simons action for the gauge field. The final Lagrangian has no free parameters at all, assuming that certain quantization rules constrain the mutated structure constants f^{bcd}_a.

Now, what are these bizarre three-algebras? Do they exist at all? In fact, there is at least one non-trivial one, with four "colors" and f_{abcd} being proportional to the completely antisymmetrized epsilon_{abcd}. However, Bandres, Lipstein, Schwartz argue that it is difficult - at least for them - to generalize the four-color SO(4) into a more general case. Not even otherwise natural structure constants of the octonions seem to satisfy the required mutated Jacobi identity.

Higgsing and applications to M5-branes and M-theory

After you absorb all these novel three-algebra insights, you should read the new paper by Mukhi and Papageorgakis, fully deriving the D2-brane supersymmetric action from a mutated Higgsing of the M2-brane three-algebra action. That's pretty fascinating unless there is a hidden catch somewhere. The four-color Bagger-Lambert SO(4) algebra is eventually broken to the diagonal SU(2) inside SU(2) x SU(2), ending up with the U(2) supersymmetric Yang-Mills theory including the center-of-mass degrees of freedom.

Mukhi and Papageorgakis had to correct a confusion in the literature - some people expected, by counting the moduli, that the SO(2) 3-algebra theory should have led to the SU(3) theory for three M2-branes. Shiraz Minwalla importantly told them that this couldn't be the case because such a reduction would imply that there exists no non-trivial theory for two M2-branes.

I haven't known the supersymmetric action but I have already worked on a similar setup a year or two years ago and I think that I slightly know how an analysis of M5-branes using these M2-brane degrees of freedom can be made, including the mutated 3-version of the 't Hooft limit. Tomorrow, Berman, Tadrowski, Thompson will study open membranes and fivebranes in this framework. One day later, Mark van Raamsdonk will frustratingly argue that the moduli space of the BL theory has an unwanted O(2) quotient (missing dimension) and superconformal primaries can't be easily constructed.

So if some readers don't know what topics are hot right now, let me declare three-algebras of M2-branes to be the hottest topic right now. ;-)

And that's the memo.

Update: Newer articles about the research direction contain the phrase "membrane minirevolution" (click).

Scientific American interviews climate realists

Includes Gray, Morano, Spencer...

Joseph Liouville: an anniversary

Joseph Liouville, a 19th century string theorist and politician, was born 199 years ago, on March 24th, 1809.

He lived with his uncle for a few years, showed his talents as a kid, attended all kinds of schools, and met important French mathematicians and physicists. Throughout his life, he wrote about 400 technical papers.

He was also a science official. At some moments of his life, Liouville was defeated by Count Guglielmo Libri Carucci dalla Sommaja, a guy who escaped France during the 1848 revolution to avoid prison sentence for stealing precious books and manuscripts. ;-)

As a moderate republican politician, Liouville was depressed for years after 1849 when he lost an election because working-class socialist radicals and similar political foam became "hot" at that time. He recovered and 1856 and 1857 were among his most scientifically fruitful years.

Science

There have been many different disciplines of mathematical sciences where Liouville left us valuable insights. For example, he was the first man to prove the existence of transcendental numbers (that are not solutions to any algebraic, polynomial equation with rational coefficients). The simplest (but later) example he found is

0.1100010000000000000000010000...

that only has "1" in place "n!". It is so close to the rational numbers that approximate it yet so different that he could show it was not algebraic. An older example he found used continued fractions. Liouville also investigated number theory.

In theoretical physics, he is known for Liouville's theorem, the local continuity equation for a probability distribution function on the phase space (with the current explicitly expressed in terms of derivatives of the probability density, as dictated by the Hamiltonian equations of motion).

He studied various differential equations involving eigenvalues. See, for example, the Sturm-Liouville problem. Many of the problems he studied resemble the tasks one must routinely solve in quantum mechanics - even though he lived 100 years earlier.

Liouville and string theory

But string theorists will surely know him for the Liouville action, also known as the Liouville theory. How the hell could a 19th century mathematician write down an equation for two-dimensional non-critical string theory including the linear dilaton and the exponentially increasing tachyonic wall? Something that is a frequent ingredient of many perturbative string-theoretical constructions? And believe me, he did so. ;-)

The answer is that Liouville's equation is truly natural and someone who studies how to solve partial differential equations and what non-trivial pieces they are made out of will inevitably run into such an equation.

The string-theoretical terminology for Liouville's equation arises from a more general type of a differential equation that Liouville studied, namely the equation requiring that the Laplacian (or d'Alembertian) of the function "u" is equal to the exponential of "u". When "u" is interpreted as the coordinate "X_1(sigma,tau)" in spacetime along which the dilaton is linear, a coordinate that is mixed with the exponent encoding a Weyl scaling and a coordinate treated as a function of the worldsheet variables, Liouville's 19th century equation becomes the same thing as the equation of motion for "X_1(sigma,tau)" in non-critical string theory.

In fact, Liouville didn't just encounter the same equation: he studied it in the context of very similar mathematical procedures that string theorists do before they end up with Liouville's equation, namely an analysis of conformal transformations.

More generally, all kinds of similar, generalized, or nearly-equivalent equations of this kind are referred to as Liouville's equation, for example

y'' + g(y) y'² + f(x)y' = 0

You shouldn't confuse non-linear Liouville's equations with the linear equations that appear in Liouville's theorem or the Sturm-Liouville problem discussed above.

I have emphasized this point many times but let me say it once again. String theory naturally incorporates, explains, interprets, and unifies most of the deep mathematical ideas, concepts, and equations inspired by and/or indirectly or directly connected with the laws governing the physical Universe. There is really no way for a real 21st century mathematical or theoretical physicist to "cut string theory off" without amputating his whole brain.

And that's the memo.

ABC's eco-fundamentalists attack Fred Singer

TV segment, HTML, News Busters comments

I know this kind of TV programs too well from the era of communism - when the target wasn't Fred Singer but people like Václav Havel - and some old films I have watched indicate that the Nazis used to create a very similar stuff. The content is pretty much isomorphic. In both cases, the people who would agree with Havel or Singer are intimidated by the powerful "majorities" or a "working class". The technical arguments are not discussed at all.

Havel would be indirectly connected with the Nazi regime through his family and through the people who collaborated with it; Singer is linked with the oil industry (that currently contains a lot of dishonest and cowardly CEOs co-operating with the environmentalist ideologues anyway). The details are different but structurally speaking, it is the very same type of propaganda. While I surely admit that the communists were bad, I really don't remember a single hit piece at this degree of bloodiness, especially not against a scientist who is 84 years old.

A smiling Dan Harris asks Dr Fred Singer a highly "intelligent" question: "How would you describe yourself, as a skeptic, a denier, a doubter?" And Fred Singer is also smiling and gives him the correct answer: "a realist". We've been recently discussing these terminological matters. An alternative description is "cool heads" vs "hot heads".

I just admire Singer's nerves, balance, and courage. If I were asked the same "question", my face would turn red - in fact, it turned red even when Singer was attacked :-) - and I would probably ask the jerk: "And how would you describe yourself, a brown shirt, a religious bigot, a terrorist, or just a plain idiot?"

The whole hit piece is an amazing demonstration of brainwashing and irrationality. For example, the first sentence says:

One of the most influential scientists in what's been called "The Denial Machine," for decades, Fred Singer has argued loudly that global warming is not dangerous despite the vast majority of scientists who agree it is.

First of all, it has never been called a "Denial Machine" by any serious person, only by one or a few would-be journalists and a couple of their undemanding readers. Just because a scientifically illiterate layperson such as Sharon Begley uses an insulting term for a scientist who knows roughly 500 times more than she does, is not enough to make the statement "it has been called..." on TV honest or correct. Why did Mr Harris hide that it has been called this way only by a scientifically illiterate environmental activist, not by a serious person and certainly not by a good scientist?

Well, it is not hard to guess. An idiot from Greenpeace is later used as a kind of authority in the show. He doesn't know anything and he can't really speak but he shows the would-be journalists a page ("Exxon Secrets") with smears and irrelevant indirect "links" in a combinatorial graph. When did it exactly happen that TV channels in the U.S. consider activists from extreme environmentalist organizations to be more reliable sources of facts about science than John Wheeler's famous students from Princeton?

Second, the sentence clearly includes the assumption that scientists are determining - and have to be determining - their opinions by aligning themselves with "vast majorities": they repeat this assumption roughly four times in the program. Well, some of the scientists do it this way which is why their "scientific" opinion should be completely discarded: they haven't used the scientific method to obtain their opinion and as far as I can say, they are just worthless parrots and parasites robbing the taxpayers who simply defend a party line in science - something that shouldn't exist at all.

Moreover, it is not really the consensus that decides about the opinions of irrational propaganda makers such as Sharon Begley. Among many other disgraceful things, she has also run a hit piece against something that could also be called the "majority opinion" in high-energy physics; recall Barton Zwiebach's reply to it. How is it possible that in that case, the majority doesn't matter? What actually drives her rants is left-wing politics. The more leftist side is always the "winner" in her propaganda pieces. Whenever her opinions and interests are in a minority, she promotes clichés about the discrimination by a majority. But once her opinions become a majority somewhere, she uses the "principles" about the need to completely eliminate the minorities and heretics. There is never any substance in her writings. And these days, there are literally thousands of "journalists" of this kind around. We are all immersed in a gigantic ocean of dumb, ideological garbage.

The double standards in judging minorities and majorities is how the totalitarian ideologues have always been thinking and acting which is why they have crippled whole portions of the world so many times in the past and why they are so dangerous today, too. Those parties - such as NSDAP or the communist parties - would once pretend to be small, suppressed, and cute groups that deserved support. But once they exceeded (or fluctuated above) 50%, they took over and the competition, democracy, and debate was all over. In this respect, there is no difference whatsoever between the Nazis and the environmentalists.

Nuclear winter

The program also says that Singer has disagreed with "mainstream science" in the past. One of their shocking examples is nuclear winter. Well, it's plausible that a majority of scientists counted in a certain irrelevant way supported this theory at some moment in the past. But I wouldn't expect nuclear winter to be a good example to defend majorities or attack Singer because he has been definitely right on this one. Nuclear winter was mainly defended by media-savvy quasi-scientists such as Carl Sagan or Paul Ehrlich.

But many of those who would be labeled as "very good scientists" always agreed with Singer. Richard Feynman said "I really don't think these guys know what they're talking about" and Freeman Dyson said "it's an absolutely atrocious piece of science but ... who wants to be accused of being in favor of nuclear war?" The question was pretty much settled in 1991 when the nuclear winter theorists predicted "a year without summers" following Kuwaiti oil fires in 1991. Well, that didn't happen. See more details in Michael Crichton's speech.

Not only the scientific consensus has a bad record in science but Fred Singer himself already has a pretty good record in his disagreements with various fads sold as "consensus science".

Let us hope that the ABC's ratings will continue to plummet towards zero because in a decent society, constant promotion of this garbage should be a serious obstacle to survival.

Milan Štěrba: died as a hero

The Czech team of 400+ troops in Afghanistan has its first casualty, a hero whose blood has given a new flavor to the Czech participation in the war on terror. Sadly enough, Milan Štěrba (36) was killed this week by a suicide attack.

Sidney Coleman: Physics 253 videos

See 54 videos from Sidney Coleman's 1975-1976 legendary Harvard lectures of Relativistic Quantum Mechanics, Physics 253.

Take a random lecture, for example the first one, and watch for a few minutes. Note the precise moment when he makes a joke or lights up each cigarette. These moments were optimized and kept constant for decades. ;-)

I am not even sure whether he would be allowed to light up the cigarette these days. I doubt it. On the other hand, he would be encouraged to bring his snowboard in the classroom and say that quantum field theory is in trouble and it is a result of oppression by white males - just like what the only student of Coleman's who didn't attend SidneyFest thinks.

Hat tip: Clifford Johnson who thought that Coleman was chewing chalk; the matches didn't help him to crack the puzzle ;-)

See also:

Sidney Coleman: Quantum mechanics in your face (1994, flv)

It's about characteristic features of quantum mechanics, entanglement (GHZM argument sold as pedagogically superior over Bell's argument), interpretation etc.

Around the 35th minute, Coleman is puzzled, just like your humble correspondent, why people - popular and even "not so popular" book writers :-) - get so confused about such a simple point and write whole books about "non-locality of quantum mechanics", something that clearly doesn't exist when you think about these setups properly. His answer, just like mine, is that secretly, in their hearts, they believe that it is classical mechanics. And they want to explain the new (quantum) theory in terms of the old (classical) one even though the only correct approach is the opposite one. That's why we shouldn't really talk about the interpretation of quantum mechanics because it is an inevitable part of the picture; we should talk about the interpretation of classical mechanics as a limit of the full theory.

I not only agree with all of his physics but find his jokes cool, wise, and relaxing. He politely asks those who didn't understand the first transparency to leave the auditorium. Then he compares native Americans and deers' intelligence to get a point through. He uses a Dr Diehard whose brain turned off once someone wrote a quantum mechanical equation - much like Coleman's brain turns off during string theory seminars :-) and so on.

Ludwig Wittgenstein and collapse

The punch line is absolutely hilarious. Philosopher Wittgenstein asked why did people say that the Sun orbits the Earth. He was told that it was because "it looks like the Sun is orbiting". Wittgenstein asked: "Hmm, and how would it look like [if it looked like] if the Earth revolved around the Sun?" :-)



Wittgenstein was referred as "one Jewish boy" in Mein Kampf, a book written by his classmate. Adolf Hitler hated him and he could become anti-Semitic because of him. Click for more details.

Coleman's point is that the same holds for the so-called "collapse" of the wave function (and also many other cases of incorrect dogmas held by various people). People think that there is a collapse because it looks like that there is a collapse. ;-) Coleman encourages everyone to think seriously about the possibility that the opposite answer is true, namely that the world is described by causal (= subluminal signals only) probabilistic laws of quantum mechanics without any collapses. And your humble correspondent encourages you to do the same thing. How would such a world look like? It would look like the real world. Welcome home. ;-)

And that's the memo. :-)

Finally, without any new comments:

Videos from Sidneyfest 2005

Record gamma ray burst: GRB 080319B

On Wednesday morning, at 7:12 am Central European Time, NASA observed a gamma ray burst whose after glow you could see with your naked eye for 30 seconds. The star used to have 40 solar masses and its distance was 7.5 billion light years, more than 1/2 of the visible Universe away from us. It was by far the most distance GRB ever seen. The previous record distance was 2.5 billion light years.

Google News, a report by Rudolf Novák, an astronomer from Brno, Czechia and others who saw it.

Happy Easter

Three preprints on cosmoclimatology

During the last week, there have been three cosmoclimatological preprints by two teams on the arXiv. Rusov et al. (Ukraine) argue that all observed climate change at the timescale of millenia and millions of years can be explained by two factors, namely the the solar output and the galactic cosmic ray flux that determines the cloudiness.

Rusov et al. I (PDF)
Rusov et al. II (PDF)

The first paper studies the cloud condensation in terms of refined equations of the Twomey effect. In the second paper, their bifurcation model is compared with the EPICA data.

Contrarians

On the other hand, Terry Sloan (Lancaster) and A.W. Wolfendale (Durham) show that in some places, the cloud cover is anticorrelated with the cosmic ray flux relatively to what is expected. At the 95% confidence level, they claim that less than 23% of the changes of the cloudiness during the 11-year cycles is caused by cosmic rays.

Sloan & Wolfendale (PDF)

I personally find all preprints plausible to some extent. It is very conceivable that cloudiness is controlled by a lot of things including largely unpredictable drivers that you might call a noise.

A very convincing criticism of the paper by Sloan and Wolfendale was written by Nir Shaviv in April 2008.

Hat tip: Physics arXiv blog

Crackpot world: "Matrix universality"

I am going to explain, using Lee Smolin's new paper,

Matrix universality of gauge field and gravitational dynamics (PDF),

why he is a textbook example of a crank and what it means. The paper argues that all theories in the world are equivalent to each other and encoded in the formula "S=Tr(M^3)". ;-)

But let me start in 2002. By sending me an e-mail, Lee Smolin invited himself to Harvard, quoting his favorite clichés about the diversity of ideas. All alternative physicists might want to learn his "right" way to be pushy and obtrusive. ;-) I didn't really pay for the visit and because I knew that he had been invited to other places before, such as Rutgers University, I told myself: "Why not?"

Before the lunch in the Society where I invited him as well, he told me about a "great" idea, namely the equivalence of M-theory and three-dimensional Chern-Simons theory. His argument was as follows:

I don't believe that M-theory is complicated. It must be simple. And because the Chern-Simons theory is simple as well, they must be equivalent.

First, I exploded in laughter. However, within a minute, it became obvious that Lee Smolin was either dead serious or he would continue to pretend so for quite some time. I was thinking about the best way to call a physician but he didn't look particularly dangerous so I decided it wasn't my job.

In physics, we have learned about many equivalences or dualities - fascinating and non-obvious relationships that prove that the theories we study are important because they can materialize in many ways. But in each case, there exists a very non-trivial body of evidence (or full proof) supporting such a relationship. Only when such evidence exists, there is a reason to talk about a duality.

The probability that two randomly chosen theories are equivalent is comparable to 10^{-500}. Make no mistake about it: Lee Smolin's identification of two obviously different theories is on par with conspiracy theories that electromagnetism is governed by Elvis Presley who lives in ToraBora.

I doubt it is correct to say that M-theory is "simple" and even Chern-Simons theory is tough when you try to compute things that go beyond the Lagrangian. But even if these two theories were equally difficult, you're extremely far from having evidence supporting the claim that they are equivalent. In fact, when we talk about dualities, the two equivalent descriptions usually don't look equally complex! Quite on the contrary. In a typical point of the moduli space, one description is weakly coupled (and easier) and the other is strongly coupled (and harder). Smolin has made every single error he could have made.

The paper

Those six years haven't changed much and now, in 2008, he has the courage - and favorable external circumstances - to submit this complete lunacy right into the hep-th archive.

In the paper, he argues nothing less than that virtually all theories of physics are equivalent to each other. That's a pretty bold statement - more precisely, it is a sign of a complete breakdown of the author's ability to make a judgement. A few pages of irrelevant comments about the anthropic principle and weird speculations about the laws of physics that must evolve in time (a very characteristic feature of Smolin's own character) - statements that are both ludicrous as well as unrelated to the bold claims announced in the abstract - are followed by this "big equivalence" described in many verbal ways, using buzzwords such as "universality class" etc. Technically speaking, all the statements are obviously incorrect.

To make things even more bizarre, he represents all gauge and gravitational theories by a representative that is claimed to be equivalent to all of them. It must have a lot of degrees of freedom, so Smolin chooses an N x N matrix. And it must have a non-quadratic action leading to non-linear equations of motion. Why? Because if the system were linear, even Lee Smolin would be able to see that they can't be equivalent to interacting theories.

Via Chern-Simons, BF, and Plebanski's systems of equations - neither of which has ever been connected to gauge theories or quantum gravity in any, at least partially convincing way, he claims that the simplest non-quadratic action he can choose for his matrix M, namely Tr(M^3), is equivalent to all gauge and gravitational theories in the world.

How big a lunatic you have to be to read a paper about a completely randomly chosen primitive formula claimed to describe all physical theories in the world and to believe that the author - who has already written dozens of articles of the same kind - is a serious physicist?

The only small problem with his hypothesis that even Lee Smolin himself is able to see is that his theory doesn't seem to contain fermions. (Incidentally, his reason to argue that the fermions are not there is also wrong: fermions do sometimes occur as solitons in theories with purely bosonic degrees of freedom. He hasn't made any correct analysis even in this simple question.)

Well, if his IQ were 40 points above his current level so that he could compete with average graduate students and/or if his scientific integrity were 1,000 times higher, and I am not really sure which of these two conditions is more relevant to his case, he might be able to see a slightly more extensive set of challenges faced by his "theory", for example that it doesn't contain any physics of concrete n-dimensional gauge theories or gravity.

It is absolutely trivial to see that his "theory" cannot be equivalent to a single gauge theory or a quantum-gravitational background that has ever appeared in serious scientific literature and the 3+1 additional conjectures written down in the conclusions are wrong, too. In all cases, Lee Smolin only tries to satisfy one consistency check or less. His reasoning is similar to the statement that an elephant is the same thing as a truck because they are equally large, while paying no attention to other possible sources of inequivalence between trucks and elephants.

One can simply look at the spectrum and the physical amplitudes. And they are obviously different. Is Smolin really so unbelievably incompetent that he can't see that a random, purely bosonic matrix model in 0+0 dimensions cannot be equivalent to QCD or any other theory that matters? Has he ever seen how physics papers dealing with similar models (matrix models, in this case) actually look like? Instead of having most of the pages filled with preposterous "hypotheses" based on a hopeless wishful thinking, serious papers actually analyze the models and only claim things that are supported by something, at least by circumstantial evidence, and some of these findings turn out to be very important robust. This is a method that Smolin is absolutely unable or unwilling to follow.

Hyping preposterous hypotheses in the sensationalist tabloid media and victimist claims that crackpots like him must be treated on par with scientists - and maybe they are more because they are the "seers" and "new Einsteins" - is his way to go.

Equivalence and something that is not equivalence

Of course that quantum theories with infinitely many degrees of freedom have isomorphic Hilbert spaces: all infinite-dimensional Hilbert spaces are unitarily equivalent to each other. But that doesn't mean that the theories are equivalent. The theories are determined primarily by their dynamical laws, e.g. technically by their Hamiltonians, and the Hamiltonians are completely different.

Saying that two theories are equivalent means that there exists a map M from the Hilbert space H1 of the first theory to the Hilbert space H2 of the second theory such that it maps the Hamiltonians h1, h2 (or other two operators representing dynamics) of the two theories to one another, i.e.

• M h1 M^-1 = h2

It is trivial to see that the spectra of two theories - e.g. the Tr(M^3) model and QCD - are not isomorphic in this way so their Hamiltonians cannot be equivalent. If you allow more general - time-dependent or non-local in time - maps between the degrees of freedom of the two theories (or if you ignore the required relationship between the Hamiltonians altogether), you could perhaps find a relationship but such a relationship cannot be described as a physical equivalence because it is completely vacuous.

Theories are determined by their dynamical laws - technically by Hamiltonians, actions, or S-matrices (the latter is "results-oriented") - and if these objects are physically different in two theories (as determined by spectra and other physical quantities independent of the formalism), the theories are simply inequivalent. That's what we mean by the word "inequivalent" and the inequivalence of two generic theories can be shown almost instantly. It is just amazing that someone is ready to create fog about these trivial matters and, even more importantly, that Ginsparg allows this bullshit to be posted on hep-th.

I urge Paul Ginsparg to cancel the endorsements needed for the author of this crackpot paper (and dozens of others) to submit additional preprints to the hep-th archive.

Roy Spencer: Climate Confusion

Roy Spencer's new book, "Climate Confusion: How Global Warming Leads to Bad Science, Pandering politicians and Misguided Policies that Hurt the Poor", is now #7 among all books at amazon.com.

Congratulations to his bestseller! (And congratulations to Rush Limbaugh who has proved that he matters.)

Roy Spencer is not only one of the big experts but also one of the major entertainers among climate skeptics and his texts are witty. This book introduces the reader into basics of weather science and climate science but also exposes psychological and political reasons that have made climate science tainted and untrustworthy.

See also The sloppy science of global warming, a new text by Spencer on Anthony Watts' blog.

Joseph Fourier: 240th birthday

Exactly 240 years ago, on March 21st, 1768, Joseph Fourier, an 18th century politician and 19th century string theorist, was born in Auxerre, France.

Parents and Napoleon

The boy's father, who was a tailor, as well as his mother were dead when the kid was nine years old. The local bishop arranged him to be educated by the Benedictine monks in a military school at the Convent of St Mark, probably a similar school attended by the Bogdanov brothers that they were showing me. ;-) The kid was happy there and fell in love with maths (and wrote some good poems). Jean-Baptiste-Joseph supported the French revolution and was given a job in École Normale Supérieure mainly for his political achievements (of course, he was jailed several times, too). Later he became a boss at École Polytechnique.

In 1798, Joseph went with Napoleon Bonaparte to Egypt and even became the governor of Lower Egypt - Fourier the Lower Pharaoh, if you wish. You wouldn't believe it but Napoleon actually established a mathematical institute in Cairo (of course, the motivation was to weaken the English influence in the region) and Fourier wrote a few papers for the institute.



The French loss in the conflict didn't destroy Fourier who became the prefect of Isère and started to do experiments with heat. After a few years in England, he became the permanent secretary of the French Academy of Sciences. Quite a career for this orphan, right? ;-)

Science

We haven't really started with his science. Some people like to say that big minds do their first revolutionary work before they are 40 (or even less). Fourier is one of many examples showing that the rule is complete rubbish.

In 1822, at the age of 54, Fourier finally publishes "Théorie analytique de la chaleur," i.e. "Analytical Theory of Heat", where the heat flux is argued to be proportional to the temperature gradients times a negative constant, the so-called Fourier's law. More importantly, he also discovers the Fourier analysis: any function may be written as a continuous combination of sines and cosines. And any periodic function may be written as a sum of multiples of sines and cosines whose arguments are multiples of "x" times the period over two pi.

This includes un-smooth and even discontinuous functions.

When I was 14 or so and I read an encyclopedia of mathematics, Fourier analysis was discussed in one of the chapters and it was a complete shock for me. At that time, I was kind of obsessed with analytical functions of complex variables that can be differentiated infinitely many times and are beautifully smooth: their values in the whole complex plane can also be predicted from their behavior in an open set. Suddenly, someone could draw an "artificial" function with discontinuities and circles and piecewise linear segments and write it as a sum of the beautifully smooth sines and cosines.

It was very shocking for me that such a thing was possible but of course, after some time, I checked that it really worked and that it is the infinite number of terms - the limit - that could violate my wrong intuition that a sum of smooth functions must be smooth.

Fourier claimed that every periodic function could be expanded in sines and cosines. Rigorously speaking, that was wrong but there exists a very mild, physically natural refinement of his statement that is correct. Consider, for example, L2-integrable equivalence classes of periodic functions to see that Fourier's statement was "morally true" as long as the morality is dictated by quantum physicists. Two centuries later, the Fourier series are famous well beyond Napoleon's empire, even among English-speaking Asians:



Joseph Lagrange's and Dirichlet's later analyses of the question which functions may be Fourier-transformed do not look particularly fundamental to me.

Needless to say, the Fourier expansion is the first step that you must do with coordinates on a string in perturbative string theory, so I count Fourier to be a string theorist, much like other giants whom we discussed previously.

Fourier has also found some theorems about various functions of the roots of algebraic equations that can be calculated in new ways. More importantly, he introduced dimensional analysis as a tool to verify that an equation has a chance to make sense. It is kind of amazing but it seems that he was the first man to do so.

Greenhouse effect

In 1824, at the age of 56, Joseph Fourier wrote the paper "MEMOIRE sur les temperatures du globe terrestre et des espaces planetaires" and established the concept of planetary energy balance and derived the phenomenon that we nowadays call the greenhouse effect. He realized that planets radiate energy by the dark heat ("chaleur obscure"): yes, it is nothing else than the thermal infrared radiation. Fourier referred to an experiment by M. de Saussure (glass on a black box under the Sun heats up the box) to justify the existence of dark heat.

The quantitative formula describing the energy content of his "dark heat" was found 50 years later by Stefan and Boltzmann.

Fourier understood that the real task was to calculate the point (temperature) where equilibrium is reached: such a point should exist because, as he knew, warmer bodies emit more dark heat. Gases that can absorb "dark heat" in the atmosphere reduce the energy losses and increase the equilibrium temperature, he correctly stated.

His energy budget correctly contained the solar radiation and the dark heat but it had one additional, unusual term: interplanetary radiation. While it is more than plausible that cosmic radiation plays a role for the terrestrial climate, it is not its direct energy but its ability to catalyze cloud formation that matters.

He died of heart attack in 1830 so he couldn't see the breathtaking application of his innocent effect in extremist environmentalist politics.

Spring begins: snowfall traffic accident

The spring has just begun today in the morning, at 6:48 Central European Time, when the Sun crossed the celestial equator.



That's the right moment for a traffic accident caused by a heavy snowfall. One hundred and sixty cars are stuck in the collision area of the Prague-Brno D1 superhighway, the most important road in Czechia, including the truck full of the Pilsner Urquell beer in the lower left corner and two popular Student Agency buses. ;-)

We had some snow in Pilsen, too. But it has already melted: the temperature at noon is 0.2 °C.

NPR: Argo: Oceans slightly cooling since 2003

NPR has aired a report about the results of 3,000 floating, temperature and salinity profiling robots deployed by the Argo collaboration in 2003. After five years, they finally sent us comprehensive data about the heat content of the oceans.

HTML, audio

The heat content of the oceans is important because 80-90 percent of the newly created heat goes into the oceans and their warming should be more uniformly aligned with any hypothetical trends. Despite the oceans' dominant role in the heat budget, there are people who find them inconvenient: for example, oceans do not suffer from the urban heat island effects for obvious reasons. ;-)

At any rate, the robots have falsified the prediction of a significant warming. There has been no significant change of the temperature since 2003. In other words, there has never been any global warming observed by these sinking robots. In fact, the oceans have cooled down a little bit. But there are only 4 oceans which is too small a number to undermine the consensus of 2,500 "top experts". On the other hand, 3,000 is more than 2,500 so if you trust robots, the consensus about global warming could be overthrown. ;-)

The NPR program is very entertaining because, for example, Kevin Trenberth, a hardcore IPCC alarmist, is proposing that cooling effects induced by the clouds might be responsible for the observational discrepancy. ;-) If Trenberth re-discovers the iris effect, after many years, I wonder whether he will remember that Richard Lindzen has done it a long time before him.



They say that global warming may have taken a "breather" or it may be on a "brief hiatus". I wonder how they figured out the "brief" word. If a model gives completely wrong numerical predictions for five-year periods, what is the exact reason that it won't give wrong predictions for ten-year or thirty-year periods? Five years is not a negligible time scale for oceans: it is pretty much equal to the effective time constant.

Iraqi scientists: is the Earth flat?

In October 2007, an Iraqi TV aired a discussion of an Iraqi astronomer with an Iraqi physicist about the shape of the Earth. The astronomer insists that one must only allow science that can be verified by the Quran. The Moon is 1 million kilometers in diameter, the Sun is twice as big, and the Earth is even bigger which is why the Sun orbits around the Earth.

The physicist, described as a heretic, uses some bizarre theoretical arguments to argue that the Earth is round. The astronomer avoids these speculations about the astronauts that are not even wrong. And he even gives an explanation why we only see the upper part of distant ships: it is because no doctor in the world knows how the eye works and whether it is able to see blurred distant objects. ;-)

If you watch the discussion carefully, you will notice that the physicist is much closer to reality but he is not flawless either. Around 3:20, he argues that the gravity on the Moon is g/6 because the lunar mass is 1/6 of the Earth's mass. It is actually 1/80 of the Earth's mass and the different radii influence the counting, too.

Repercussions

I really think that this discussion is way too similar to the discussions that physicists sometimes have with the likes of Peter Woit or Lee Smolin who are always ready to use technically silly arguments because the actual justification for their wrong statements are sociological cliches not unsimilar to the Iraqi astronomer's Islamic belief: the only reason why they can be heard is that millions of uneducated people are ready to buy and approve their irrational stupidities.

In both cases, one of the main "arguments" is that the "scientific principles" or any sufficiently complex scientific derivations can be and should be ignored because they "cannot be seen": in other words, stupid people - such as the Islamic fundamentalists or the Not Even Wrong readers - don't really understand them which is enough to "show" that they're not even science or they're false.

Also, I wonder whether the Iraqi war has strengthened the position of the simpletons similar to the "astronomer" above or similar groups. I am afraid that it has. If it has, it is too bad because similar primitive people as the "astronomer" can return the country back to the first millenium.

Frederik Denef: landscape building guide

All expert TRF readers (except for a few, 0-10, leading F-theory leaders in the world who know the sub-discipline better than the author anyway) are recommended to print and read

Frederik Denef's Les Houches Lectures (PDF)

about the construction of string-theoretical vacua.

On his 127 pages, Frederik discusses the structure and properties of the string vacua. While he dedicates a few pages to heterotic and type I strings, M-theory on G2 manifolds, non-geometrical, and non-critical compactifications, most of the paper is dedicated to F-theoretical flux vacua i.e. type IIB vacua with non-trivial axion-dilaton fields, orientifolds, and D-branes.

The paper may look long or contrived to many readers but what is important is that these insights are robust and pretty much inevitable. An extraterrestrial civilization would have to end up with pretty much equivalent papers about the string landscape at a certain level of the evolution of their science. Once you adopt the idea that the elementary particles are extended objects while the resulting theory should still reduce to effective field theories we have checked, you are inevitably led to strings and the whole structure of string theory follows.

Almost no page among the 127 pages of the paper is directly connected with a particular experiment. Nevertheless, all of them are tightly connected with one another as well as with other insights that are observationally rooted. You might feel that you are walking somewhere in between the clouds, 324 meters above the ground. Some people say that it is unsafe, religious, or unscientific to walk and talk 324 meters above the ground. But you have a structure to rely on. Is it possible to walk 324 meters above the ground and to talk to some of the low-lying clouds? Yes, it is. The rigid structure is called the Eiffel Tower. ;-)

String theory is analogous. The people who don't want to hear about things such as the Eiffel Tower or string theory are just far too narrow-minded and limited to be relevant for this type of engineering or science.

When you finish reading Frederik's paper, you will be able to pick, construct, and study your own string-theoretical vacua in the landscape. You will also remain doubtful about all kinds of anthropic questions but you will understand that these questions do not represent the bulk of the knowledge and skills that a theoretical physicist must have for his or, less frequently, her opinions to matter.

Erratic Boulder 2007

Sisyfos (CZ), the Czech scientific skeptics' club established in 1995 by astronomer Mr Jiří Grygar, writer Ms Věra Nosková, and others, distributed its tenth annual

"Erratic Boulder" anti-prizes

for "confusing the Czech public and for contributions to the development of muddy thinking". The previous winners include many famous figures such as the top singer Karel Gott, writer Erich von Däniken, and the extraterrestrial abductee Ivo Benda, a complete loon and a Czech counterpart of Jack Sarfatti.

Arch-boulders

Czech-American professor Stanislav Grof received the decadal prize for holotropic breathwork. Thanks to holography, he is able to push his artificial holotropic drugs to any place in spacetime. Grof was an ancient Egyptian priest in his previous lives, as explained by his new book. ;-)



Grof with ex-president Havel and his wife

Two astrologers, Antonín Baudyš Sr, a former minister of defense, and Antonín Baudyš Jr, his son, received the other arch-boulder for predicting the death of G.W. Bush in 2003 (or during his first term). They also predicted a victory for Jiří Quimby Paroubek in the general elections that fortunately hasn't materialized either.

Gold, silver, bronze: individuals

The bronze boulder went to astrologer Milan Gelnar. The silver boulder was awarded to Jaroslav Dušek, a popular actor who argues that people don't need to eat and they didn't need any food after the humans were created. Dušek also predicts the end of time on 12/21/2012.

The golden boulder for individuals was grabbed by Tomáš Pfeiffer who is famous for curing his patients by biotronic energy through the TV screens. Last year, Pfeiffer was unable to save a dying woman but by accident, he telepathically made her worried about his old car and the woman bequeathed her car to him. :-)

Groups

In the category of teams, the bronze boulder was picked by the Czech Association of Patients and its vice-president Karel Erben - together with a communist deputy, Ms Jiřina Fialová - for their promotion of the cure for cancer by lowering the level of homocysteine - the only contribution among the winners that could hypothetically have some merit according to your humble correspondent.

Erben was the only winner who personally picked his award. In his five-minute speech, he revealed that the pharmaceutical companies, anxious about their profits, are planning to kill him. ;-)

The silver boulder was won by Ennea, a company that sells enneagrams allowing you to penetrate deep into your own personality.

Beáta Pataky and Július Pataky were the winners among the teams. Jiří Kuchař, their publisher, represented them at the ceremony. He stressed that the victorious husband and wife run marathons barefoot. That's a very important detail because they cure people by pressing their feet and by forcing them to drink their urine. ;-)

The Pataky team is safe against the pharmaceutical companies' plots because of their mental energy barriers.

Sisyfos, me, Czechia, and the world

I have traditionally been close to Sisyfos but I have never been a member. Sometimes the typical members seemed to be lacking charisma and the sense of humor. The club also looked too leftist as far as politics went but I no longer have this feeling.

The choice of the Erratic Boulder winners is very healthy. I am afraid that in the U.S. or other Western countries, similar groups promoting science would use the anti-awards to attack climate skeptics and related inconvenient groups. It is very good that Sisyfos doesn't try to radically redefine the old good boundaries between science and pseudoscience.

Arthur C. Clarke (1917-2008)

At the age of 90, Arthur C. Clarke died today in his home in Sri Lanka (Ceylon). See Google news.



This science-fiction writer has been able to generate not only crazy ideas but also meaningful technological proposals - even though the geostationary satellites that he predicted in the 1950s probably remained the only major concept that has been realized. It is unlikely that the space elevators will join the set of dreams that have come true in a foreseeable future.

He wrote more than a hundred of sci-fi novels but I also remember his TV program about paranormal phenomena that was aired when I was a kid. Many people around me had the tendency to believe these things and I wanted to investigate it in an open-minded fashion. So I wrote detailed notes about the observed phenomena. Finally, it looked like there was nothing unusual to explain but these programs were an interesting adventure for me anyway.

It would probably be impossible to classify Arthur C. Clarke as a scientist but it doesn't mean that he had nothing to say to scientists and science fans.

Eric Berger wrote an article about Clarke, too. Incidentally, you might be interested in SciGuy's interview with NASA chief Michael Griffin who said that he was surprised that the impact of climate change wasn't viewed as a technical topic but rather a religious dogma.

Problems with black hole remnants

Cosimo Bambi wrote a new paper of the kind that I consider bad physics. He advocates a theory of black hole remnants. More precisely, it is not a real theory but a random conglomerate of phenomenological speculations: it shouldn't have appeared on hep-th because the "th" factor is completely missing.

I want to use the paper as an example to show certain irrational and unscientific tendencies that are fashionable these days. But I have to start with the technical issue of the black hole information loss, a topic that has been discussed several times on this blog.

Thirty years ago, Stephen Hawking showed that black holes should emit a precisely thermal radiation - a direct consequence of causality and methods of quantum field theory. Because thermal radiation carries no information (it is described by a universal mixed state), the information about the initial state seemed to be lost. The unitarity, a crucial principle of quantum mechanical evolution, seemed to be violated, at least in the semiclassical approximation.

There were three main possible answers:

1. the evolution is indeed non-unitary; the postulates of quantum mechanics have to be weakened and modified
2. the radiation is not exactly thermal and carries the information
3. the radiation is thermal but the information is preserved in a long-lived "remnant" that doesn't disappear

In 2008, every good physicist knows that the second answer is correct. We have explicit systems of equations - in AdS/CFT, Matrix theory, and elsewhere in the theory of quantum gravity that continues to be called "string theory" - that exactly agree with unitarity (and manifestly preserve the information) but that also exhibit all the required quantum gravity processes to be identified with black holes in general relativity. And these string-theory-based pictures agree with the Bekenstein-Hawking predictions of the thermodynamic quantities, too.

Even if you didn't believe that string theory describes the real world, the triumphs mentioned in the previous paragraph actually settle the question. Why? Because they show that Hawking's semiclassical predictions that predicted the information loss are simply not rigorous. They are not necessary. In a complete treatment, the information is preserved even though the complete treatment agrees with the semiclassical approximation wherever it should.

It means that there exist at least N backgrounds of quantum gravity where the generalization of the information-loss arguments is violated beyond the semiclassical level and where the information is preserved. In fact, this is far too modest a way to describe the real situation. In reality, all consistent formulations of quantum gravity we know confirm that the Hawking radiation does carry the information about the initial state.

Thirty years ago, when we didn't know about these descriptions of quantum gravity, it was pretty natural and reasonable to believe that a qualitative conclusion of the semiclassical approximation - the information loss - was also true at the exact level. It is pretty natural for approximations to be qualitatively correct. At the same moment, the conclusion couldn't be proved rigorously. But there was a reason to believe that the information was getting lost.

The situation today is very different. We can actually look at these black hole systems in frameworks that go beyond the semiclassical approximation and the answer is that a particular qualitative conclusion of the approximation - the information loss - simply doesn't generalize to the full theory. Because we have a more complete understanding of these issues, it is no longer "equally reasonable" to make this generalization and to assume that the radiation is exactly thermal and that the information is lost.

The real motivation for considering the answers "1" and "3" has evaporated itself. Thirty years ago, the hypothesis that an exact theory happens to agree with the semiclassical processes but it can also encode all the information could have looked as a miracle. That was why people were ready to believe that the information is lost or that there exist many remnants. But the preservation of the information is no longer a miracle in 2008. We have verified that it simply works. The estimated probabilities of the options 1,2,3 has dramatically changed.

We simply know that the information is preserved and the causality is broken by exponentially small effects. You might imagine that the information is really tunneling from the center of the black hole to infinity. Quantum tunneling is a real effect in quantum mechanics and it can generate new exponentially suppressed effects. They are small but sufficient to restore the full information.

The answers 1,3 have become completely unmotivated and bizarre and the probability that one of them is correct is much smaller than 10^{-10}. So if all people in the world understood current physics, these approaches wouldn't deserve a single person who would study them and promote them. Once we looked properly, we saw that unitarity remains a universal principle of physics and macroscopic causality holds, too.

It was just incorrect to assume that causality holds 100% even in the presence of event horizons. In reality, tunneling induces almost immeasurable, exponentially small corrections and when these small effects are taken into account, the information loss paradox is solved without introducing any new ad hoc concept such as the remnants.

What's wrong with the remnants?

For me, the main wrong aspect of the remnants is that is seems impossible to construct a complete theory that would incorporate the concept of remnants. I am absolutely convinced that this kind of an argument is the strongest one even though it is absolutely disconnected from any need to make new remnant-related experiments or observations.

I can offer you more than some negative reasons to eliminate remnants: in fact, we have a positive argument - a pretty complete theory that not only tells us that there are no remnants but it also teaches us what exactly happens and how. I happen to prefer more complete and coherent systems of answers over incomplete ad hoc answers to subsets of questions.

Various aggressive crackpots have made it fashionable to pay lip service to experimental tests of theories even in cases where it is clear that these tests can't be done. I won't jump on this bandwagon and if you kindly allow me, I will keep on considering various Woits and Smolins who promote this ideology to be irrelevant and cheap anti-scientific simpletons. Careful theoretical arguments remain the most important and the most reliable tools to decide about the validity and probability of various assertions related to quantum gravity and similar advanced scientific questions. Every good expert in quantum gravity knows so and none of them is affected by the populist empiricism.

Incidentally, Sean Carroll recently talked and wrote about the naive populist empiricism and I fully agree with him, including the video with John Horgan (except for Sean's comments on the arrow of time).

Cosimo Bambi is clearly another example of a physicist who thinks that all theories in physics are useless and one should never rely on careful calculations and analyses. So the only problem with remnants he sees are some astrophysical bounds. They're relevant - and in fact, they are sufficient to show that remnants are more or less impossible without using other tools - but they are the layperson's method to try to answer conceptual questions such as the information loss puzzle.

Because Bambi doesn't study any theory in detail and only looks at the roughest available astrophysical data, he arrives to completely different conclusions. Let us play his game for a while and imagine that it is legitimate for a physicist to neglect most of the evidence in this context - and most of the evidence is theoretical in character.

Bambi is led to a model with remnants that are not easily seen and he is thus designing contrived methods to hide them. All these things are done in order to keep an answer to Hawking's question alive - even though all good physicists know that it is no longer alive and we actually know a better, more complete, and more consistent answer. One of the weird features of his models is that the coupling constant for the black hole remnants is

• g = 10^{-10^{122}}.

That's a damn small number. We have explained, with Arkani-Hamed, Nicolis, and Vafa, that it is arguably forbidden to have tiny coupling constants in a theory of quantum gravity without introducing new and lethal light objects. Of course, our derivation is using assumptions and reasoning that Bambi would probably dismiss because he would dismiss any procedure that relies on the human brain. But what do you think, who is doing a better science here?

The expo-exponentially small coupling constant is probably impossible in the real world but even if you accepted it as a possibility, I think that you have to agree that Bambi's comment about the value below the equation 7 in his paper is deeply irrational. He says:

But we might still hope that such a tiny value can be explained in the full theory of quantum gravity.

Wow. What science is hiding behind this strange sentence about a hope? The 9/11 hijackers might have hoped that they would be given 10^{10^{122}} virgins for their services to Allah. Should science be reduced to hopes and hypes promoting these hopes? The hope seems pretty important for that paper. Should papers be built on audacious hopes? Is this the new kind of science?

Rationally speaking, it is very likely that there exists a universal rule that forbids these super-tiny values of coupling constants completely. But even if you look at this question from the perspective of other frameworks in science, such as effective field theory, you will conclude that the super-tiny coupling constant is virtually impossible. For example, if you use the rules of naturalness, the probability of having a tiny value "g" of a coupling constant is comparable to "g". So the probability that Bambi's hope is viable is comparable to

P = 10^{-10^{122}}.

Once again: that's a damn small number. Why should a scientist hope in these ways? To promote a theory that is unmotivated theoretically, disconnected from the rest of science, almost completely excluded empirically, and that tries to solve a question that has already been solved by a completely natural system of insights?

Is it legitimate for a scientist to take a speculation whose probability is, according to the standard scientific tools to estimate probabilities, expo-exponentially tiny and pretend that it is a sensible alternative that should swallow something like one third of the research? I beg to differ. If a possibility looks extremely unmotivated and unlikely according to the cutting-edge expert criteria, it should get much less attention than the theories that actually make sense, that agree with the world as we observe it and with its generalized principles. One paper about silly models is one too many.

Does Bambi has someone around to tell him that his speculations are scientifically inexpensive, don't respect any standards of rigor or realistic estimates of probabilities, and the main reason why he wants to construct these models is his superficial knowledge of black hole physics and his ignorance about many detailed principles and insights that are essential in this discipline?

I think that similar papers are going to spread if the haters of theoretical physics - those who like populist proclamations about "testability" and similar crap - are not eliminated from the system. A vague and irrelevant connection with a randomly chosen astrophysical observation could become a sufficient reason to promote and publish incoherent papers that don't fit together and that are based on assumptions whose probability is, by a scientific counting, comparable to 10^{-10^{122}}.

The standards in physics began to deteriorate and loads of unintelligent dopes have contaminated the scientific community and its suburbs in the name of political correctness, diversity, promotion of mostly irrelevant links with other groups such as the experimenters (in the context of a purely theoretical discipline such as black hole thermodynamics), and similar crap.

They are using modern channels of communication to strengthen their case - and their goal is exactly the opposite from the very purpose of science which is to eliminate crappy ideas. The main technique of the scientific method is exactly to throw papers such as Bambi's paper to the recycle bin. Instead, the media and blogs invent stories about diversity and victims to promote similar crap. If this tendency is not stopped, it will feed itself because a new generation of physicists without standards and qualification will influence the creation of the following generation.

That would lead to the end of science as we have known it but we can stop the bandwagon before it's too late.

And that's the memo.

Paris

The trip to Paris has been a lot of fun, mostly due to the very hospitable and entertaining hosts of mine, Igor and Grichka Bogdanoff. Some time ago, I had really no idea how well-known they are in France. But they are extremely famous, indeed. Every third person on the street wants a signature or a photograph. ;-)

You can imagine that we talked about physics with the brothers and not always agreed about it ;-) but it couldn't destroy the experience.

The only place in France I had visited before the last week was the French Riviera. But this time, I had to behave as a French guy who doesn't speak any French - except for Amitiés and Amicalement, two important words for the book signing, and three more. ;-) Lumo English was the only channel of communication for the interviews.

The list of required conventions included the double-kissing, a heavy challenge for a Central European's immunity system. I still don't know whether I was licking the girls' and ladies' faces just like the native Parisians do. At any rate, it is a mystery for me why the European Commission hasn't banned this friendly but hygiene-busting double-kissing tradition yet. ;-)

The Apple can be worked with, after all, but in my case, it is much less efficient than Windows.

Paris: musings

Saturday was the main day when I had to see all important places in Paris. While the 19th century buildings in the Western suburbs looked unimpressive or even ugly, I was thrilled by the historical center. The majestic Royal Palace led me to the doubts whether it was a good idea for their country to abolish the kingdom.

The Louvre was just amazing. There are so many fascinating sculptures and paintings in it. If the gallery were destroyed, the losses would be kind of incalculable. Why? Because price only makes sense for "perturbative" changes of the ownership or marginal production. Non-linear effects begin to become important if you deal with a lot of value at the same moment. Do you think that the value of 1,000 historical paintings is smaller or greater than 1,000 times the value of one of them?

While I referred to Mona Lisa as a symbol of the museum, I actually think that this particular painting is way too overhyped. It is somewhat puzzling for me whether the people see something so extraordinary puzzling about her smile that the painting is so much more famous than others. I tend to believe that the fame is a social construct, a result of groupthink.

I also had the feeling that many fields of human activity have simply peaked. Those old artists and sculptors were able to do amazing things even 500 years ago. We have seen a lot of modern trends - cubism is among the most decent examples - but would be the modern artists able to paint the old-fashioned paintings? I tend to doubt it. If you invent a new style, do you have the right to say that it is progress? It seems to me that much of the progress has been negative.

It is more natural for me to have a respect for artists who can do the same or similar things as the classical artists. Many modern artists or musicians who create paintings without a glimpse or realism or music without melodies are promoted by pure hype.

The technologically advanced architecture is another field that may have peaked - about 100 years ago. It is hard to get rid of this feeling when you see the Eiffel Tower. I was there twice. The first time, on Friday, I used the staircase but the top floor was closed. On Saturday, I was decided to go to the summit. After 40 minutes in the line, the display said "Top Floor Closed". I was angry and pretended to be even more angry than I was. I told the black cashier I wanted to the top floor. She said it was closed. Another obvious question was answered, too: the top floor could open in one hour or a couple of hours.

I decided it was outrageous that they closed it and decided to wait in the cashier area for 10 minutes or so: it wasn't too likely that they would open it before I would become impatient. Shockingly enough, 1 minute later, the display said that the top floor was re-opened so I could instantly go to the top. This 1 minute interval is very short and it is an example of fine-tuning that was, exceptionally, playing in my favor, unlike most fine-tunings in my life.

Would we be able to build a new Eiffel Tower today? Or a bigger one? I know that people build skyscrapers but isn't the tower kind of more impressive anyway? Why can't we return to the Moon easily even though it was apparently so simple for folks who lived and worked 40 years ago? Sad.

Notre Dame, Sacré Couer, Pantheon, and other fascinating buildings have led me to the question whether the religion is so irrational, after all. If religion was a major driving force for people to build similar cool things, is it such an irrational thing? Cannot we say that for practical purposes, it is a very good and desirable spiritual thing?

"Not Even Wrong" as a source of information

On Sunday, right before 2 p.m., I roughly knew where I should have been at 2 p.m. but not exactly. So I opened "Not Even Wrong", an anti-physics website. It said: "At 2 p.m. on Sunday, Lubos Motl will be appearing at the France Television booth at the Salon du Livre..." I followed the instructions and it worked well. As far as I remember, it was the first time when a true and useful statement appeared at "Not Even Wrong". Later I was trying to find out the location where I spoke on Monday but the aggressive crackpot forums didn't help me in that case.

What was less helpful was that someone announced a bomb at the Salon du Livre a few hours later: finally, I was liberated from the French grammar and spelling because we had to leave the building. ;-) It is not clear whether it was Peter Woit or someone else who informed the officials about the bomb. At any rate, it was someone who enjoys similar methods and who has a similar degree of respect to results of intellectual creativity.

To answer a question: no, I don't really believe that the bomb was installed because of us.

Nir Shaviv answers to RealClimate.ORG

Nir Shaviv, professor at the HUJI (click!) and a leading expert in cosmoclimatology, replies to a criticism by RealClimate.ORG.

Get ready for a discussion about the Milky Way and its spiral arms. For example, if you really want to believe that climate change is man-made and dangerous, you should also join RealClimate.ORG in believing that our Galaxy with four major spiral arms has two spiral arms only, a new "consensus science" supported by a "majority of scientists in the world". ;-)

PC witch hunts: Geraldine Ferraro

Geraldine Ferraro, the 1984 Democratic vice-presidential candidate, was asked why the support for Obama is so strong. And she said something that must be absolutely obvious to hundreds of millions of people in the world: it is partly because he is black. It's the concept that the country - and maybe the world - started to like. Barack wouldn't be where he is if he were white. It's just very fashionable to support a prospective African American president these days.

PC witch hunts began instantly. The lady is clearly a courageous character - so far I would say more so than e.g. Larry Summers.

In the interview above, she also proves that the opinion has nothing to do with her personal interests. Quite frankly, she also admits that she wouldn't have appeared on the 1984 Democratic ticket if she were a man with the same record. In 1984, it was already a "hot trend" to promote women in politics and elsewhere. She could probably do the job well but she realizes that her nomination was partially due to positive discrimination.

Women in politics are rare but they are no longer viewed as a sensation. Times are changing pretty fast. I remember that in 2001, we would talk about these - and many other things - with Jochen Brocks. He was enthusiastic about Hillary Clinton, claiming that she was the real "brain" behind the presidency of Bill Clinton. I was a bit skeptical but I always respected this presidential pair, to a large extent.

The situation has changed. A woman in the White House is not "quite" such a historical event anymore. And millions of people want something really "cool" or "nice" which is why Obama enjoys a much stronger support from the media and many other relevant entities than Hillary does. Meanwhile, Hillary has become a conventional candidate protecting America as we have known it for a century or two, a candidate imagining politics as a competition between ideas, programs, and interests. It seems that much of the U.S. nation wants something entirely different: a fuzzy post-democracy controlled by the P.C. police.

In some sense, Geraldine Ferraro is saying, in a much more careful, peaceful, and cautious way, the same thing as Ann Coulter: the liberals are thrilled that they could find a black man who can walk and talk so they want to put something that they secretly consider an amazing anomaly in the White House. There's a lot of provoking exaggeration in Coulter's words but she is essentially right.

I have nothing much against Obama but his career is a huge bubble of hot air driven largely by his colorful ethnic origin. He is also viewed as a candidate of reconciliation - but it is only because there are thousands of journalists and other semi-influential pundits and officials at various places who treat him as a pet and who instantly attack all of his critics.

In such circumstances, it is pretty easy to behave peacefully but I am not sure whether it is exactly a good recipe to preserve democracy and freedom in America or whether it is a strategy to produce another Zimbabwe, after a few years. The hysterical attacks against men and women such as Geraldine Ferraro - who is a Democrat and a traditional darling of the "progressive" ideals herself - don't look terribly promising for America.

It is great that Ferraro doesn't allow those activists to intimidate her but people like that are in a somewhat difficult situation. Naturally, the conservatives should be those who should be defending people against unjust "progressive" attacks. However, most of the conservatives don't seem too eager to defend a Democrat and some of them have become "progressives" themselves.

Incidentally, the weird Harvard professor who wrote the New York Times op-ed about the skin color and hair color of actors in the Clinton 3 a.m. commercial - the op-ed that Ferraro referred to - is Orlando Patterson. The op-ed is absolutely crazy. It creates a hypothesis that some kids in the dark in the ad could actually have been Hispanic and if it is true, then it proves that the Clinton campaign is racist.

These "sub-conscious" games with symbols are absolutely amazing and resemble the old-fashioned witch hunts many centuries ago. When I am saying that Obama is where he is mostly because of his skin color, it is not a speculation based on homeopathy of invisible sub-conscious symbols interpreted in a surreal and convoluted way. It is a direct reflection of facts - thousands or millions of people who explicitly say that they would vote for Obama because it is a historical decision to be voting for a black guy.

I am - and Geraldine Ferraro is - just saying the very same thing that they are saying, with the appropriate grammar modifications needed to talk about a third person. But suddenly, the very same indisputable fact becomes controversial when someone else says it. How is it possible? Is the truth so relative that it must be celebrated when one person says it - that it is great to send a message by choosing a non-white president - while others must be burned at stake when they say the very same thing with a lower degree of excitement?

I can give you piles of examples. For example, Gary Kamiya at salon.com (or most of LiveWire) wrote explicitly that he is voting Obama because he is black and if he were not black, Kamiya would vote for Hillary. Don't try to waste my time by asking me for thousands of other explicit examples like that but be sure you could have them. A bulk of Obama's base is similar.

Myths about the Planck scale distortions

I just read a rather frustrating conversation between Sabine Hossenfelder and Moshe Rozali at Backreaction. Moshe, an associate professor at UBC in Canada, is trying to explain, in a typical Moshe-like excessively polite way, that Sabine, a postdoc, is making a rather elementary mistake that makes pretty much all papers that she has ever written nonsensical.

He tries to encourage her to be less sloppy. Sabine is apparently convinced that an angel guarantees that she can't be wrong and refuses to understand very clear, indisputable, and sometimes really transparent statements and arguments, indicating that she thinks that she is "teaching" Moshe new things. ;-(

Discovering new physics by misprints

Sabine believes in all kinds of unmotivated and almost certainly impossible distortions associated with the Planck scale. And she is not the only one, for that matter: there are many people similar to Giovanni Amelino-Camelia or Jack Ng. One textbook example is a "lower bound on the wavelength" (see the comments under her article) that she seems to consider as a fact. Needless to say, there can't exist any lower bound on the wavelength. Why? Because any wavelength is related to any other wavelength by a boost - by a Lorentz transformation that is a symmetry of Nature (and of quantum gravity, at least in the flat space superselection sectors of the Hilbert space).

The fact that there can't exist things such as a "lower bound on the wavelength" has been known at least since 1905 when Einstein realized that one inertial observer will see a different frequency than another observer who is moving with respect to the first one. Have you heard of time dilation or the Doppler shift? Because both observers have the same rights, according to the special relativistic bill of rights, both values of the frequency or the wavelength are equally good, too.

Special relativity has become a pillar of general relativity and general relativity is one of the components of a theory of quantum gravity. You can't just throw away the insights of 1905. They are alive and kicking. In particular, it is impossible for one value of the wavelength to be allowed and another value of the wavelength to be forbidden.

Lorentz symmetry might be broken but there doesn't really exist a glimpse of evidence or motivation why it should be broken. Such a breaking might be studied as a possibility, to some extent, but it would cause many problems, it would most likely return us philosophically before 1905, and the people who say that such a breaking is needed in quantum gravity are clearly wrong because string theory satisfies all the required properties of quantum gravity but it also respects the Lorentz invariance in flat space.

This symmetry doesn't mean that the curved geometry including the backreaction has a Lorentz isometry. It means that one can create a Lorentz-boosted configuration (including the curved geometry) for every initial configuration and they obey the same laws. If one curved spacetime solves the equations, the boosted spacetime solves them, too. Moreover, the boost doesn't change the asymptotic geometry of the flat space which is why the symmetry acts inside the same superselection sector - a fact that makes the symmetry really useful.

Quantum gravitational limits on the minimum length apply to the internal structure of bound states (you can't probe the internal architecture of matter too accurately if your probes are extended) but they cannot apply to the wavelength of one photon or graviton. The very same comments are true about the uncertainties. If there are inherent Planckian uncertainties in the measurement of distances, they apply to the internal geometry of a physical system but not to the center-of-mass position of the whole physical system embedded into flat space - an observable that behaves just like it behaved in non-gravitational physics.

The latter point is also easily seen: the center-of-mass degrees of freedom are complementary to the total momentum (that can have any values, by Lorentz invariance). If you simply Fourier-transform the wavefunction in the momentum variables (that must exist), you obtain the wavefunction in the position variables, just like you always did. Gravity doesn't change anything about this procedure. The objects themselves include the curved space around their mass distributions but this is just a detailed description of the identity of these objects. The symmetry doesn't disappear.

Vague, universal symbols

I was trying to understand why these trivial points are so enormously difficult for many people who claim to be interested in quantum gravity. My best explanation is that they interpret symbols in a sloppy way. What do I mean?

Take a sexy female alternative physicist with a male voice, as a beloved TRF reader has pointed out ;-), for example Dr Louise Riofrio. What is her most important equation? Well, it is GM=tc^3. Now, many readers haven't heard about this famous equation but let us study its meaning and the psychology behind it. :-)

The first comment I would say is that Louise - much like most amateur physicists - use symbols for observables without paying too much attention what these observables actually mean. So when she writes "M", it is supposed to be a universal "M" (mass) across the Universe. In the same way, "t" is a universal time that is also accepted everywhere. Louise doesn't have to explain her formula, its origin, and its interpretation in detail: the formula itself is a holy word.

Most readers might know that the universal quantities appearing in her formula don't exist. There are many different masses in the world (for example the mass of an elephant or a cow), many different times (each observer in relativity has a different way to measure times, and she can still measure the duration between any two events she likes), and moreover, the laws of physics are local and describe particular objects or regions of space so you should better avoid relations between the mass of the whole Universe and other "global" quantities because they are almost guaranteed to be violated. Even if you are lucky and your private relationship is not violated, it is not too useful because it would only relate or predict one or two quantities in a Universe with effectively infinitely many degrees of freedom.

Now, if you could explain the previous paragraph to Dr Louise Riofrio, she would suddenly understand not only why her equation is wrong but why her whole method of thinking and "discovering new physics" is wrong. I guess you won't succeed in this magnificent pedagogical task. ;-)

The case of Sabine Hossenfelder is pretty much isomorphic but letters like "G, M, t, c" are replaced by "delta x, E, p". Once again, in Sabine's setup, there is a universal "delta x" in the Cosmos, much like a universal energy "E" or momentum "p". And they must be subjects to similar, Hossenfelderian laws of physics. What the laws can be if you have three or four letters to play with?

Well, there can be a relationship between "E" and "p". But the simple one, the relativistic dispersion relation, has already been found by Einstein so Sabine and similar fans of physics inevitably decide to write a different one. They must modify the old one. Because they call themselves "quantum gravity physicists", they write down a random formula incorporating the Planck scale.

Just to be sure, rationally speaking, there is absolutely no reason, evidence, or justification for someone to modify the relativistic dispersion relation. All the alternative formulae are unmotivated and, as far as we can say today, probably incompatible with a consistent theory resembling general relativity in an appropriate limit. All known advanced theories to describe anything in the world are compatible with the good old dispersion relation and all useful or promising modified relations we have seen may be interpreted in terms of a spontaneous symmetry breaking, starting from the old ones.

And to write new formulae just in order to find a new place where your Planck scale could occur is just plain silly; however, certain people are always more eager to incorporate random misprints and distortions into old equations than to consider the possibility that some of those could be necessary and exact. If you want to find something new, true, and important about theoretical physics, you should better look elsewhere. There are hundreds of other places where you could look and if you don't know them, it's too bad because you are really imagining that physics is about the "E=mc^2" written on the T-shirt. It's not.

The story about "delta x" is analogous. What laws can Sabine write down that would involve this universal "delta x"? Well, the symbol is similar to the symbols in quantum mechanics where the uncertainty principle is one of the most famous principles. But in quantum gravity, one can write a simpler inequality involving the Planck scale, namely "delta x > Planck length".

Suddenly, you can write eleven or more of (crappy, absurd, and virtually identical) papers about the "minimum length".

Now, the inequality is a fair qualitative idea that was written down decades ago, that you can keep in mind, and that you can "derive" by dimensional analysis. And it can have a serious meaning if you are extremely careful about the interpretation of "delta x". But that's not what Sabine wants to do. She wants this inequality to be a general law of physics that applies to all quantities that might deserve the symbol "delta x".

Needless to say, such a hypothesis is simply wrong.

The center-of-mass position of a physical system doesn't have any uncertainties of this kind. Objects that are embedded into an asymptotically flat (or other well-defined) space are "rooted" at infinity so tightly that uncertainties simply disappear. As explained above, the internal geometry can be and probably is uncertain but the center-of-mass position can't be limited by a new uncertainty principle. The center-of-mass degrees of freedom are the canonically dual quantities to the total momentum and the latter certainly does exist.

Analogously, new things appear when the energy exceeds the Planck energy but you must carefully interpret the term "the energy" in this sentence. For example, it can mean the total center-of-mass energy in a collision (and you start to create black holes when the energy is higher than that). If you only talk about the energy of one object or the energy measured in an arbitrary reference frame, there is clearly no new effect or transition (i.e. nothing special) near the Planck value, as guaranteed once again by the Lorentz symmetry.

But the new Einsteins usually don't care. They think that Einstein's main contribution is "E=mc^2" and they try to offer something analogous. Louise teaches us about her "GM=tc^3", Sabine teaches us "E = randomfunction(p, Planck scale)" and "delta x > Planck length", and both of them - and, frankly speaking, dozens of others - seem to think that this puts them at Einstein's or string theorists' level.

(Ms Hossenfelder declared on her blog that she has forgotten about her writings about random modifications and deformations of dispersion relations. See e.g. hep-th/0510245 where three variations of the silly idea, namely GUP, DSR, MDR, are even linked with each other. Ten more related papers can be accessed from the previous link.)

However, both Einstein as well as serious physicists today are using and must be using symbols very carefully. There is no room for a universal "E" or universal "p" or universal "delta x". In fact, both Einstein (the real one) and the contemporary serious physicists have been working, are working, and must be working with hundreds of various energies "E" and momenta "p" and uncertainties "delta x" and they must never forget how the particular quantities are defined and distinguished from each other - even if they have the same dimension.

The Devil is usually in the details.

I am afraid that this cognitive step - and, more generally, rigor - is just way too difficult for certain people. With their assumptions about the meaning of observables and the universal sketch of a task for new physicists, it is pretty much inevitable that they must end up with another incorrect equation or inequality relating ill-defined symbols. Do you want to help them in their research? What Louise or Sabine want you to tell them is how they should modify the shape of the wooden earphones.

Louise would be excited if you told her about a new relationship between "G" and "M" - for example, she was thrilled when I translated her equation into the Planck units :-) (M=t) - and Sabine would think that you are a constructive physicist if you proposed another but equally absurd "vacuum" dispersion relation between "E" and "p" or if you derived a new incorrect consequence of her incorrect assumptions about "E", "p", or "delta x".

It is unfortunately much harder to explain them that they are doing something really stupid with the very method how they use their brains. It is much harder to liberate them from their extremely naive and narrow mental boxes. It is much harder to explain them that they could be perhaps making variations of the same elementary mistake all the time. It is hard to convince them that if they tried a little bit harder and restricted their excessive arrogance and unjustifiable self-confidence, they could perhaps learn some new things and fix their old misunderstandings.

And that's the memo.

Funny student exam answers

Click here!

Hat tip: Willie Soon

Technical comment: Although I am a Microsoft fan, I really recommend you Firefox 3 beta 4 that was released today. It works very well and is much faster than MSIE, especially if you test it on pages with excessive and redundant scripts such as this blog.

Stephen Hawking - Master of the Universe

The U.K.'s Channel 4 started to broadcast their program about Hawking and physics:

Put all five parts in a queue.

I will embed the last, 5th part that starts with no one else than Andy Strominger:



The second part of the program, 2/2, also 5 times 10 minutes in length, has already been posted two hours ago, too:

1, 2, 3, 4, 5

There is a lot of modern phenomenology and string theory in it etc. Be ready for Lisa Randall in the mountains, six Edward Wittens drinking wine, detailed explanations of Hawking's software to choose words, Michael Green about gravity in string theory, and many other things.

The movie will show you not only why Hawking puts most of its hopes to string theory but also how he returned to his first family. It is a good program, I would say. It has its flaws. For example, I find Michio Kaku's comments slightly more non-rigorous than what they could be. ;-)

UAH & RSS: 0.07 °C m-o-m warming

RSS and UAH agree that February 2008 was 0.07 °C warmer than January 2008, as far as the temperature anomaly goes. In the case of RSS MSU, this still makes February 2008 to be the 2nd coolest month since January 2000, after the record-breaking January 2008.

GISS NASA showed the month-on-month warming as 0.14 °C but with the 0.26 °C anomaly, February 2008 also remains the second coolest month since December 2000, after January 2008.

La Nina has been downgraded from "strong" to "moderate-to-strong" again: see "status". It will continue through Spring 2008 and, according to 50% of the models, to Summer 2008 (or more).

The Sun remains blank of sunspots, with solar flux at 70. A strong solar wind above 600 km/s can make Auroras likely.

Scafetta and West argue in Physics World (March 2008) that the Sun is responsible for up to 69% of the recent warming, depending on the choice of a TSI reconstruction. They look at 11- and 22-year cycles, normally dismissed as noise.

Alexander Ač recommends us a video about the cosmic-climate connection, Svensmark, Shaviv, and others. The program, The Cloud Mystery, has six parts and I am sure you will be able to find them.

String Vacuum Project 2008

Keith Dienes, Gordon Kane, and Stuart Raby organize a kick-off meeting of the String Vacuum Project in Arizona, in April 2008. Click their names to see details.

They have their own explanations why it is important and I fully agree with them, except for the implicit assumption of the "statistics" sub-project that one should adopt the "democratic" measure on the space of vacua. But let me say one more thing:

String phenomenology has become a rather extensive field and many experts may have become over-specialized. I think that some people are focused on heterotic vacua and others are focused on type IIB flux vacua or type IIA braneworlds.

I think that a kind of "thermal" exchange between the groups is desirable not only to share their insights but also to evaluate the relative merit of the different corners of the landscape and to find and appreciate new dualities and relationships if they exist.

This project to classify the compactifications could be, in some sense, analogous to the mathematicians' project to classify all finite groups. It took several decades but it was eventually completed. An "atlas" of string compactifications could require a similar or greater effort.

Defending the inevitability of the anthropic reasoning

Bert Schellekens has written down a web page that defends the anthropic reasoning as a necessary feature of a realistic theory. Sorry, the page will be displayed as an XML source in Internet Explorer: try Firefox here.

The picture that summarizes his opinions is the following:



In words, if you have a theory of any kind that would lead to a unique prediction of physical phenomena, it is very likely that its prediction for low-energy parameters would be incompatible with complexity, life, and intelligence. Once you use this prediction as evidence in Bayesian inference, the probability that an explanation based on a unique vacuum is correct plummets.

The statement in the previous paragraph might very well be true and I can imagine that the proponents of the anthropic principle will be proven correct in the future when they say that it is pure wishful thinking for someone to argue that the "intelligent" Universe around us should be described by a unique solution to some underlying equations. Intelligence is rare and apparently independent of the predictions of a unique theory so it is unlikely that they overlap.

Schellekens also presents a far-fetched loophole that sounds as a science fiction: the equations determining a unique solution are actually secretly equivalent to some equations that try to maximize the amount of intelligent life in the Universe, so there is nothing unexpected if the unique vacuum agrees with one of the rare intelligent regions. ;-)

This is actually a very intriguing idea that I have been trying to make more quantitative many times. How do you measure that our Universe is intelligent? For example, are universes with a high Kolmogorov complexity those that you want to get?

Not really. The Kolmogorov complexity is the size of an exe file that is capable to produce a given pattern, information, or a sequence of bits. In other words, the Kolmogorov complexity is the amount of information after a maximum compression.

Is our Universe exceptionally rich or exceptionally poor in Kolmogorov complexity? I think it is neither. Much of the useful information in our Universe is redundant - for example, books are printed in many copies - but it is not true that everything in our Universe including its history (that depended on random outcomes of quantum events) can be generated from a tiny amount of "bits" to start with.

But it is very tempting to try to find a quantity that could express how much the Universe is able to print and refine books and reproduce, mutate, and improve animals or corporations. If this quantity had a simple enough definition, it could actually be equivalent to a refined version of a Hartle-Hawking prior probability distribution on the landscape. ;-)

This sounds as a real miracle but I tend to agree that if someone believes that the intelligent life only occurs in a small portion of the low-energy parameter space, a belief like the miracle above (or a belief that the laws of mathematics are simply lucky and put a unique solution to an intelligent region) is kind of necessary to avoid the anthropic reasoning completely. Do I believe it? I don't know and it is a good idea to be open-minded about open questions. But it is probably not the possibility I would bet the ranch on. I find it more likely that the intelligent life is simply not as rare as the anthropic people would like to believe.

Hawking radiation "heard"

The physics arXiv blog (don't get too confused by the officially sounding name!) has pointed out a pretty entertaining condensed matter "experiment":

Carusotto et al. (preprint)

The Italian team has constructed an acoustic counterpart of a gravitational black hole out of a flowing one-dimensional Bose-Einstein condensate. The velocity creates a sonic barrier, a version of the event horizon.



And this "acoustic black hole" indeed does emit Hawking radiation composed of phonons, as demonstrated by long-range patterns in the density-density correlation function of the gas i.e. by everything strange about the picture above away from the yellow diagonal line.

I haven't told you one more disappointing thing. Even the acoustic "experiment" has so far only been done numerically. Some skillful experimenters will hopefully do better. ;-)

Jack Gallant: reading your mind

Dr Jack Gallant claims to be able to read your mind. Volunteers were looking at 1,750 photographs while they were scanned by fMRI - functional magnetic resonance imaging. When they were shown 120 additional photographs, the system was able to guess the right picture correctly in 90+ percent of the cases! ;-)

FoxNews, Tech Shout, UPI

That could turn out to be a fascinating new technology, bringing some scenes from science-fiction movies closer to reality.

Frederick Seitz (1911-2008)

Frederick Seitz, one of the founding founders of condensed matter physics, was born on the Independence Day of 1911 to a family of German immigrant baker in San Francisco and left us on Sunday, March 2nd, 2008, at age of 96+.

L.A. Times
New York Sun
The New York Times
The Washington Post

He started to study biochemistry but switched to mathematics pretty soon afterwards, to earn a degree at Stanford in 1932.

One of his main pioneering contributions to condensed matter physics was back in the 1930s. As Eugene Wigner's graduate student at Princeton (he only needed 2 years for the PhD degree), he calculated some physical properties of bulk sodium from the known properties of sodium ions. Similar work was useful for the later development of transistors and electronics.

In 1940, he published "The Modern Theory of Solids" that became the Holy Scripture of the field for quite some time; see other things at amazon.com. The 1943 text "The Physics of Metals" was quite authoritative, too. During the war, he helped to develop armor-piercing bullets for the army and find design problems with the atomic bomb (with Wigner). Later, he was working on the Hydrogen bomb, too.

In the following decade, he studied the diffusion leading to crystalline structures of atoms (and defended resumption of atmospheric testing after some Soviet provocations).

Since the late 1950s, he focused on administrative work as a boss of the American Institute of Physics and NATO's science advisor. In 1962, he was elected president of the National Academy of Sciences that used to be a part-time job. He transformed it into a full-time job and tried it for the first time.

In 1968, he became president of Rockefeller University. He couldn't expand it much because of the economical weakness of the 1970s. But he created some PhD and MD programs and founded a center for ecology. R.J. Reynolds Industries approached him in 1978 to oversee USD 45 million dedicated to medical research.

Almost none of it was connected with smoking but loads of aggressive activists - that scum has been around for quite some time - have promoted him to a symbol of suppression of the smoking-cancer links anyway. In fact, he was convinced that active smoking causes cancer since he was a kid (from his dad): he has never changed opinions about it. He was skeptical about the health effects of secondhand smoke.

In the 1980s, he became the chairman of the SDI (star wars) advisory board. In 1984, he founded the George C. Marshall Institute in Washington together with Jastrow and Nierenberg and became a leading climate skeptic, criticizing the 1995 IPCC report and urging scientists to sign the Oregon petition in 1998 (18,000 did). Before that, in 1997, he wrote "The Science Matrix" about the rise of the scientific method. He has also disputed the damaging role of CFCs for the ozone layer.

Even very recently, he was very active. In 2008 (!!!), he published the autobiography, "On The Frontier". He wrote e.g. the foreword to the NIPCC report in February 2008.

His awards, including the 1973 National Medal of Science (for condensed matter physics), and four great-grandchildren could be listed here. Seitz believed in a form of God represented by a great remaining overwhelming mystery of the Universe. The world has lost a rather exceptional figure.

Trans-Planckian gravity: Bambi-Freese paradox

Cosimo Bambi and Katherine Freese argue that there exists a general paradox in quantum gravity. It goes as follows:

There exist trans-Planckian, massive particles in quantum gravity, for example extremal black holes. Their lifetime is much greater than the Planck time, too. Consequently, the loops in Feynman diagrams involving these massive particles will make it possible to violate the baryon or lepton number for long periods of time in pretty much every theory of quantum gravity.

If you actually think a little bit rigorously about these things, their conclusion turns out to be, of course, completely wrong. Let us look at these things in detail.

Generalized uncertainty principle

First of all, you can see that the authors are complete outsiders in quantum gravity. Pretty much every sentence is slightly - or more than slightly - wrong. For example, at the beginning, they discuss the generalized uncertainty principle(s). A punch line of theirs is that "Delta x" is always greater than the Planck length.

This is a popular simplified assertion that we often use to describe the effect of quantum gravity on distances but one certainly cannot interpret it in the way that Bambi and Freese do. Their main problem here is that they use the same symbols for many different things and they are able to confuse themselves.

When they say that "Delta X" is greater than the Schwarzschild radius of an object, they clearly talk about "Delta X" that is the internal radius of an object. On the other hand, they seem to use "Delta X" as the uncertainty of the position of the center of mass at the end. The internal radius and the uncertainty of the position are very different things.

If you understand quantum mechanics of the Hydrogen atom, what would you think about a person who confuses the radius of the electron with its position uncertainty in the Hydrogen atom i.e. with the Bohr radius? A quantum gravity expert obviously thinks the same thing about someone who does the same childish mistake as Bambi and Freese.

In the literature, most of the talk about the "minimum length" in quantum gravity is a vague sloppy babbling of incompetent people who don't have enough imagination to ever understand how Nature actually solves these things - think about profoundly and permanently confused authors such as Ng, Amelino-Camelia, Hossenfelder, and dozens of others. In reality, something new is indeed going on at the Planck scale, but to assume that

1. it must be possible to talk about distances even in this regime and
2. all the distances must always be strictly greater the Planck scale

is a double naivite. If you actually look at any consistent realization of quantum gravity - and we have quite many setups to do so, including AdS/CFT, Matrix theory, perturbative string theory, and more informal descriptions of quantum gravity involving effective field theory - you will see that the "generalized uncertainty principle" in the strict Bambi-Freese sense is certainly wrong. Sometimes we cannot talk about distances at all because it is no longer a good degree of freedom. But even when we can, there are cases in which it can be sharply defined.

More concretely, you will see that in contradiction to their statements, the position of the center of mass of a black hole - or another object - can be arbitrarily sharp. It is, in fact, a consequence of Lorentz invariance. In particle physics inside the Minkowski space, one must always be allowed to construct particle states with well-defined momentum vectors. And it is always possible to define a complementary operator of the center-of-mass position that can always have its eigenstates.

It is true that the internal structure of an object cannot be shorter than a Planck scale - but in specific vacua with additional couplings or radii, you must be very careful which Planck scale you talk about. However, this comment certainly doesn't mean that every quantity whose dimension is that of length must be greater than the Planck scale. Quite on the contrary.

Even if you are a bizarre, speculative alternative physicist who thinks that the reality is described by an entirely different theory of quantum gravity than the theory we still call "string theory", you must agree that string theory provides us with one or many realizations (depending how you count) of a physical system that satisfies all the consistency criteria expected from a theory of quantum gravity. So it is certainly sufficient to falsify many "general" statements about quantum gravity as long as they are incorrect.

And the statement about the uncertainty of the center-of-mass position in every theory of quantum gravity is certainly incorrect. Consider, for example, Matrix theory. It is easy to construct eigenstates of the operators Trace(X_i) and falsify the Bambi-Freese "generalized uncertainty principle".

Even more problematic is their statement about the "minimum time" associated with a massive object because it combines the confusion discussed above - the incorrect identification of the internal structure with the center-of-mass position - with some frequently used incorrect interpretations of the "energy-time uncertainty relation".

Their three worries

Still on page one, they list three possible worries resulting from their sloppy thinking:

1. long-lived virtual macroscopic objects
2. light particles with trans-Planckian energies
3. super-Planck heavy processes contributing to B or L violation

It almost looks like a homework exercise from a textbook, showing three serious conceptual errors that a student may make. The solution is, of course, that

1. all generic trans-Planckian heavy objects in quantum gravity that have at least a marginal right to be considered elementary are black holes
2. in effective field theory, the energy can only be integrated up to a cutoff, and the cutoff should never exceed the Planck energy for very general reasons
3. because of the first point, the only heavy particles that would deserve to occur in loops of Feynman diagrams are black holes but I will argue below that we know for sure that any contribution of theirs that could cause B or L violation should be erased because they are not really elementary particles or because of other reasons.

OK, let me assume that the reader is familiar with basics of quantum field theory so he or she knows that their point (2) was really silly: any result that you obtain by integrating the loops over energies much greater than the Planck scale is clearly unphysical and shows that you didn't renormalize things correctly or you misunderstood what a cutoff is.

The remaining points are (1) and (3) and they are really equivalent.

Loops of big objects

If your theory admits composite objects, such as the Hydrogen atom in the Standard Model, should they be allowed to run in the loops of Feynman diagrams? Under normal circumstances, the answer is, of course, No. Feynman diagrams represent a perturbative expansion of a well-defined theory with well-defined fields at the tree level - and this set doesn't include the Hydrogen atom. If you derive the Feynman rules e.g. for QED properly, the Hydrogen atoms are simply not running in the loops. Period. Electrons and quarks (or protons, in an effective theory wit hadrons) are. Hydrogen atoms in loops would amount to double-counting.

But is there some sense in which large objects can become virtual particles? Perhaps - but one must be more careful.

Heavy elementary objects

In all consistent definitions of quantum gravity we have, generic extremely heavy elementary particle species can always be interpreted as microstates of black holes. To be sure, the term "quantum gravity" in the previous sentence is equivalent to "string theory" because "consistent theories of quantum gravity we have" and "string theory" is the very same thing. But I deliberately used the term "quantum gravity" because the conclusion has nothing whatsoever to do with strings per se. The rule applies to the vacua (and their descriptions) which contain no perturbative strings, too. It is almost certainly a general fact about quantum gravity.

There are many similar facts about quantum gravity that have been demonstrated in so many inequivalent ways and in so many complementary descriptions that they have become a part of our general understanding of physics. If you learn them, you will be able to answer most of the questions and fix most of the errors in the papers by all these confused quantum gravity outsiders. These qualitative questions - about the transitions between the light and heavy objects, about the uncertainty relations at the Planck scale etc. - have simply been answered for quite some time.

For example, as long as your particles collide with energies lower than the Planck scale, the low-energy effective field theory description is legitimate. However, trans-Planckian collisions inevitably start to produce black holes. Black holes may be viewed as very heavy elementary particles. But general relativity including event horizons becomes much better zeroth approximation to understand physics of these heavy "elementary particles" than perturbative Feynman diagrams: general relativity is weakly coupled while the Feynman diagrams are strongly coupled in this regime. You are almost guaranteed to get wrong answers if you only consider the "elementary particle" picture and only pick a few loop diagrams.

I think that every competent person would agree with me even though we can't offer any rigorous and universal proof of the assertion, especially because some of the words (including the term "quantum gravity") are not rigorously defined. But I want to emphasize that our understanding of these general insights about quantum gravity is completely independent of our - so far incomplete - knowledge of the right vacuum, background, or compactification of string/M-theory that describes the world around us.

Why is it independent? Simply because these qualitative results hold in all of them. 10^{500} is not high enough number to create this kind of diversity that would allow us to violate the general rules of quantum gravity.

Loops of black holes

So do the extremal black holes inevitably lead to fast processes violating the baryon or lepton number? No, they don't. Just follow Feynman's method to think about other people's ideas: keep a specific enough example of the situation that the other person talks about in your head. If you do so, you will clearly see that the general conclusion by Bambi and Freese is incorrect.

For example, pick any known semi-realistic vacuum of string theory. Much simpler and more symmetric vacua would be enough, too. Try to follow the Bambi-Freese arguments and check which of them work and which of them don't work in your particular example. Once again, even if you believe crazy speculations that there exists another consistent theory of quantum gravity that has nothing to do with string theory, you will be able to falsify their general conclusions because 10^{500} counterexamples are enough. ;-)

Even your one counter-example is enough.

So when will their arguments fail? As I have said, you will see that their comments that the center-of-mass position of an object cannot have eigenstates will be wrong in your picture. But concerning their main argument leading to the baryon or lepton number violation, you will simply be unable to reproduce it.

Why? Because string/M-theory instructs you to use different rules to compute scattering amplitudes than Bambi and Freese do. In the correct rules, you never explicitly include loops of large black holes. For example, in perturbative string theory, you sum Feynman diagrams that look like Riemann surfaces. They can be informally interpreted as a summation over all possible particle species that arise as vibrational patterns of a string. But again, this translation is inaccurate because it would lead you to different regions of the moduli space of Riemann surfaces that you should use for integrals.

The rules of string theory naturally generalize the rules of a quantum field theory with infinitely many species but they are not quite identical.

When your calculation is finished, you will see that very large black holes "in loops" cannot cause any very large violation of the baryon and lepton numbers. Instead, you will see that string theory - and quantum gravity - suppresses the processes induced by quantum gravity effects by the Planck scale. For example, for a baryon-number-violating dimension-six operator O, the expected induced term in the low energy Lagrangian will be

• O / M_{Planck}^2

which is compatible with observations (at least so far), except for theories with a low gravity scale where the potential problem is appreciated by the model builders. There will never be an amplification of such a term by a very large life expectancy of a very large black hole running in the loop. This is simply not how quantum gravity works. And I would say that quantum field theory doesn't work in this fashion either. The argument of the Bambi-Freese type would look naive even in the context of ordinary, non-gravitational quantum field theory.

Instead of vague pseudo-arguments based on shaky assumptions and speculative generalizations of Feynman rules, we can use the actual, established, tested rules of quantum gravity to see that the "paradox" definitely doesn't occur.

It is illegitimate to use the Feynman rules including black holes loops and even if we succeeded to translate the stringy calculation into a calculation similar to the Bambi-Freese setup, string theory would urge us to either eliminate some regions of the moduli space or include exponentially decreasing coupling constants or eliminate some species from the loops altogether. Perhaps, it would lead to cancellations that Bambi and Freese didn't expect.

I don't know which answer is correct because I don't know how to reorganize the correct calculation in the Bambi-Freese fashion, including the black hole loops. But I don't need to know these things to be sure about the answer to the main question: the existence of large black holes simply doesn't cause any arbitrarily strong violation of the baryon or lepton numbers. While it would be interesting to have a field-theoretical reorganization of some calculations that includes black holes in the loops, physicists are not obliged to find one. They can believe that it doesn't exist: I tend to believe it doesn't exist. However, if Bambi and Freese use such a speculative framework for their argument, they are expected to actually construct such a framework.

Everyone who has learned some string theory knows these things. But still, some results of string theory look mysterious - even though we know for sure that they are correct - because of arguments similar to those by Bambi and Freese.

Matrix theory: large gravitons

For example, in Matrix theory, the gravitons are represented as large bound states of some particles called D0-branes. The internal size of these bound states increases as a power of N, either as N^{1/3} or N^{1/9}. At any rate, if you send N to infinity which you really should, the bound states representing gravitons become astronomically large in Planck units. Nevertheless, these large clouds, even if their centers are a micron away from each other which means that the clouds are almost perfectly overlapping, will avoid any interaction with each other.

It is very surprising but we have some general words that explain "why" it is so. Supersymmetry cancellations could be a part of the answer. On the other hand, we probably need some inherently stringy explanation that doesn't rely on supersymmetry. The most typical comment we say to explain "why" the interactions between the clouds are negligible - a comment whose variations apply to many similar situations in string theory - is that most of the degrees of freedom responsible for the large internal radius are connected with very high frequencies and their effects on the slow degrees of freedom therefore cancel very accurately.

Again, it is important to understand that this mystery doesn't mean any uncertainty about the answer. The answer is certainly that the clouds' interactions are almost zero. The confusion is a psychological one and it is difficult to formulate it accurately enough so that it becomes a sharp paradox. There exist many situations in string theory where the theory shows that it is smarter than we are and it is able to achieve things that we would a priori consider impossible - including all the dualities, mirror symmetry, holography, interpolations between theories with different numbers of dimensions, and so on.

We can eventually understand the miracles, too. But it is true that Nature is often faster than we are. However, the goal of physics is not to paint ourselves as geniuses and fool and humiliate Mother Nature. The goal is to understand Nature.

Finally, I want to emphasize that even if our understanding of the Universe is not complete, there are many qualitative insights about quantum gravity that will never change because they are independent of the kind of ignorance that remains. The qualitative behavior of particles and black holes near the Planck energy and beyond has been understood. It is time for all authors of good and tolerable papers to learn these things.

And that's the memo.

Hungarian conversion: runaway greenhouse warming impossible

In this weekly dose of peer-reviewed skeptical climatological literature, we visit Hungary.

Ference Miskolczi: Greenhouse effect in semi-transparent planetary atmospheres

Amusingly enough, the author interprets the differential equations describing the absorption of infrared light by the atmosphere as a realization of equations of general relativity and discusses a term missed by Arthur Eddington and Arthur Milne around 1922. ;-)

It's too early and I don't quite understand what the author is doing and cannot confirm the work - and some readers will hopefully try to follow the actual paper - but the results are as follows.

In his modified model, the near-surface air temperature is higher, the surface temperature is lower, and the climate sensitivity is much lower than the IPCC numbers. Some of the predictions of his model are claimed to be successfully compared to data from both Earth and Mars.

Most importantly, the actual greenhouse warming is claimed to be strictly bounded from above: it cannot exceed a certain limit. This is what I used in a naive model of greenhouse warming and I am slightly skeptical that a corrected mistake could justify such an unusual outcome.

Nevertheless, it is at least found in a peer-reviewed paper. And indeed, it is a robust explanation of the absence of runaway climate changes in the geological past as well as the constant overestimates of warming trends by the popular greenhouse models.

Miskolczi wrote the paper a few years ago but his colleagues in NASA killed it until it was published in Hungary.

Daily Tech: Basic greenhouse equations "totally wrong"

adds a fascinating story of Miklós Zágoni who used to be Hungary's most outspoken scientific supporter of the Kyoto protocol. He has read Miskolczi's paper, fell in love with it, and saw the light. ;-) There is no longer any crisis for him and he is trying to explain the paper and its magnificent agreement with observations to others.

This story reads like a fairy-tale. A kind of goulash fairy-tale.

Hat tip: Marc Morano

Lindzen vs Rahmstorf: an exchange

PDF file (Lindzen's article; Rahmstorf's semi-reply; Lindzen's response)

This exchange is kind of interesting because both participants are highly regarded figures in climatology and they approach the problems as physicists.

Funny or scary interruption: two days ago, I wrote that I was hoping that Al Gore and the alarmists wouldn't try to realize their goal about the "consensus" by explosives directed against New York's Times Square. Today, a small explosion rocked Times Square. Witnesses from the Marriott Marquis hotel described their perceptions.

Still, you can see that that quantitative and rational evaluation of reality has its limits in the case of the climatic hot head (Stefan Rahmstorf). On the other hand, the climatic cool head (Richard Lindzen) is able to estimate the likelihood of various models scientifically even if the conclusions look sensitive politically.

He knows how to use Occam's razor and how to compare the likelihoods of contrived explanations with many assumptions (an effect is strong; it is masked at many places where we could observe it; etc.) and natural explanations without any excessively special assumptions.

Sometimes, the bias is far too obvious. For example, whenever Rahmstorf talks about the natural effects influencing the climate, he says that they are "masking" the man-made global warming. Such a language trick is equivalent to an unjustified, propagandistic assumption about the sign of an effect and it is very clear that once he formulates a hypothetical explanation in this way, it can't be studied scientifically because its very essence is a dogma. In reality, many of these effects can have - and probably do have - the opposite sign than Rahmstorf implicitly assumes (including the total feedback of the clouds or the regulating effect of the oceans).

Commercial: John Tierney of the New York Times wrote a rather deep and comprehensive analysis of the financial and other motives of scientists and people around science, including government officials and corporations

Rahmstorf, a former general relativist, is not quite stupid but some of his comments are sort of incredible. For example, he argues that the consistency of a model with the historical data shouldn't affect our confidence in these models. He offers a lot of minor technical errors, for example arguing that there was no El Nino in 2005 (although an El Nino episode ended in JFM 2005); that AGW used to be outlandish decades ago (compare with the 1958 movie we discussed recently).

Rahmstorf also makes a typically layperson's mistake when he thinks that the climate sensitivity can be measured "directly" without having any theory or model in mind. Incredibly, he seems to be using "fingerprints" as evidence for the greenhouse theory of the climate, even though the theoretical fingerprints clearly disagree with the reality.

Richard Lindzen also doesn't buy Rahmstorf's bizarre comparison of climate science with general relativity (and their trustworthiness, including an identification of relativistic crackpots with climate realists), emphasizing how troubled Einstein was because of a single parameter (the cosmological constant) while the consensus climatologists don't seem to care about dozens of important yet unverified adjustable parameters, fudge factors, and other arbitrary assumptions in their models.

WMAP: five-year data released

It's been two years since the publication of the WMAP three-year data. As some of the readers know, 3+2=5 so the only sensible thing that the WMAP team can publish right now are the five-year data.

WMAP 5: main page
WMAP 5: papers
WMAP 5: Phil Plait
WMAP 5: Sean Carroll

Theoretical physicists and non-experimenters will primarily care about the cosmological interpretation.

Don't expect a revolution here. Some numbers got a little bit more accurate, following Lord Kelvin's prescription for the completion of science. For example,

• the Hubble constant is 70.1 +- 1.3 km/s per Mpc
• the relative density of dark energy is 72.1 +- 1.5 percent
• the relative density of dark matter is 23.3 +- 1.3 percent
• the relative density of baryonic matter is 4.6 +- 0.2 percent
• the age of the Universe is 13.73 +- 0.12 billion years
• the global mean temperature dropped to 2.725 K by now (outside the urban heat islands such as stars, plus minus the fractions of the degree from the image above), confirming worries about global cooling ;-)
• the recombination occurred on 375,900th (+- 3,100) birthday

Interestingly enough, the team can exclude the existence of very massive neutrino species: the total sum of the neutrino masses is below 0.61 eV, at the 95% confidence level. Entertainingly enough, they have a non-particle-physics measurement of the number of neutrino species: it is 4.4 +- 1.5 which makes the value 3 tolerable. ;-)

Tensor-to-scalar ratio is below 20% at 95% confidence level, making theories with gravity waves and with the spectral index above one disfavored.

Heartland Institute @ Times Square: climate conference ended last night

The 2008 International Conference on Climate Change Sponsored by The Heartland Institute

March 2 - March 4, 2008
Marriott New York Marquis Times Square Hotel
1535 Broadway, New York City, U.S.A.

Update: Summary for policymakers of Fred Singer's or our Non-governmental International Panel for Climate Change (NIPCC), a distinguished body that has superseded ;-) the IPCC: PDF file. Check out John Tierney's reaction.



Conference website

Investor's Business Daily
Reuters: Roasting Al Gore
CBS & The New York Times had the courage to mention the conference: Andrew Revkin was nearly assassinated by the extremists
Revkin's blog
New: Ronald Bailey's detailed report on Monday's talks (II)
New: Revkin @ NYT reports on Monday's talks
New: Washington Post reports on Monday's talks
New: New York Sun
New: Czech Press Agency (the most balanced coverage)
New: Chris Horner for Human Events
New: Wall Street Journal
New: Alan Caruba (NJ) reports
New: "Ostrich Brigades"
New: UPI (short)
New: WorldNetDaily + Dakota Voice
New: PR-inside
New: Journal Now (NC)
New: Town Hall
Finance Post
Bush has "no opinion" on the conference but NYC is great for the meeting and he will "take steps" on AGW

Participants (bios, 17 pages, speakers include Avery, Ball, Balling, Bellamy, D'Aleo, Ebell, V. Gray, W. Gray, Horner, Idso, Illarionov, Izrael, Klaus, Legates, Lewis, Loehle, McKitrick, Michaels, Milloy, Monckton, Morano, Morris, Murray, Patterson, Peiser, Reiter, Seitz, Singer, Slagle, Soon, Spencer, Stossel, G. Taylor, M. Taylor, Watts, and many others)
9-page schedule, 44-page program

I hope that Al Gore won't manage to organize a terrorist attack against Times Square to advance his dreams about the "scientific consensus".



A new CNN report compares the distinguished conference speakers to the Flat Earth Society. Via NewsBusters.



Last night, Václav Klaus was interviewed by CNN's Glenn Beck (transcript, video above), saying that social scientists should participate in the climate debate because it is a social phenomenon; that it is politically incorrect to be a skeptic; and that he was re-elected anyway. ;-) He also explained why the word "progressive" would only be used by suicidal politicians in the post-communist world.

He also gave the keynote speech on Tuesday morning (CNSnews), received a thunderous standing ovation from roused skeptics, and he will return to Glenn Beck's show on Wednesday night (video).



At the end, the participants have endorsed the Manhattan declaration, recommending the world leaders to abandon all irrational policies and misinformation dictated by the global warming orthodoxy.

A feminist babbler will lead Harvard College

Evelynn Hammonds, a black postmodern feminist science-hater, was chosen to lead the Harvard College.

During the anti-Summers witch hunts, this pseudointellectual was the chairwoman of the "Women Task Force" - the Feminazi Inquisition - and one of the main people who forced President Summers to throw USD 50 million out of the feminist window. Whenever I heard her speaking at the FAS faculty meeting, I was really down.

In her "scholarly" work, she has criticized science as an industrial tool of the evil straight white males to oppress the sexuality of the nice black female lesbian people: see e.g. her masterpieces "Black (w)holes and the geometry of black female sexuality" or "Conflicts and tensions in the feminist study of gender and science".

In the physics title above, you could also replace "l" by "r" in the second word.

She has also co-authored articles arguing that the doctors shouldn't be allowed to look at race when they try to cure their patients. Her work is a textbook example of the postmodern trash whose worthlessness was demonstrated by Alan Sokal, among others.

I personally find it outrageous that people of this kind are awarded degrees these days. But when this woman becomes the dean of a college of one of the most famous universities in the world, expected to control all of its undergraduate education and to be even able to integrate the feminist studies into the curriculum, we might start to be afraid that the situation has become irrepairable.

Singularities and stringy geometry

Clifford Johnson wrote a nice report about David Morrison's lecture about the resolution of singularities in string theory and I want to add a few words, too. Most of them will be very general and philosophical, some of them will be slightly more technical.

Singularities as mantinels of our current knowledge

Singularities are objects or theoretical constructs in which something is infinite, uncontrollably high, dense, maximally squeezed, and so on. But the adjective "infinite" is usually a mere artifact of our incomplete knowledge about the particular physical situation or a class of questions. When we look more accurately, we see that the old quantities cannot really become infinite as we used to believe. Instead, there is a new layer of phenomena or knowledge - or "new physics", as physicists like to say - where new objects and theoretical constructs become finite. Our microscope or telescope can focus on the new realm and inform us about things that were impossible to seen in the previous picture of the world.

Let me tell you a few examples.

Millenia ago, people were scared by thundestorms, hurricanes, and rainbows. They were apparently created by an infinitely powerful god who was flying at an infinite altitude above the flat Earth. Of course, when the people gained a little bit of self-confidence and some skills, they realized that this particular god was finite and lived at an unimpressive altitude of a few miles above the surface. The atmospheric science was born and it has instantly regulated the singular notion of the climatological god. The replacement of an anthropomorphic and anthropogenic god in an infinite atmosphere by a finite and natural atmosphere was arguably one of the greatest developments in climate science and judging the current climate science by the fashionable global warming religion, much of the current progress goes in the negative direction once again. ;-)

The Earth used to be visualized as an infinite plane which led the thinkers to all kinds of paradoxes. These paradoxes were solved by a new picture of infinity. The Earth isn't really infinite, after all.

There are many examples of this kind but I want to get closer to modern theoretical physics in the conventional sense. There are many quantities in physics and they have certain units. We may imagine the value of each of them to be infinitely large or infinitely small. But something new and surprising may happen whenever you take it to the limit.

Eliminating units and solving infinite paradoxes

We may start with the distance but it is more historically and physically meaningful to start with the velocity. 103 years ago, you could have asked many questions about the phenomena that occur when velocities of objects become infinite. However, Albert Einstein developed his special theory of relativity. According to this framework, the velocity can't really grow infinite. In fact, it can't exceed the speed of light. Instead of a velocity v, it is more natural to talk about the dimensionless ratio v/c. The mysterious realm of an infinite velocity has been resolved. All paradoxes based on infinite speeds have evaporated.

In this particular case, v/c can't be greater than one and the sharply defined number one has a special meaning. In other contexts, we will see different things going on.

When 19th century physicists studied the atoms, they could have asked all kinds of questions what happens when an electron approaches the nucleus too closely. Quantum mechanics taught us that there is a whole new realm of physical phenomena that become relevant at very short distances.

Quantum mechanics

Because of the uncertainty principle, electrons can't really collapse to the nucleus, at least not for too long periods of time. The angular momentum can't go to zero: its spectrum is discrete. Note that just like 1/v can't go to zero, the angular momentum can't either but the detailed explanation is different. In the case of 1/v, it is always greater than 1/c and its allowed values are continuous. In the case of the angular momentum J, it must be a multiple of hbar/2. Instead of the angular momentum, I could also talk about the action. When the action - the integrated Lagrangian - associated with a physical process becomes too small, comparable to hbar, new physics of quantum mechanics starts to dominate.

Again, quantum mechanics has introduced a new layer of knowledge. When any physical quantity approaches a number comparable to Planck's constant, we must start to be very careful. New insights protect us from paradoxes and even in the absence of paradoxes in the old classical theory, quantum mechanics can tell us some new, unexpected answers to our questions.

Special relativity allows us to relate meters and seconds in our system of units: the speed of light is the conversion factor. Quantum mechanics allows us to identify energy with frequency - there are many equivalent ways to say what it is doing - and it reduces the independent units to one. Particle physicists would probably choose one GeV and its powers as the unit for anything. ;-)

In quantum field theory, one would naturally talk about the substructure of matter and effective field theories at ever shorter distance scales, as organized by the techniques of the renormalization group. They explain what is happening inside the atom, inside the nucleus, inside the proton - objects that used to be viewed as infinitely small. But instead, let us look at a related example involving quantum gravity.

In the quantum field theory setup, we ended up with the unique unit of one GeV and its powers.

Quantum gravity

But one independent unit is still one too many. When you set Newton's constant equal to one, or something equivalent, all quantities may be expressed as dimensionless numbers. Once you do it, you shouldn't be shocked if there is new physics whenever a quantity that used to be much greater than one approaches the values of order one or smaller - or vice versa, when an old quantity that used to be much smaller than one approaches or exceeds one.

If we set c=hbar=G=1, we deal with units of quantum gravity. The distance is naturally expressed in multiples of the Planck length. So we shouldn't be surprised that new physical phenomena occur when distances shrink down to one Planck length or times shrink to one Planck time.

This result of a dimensional analysis is pretty universal - regardless whether you understand string theory or not - and the only really plausible yet simple way to change this dimensional analysis is to change the dimension: the dimension of space. With large or warped extra dimensions (or something that must be effectively equivalent to them), new fundamental units of length may occur - higher-dimensional Planck lengths or string lengths of various types. They may be substantially different from the conventional Planck length as calculated by Max Planck.

The new physics near the Planck length is not only expected, with the logic sketched above, but it is badly needed. We know that things can become extreme. If you allow mass to collapse, the density of matter could a priori converge towards infinity, much like when you approach the Big Bang. As you get closer to the infinite value, it is becoming increasingly clear that something is missing in our knowledge.

Singularities in hidden dimensions

The singularity inside the black hole is actually a subtle type of a monster that is still not completely understood. In string theory, we can solve problems that are - from a purely geometric viewpoint - in the same universality class but that offer us better tools to nail the question down. Why? We can study vacua with extra dimensions - such as our Universe - and imagine that certain geometric features of the extra dimensions shrink to zero size just like in the case of the black hole. However, this singularity may still be extended along all three conventional large dimensions of space. And one can actually achieve this arrangement without any energy density.

Our stories about special relativity and quantum mechanics above represented two templates what may happen when some characteristic distances on the shape of extra dimensions shrink to very small values. Some people from the loop quantum gravity sect and related denominations assume that the quantity called "length" in quantum gravity must have the same properties as the "angular momentum" in quantum mechanics, namely that it must have a discrete spectrum.

This idea is extremely far from being necessary. In fact, one can see that it is naive, wrong, and reveals a profound lack of imagination, education, and talent of the proponents of such ideas. In some sense, the analogy of "length / Planck_length" with "c/v" in special relativity is much more correct in many cases: the spectrum of "length" of a geodesic inside the extra-dimensional shape remains continuous but something repels it from the value zero. A discrete spectrum would lead to contradictions with special relativity and with the existence of scalar fields.

But it is indeed true in certain situations that the length - or a volume - cannot shrink below a certain limit once you take the new physics of quantum gravity into account. In other cases, the value of zero can be achieved but it becomes completely harmless. There is a new, dual language in which a geometry with very short distances or volumes of spheres can be reinterpreted as a smooth theory expanded around a pretty normal point in the configuration space. Such a new description - such a duality - is another scenario how the paradoxes of the infinitely shrunk geometries can be resolved in many cases.

Constraints of geometry and mathematics

What is important and what the fifth-class physicists probably can never understand - because they are missing a lot of required neural cells to get this point - is that there exist hugely stringent mathematical constraints on the candidate new physical laws that supersede the normal laws of geometry and classical physics in the extreme conditions. Other physicists not only understand that these constraints exist but some of them can, in fact, fully take them into account in their active research.

When you listen to Dave Morrison's lectures, you may get very privy to this kind of reasoning. You may get familiar with examples that were known to mathematicians before the correct answers were actually given by string theory. These mathematicians who studied the complex manifolds realize very well that string theory is clearly the right framework to address all these issues and to nail them down.

For example, there exist "moduli spaces" of manifolds that solve Einstein's equations of general relativity: the whole family is Ricci-flat. You can also show that this "moduli space" of possible solutions of general relativity also contains geometries similar to the "conifold" - manifolds that include a singularity. So the existence of a singular manifold is clearly compatible with the approximate laws of physics - general relativity - and it is thus necessary to have a consistent picture what happens when your world approaches this shape.

String theory has shown that the moduli space is actually complex: an inherently stringy degree of freedom, the stringy generalization of a Wilson line (the integral of a stringy B-field) - an integral of a 2-form potential over a 2-cycle of the geometry - adds the "imaginary part" to the previously well-known "real part" - the inverse area of the 2-cycle. With this "complexification", one can describe the space of possible shapes of the manifold and possible topology changes beautifully. You can circumvent the singular point if you wish, just like you can make a trip around the point z=0 in the complex plane.

Again, there exists more than one answer to the question what happens to spacetime when it shape approaches the singular shape of a "conifold". One answer is based on type IIA string theory and another one on type IIB string theory. But it seems very clear by now that all legitimate and consistent answers are part of string theory: string theory should really be defined as the set of all possible complete sets of physical equations that describe geometry in the heavily quantum regime. And be sure that all the consistent solutions so far have been very tightly interconnected.

One thing is obvious. Whoever claims that he is a theoretical physicist and he or she can answer these fundamental questions without learning string theory is simply a crackpot.

Let me try to present a more detailed summary why it is so. The space of small compact geometries that solve Einstein's equations is arguably essential for everyone who wants to understand general relativity in the regime of very short distances. These spaces can be shown to include singular points - such a point corresponds to a whole geometry of space that has singular points in them itself and you shouldn't confuse these two singularities in the moduli space and in the real spacetime.

At any rate, the singularity in both contexts is a potential source of infinities, paradoxes, and unpredictability: you should ask what happens when the space approaches this particular shape which is what it can apparently do according to Einstein's rules of the game. Possible answers are extremely constrained. Why?

End of the world

For example, when I discussed things like the flat Earth at the beginning, I should have mentioned the "end of the world" where ships fall down the hill. An end of the world is an extremely dangerous theoretical construct because it is not easy - or possible - to design physical laws describing what happens when you get there. Many readers surely remember how they were solving this problem - what happens when you come to the end of the world - and it was tough. There are solutions but they are constrained a lot. For example, there can be a perfectly reflective mirror at the end, the so-called orientifold plane.

Or you can order an angel to remove the souls from the end of the world but such an angel theory - even if you accepted theories "glued from pieces" in such a way - will still not explain what the people who approach the end of the world actually see. It is tough. Another example: An end point of a string can exist (a part of an open string) but it must have either Neumann or Dirichlet boundary conditions; the boundary terms in the variation of the action would otherwise fail to vanish which would ruin the equations of motion in the bulk, too. It is not true that anything goes.

Similar huge constraints exist not only for the real space but also for various moduli spaces, more abstract versions of spaces that appear in physics. A moduli space is the space of possible values of all massless (or light) scalar fields that appear in a theory (or parameters that describe its solutions). If a quantity or a scalar field - such as the area of a 2-cycle - can only have values between 0 and infinity, you should always know what happens when the size goes to zero. Will it bounce? If it does, then the value really goes from -infinity to +infinity and it is another case of the mirror. But a mirror requires the values of -x and +x to be equivalent. Are they?

In the case of the shrinking conifold, this is actually not the right solution. The correct solution involves the "complexification" of the moduli space sketched above. But once you deal with complex numbers, you are extremely constrained, too. Recall that when you know an analytical function in a small region of the complex plane, you know it globally. If your theory includes complex numbers and holomorphic functions, believe me that you are constrained a lot.

The people who will tell you "all quantities are discrete and all problems are solved" are as naive as the primitive humans who say that an omnipotent climatological god is responsible for all weather phenomena. These people are just dense and they have nothing to say about these hard and exciting questions. In real science, different questions often have different answers. The questions how a particular singularity is "resolved" are surely examples.

The people who will argue that everything goes and a universal answer such as the "discrete spectrum of geometric quantities" is perhaps good enough to explain everything about quantum gravity - but who will actually tell you nothing about the spectrum of allowed values of the relevant quantities etc. - are just religious bigots who are not interested in the actual scientific answers to tough questions but who prefer to repeat clearly wrong and naive, non-quantitative dogmas for long enough time so that some intellectually challenged listeners will start to take them seriously. Lee Smolin is indisputably a textbook example of these manipulative pseudoscientists.

These questions are tough but they can be answered and many of them have already been answered. We know that one can "circumvent" various singularities in a complexified moduli space, jump to another branch of the moduli space describing a different topology, and identify the topology change with a condensate of physical objects living in the previous topology - or at least a condensate of objects that continuously transform into something that becomes a well-known physical objects when the geometry is de-singularized and "large".

Geometry and physics - background and particles or other objects - get mixed with each other. They rely on each other, non-trivially interact, can transform to each other, and can be equivalent to each other. The people who still want to study quantum geometry and physics within this geometry in isolation have completely misunderstood everything important that has been discovered about quantum gravity.

Finite diversity of resolutions

There are many kinds of possible explanations and dual descriptions what happens in these extreme conditions. For example, mirror symmetry implies that physical phenomena in two universes whose extra dimensions have two extremely different shapes are nevertheless completely equivalent if the manifolds are related by "mirror symmetry".

This is a concept that is obviously deep according to any good mathematician who is interested in complex geometry - but more generally, it is also crucial for any physicist who is interested in compact solutions to Einstein's equations. The full physics of string theory is clearly the most complete framework to answer and clarify properties of mirror symmetry at the most fundamental level. Because two very different shapes can lead to exactly equivalent physics, string theory shows us that there is something more fundamental about their "cosmological code" than the conventional concepts of geometry.

At the same moment, this insight - whose universal explanation remains mysterious despite the available technical proofs in many classes of formulations - is so captivating only because we can actually show that the objects related by mirror symmetry are continuously connected with large manifolds where the standard rules of geometry and old-fashioned physics do work. If we were not able to show that we are talking about two a priori different representations of a geometry, something that we have known from our previous approximate theories of reality, their equivalence would be unspectacular. We can show the equivalence of many pairs of objects that are non-geometric.

So if someone provides you with a model but he cannot show that it is equivalent to general relativity in the regime where it should be - long enough distances (and most typically, one can actually show that it cannot be equivalent to it) - then this model has no relevance for the questions about the fate of singularities in general relativity.

It has been overwhelmingly clear for quite some time that string theory is absolutely crucial to properly answer questions about the extreme geometrical environments and that the answers to questions in the well-known, highly supersymmetric contexts obtained from string theory are correct. Whoever tells you in 2008 that he is going to solve some well-defined puzzles of quantum gravity in contradiction to string theory is a retarded charlatan and I've been simply overwhelmed enough by the constant flow of this trash that it has helped me to escape the officially active research.

Sorry but I can't afford to tolerate this scum in the comments.

While it is true that theoretical physicists have not classified all possible answers to similar questions, all qualified theoretical physicists as well as mathematicians focusing on geometry are able to tell you whether a particular story about the fate of a singularity is true or not, when it is fully formulated, and whether it is plausible or not, when it is partially formulated. At least in all cases we have seen so far, it is the case. Everything boils down to pretty rigorous mathematical questions and be sure that answers to mathematical questions are usually less vague than postmodern babble of spin-foaming pseudoscientists.

The known stories - collections of new physical concepts and phenomena relevant for physics under extreme circumstances - pretty much cover all of the imagination of the best theoretical physicists and mathematicians in the field. In fact, many of the cute answers provided by mathematics and physics were surprising and people only learned them when the equations forced them to discover them.

But the diversity of the solutions doesn't allow you to say that everything goes. The number of qualitatively different possible outcomes of a shrinking conifold is finite and each of the outcomes is completely well-defined. Good physicists in the field know these things, the bad ones are confused and generate loads of "possible alternative answers" that every qualified person is able to rule out within a few minutes.

I think it is an absolutely paramount requirement for science to eliminate answers that can be shown to be wrong and, at the sociological level, to eliminate the people who have shown that they are only able to produce wrong answers. It is extremely bad for science if the journalists, media, and other non-scientific channels are helping to flood science with politically convenient loop quantum gravities, spin foams, dynamical triangulations, their proponents, and gigatons of similar garbage in order to dilute the concentration of valuable physics and valuable physicists (and the resources available to this group) to arbitrarily low values.

The point where the concentration of serious physics in the ocean of nonsense converges to zero is another example of a singularity and I hope that this one will also get resolved soon - by imposing a cutoff that won't be breached too easily.

And that's the memo.

Third country in space: 30 years

Today, it's been exactly 30 years since the moment when the third country sent its man to space.



Vladimir Remek who is 50% Czech, 50% Slovak and who flew aboard Soyuz 28 - together with Alexey Gubarev - became the first non-Soviet, non-American man in space. Today, he is a member of the European Parliament for the Communist Party of Bohemia and Moravia.

Tibet: 1.65 million people snowblind or frostbitten

Xinhuanet

In Tibet, 500,000 animals have died during the harsh winter. 3,100,000 others are on their way.

1,600,000 people in the region are either snowblind or frostbitten. 130,000 have no fuel left, 350,000 are hungry, and 110,000 need extra clothes not to freeze. The local government only has 10% of the money it needs to deal with the weather, offering a brutal example of the importance of wealth for facing any kind of unpleasant or extreme weather.

See also:

China's war on snow havoc

Happier news

New South Wales is doing better. Its ski resorts have received some snow. Not bad for a summer.

Upstate New York has edited its record book because of record cold temperatures. Many U.S. towns have endured their snowiest February on record.

But remember: Record cold events can't end global warming worries. A pleasant warm weather should make you more worried but nothing can ever make you less worried as long as you are a nice person who is not corrupt. ;-)

A far-right rally in Pilsen

I took 132 pictures at a bizarre far-right rally in Pilsen today:

Thumbnails I, thumbnails II

The mayor banned the previous rally in Pilsen but the courts decided that his ban was unconstitutional so the rally was organized again. In a truly free country, mayors sometimes have a hard time to get away with similar common sense decisions but it doesn't necessarily mean that the far-right citizens represent an actual threat.



They gathered at the central municipal bus station. Some of them were late because of Big Wind Emma that is just visiting Central Europe. Once they started, they gave a few nervous speeches defending the freedom of speech - something that they have absolutely received, as far as I can say - and speeches against the democratic establishment and against the government, especially against its members whose roots are not 100% Czech.

Video (for Czech public TV): by Ondřej Giňa; I talked to him and took his picture

In the very same speeches, there has also been a lot of pro-worker stuff, something that I would classify as a far-left populist propaganda; with these guys, you can't really say whether they're right-wing or left-wing, only that they are morons. None of the 150 people looked particularly dangerous or aggressive but these features could be context-dependent. Some cops were saying "if these guys are extremists, it must be pretty hard to tell, even if you live with them and they return home".

The police has used the event to show its muscles. They were simply impressive. A helicopter, water cannons, a lot of horses, dogs, trucks, tanks, hundreds of cars, and 1,000 cops with all kinds of fascinating equipment. You could call it a massive overreaction but it was fun anyway. They completely isolated the center of the city - around the Square of the Republic - and safely separated the neo-Nazis from the anarchists. In the neo-Nazi speeches, all the anarchists who gathered near the Pilsner Synagogue (the third largest synagogue in the world) for an anti-protest were described as Jews, a remark that made everyone who was not neo-Nazi laugh out loud.

I wonder how much did the police pay for this entertaining theater. Maybe next time, the neo-Nazis should be encouraged to buy tickets to fund the event; a ticket would clearly have to cost thousands of dollars to cover the police expenses. ;-) On the other hand, it might be useful for the police men and women to have some training, and a semi-serious opportunity like this one could be somewhat more exciting than a completely artificial drill. So when I combine my mixed feelings, it is probably a good idea to give those 150 nuts as much freedom as they want and use the overwhelming power to make them harmless.

The Pioneer anomaly: new stories

The Pioneer anomaly seems to have new siblings:

SPACE.COM, USA TODAY (the same text)

For five out of six space probes in a certain ensemble that are influenced by the gravity of Earth, a new anomaly could be confirmed. The measured deviation of the velocity from the expected value seems to be two orders of magnitude greater than the available accuracy of the measurement.

The sixth probe, Messenger, exhibits no observable anomaly but it could be just because of a rather accurate symmetry of this probe's trajectory with respect to the Earth's equator assuming that the anomaly has something to do with the Earth's rotation. Nevertheless, it looks strange and a reader who is really competent should do a proper calculation taking all possibly relevant effects of general relativity into account.

Thanks to Gene Day!