No more champagne And the fireworks are through Here we are, me and you Feeling lost and feeling blue It's the end of the party And the morning seems so grey So unlike yesterday Now's the time for us to say...
Happy new year Happy new year May we all have a vision now and then Of a world where every neighbour is a friend Happy new year Happy new year May we all have our hopes, our will to try If we don't we might as well lay down and die You and I
Sometimes I see How the brave new world arrives And I see how it thrives In the ashes of our lives Oh yes, man is a fool And he thinks he'll be okay Dragging on, feet of clay Never knowing he's astray Keeps on going anyway...
Happy new year Happy new year May we all have a vision now and then Of a world where every neighbour is a friend Happy new year Happy new year May we all have our hopes, our will to try If we don't we might as well lay down and die You and I
Seems to me now That the dreams we had before Are all dead, nothing more Than confetti on the floor It's the end of a decade In another ten years time Who can say what we'll find What lies waiting down the line In the end of eighty-nine...
Happy new year Happy new year May we all have a vision now and then Of a world where every neighbour is a friend Happy new year Happy new year May we all have our hopes, our will to try If we don't we might as well lay down and die You and I
In this 1980 video, Agnetha (blonde) and Björn (standing) have been divorced for one year while Anni-Frid (brunette) and Benny (piano) would divorce in the following year.
More importantly, 2008 will be the international year when the LHC gets activated (in May) and the successor of George W. Bush will be chosen (in November): some people can't wait till 2008.
Two topics about the relationships of science and society were recently discussed in the physics blogosphere: funding cuts, especially for high-energy physics, and the desire of elite universities to absorb the top research in cutting-edge disciplines. Let me briefly say what I think about both.
Funding cuts
For the year 2008, high-energy physics has seen the heaviest losses in the U.S. but also the U.K. Fermilab is one of the major casualties and the resources will drop by 10 percent or so. Various scientists protest. Generally, I think it is usually good if science is getting enough funding but it is certainly no dogma.
There are at least two basic reasons why funding reductions for facilities such as Fermilab are justified:
Decreasing relative capacity of the facility to make dramatic discovery
Damaged public perception of high-energy physics
Because I think that the society should be deciding about some "microscopic" numbers determining the total resources for science and their separation to a few roughly defined subdisciplines (but not the internal detailed redistribution that should be decided by the experts), these two reasons make it natural that the funding simply has to go South.
Fermilab vs the LHC
Concerning the Fermilab, I find it obvious that when we expect that the facility is soon going to become obsolete and superseded by the CERN's new collider, the calculation whether it is a good idea to invest a lot of money into Fermilab inevitably shifts.
Well, the luminosity and the energy per particle will simply become cheaper in less than a year, unless a catastrophe occurs. The market of ideas and experiments has to respond to this fact. A rational response is that it is probably a better idea to save the money and wait for the LHC that will be able to transform the same amount of money into a greater expectation value of scientific results. Many people are dissatisfied but most of the dissatisfaction is driven by personal interests, not a genuine interest of science.
Public perception of science
The second reason that has almost certainly contributed to the cuts is a deteriorating perception of high-energy physics by the public. The two infamous books and the media campaign surrounding them is a finite part of the story.
As far as I know, every single high-energy physicist - graduate student, postdoc, professor - at every good enough place knows that the comments of people like Peter Woit or Lee Smolin about physics are completely worthless pieces of crap. Peter Woit is a sourball without a glimpse of creativity who only spreads bad mood and confused, superficial propaganda. He has never contributed anything substantial to science and it is likely that he will never contribute anything of this kind in the future.
He's a typical incompetent, power-thirsty, active moron of the kind that is capable to destroy whole countries if he gets a chance to do it: think about someone like Robert Mugabe.
Analogously, Lee Smolin is a prolific, full-fledged crackpot who has written dozens of papers and almost every single one is a meaningless sequence of absurdities and bad science. Once again, everyone in the field knows that. But a vast majority of the people in the field think and say that these two people and their companions don't matter; they don't have any influence, and so forth.
However, in many cases, this slogan only justifies scientists' escape from their broader responsibilities. In other cases, the formulation is a symptom of pacifism after it has lost any touch with reality. The reality is that the two pseudoscientific ideologues - and a few others - have a significant influence on the society. 99% of the public are simply unable to figure out that Smolin's or Woit's writing is just garbage that no well-informed person should pay any attention to. They are unable to do it themselves and they have virtually no channels where they can learn this otherwise obvious fact from the people who can figure it out.
So the public image of high-energy theoretical physics and many of its proxies inevitably deteriorates. The funding cuts are partly explained by this fact even though there are other reasons, too.
Concentration of brains
The second topic I want to discuss is concentration of brains. As Cosmic Variance reported, Drew Gilpin Faust, the new president of Harvard University, said that less elite universities should prepare that they won't have funds to compete with elite places such as Harvard in cutting-edge scientific fields.
Now, I find it obvious that this is what leaders of powerful places probably expect - or at least pretend to expect - and what they want others to expect, too. And it is mostly true, too - at least in the long run.
Skillful and lucky people can occassionally accumulate in a place that is not the most expected one. But these are statistical fluctuations that can go in both ways and that usually average out in the long term. For example, Rutgers University became one of the leading string-theoretical think tanks in the early 1990s. They group was kind of lucky with people and with funding, too. What has happening at Rutgers University could have occurred in some of the Ivy League schools instead.
However, these things are unlikely to last. If a place has superior financial capabilities, it will eventually attract the people it needs to attract to become the top place. Moreover, such an outcome is good for science for the same reasons that make big corporations more efficient than their small competitors in the commercial sector and that makes imperialism work better in most respects than primitive forms of capitalism. A certain critical mass, an increase of helpful interactions, and an efficient self-organizing distribution labor of contribute to exhanced power and creativity of places with a lot of brains and resources.
This result is only to be expected if things work properly. Of course that if they don't, a place with a lot of brains is also able to waste a lot. But once again, in the long run, things should work most of the time so the argument assuming that things work is likely to give at least the right sign of the result.
So I don't believe the ideas that a uniform distribution of places and scientists is the healthiest environment for scientific progress. Just like the concentration of capital is essential for capitalism to achieve many things, the concentration of intellectual capital (as well as ordinary capital that scientists sometimes need) is often necessary to achieve certain results in science, too.
In the case of accelerators, the most extensive experiments on Earth, there is no doubt about it. But even if you look at the following category of scientific activities according to the magnitude of their projects - such as various genome projects - it is still likely that the concentration of experts into a few places will be a superior arrangement that will lead to faster progress for the same money.
What I wrote above might agree with the words of the current president of Harvard University and others. On the other hand, every sane person should also realize that only one of us is making a pure intellectual analysis here. The other one is also playing a game expected from a particular job, attempting to achieve certain goals. Of course that it is expected that the president of an elite university tries to make his or her university more exceptional.
But others have different tasks. In the short term and medium term, there also exist other mechanisms that allow e.g. a prestigious biological center to appear at an unexpected place. So the leaders of places of different sizes will obviously simplify the situation in different way and present different visions about the future of science and technology simply because their roles justify different strategies. It is obvious that different opinions will be heard and one shouldn't be shocked about it.
English subtitles are included. The videos were posted by no one else than an Islamist nutcase. These Sirs are slowly switching to YouTube, an invention of capitalist infidels. ;-) The message is encouraging. Much like his previous video in which Prof bin Laden endorsed Prof Chomsky, his comments are virtually identical to the comments about the war by DailyKos.com or MoveOn.org except that bin Laden is much more peaceful than they are.
There is no indication that he is capable to do anything. Moreover, he seems to surrender in Iraq because he treats Iraq in a similar way as Israel. Both countries are painted as targets of his holy anger and Israel is supposed to be wiped away off the map. But it is not explained what the methods to realize his dreams could be, except for unsophisticated and weakening murder procedures that they were showing the world for several years.
He assures those who fight for freedom that they will be unhappy even if they win while Osama's side has nothing to lose, except for chains. This slogan shows Osama's conversion to a Marxist notion of class struggle. Again, he wants to take credit for the collapse of the Soviet Union. Also, no one will prevent them from dying an honorable death. Well, he seems to be right. For example, your humble correspondent will certainly not prevent them to do so and I hope it will be not only an honorable but also a speedy one! :-) Osama's speech is full of moralist and pacifist clichés. He also accuses America of plans to steal the Iraqi oil, nothing new for people who have listened to leftists for years.
Sadly, Benazir Bhutto had to sacrifice her life because of some of those fanatics who were still anomalously alive. My main interaction with her was that I received a book about her because my photograph of the Radcliffe Institute where she studied was used in it. See the story.
It is being said that only once in a decade, it is possible to ice skate on the Hracholusky dam (map) near Pilsen. Most of the time, the ice is either melted or covered by snow. The exceptional time occurs this month. The ice was very smooth so we could skate almost 10 miles without any interruption.
Tomorrow, the Prague Castle - I really mean the Hradčany Square pictured above - will host a cross-country skiing competition organized by Ms Kateřina Neumannová, our 30-kilometer freestyle 2006 Olympic winner. 60 trucks of snow from Šumava were needed to improve the skiing conditions. ;-) See photographs of the transfer.
Translation (read the comments below this box first)
0:02 These clouds don't bring us any blessing: they are coming from the West. Using wind and clouds, the American imperialists sent the potato beetle to attack our republic.
0:20 A father with his son just saw something. They bend over and find something on the road. That's him: the American bug, the newest criminal gadget of the American barbarianism. This year, we found it even at places where it kind of naturally doesn't belong: on the wood instead of potato crops. We found it on the dumping ground. Another American bug climbs a wall.
0:46 A bug distributed by wind and aircraft from the Western and Southern borders, it is also brought here by the U.S. agents in small boxes and bottles. Those who sent the insatiable bug here expected it to find a path to our potato crops. They counted that it would unstoppably eat what was growing for us. They expected it to create thousands of eggs that would transform into red-orange larvae. What do the American imperialists want?
1:15 They want the most dangerous foe of potatoes to destroy our advanced potato industry in order to strangle our nutrition, food production, and the industry that uses potatoes as a resource. These larvae are the culture of the war-loving atomic packers.
1:34 However, the imperialist Sirs were writing a bill without a waiter. They were computing and they have miscomputed once again. Our government has established strict policies to protect us against a disgraceful attack by our enemies. Even those who live in the West should already know it: in our country, words and acts are close to each other.
1:55 All of us, and especially the youth and pioneers, are beginning to fight. We will find every single American bug and destroy it. Each place where they are found will be disinfected. Each place will be properly identified. Technology will help us to fight the intruder. [Tons of DDT are poured over the land.] We invest all of our strength to save the fruits of our work. This is our immediate defense against the attack by our enemies.
2:36 We won't let them become a pupa under the ground. Even in the depth of soil, we will find them and liquidate them. This is our answer to the hostile attackers. We have dealt with [executed] Horáková, Pecl, and their companions. We will deal with the Colorado potato beetle, the American bug, too. We will save and clean our fields and our harvest from the American epidemics. We don't want stuff of others: but we won't sacrifice ours.
This Czechoslovak communist propaganda video from the 1950s is a great example showing that the anti-American environmentally loaded propaganda is nothing new. The videoclip above is almost identical to the contemporary propagandistic movies and news about Americans causing global warming.
Because it's in Czech, let me explain some background (even though you will understand some parts of the video anyway).
The Colorado potato beetle (Czech: Mandelinka bramborová), a bug that eats potato crops, started to intensely propagate throughout Europe in the 1940s because of much improved potato transportation. The Nazi propaganda used it to argue that the U.S. Air Forces were distributing the bug by their aircraft. Amusingly enough, the communists adopted the very same thesis, regardless of the uniform nature of the expansion of the bug across Europe.
Now you should look at the video and read the translation right beneath it.
Criticism
Now, what's wrong with the video? Why is it propaganda? Most obviously, the content of this video is not true. The bug was spreading due to natural reasons and as a by-product of technological progress, not due to the American imperialists. But let's imagine that the basic hypothesis could have been true and we were just uncertain. Note that virtually all of my criticism of the videoclip applies to the global warming propaganda, too.
Well, even if we didn't know that it was really untrue, the movie deliberately oversimplifies the story. It is inconvenient for them to say that the bug spreads because of many known reasons and some unknown reasons. They choose one convenient, anti-American explanation only and they have presented it repeatedly. Note that the basic idea - that it was the evil Americans who sent the bug - is repeated many times throughout the videoclip. They rely on Goebbels's thesis that a lie repeated many times becomes the truth.
Also, the Americans are deliberately connected with an emotional adjective - imperialist - that should gain a very negative connotation as a result of all this propaganda even though the economic system of "imperialism" would have clearly nothing to do with the bug even if it were deliberately propagated by the U.S. agents. Also, the bug is constantly connected with the adjective "American" in order to associate America with bad things. They seem to forget that not only the bug but also potatoes themselves came from the Americas.
The propaganda movie uses children and emotional scenes evoking the idea that the children would have no future because of the evil Americans: the purpose of this strategy is to change a possibly rational approach of people to these matters into an emotional one. This aspect of the ancient Stalinist videoclip is reproduced by An Inconvenient Truth and other contemporary propaganda pieces without any modification whatsoever.
Another subtlety is that these videoclips deliberately encourage people to believe in various convenient scientific myths, for example that clouds can carry a beetle (or its eggs) for hundreds of kilometers. In the same way, An Inconvenient Truth deliberately encourages people to think e.g. that the CO2-temperature relationship proves the influence of CO2 on temperature even though it is known very well - and arguably even to the producers of the movie - that the direction of the main causal link certainly goes in the opposite direction.
The videoclip presents the situation in a black-and-white fashion. Finally, it is emphasized by the movie that the whole nation is unified and it has switched from words to action. In reality, it is, of course, a complete nonsense because only a small portion of the nation would participate in the extermination of the bug. Also, an off-topic comment about the execution of Ms Horáková and Mr Pecl is incorporated in order to intimidate possible critics. The very same insights apply to a fight against global warming. Quite obviously, a vast majority of the world's population doesn't participate and cannot participate in overly ambitious projects to radically change the role of carbon in our lives. And many people disagree with these projects as long as they have the basic freedom to do so. But the movies associate the skeptics and critics with various unpopular and losing groups from the past.
The technical details of the anti-American propaganda keep on changing but their dirty tricks and dishonest nature survive without any change.
John von Neumann was born on 12/28/1903 as Margittai Neumann János Lajos to a rich Jewish family of a banking lawyer in Budapest. He was one of the greatest 20th century mathematicians.
János, nicknamed "Jancsi" (Johnny), was the oldest among three brothers and a child prodigy. He entered a German-speaking school at age of 8. Two years later, his father acquired "von" for his services to the Austrian-Hungarian monarchy. His son became János von Neumann, a name later changed to Johann von Neumann. Johann received his PhD in mathematics at age of 23, earning degrees from chemical engineering at the same time (because his father wanted him to be rich, too). By the time he was 25, he had published 10 major papers. Five years later, the figure jumped to 36.
His family moved to the U.S. in 1930. Johann changed his name to John and became one of the first four or five employees of the IAS, Princeton together with Einstein, Gödel, and one or two more. For his first wedding in 1930 to work, John converted to Catholicism and this religion stuck. In 1957, he was diagnosed with pancreatic cancer that quickly took over his body and killed him: it was probably a result of his work in Los Alamos discussed below.
Weather science, global warming, and security
Because this is also a global warming blog, let me start with a fact that is neither terribly important not too well-known. One of his hobbies was to forecast weather. As a result, he has also designed a sophisticated project that could have efficiently raised global temperatures and make the world a better place: it was an ambitious project of a man-made global warming. He wanted to spread colorants on the polar ice caps in order to reduce the albedo and increase the absorption. ;-)
Nowadays, most people no longer have the courage to add a few balmy degrees to the global temperature. In fact, some people don't even have the courage to do nothing!
John von Neumann also wanted to preemptively nuke the Soviet Union to prevent the damn communists from getting a nuclear bomb; later, when it was too late, he invented the mutually assured destruction doctrine. When you combine the previous two sentences, it is not hard to guess that he would recommend to nuke the IPCC, Al Gore, and similar dangerous crap today, too. In the U.S. Senate, he described his political ideology as "violently anti-communist, and much more militaristic than the norm". Well, I am on the same frequency. :-)
Von Neumann was a frequent consultant for Standard Oil, CIA, Pentagon, the Rand Corporation, IBM, and others. I am sure that the contemporary far-left nuts would love him! ;-)
Logic
At the end of the 19th century, mathematics was already based on meticulous axiomatics. Suddenly, Russel's paradox emerged. If you don't know, its essence is a "set M containing all sets X that are not elements of X i.e. themselves". Now ask, is M an element of M? If it is, it's not, and vice versa. To solve this paradox, it must be illegal to construct such a set M.
There are two basic strategies to get rid of the contradictions: the Zermelo-Frenkel approach that only allows you to construct "small enough" sets constructively or "from below" and the notion of "class" that allows you to construct classes (more general concept than a set) such as M but they are not guaranteed to be sets and only sets such as X may be included into classes. These approaches were known from the early 20th century and 20 years later, von Neumann essentially completed them.
However, the story was not over because in 1930, Kurt Gödel announced his incompleteness theorem. Incidentally, von Neumann was an important "ear" for Gödel, for example when Gödel was making his pioneering steps in P & NP completeness.
Foundations of QM
Von Neumann decided to write down axioms for quantum physics. Observables are linear operators, and so forth. His work has conceptually unified Heisenberg's matrix mechanics with Schrödinger's wave mechanics although Paul Dirac's realization of this task was more concrete and became more popular with the physicists.
He also knew that the probabilistic predictions of quantum mechanics couldn't have been an approximate reflection of a deterministic theory. So he "proved" the first hidden-variable no-go theorem. Its main conclusion was right but the demonstration included a conceptual error. He also proposed a new kind of logic for quantum mechanics that didn't respect commutativity of conjuction and other things.
Physicists including your humble correspondent always preferred to keep the normal logic. I really don't understand how one could work with von Neumann's strange rules. The consistent histories, the most complete framework to interpret quantum mechanics today, imply that exactly those quantum histories (sequences of projection operators at different times) for which the classical rules of logic work - the consistent histories themselves - are allowed. A new logic is unnecessary and, using the jargon of consistent histories, it is inconsistent. :-)
Economics
Von Neumann has introduced methods from mathematics and natural sciences - game theory and general equilibrium theory - to economics and found a strategy to minimize the maximum loss (the minimax theorem, something that has some links to von Neumann algebras). He has also incorporated imperfect information to the picture and invented backward reduction in game theory.
Nuclear bombs
John von Neumann participated in the design - the optimal angles and altitude - of explosive lenses, a gadget needed to compress the plutonium core of the Trinity test and the Fat Man that was sent to Nagasaki.
He was a member of the committee that was choosing the targets. What was his first choice? Well, everyone who knows the dangerous attempts of some loons today to globally regulate carbon must guess what is the right answer. Yes, his first recommendation was Kyoto, a cultural center. Finally, however, they chose Hiroshima and Nagasaki.
Robert Oppenheimer remarked that the physicists in the Manhattan project "had known sin". Von Neumann's response was more constructive. He said that "sometimes someone confesses a sin in order to take credit for it". ;-) He continued unperturbed and filed a secret patent how to use a fission bomb to initiate a fusion bomb. It was not quite the ultimate Teller-Ulam design but it was in the ballpark.
Computer science
During the hydrodynamic simulations for the Hydrogen bomb, he co-fathered the Monte Carlo method and invented the middle-square method to generate pseudorandom numbers. The hydrodynamics programs including his "artificial viscosity" later turned out to be very helpful for astrophysics.
At some moment, von Neumann outlined the von Neumann architecture: the same memory is used both for programs and data. It became standard. When we talk about a good architecture, you might also ask what were its lame competitors. Yes, it was primarily the crappy Harvard architecture ;-) where the two "memories" were separated.
John von Neumann is the father of the field of cellular automata. He advocated self-replicating automata for mining of an entire moon or asteroid belt ;-) and worked out a toy model for such automata on paper. As far as Al Gore Rhythms go, von Neumann invented the merge sort algorithm and was able to simulate a fair coin with a biased coin.
Summary
John von Neumann was a polymath, the kind of a genius who would not be tolerated by the mediocre scholars dominating the contemporary Academia.
In this weekly dose of peer-reviewed skeptical literature about the climate, we look at a paper called "Quantifying the influence of anthropogenic surface processes and inhomogeneities on gridded global climate data" by Patrick Michaels and Ross McKitrick that was published two weeks ago in Journal of Geophysical Research - Atmospheres.
The question is whether the land surface temperature data are reliable.
The authors choose a McKitrickish strategy whose earlier versions I found kind of amusing but this particular paper looks rather ingenious to me (even though it is an improved version of their 2004 paper).
They start with the following thesis. If the temperature data really measure the climate and its warming and if we assume that the warming has a global character, these data as a function of the station should be uncorrelated to various socioeconomic variables such as the GDP, its growth, literacy, population growth, and the trend of coal consumption. For example, the IPCC claims that less than 10% of the warming trend over land was due to urbanization.
However, Michaels and McKitrick do something with the null hypothesis that there is no correlation - something that should normally be done with all hypotheses: to test it. The probability that this hypothesis is correct turns out to be smaller than 10-13. Virtually every socioeconomic influence seems to be correlated with the temperature trend. Once these effects are subtracted, they argue that the surface warming over land in the last 25 years or so was about 50% of the value that can be uncritically extracted from the weather stations.
Moreover, as a consistency check, after they subtract the effects now attributed to socioeconomic factors, the data from the weather stations become much more compatible with the satellite data! The first author thinks that it is the most interesting aspect of their present paper and I understand where he is coming from.
These correlations might look irrational but there exist pretty convincing mechanisms that can explain these correlations: the urban heat islands become just one example. If you want to hear another example, a poor country cannot afford to paint the stations too often. They get dark and absorb an increasing amount of light which warms them up.
A part of the claimed correlations may turn out to be accidental or results of spatial autocorrelation but the general lesson that the data from thermometers inside particular stations don't just naively measure the "real" temperature in the troposphere above the region but many other things is certainly a correct and important one.
Johannes Kepler was born prematurely near Stuttgart on 12/27/1571. His grandfather was a mayor of their town but once Johannes was born, the family's fortunes were already dropping. His father was a mercenary and left the family when Johannes was five. His mother was a healer and a witch which has also led to some legal problems.
Johannes was a brilliant child with early inclinations to astronomy. In Graz (1594-1600), he was defending the Copernican heliocentric system. At that time, there was no clear difference between astronomy and astrology. Therefore, Kepler also invented the ADE classification of planets orbiting the Sun. ;-) This attempt resembled, but was not identical to, Garrett Lisi's hopeless attempt to unify. Kepler also wrote that the Universe had to be stationary.
In 1600, Kepler finally met Tycho Brahe in Benátky nad Jizerou (see the picture), a central Bohemian town where Brahe built an observatory. Brahe quickly recognized Kepler's magic theoretical powers. Their negotiations about the new Kepler's job in Prague were accompanied by arguments and tension. Fortunately for the Czech capital, Kepler had more serious problems with Graz where they expected him to convert to Catholicism. Finally, Kepler moved to Prague, including his family.
He became the imperial mathematician of our monarchy, an advisor to Emperor Rudolph II, a predecessor of Václav Klaus and a great sponsor of arts and sciences pictured above, and 11 most productive years of Kepler's life were just getting started. Kepler was also giving his political recommendations to the empire although his common sense was more instrumental than the stars.
In Prague, Kepler established modern optics (he understood geometry of lunar shadows, the inverse-square law controlling the light intensity, and other things). In 1604, he started to observe SN 1604, a supernova also known as Kepler's star, in the constellation Serpentarius, the 13th sign of the zodiac in which your humble correspondent was born. Click at the link and see Kepler's beautiful drawing of Ophiuchus, as the constellation should now be called. It started to be clear to him that the heavens were not as constant as Aristotle used to think.
Kepler's laws
In 1602, Kepler discovered the law that we derive from the conservation of the angular momentum these days. He had a somewhat strange, non-Newtonian interpretation of it: the Sun provides the planets with motive power that decreases as they get further from the Sun which means that when the planets are far away from the Sun, they move more slowly. ;-)
Tycho's very accurate data about Mars were very important for Kepler. Incidentally, Mars may be hit by an asteroid in one month: the probability exceeds 1 percent.
After 40 years of failed attempts, Kepler finally got the right idea about the shape of the orbit in 1605. Why didn't he think about the ellipse - the shape dictated by his first law - earlier? Because it was too simple and Kepler thought that the astronomers would have figured out such a solution a long time ago if it were correct. This story hides at least two general lessons.
The first lesson is that it is sometimes easier to learn important insights from examples that are not the simplest ones because their patterns are sharper, more visible, and more characteristic and they cannot be confused with others. The simplest cases and solutions often look too singular and their modest internal structure is a bad starting point for generalizations. More complex examples typically "pinpoint" the right general law or algorithm uniquely or almost uniquely.
The second lesson is a sociological one. While it may be more likely that a simple solution should have already been found by others, they may have overlooked it, too. And if they did, such a simple solution might be much more valuable. I think it follows that scientists shouldn't ignore a topic just because it was found uninteresting or unrealistic by many others.
On the other hand, you are never guaranteed to succeed. If you attempt to do something simple that has been tried by many others, you are less likely to find something new, especially if you are less gifted than Kepler.
Kepler realized that the Mars data agreed with the ellipse beautifully and he has abruptly and correctly deduced that all planets had elliptical orbits even though he couldn't have done the numerical calculations for all the planets (he had no postdocs and grad students). In 1610, Kepler also had a healthy and friendly exchange with Galileo Galilei, supporting his discovery of the moons and helping him and others to improve the telescope.
The last law of planetary motion I didn't mention was the third one: the orbital times squared are proportional to the distances cubed. Kepler included this law as an example of the harmonies that the Creator used to decorate the heavens.
Religious tension in Prague
Unfortunately, politics slowed the progress down in 1611. Rudolph II became seriously ill - and died in 1612 - and his brother Matthias who was 5 years younger and who was already controlling Austria, Hungary, and Moravia was able to grab the kingdom of Bohemia, too. This, of course, meant a dramatic decrease of the influence of so-far-dominant Bohemia within the Holy Roman Empire. It also meant a dramatic weakening of the conditions to do research in Prague (and elsewhere, for that matter). While Matthias confirmed Kepler's job and salary, he allowed him to leave for Linz, Austria. In Linz, Kepler was teaching at the district school and he was calculating the year of Christ's birth.
That was a pretty bad development for science. At least, Kepler's second marriage was much happier than the first. However, his writing got much less quantitative than during the golden years in Prague. It became somewhat astrological and similar to his early years. A monument to Brahe and Kepler at the picture above is in Prague 6, Pohořelec, a former place of another observatory of Brahe near the Prague Castle.
Jacob Bernoulli
Another guy who was born on December 27th was Jacob Bernoulli, namely in 1654. His parents wanted him to do theology but he preferred mathematics and astronomy. The Bernoulli numbers that appear in Martin Schnabl's solution to string field theory and elsewhere belong among his discoveries. However, you should be careful: there were 8 good mathematicians and physicists in his family. For example, the laws of hydrodynamics and aerodynamics are due to Daniel Bernoulli.
John Horton Conway, a famous English mathematician, was born exactly 70 years ago, on 12/26/1937. Congratulations! He has contributed great things to game theory and algorithmics, group theory, geometry (classification of polychora), knot theory (applications of skein relations that led to knot polynomials), and theoretical physics.
How is it created? The first entry "1" is read off as "one 1", so you write "11". This is read off as "two 1's", i.e. "21". That is read off as "one 2, one 1", i.e. "1211", and so forth.
If you started with "22", it would be a fixed point: "two 2's", "two 2's", and so forth.
Otherwise you can prove that only the digits 1,2,3 will appear anywhere in the sequence. More interestingly, the sequences may contain one of 92 different "audioactive atoms" composed out of 1,2,3 that don't interact with their neighbors. Numerologist Conway has jokingly identified them with chemical elements. For each digit larger than 3, if you allow them at the beginning, there also exist two "transuranic" elements.
The strings increase in size. You can prove that a new entry is asymptotically 1.303577... times longer than the previous one. This Conway's constant is actually the only real positive root of a known and "simple" polynomial of degree 71. ;-)
"Game of Life" and other fun things for adult children
Conway's inventions in recreational mathematics and his popularization pieces and books are far too numerous to enumerate here. He can calculate the day of the week in two seconds or so, using his Doomsday Al Gore Rhythm. Also, Conway's "Game of Life" remains the most popular cellular automaton although the suggestion that the game contains all essentials of life is surely and dearly exaggerated.
John Conway, a worker in the classification of finite groups, is also a big shot in the sporadic groups, the father of the Conway groups, and a co-father of monstrous moonshine involving the monster group.
Free will theorem
Recreational mathematics may be fun but it is somewhat orthogonal to the main interests of this blog. And we have already spent quite some time with finite groups (and their application to gravity in AdS3) on this blog anyway.
Instead, I want to mention the free will theorem, a robust result about the foundations of quantum mechanics that Conway proved in 2004, together with Simon Kochen, a colleague from the Princeton math department. It is a fascinating and crisp modern version of the no-go theorem for hidden variables that shows that Conway really understood what quantum mechanics is all about and why you should never mess up with its probabilistic character and with the apparent fact that the individual random results of microscopic measurements cannot be explained by any mechanism.
The no-hidden-variables theorems usually show that there can't be any hidden variables that would "materialistically explain" the otherwise random outcomes of quantum experiments as long as you agree that it is impossible for the actual physical information to propagate at arbitrary speeds. Because Bell's inequalities (or, alternatively, assumptions that would lead to "paradoxes" via the Kochen-Specker theorem) are violated in Nature, it follows that a hidden variable theory has to be non-local. You have heard me saying that such a non-local theory would inevitably be acausal and Lorentz-breaking - which really means unacceptable - and Conway and his collaborator have indeed proved this implication.
The free will theorem is a very cute sharpened reformulation of the hidden variables no-go theorems that can be phrased in the following way:
If experimenters have free will, then so do elementary particles.
Because this statement may sound too entertaining, let me emphasize that it is not a caricature of the theorem. They actually prove nothing else than the exact, most obvious interpretation of the sentence above.
So if you accept that an experimenter's decision to press particular buttons during his experiments has no calculable "materialist" explanation - if the experimenter's decisions during the experiment are not functions of his history, heritage, or environment, allowing us to say that his decisions resulted from the "free will" - we must also accept that there can't be any "materialist" explanation of a particular behavior of elementary particles: particles have the "free will", too. The outcomes of events involving microscopic physical systems must be truly random and unexplainable by the environment, too, which may be interpreted as a "free random decision" of the particular particles. There can't be any hidden variables that would dictate particles how they should be measured in particular experiments as long as you accept that there are no hidden variables that would dictate experimenters what buttons they should press or what buttons they are allowed to press under certain circumstances.
Another temporary disagreement with Stephen Adler - answer by Conway and Kochen - has been resolved and we will focus on the blockquoted list above.
The first preprint is entertaining enough for you to look at it. They discuss the free will, simpletons, fish, a spin-one EPR setup (for which they also proved a stronger version of the quantum xerox no-go theorem a month ago), and the cute old Kochen-Specker combinatorial proof that one can't define 101 functions i.e. assign consistent colors to certain 33 axes in space. They show that hidden variable theories and also a bizarre scenario by Ghirardi, Rimini, and Weber (GRW) are impossible. If you don't remember The Fabric of the Cosmos by Brian Greene, the GRW theory suggests that the classical character of macroscopic physics is achieved by "stochastic hits", occassional spontaneous "collapses" of the wave function of some kind, induced by weird non-linearities added to the Schrödinger equation. Incidentally, GRW has over 750 citations - it is a whole industry of pseudoscience. The result by Kochen and Conway is thus stronger than Bell's theorem because it falsifies two unprofessional (or "unromantic", using Bell's jargon) classes of interpretations of quantum mechanics instead of just one.
Conway and Kochen show that the only way how GRW might be right is that the stochastic hits not only control the particles' behavior but also all experimenters' actions which seems as a fantastic enough possibility for us to say that it is impossible. They emphasize that the problem with the hidden-variable and GRW theories is not that randomness is needed to reproduce the real observations. What they really prove is that there can't be any underlying reason - deterministic or otherwise - behind the particles' behavior in a given situation or experiment: you really have to admit that their random behavior is not a function of any data in their past cone: it depends on their "free will". With this language, Conway and Kochen put a positive spin on this philosophical conclusion: it is all about freedom and the hidden-variable theorists as well as GRW are really freedom-haters. ;-)
Bassi, Ghirardi, and Tumulka didn't really understand anything but their criticism has convinced Kochen and Conway to make their proof much more efficient. In the last preprint, they only assume a simple "MIN axiom" about the experimenters' free will. And they only spend half a page in proving their theorem. It is this minimal version of their proof that I have always had in mind - and independently found - when I argued that the "unexplainable" probabilistic interpretation of quantum mechanics is both necessary and sufficient to preserve special relativity.
Much like in the case of the arrow of time, the issue of "free will" in quantum mechanics, if you allow me to use this jargon, seems to reveal that some people simply can't get rid of a certain religious zeal about these matters. They just believe that some explanation that denies the "free will" and has a "materialist" description of the real state of the physical system must be possible. They believe that if one particular model of this kind fails, there must exist a slightly modified model which is fine. However, people like Kochen and Conway prove that this whole huge class of models - the whole way of thinking and all possible modifications of the hidden-variables or GRW models that hundreds of generations of physicists and philosophers could be constructing for thousands of years - can be safely ruled out by a half-a-page proof.
Ghirardi, Bassi, Tumulka et al. just don't seem to be able to swallow such a result. See Tumulka's habilitation thesis posted in November 2007 that shows no progress whatsoever. Another recent confused paper of this kind was written by Daniel Bedingham. One year ago, Gerard 't Hooft has also offered his own analysis whether John Conway had the free will to throw his coffee across the room. However, I am afraid that 't Hooft has only discussed how the free will would look like in the old-fashioned, philosophically trivial deterministic world rather than the real world around us.
But there is also a difference between Ghirardi and Bassi on one side and Tumulka on the other side. Tumulka believes that a GRW-like theory may be fully Lorentz-invariant which is clearly wrong: his GRW-like "counterexample" to the Kochen-Conway theorem has no interactions which is a huge defect because interactions are essential for a "measurement" to occur and for us to have any problem to solve and data to explain at all. On the other hand, Ghirardi and Bassi agree that such a theory can't be fully Lorentz-invariant. Instead, they hope that their future theory's predictions will be effectively Lorentz-invariant in a stochastic sense but one reference frame is fundamentally privileged.
Curie's principle
Kochen and Conway have not yet been able to show that such a stochastic agreement assuming only one fundamentally privileged reference frame is impossible - and it is quite likely that it is logically possible (just imagine a "simulator" of a real quantum world with some random changes designed not to change the statistics) - but they defend a principle first articulated by Pierre Curie that a theory should have all the exact symmetries that seem to be exact experimentally. I agree with this principle. For example, if there is no experimental way, not even in principle, to find a privileged reference frame, our theories shouldn't have one either.
Can I rigorously prove Curie's principle? Not really. Why do I believe it? Because the experimental validity of a symmetry is an important and general insight and a powerful constraint that should be taken seriously, much like (and perhaps more than) other forms of empirical data, while all attempts to show that a known symmetry is an approximate coincidence is nothing else than a belief that a "miracle" will cure something that otherwise looks like a contradiction between a theory and experiments.
But Occam's razor tells us not to believe such "miracles" and to eliminate non-trivial constructions predicting new otherwise unnecessary phenomena that seem to be absent in the empirical world - unless we have a good reason. Also, Gell-Mann's totalitarian principle teaches us that a theory that fundamentally disrespects a symmetry is likely to violate it substantially, not just by a tiny and unmeasurable amount. It is this combination of empirical reasoning, Occam's razor, and Gell-Mann's principle that leads me to accept Curie's assumption, too.
Now, this assumption can't be a universal dogma: indeed, we know various symmetries (such as the baryon number conservation) whose violation hasn't been seen experimentally so far but seems likely anyway. But in the case of the baryon number, its violation is likely because one can't construct satisfactory theories of high-energy phenomena (or quantum gravity) that would exactly preserve the baryon number (except for theories where it is a gauge symmetry with an unnaturally small coupling constant). The baryon number violation seems to be a derivable assertion. On the other hand, we don't seem to gain any explanatory power from a hypothetical GRW-like violation of the Lorentz symmetry. The probabilistic explanation involving the "free will" just seems to be a more successful description of known experiments than the awkward fine-tuned theories with effective symmetries that are not symmetries at the fundamental level.
There is another, complementary difference between the accidental baryon number symmetry and the accidental Lorentz symmetry in theories of the GRW type: the former can be proven to approximately hold in the Standard Model at low energies - this accidental symmetry is thus not a real "miracle" - while the latter has no known derivation, except for one based upon wishful thinking and philosophical prejudices.
Proper science vs dogmas: once again
We should believe the theories and philosophical principles that actually seem consistent with the observed phenomena, whether their philosophical background is psychologically convenient to us or not. In science, the question such as "does a particle have the free will?" is not and cannot be answered a priori. A physicist must be a priori open-minded about the answer. When he properly and logically analyzes the results of experiments involving entanglement, he finds out that the particle simply does have and must have the "free will", whether this answer was pleasing or expected or not: an underlying explanation of a particular random outcome of a microscopic experiment simply cannot exist, not even in principle, whether you like this conclusion or not.
The wrong assumption of a hidden "explanation" beneath every microscopic event could have been compatible with classical physics but quantum physics clearly shows that it was a wrong intuition based on our limited, approximate, classical everyday experience. Quantum mechanically, particles do have the free will!
Science is about a fair and balanced treatment of possible answers, about logical analysis and experimental verification. It is not about preconceived dogmas about the answers and ad hoc definitions of "science" or "good science" that might implicitly include incorrect assertions about reality.
It's Christmas Eve which doesn't mean that physicists are not born. We will talk about two famous people born on Christmas, namely Jesus Christ and James Joule. ;-)
About 2008-2013 years ago, Virgin Mary talked to archangel Gabriel, a boss of God's P.R. department. It is believed it was on March 25th. She remained a virgin legally. Nevertheless, the annunciation has also served as conception biologically. Atheist scholars often argue that Christmas is celebrated around December 25th because Christianity wanted to absorb the Roman cult of the unconquered Sun (Sol Invictus), a paganic holiday celebrating a sun god and introduced by Aurelian, a Roman emperor, in his attempt to establish a new imperial religion.
However, Benedict XVI, the current Pope, offers a different theory explaining December 25th. He starts with March 25th, the date of conception that he represents as a figure from the new Gregorian calender, and adds 9 months. Roman emperors are thus completely eliminated in his approach. You might protest that one unknown number is calculated from another unknown number. But don't forget that the Annunciation is God's revelation that can be used as legitimate input of all your calculations. You might also object that pregnancy didn't have to last exactly for 9 months. But this objection can also be resolved: the Pope said it was exactly 9 months and the Pope is infallible. ;-)
Commercial:Queen Elizabeth revealed her new YouTube channel. She shows a 50-year-old groundbreaking TV speech in which she criticized various crackpots and haters.
From Jesus to Joule
James Prescott Joule (12/24/1818 - 10/11/1889) was born as the son of a rich brewer. He was tutored at home - except for a short course that James Joule and his brother Benjamin received from John Dalton who had to retire soon because of a stroke. Nevertheless, arithmetics and geometry taught by Dalton impressed James Joule tremendously. He was intrigued by electricity, too.
Anyway, he became a manager of the brewery. Science was Joule's hobby. One of his goals was to replace steam engines by electric motors. So he started to publish in Annals of Electricity around 1838. Two years later, in 1840, he discovered Joule's law: the amount of heat generated by a conducting wire equals Q = R I² t. He hoped to impress the Royal Society but he was treated like other people from towns with breweries: as a provincial dilettante.
Joule studied the efficiency of various energy sources and possibilities how energy can be converted from one form to another. Outside the Academia and outside the engineering profession, he discovered the equivalence of heat and work and the first law of thermodynamics. Today, we use Joule as the unit of both heat and work. It is expressed as the product 1 J = 1 kg m²/s² and seems unspectacular but Joule's discovery was nevertheless one of the classic, ancient cases of unification.
You should realize that heat used to be viewed as an independent physical phenomenon whose relationship with other concepts in physics was unclear. Even today, many people look at heat in this way before they learn the correct explanation and some of them never do. Isaac Newton himself thought that heat was a form of liquid. It used to be measured in different units. One calorie was defined as the heat obtained by cooling 1 gram of water by 1 °C. Once Joule's discoveries are appreciated, we don't need to consider an unmotivated and ill-defined liquid such as water or temperature differences: heat can be expressed in the same universal units as mechanical work.
The fate of units
Every basic unit in physics can be viewed as a major mystery waiting for its discovery. Joule was able to express calories in ... Joules although his estimate was not terribly accurate: the first law of thermodynamics had to be discovered along the way. Kelvin degrees can be expressed in Joules, too. You need Boltzmann's constant to convert Joules to Kelvins but you will only understand this conversion as a natural one if you figure out that heat itself is energy stored in microscopic degrees of freedom of matter: statistical mechanics is needed.
There are other a priori independent units that can be converted in a similar way, requiring analogous discoveries. The electric and magnetic units may be expressed in grams, centimeters, and seconds, too: that's what CGS/Gauss's units do. In SI, you are left with seven basic units. Ampere may be re-expressed in kilograms, meters, and seconds. It was only reintroduced into SI to deal with different conventions where the speed of light should be put into Maxwell's equations in CGS units (CGSE/CGSM etc.).
Candela is a partly subjective quantity because it can only be defined if you realize what frequencies of light are visible by the human eye. In other words, you can eliminate candela from the list of basic units and replace it by the full function encoding power carried by light at different frequencies. Kelvin is re-expressed in Joules using statistical physics, as we have already mentioned. Mole is also eliminated once you learn what Avogadro's constant is: you may then count matter directly in atoms and molecules.
What is left is meter, kilogram, second. Meters can be converted to seconds as soon as you discover special relativity and realize how fundamental a role the speed of light plays in theoretical physics and how unnatural it is to have different units for distance and time. Inverse seconds that measure frequency can be expressed in Joules that measure energy, eliminating one more independent unit, if you are Max Planck and if you discover a basic fact about quantum theory, namely the energy carried by a quantum of radiation at a given frequency, E = ħω. These facts also allow you to say that (and why) the angular momentum (or the action) is a dimensionless quantity.
With relativity and quantum mechanics, you are left with one independent unit. Because you will have probably understood the basic framework of relativistic quantum field theory at this point, the independent unit will probably be chosen to be 1 GeV, because of cultural reasons linked to particle physics. But one independent unit is still one too many. In quantum gravity, you may set Newton's constant equal to one (or to 1/8π) and everything becomes dimensionless.
It may actually be better to put a different constant instead of Newton's constant equal to one because Newton's constant is a low-energy phenomenological coefficient and at very high energies, there might be more natural objects to fix your units. For example, if the strings in the real world were weakly coupled, alpha' could be an equally good or better quantity to be set equal to one.
Once all your quantities become dimensionless, you have the right framework to describe physics in terms of mathematics, eliminating all kinds of unexplained conventions and incomplete descriptions. But physics is not yet over because you must still explain the numerical value of many universal dimensionless quantities that appear in Nature.
The reason why I wrote these trivial things is that many people - e.g. those who work on the so-called Variable Speed of Light theories - misunderstand them. They think that progress in physics is obtained by introducing new coefficients, new units, and new time-dependence of universal constants. Well, it may be progress but it would be negative progress. The goal of science is to explain increasing collections of numbers observed in Nature by equations built upon a decreasing number of independent concepts, assumptions, and parameters.
Incidentally, the Czech children still learn that "Joule" should be pronounced as "džaul". This information is promoted by the experts who "know" English and who know it is not pronounced as "yoaleh" as most Czechs would expect. ;-) Only when I came to the U.S., I learned that it was pronounced as "džúl" outside Czechia.
More than 400 scientists oppose the so-called consensus about climate change. Details of their statements, results, and links have been collected by James Inhofe's office.
As soon as a few more alarmists are caught, the ending will be approaching: look how the manbearpig jumps back and forth.
Chris Horner beats David Roberts and Alan Colmes in a discussion about the report. Mine is bigger than yours, Horner told Colmes, talking about the lists of scientists who actually endorsed something, and Colmes had to agree that Horner's is impressive.
Vladimir Alexandrovich Fock (12/22/1898 - 12/27/1974) was born in Saint Petersburg, Russia. He has contributed to mechanics, theoretical optics, theory of gravity, physics of continuous medium.
But we primarily know him as an important quantum physicist. In 1926, he independently derived and generalized (to the case of magnetic fields and velocity-dependent forces) the Klein-Gordon equation, also referred to as the Klein-Fock-Gordon equation.
Because he understood that the harmonic oscillators played a crucial role in quantum field theory, he decided to invent a catchy name for the Hilbert space of a multi-dimensional harmonic oscillator that represents creation and annihilation of particles. Today, we call it the Fock space. ;-) The eigenstates of the number operator are referred to as Fock states.
In 1930, he developed the Hartree-Fock approximation and a related quantity, the Fock matrix, is also named after him.
Einstein, Lenin, Stalin
But what I want to talk about is the relationship between communism and general relativity. Throughout his life, Fock was a loyal Soviet physicist. But it doesn't mean that he always agreed with the communist majority or that he was co-operating on the communist crimes. In fact, the Marxist philosophers used to dislike general relativity while he was the main proponent of GR among his Soviet contemporaries.
For most Marxists, it wasn't quite a Jewish pseudoscience but it looked too abstract for their small working-class brains, too relative and free for their hard-line totalitarian approach to life and freedom, and it was incompatible with various Marxist or Soviet expectations and interpretations, for example the expected infinite extent of both space and time. They also disliked that it was again possible to describe physical phenomena in non-inertial frames (such as the geocentric picture).
These intellectually limited communists were criticizing general relativity for pretty much the same "reasons" as stupid communists in 2007, such as Peter Woit, criticize string theory. I don't want to talk about the incoherent bunk because it made no sense just like it makes no sense today. Read e.g. Gorelik's essay if you want to know a little bit more. What is important is that the dumb yet powerful official Soviet ideologues were imposing certain politically correct restrictions what Soviet scientists could have been doing and believing and general relativity was already outside the box.
However, Fock was ready to paint general relativity as a materialist theory and he managed to get away with it. He was in no way a dissident but he was an example of the people from the "gray zone" who could sometimes do some "moderately courageous" acts. Fock was an honest, dignified, fearless and, strange as it may seem, law-abiding person. Nowadays, Marxists view general relativity as a part of their "scientific" world view. For example, a Marxist page says that
In Einstein’s “general” theory of relativity, the mass of the sun warps the space around the sun. The greater the sun’s mass, the greater the warping effect. A body moving with an initial speed in the neighborhood of the sun will move away from the sun and not be bound to it. But if the initial speed is decreased, a point is reached at which the gravitational pull of the sun will capture the object and it will go into a stable orbit around the sun. Clearly, this qualitative change (the capture of the object into a stable orbit) is brought about by the succession of quantitative changes in the initial speed of the object, which is part of the dialectical process.
As you can see, not only general relativity but also perturbation theory are small parts of the Marxist philosophy. The Marxist comments about relativity (and about the general transmutation of quantitative changes into qualitative ones) are completely silly and meaningless but what is important is that this crap helps them to be compatible with a correct theory of physics which is a good thing.
In their relationship towards general relativity and cosmology, Marxists remained obnoxious bigots, see e.g. this 1982 essay by Theckedath, and they have still some problems with the Big Bang and the possible finiteness of the Universe, but they already accept equations of GR, at least in some contexts, and this progress is partially due to the research as well as philosophical interpretations of science by people such as Vladimir Fock.
Both communism and Nazism were trying to influence natural sciences but I would say that the actual impact was much weaker than the impact of environmentalism on climate science or the impact of feminism on biology. The environmentalists are eager to suppress any research of the actual natural mechanisms driving the climate while feminism and other egalitarian ideologies are eager to suppress the research of all parts of biology that unmasks differences between various groups of people. Nazi and communist leaders of science were biased but I am afraid that they were not *that* biased.
Blue - current members. Green - will join. Yellow - expressed interest. Click for a Chinese article about the event.
Since the midnight, no passports are needed on Czech borders and probably not even the airport. While this is another step in transmuting our post-socialist country into a full-fledged, standard democracy, I am clearly less excited than during similar events in the past.
First of all, Czechia no longer needs any "confirmation" of its current status. Second of all, the passport checks are the easiest part of crossing the border. I certainly hate complicated bureaucracy but in the case of passport checks, they might be already too easy.
The members of the Schengen zone save a few seconds with the passport check but they also lose some ability to regulate who enters the country from other member states of the Schengen zone.
David Joseph Bohm (12/20/1917 - 10/27/1992) was born in Pennsylvania into a Jewish family of immigrants from Eastern Europe, 43 days after the Great October Socialist Revolution. As you can expect, this paragraph is probably going to be the most flattering one. That's why I also choose the first paragraph to mention that Bohm's most valuable contributions to physics is the Aharonov-Bohm effect - that showed that the Wilson line is a physical observable in a quantum theory even if the magnetic field strength vanishes - and the Bohm diffusion (of plasma in a magnetic field). He also wrote a decent book on quantum mechanics but this book already had some bias related to his unorthodox interpretation of quantum mechanics. See Chapter 23 where he writes that quantum mechanics cannot exist without a classical theory etc. - things that we surely consider wrong today.
Politics
In May 1949, as soon as McCarthy's policies were implemented, he was asked to testify about his (former?) colleagues from the communist movement. He refused to testify and was arrested and fired. I don't dispute that these events look unfortunate and suspicious. And I am not able to say whether Bohm actually had the right not to testify at the time. Nevertheless, I am completely sure that Bohm's involvement with the dangerous organizations is being generally underestimated.
Some people even want to dispute that he was a radical communist. Already in the late 1930s, he became active in the Young Communist League, the Campus Committee to Fight Conscription, and the Committee for Peace Mobilization. All three organizations were classified as communist organizations by the FBI long before McCarthy's era.
I find it understandable that in the late 1940s, when the tension between the capitalist and communist worlds increased, these two worlds were protecting themselves from the other world's spies and their fifth columns that undoubtedly existed.
While there might have been qualitative similarities between the events in both portions of the world, it is just unacceptable for me to say that "the same things" were taking place in both regions. While Stalin and his comrades in the Soviet bloc were routinely killing millions of inconvenient people, only a few thousands of people were investigated and/or arrested during the era of McCarthyism in the U.S.
Sorry but it is not the same thing. The communist threat was real and many countries that were less lucky than America after the World War II became victims of this totalitarian system for almost half a century. My country was among them. Please feel free to call me a McCarthy apologist but I am convinced that a comparable care was needed, after all. David Bohm was among the most active communist activists so it is natural that he was investigated and it is equally natural that his refusal to testify wasn't viewed as helpful by the folks responsible for the security of America.
We may ask: in the ideal democratic world, does a person have the right to believe in communist ideals? Well, he almost certainly does. But at some moment, we must carefully distinguish beliefs from real acts. The processes that were taking place in the late 1940s were not about Platonic beliefs. They were about the establishment of criminal regimes in whole countries and subcontinents.
The fuss wasn't about dreams and values: it was about actual plans to change the society and about the ability of freedom and democracy to protect themselves. Much like other people who have had problems with democratic laws, David Bohm was able to escape to Latin America.
Bohmian mechanics
Bohmian mechanics is profoundly wrong but what also irritates me is that it wasn't really invented by David Bohm. I will talk about its being incorrect for a long time but let me start with the comment that the interpretation was published as the "pilot wave theory" by Louis de Broglie in 1927. In 1952, Bohm wrote down a very straightforward multi-particle generalization of de Broglie's equations and added a very controversial version of "measurement theory". Is it a substantial improvement you expect from 25 years of progress?
The basic idea of the pilot wave theory is simple and superficially natural. The wave function is a real wave but besides this wave function, there also exists an actual particle that has a well-defined position and velocity, after all. The role of the wave function is to "push" the particle away from the interference minima. One can rewrite and reinterpret the Schrödinger equation in such a way that the probability distribution to find the real particle at a given point mimicks the prediction from the wave function if it did so at the beginning.
Louis de Broglie wrote these equations for the position of one particle, David Bohm generalized them to N particles.
I think that in analogous cases, we wouldn't be using the name of the "updater" for the final discovery. For example, we use the term "Schrödinger equation" even for the multi-particle case although Schrödinger didn't really discover - or understand - the role of his equation in more general setups.
But that's a detail. What is much more important is that Bohm's interpretation is profoundly incorrect.
Determinism vs unnecessary superconstructions
Einstein wanted to preserve determinism or at least "realism": he wanted physics to imply that a particle or another physical system has well-defined values of certain quantities already before they are measured. When I was a high school kid, I remember that I had the very same sentiments. But the general conceptual problem was a simple one. So I decided to construct/understand a working "realist" version of quantum mechanics in three months and because I inevitably failed, I simply started to believe orthodox quantum mechanics.
"Realism" in the technical sense has been a part of physics for centuries and something may be philosophically attractive about it, at least for the people who have spent some time with classical physics. However, is it a sufficient justification for the pilot wave theory?
Einstein's answer, much like mine, was a resounding No. He called the picture an unnecessary superconstruction. One can perhaps create classical mechanistic models that mimic the internal workings of quantum mechanics in many situations. For example, one can write a computer simulation. But you can't say that the details of such a program or Bohmian picture is justified as soon as you confirm the predictions of conventional quantum mechanics.
The mechanistic models add a new layer of quantities, concepts, and assumptions. They are not unique and they are not inevitable. The similarity with the luminiferous aether seems manifest. If they only reproduce the statistical predictions of quantum mechanics, you could never know which mechanistic model is the right one: it could be a computer simulation written by Oracle for Windows Vista, after all. Moreover, the mechanistic models brutally violate certain symmetries and other properties (Lorentz symmetry and locality) as well as the democracy between different observables and the emergent character of the classical limit. Let me discuss these problems one by one.
Locality and Lorentz invariance
Multi-particle Bohmian mechanics requires one to introduce the wave function of many positions and treat it as a real wave. This object is manifestly non-local and has the ability to propagate signals faster than light, at least in principle.
Although the theory is constructed to be as similar to proper quantum mechanics as possible, this feature makes its essence dramatically different. In proper quantum mechanics, locality holds. If one considers a Hamiltonian that respects the Lorentz symmetry - such as a Hamiltonian of a relativistic quantum field theory - the Lorentz symmetry is simply exact and it guarantees that signals never propagate faster than light.
In proper quantum mechanics, one can define the operators that generate the Poincaré group and rigorously derive their expected commutators. Also, it is exactly true that operators in space-like-separated regions exactly commute with each other. This fact is sufficient to show that the outcome of a measurement in spacetime point B is never correlated with a decision made at a space-like-separated spacetime point A.
These facts allow us to say that quantum field theory respects relativity and locality. The actual measurements can never reveal a correlation that would contradict these principles. And it is the actual measurements that decide whether a statement in physics is true or not. Bohmian mechanics is different because these principles are directly violated. You may try to construct your mechanistic model in such a way that it will approximately look like a local relativistic theory but it won't be one. Consequently, you won't be able to use these principles to constrain the possible form of your theory. Moreover, tension with tests of Lorentz invariance may arise at some moment.
Many people often say that normal quantum field theory is non-local. This is partly because of a wrong terminology, partly because of a misunderstanding of the probabilistic interpretation of quantum mechanics. Quantum field theories such as QED are perfectly local and we call them local. The Lorentz symmetry perfectly holds and one can show that the measurements are perfectly uncorrelated to space-like-separated decisions: whether something is uncorrelated may only be found by a repeated experiment, of course. The statement about a vanishing correlation is true both experimentally as well as theoretically, assuming a probabilistic interpretation of quantum mechanics.
The wave function may look like a non-local object but the statement that it makes quantum mechanics non-local is a misconception. As long as it is interpreted probabilistically, the question about locality depends on the actual observables and their commutators outside their light cones. Because these commutators vanish in QED, the theory is perfectly local and every experiment will confirm that it is impossible to send superluminal signals. There is no experimental hint of non-locality and if you abandon strange philosophical prejudices, there is no theoretical evidence of non-locality either.
Problems with spin
Bohmian mechanics remembers the positions of particles. What does it do with their spin? You can easily see that there is no solution that would agree with experiments and that would also treat different observables in the same way.
If de Broglie and Bohm claim that a particle should also have a well-defined position and velocity, it should naturally have a well-defined z-projection of spin, too. But once you adopt such an assumption, you clearly break the rotational symmetry. Particles would only have classical projections of spin with respect to the z axis so the z axis is preferred and you can measure its direction, at least in principle, uncovering anisotropy of space. The rotational symmetry of a theory including spinors heavily depends on the probabilistic nature of quantum mechanics.
If you give up the equal treatment of position and spin and decide to treat spin differently and give an electron well-defined binary-valued projections of spin with respect to all axes, you will also encounter problems. Bell's inequality will show you very sharply that the required dynamics is completely non-local but you will also have problems with the Lorentz invariance and the precise rules for the evolution of the discrete function of the direction.
The probabilistic meaning of the spinorial wave functions is completely essential for us to be able to translate a physical arrangement to any convention, including an arbitrary choice of the z-axis.
There are no preferred observables
All these problems are related to one general problem of Bohmian mechanics and this whole line of reasoning. Because experiments eventually measure some well-defined quantities, the likes of Bohm think that there must exist preferred observables - and operators - that also exist classically. They are classical to start with, they think. Positions of objects are an important example.
But the quantum mechanical founding fathers have known from the very beginning that this was a misconception. All Hermitean operators acting on a Hilbert space may be identified with some real classical observables and none of them is preferred. Moreover, the question which of them will emerge as natural quantities in a classical limit cannot be answered a priori. Which observables like to behave classically? Well, it is those whose eigenstates decohere from each other.
But the details of decoherence depend on the Hamiltonian of our physical system. The emergent classical eigenstates therefore cannot be "assumed" from the beginning - which is what the pilot wave theory is doing. Instead, they must be dynamically calculated. At least a qualitative calculation is needed to show that the "dead cat" and "alive cat" are good classical eigenstates that you may obtain as a result of a measurement but their generic complex superpositions are not. These facts are all about decoherence and decoherence depends on the Hamiltonian.
In the past, people could have used phenomenological rules that said which preferred directions in the Hilbert space behaved as "classical eigenstates" ("dead cat" vs. "alive cat", for example). But those phenomenological rules didn't quite explain why the states were what they were and they didn't allow one to calculate the time scale where the classical limit becomes a good replacement of quantum mechanics. Decoherence can do both - it is clearly a superior modern component of measurement theory that supersedes its phenomenological predecessors.
If I summarize, the pilot wave theory was known to be misguided 80 years ago but it has become even more incompatible with proper physics in the second half of the 20th century. Mechanistic models of state-of-the-art quantum theories are not available: it is partly because it's not really possible and it's not natural but it is also partly because the champions of Bohmian mechanics are simply not good enough physicists to be able to study state-of-the-art quantum theories. They're typically people with philosophical preconceptions who simply believe that the world has to respect their rules of "realism" or even "determinism".
But science is not about beliefs and the world doesn't respect these principles. It has been established that the right description of the world is probabilistic. 80 years ago, the only reason to believe so was that a hidden-variable theory couldn't tell us any new useful predictions of experiments and it looked unnatural and contrived. Today, we have some more concrete reasons to know that the hidden-variable theories are misguided. Via Bell's theorem, hidden-variable theories would have to be dramatically non-local and the apparent occurrence of nearly exact locality and Lorentz invariance in the world we observe would have to be explained as an infinite collection of shocking coincidences.
I just don't think that this is a rationally sustainable belief. It's just another repetition of the old story of the luminiferous aether.
Bohm vs Pauli and Bohm vs Feynman
David Bohm was almost certainly the person whom Wolfgang Pauli addressed the famous sentence "it is not even wrong" and the theories that Bohm was offering Pauli were probably related to some non-orthodox models of quantum mechanics discussed above.
The readers of Feynman's books may remember that when Feynman decided to investigate supernatural phenomena, he was told that Uri Geller has convinced "a professor David Bohm" of his supernatural powers. As an old man, Bohm started to believe all kinds of nonsensical supernatural theories. This fact sounds even more crazy when you realize that Marxism is supposed to build on common sense and atheism. But it is not such a paradox, after all. These extremes - a mechanical model of quantum mechanics on one side and Uri Geller's magic on the other side - share a certain feature, namely their large distance from reality and an elevated role of philosophical and religious preconceptions.
To summarize, my portrait of David Bohm wasn't the most flattering one but it is how it sometimes works out. Nevertheless, he was an interesting character.
Sorry for the break. Yesterday I played a high school teacher of English in 3 classes - it was fun - and today we attended a neat picnic full of VIPs in Prague.
Awards are not too important and the Person of the Year is not such a terribly important award but on the other hand, it may turn out to be more relevant than the peace Nobel prize in a foreseeable future. The top eight candidates for Time's Person of the Year 2007 were:
Who could be the winner? The Huffington Post, a far left-wing blog, wrote:
Given former U.S. Vice-President Al Gore's massive passion and visibility advocating environmental causes, it is virtually impossible to see anyone else getting the nod. From carbon footprints to going to Bali, to winning the Nobel Peace Prize, who else?
With a breathtaking combination of arrogance and ignorance, the loon on that blog keeps on explaining that Al Gore is effectively God and that the only competitor could perhaps be Barack Obama. But Russell Shaw is surprisingly able to figure out that Barack Obama couldn't have really been included even in the top eight because he hasn't achieved anything substantial in his life so far. He hasn't even won any primaries so far.
Well, the world fortunately doesn't quite follow predetermined plans of far-left ideologues although they would undoubtedly prefer a world that does follow their desires. The Time magazine has decided that
is the guy whose cool eyes say "I am in charge" and he must become the person of the year. The portrait of Putin is pretty interesting to read. At any rate, Putin is indeed a powerful figure who is certainly very good in calm calculations related to power and strategy. He is an old-fashioned leader who may have learned from Machiavelli.
His position in Russia is arguably compatible with democracy but it is not far from its boundary either. And the position of Russia may have increased in 2007. The Big Bear also knows how to benefit from many international mechanisms including the attempts to regulate carbon.
Lawsuit?
Human Events, a right-wing blog, writes something that looks like a hoax to me but in this crazy world, I can imagine that it is true, too. They write that Al Gore has sued the Time magazine because they haven't chosen him! ;-) Do you think that the Human Events article is serious? Al Gore is certainly one of the most arrogant failed politicians in the world but is he *that* arrogant? I just find it hard to believe.
The "accusations" in the hypothetical "lawsuit" sound completely ludicrous. Whether the people in control of the Time magazine denied the right to vote to some nutcases in their team who would vote for Gore is clearly up to them: it is their award, after all. They create the rules. I would not only deny the right to vote to the people who would support someone like Gore but I would send them to a psychiatric hospital, too.
What the hell is illegal for a magazine to eliminate a fashionable jerk from the possible winners of its award? I don't believe that there exist laws that would force bosses of a magazine to give dumb employees the equal right to vote in an award they own and define. Can you imagine that someone would sue the Nobel prize committee because of alleged things that happened before they announced the winner?
There exist similar articles, e.g. about Al Gore requiring a recount, that I believe are jokes. But with the Human Events, I am not 100% sure although the answer "it is a hoax" sounds more likely.
Eric Berger, the Houston Sciguy who has been sufficiently balanced and correct (but politically incorrect) to trade links with TRF :-), is hosting and moderating
When: Today, Monday 12/17, 3 pm EST (9 pm Central European Time) Alarmist: Andrew Dessler, Texas A&M Realist: Tim Ball, University of Winnipeg (retired) Internet audio provider:Blogtalkradio (ask questions here and listen here) Hat tip: Papertiger
After the debate: Tim Ball had technical problems and couldn't participate. Dessler was speaking pretty well but he was confined by many of those religious notions that scientists are shamans who are just experts and must be trusted because of their "consensus".
So he failed to answer most of the technical questions - maybe he didn't answer a single one. He just said "It is the holy word that the experts believe so you must also believe it just like you must believe your physician when you have cancer" many times. Several pretty good skeptical non-scientist participants (and scientists from other fields) called and explained him that his words are no arguments and no answers but he really didn't get it.
He is certainly not the only person who doesn't understand the difference between science and propaganda. It turned out that Dessler doesn't really trust computer models, satellite measurements, balloon measurements, and many other things. But he just happens to believe that it is nevertheless very likely that the orthodoxy is right. He couldn't justify this surprising belief. But he probably thinks that because he is paid as a scientist, he is guaranteed by God to be infallible even without any rational arguments.
Bonus:a study from the Norwegian University of Science and Technology has shown that the stronger ecological footprint (and more intense consumption of resources) a society has, the less likely it is to participate in an armed conflict. Al Gore and the IPCC have thus received a Nobel prize for promotion of war, not peace. With a little bit of exaggeration, they are the new Adolf Hitler and NSDAP.
Peer-reviewed skeptic literature:Petr Chýlek and five more co-authors argue in Journal of Geophysical Research that the climate sensitivity is about 50% of the IPCC values when aerosols are taken into account. That translates to something between 1.1 and 1.8 °C of warming from doubling of CO2 i.e. between 0.5 and 1.2 °C of warming between 2000 and 2090 when the doubled value is expected to be reached.
William Thomson, 1st Baron Kelvin, OM, GCVO, PC, PRS, FRSE (26 June 1824 – 17 December 1907) was a culminating hero of classical physics.
While his grandfather was a farmer, his father was an engineer who later became a professor of mathematics. At the age of 9, William survived serious heart problems. I would guess that this childhood experience may partially explain why Lord Kelvin became such as a tough and even severe figure as an adult.
As a student, he won a prize for an essay about astronomy. However, he focused on continental mathematics very soon afterwards. Recall that Britain was working in the shadow of Isaac Newton whose approach to mathematics was heuristic or phenomenological, if you wish. On the other hand, continental Europe had been excited about rigor for quite some time.
Thomson encouraged Faraday to make a discovery and the Faraday effect is partially a result of Thomson's moral support. But Thomson's key early contributions occurred in thermodynamics.
At the age of 23, he was already viewed as a mature yet maverick scientist. At an Oxford conference in 1847, Joule tried to debunk the old "caloric" theory of heat that assumed that the heat was a fluid. Thomson was skeptical but started a serious research. He declared himself to be a member of the French clique of Carnot and Clapeyron and analyzed what the non-existence of a perpetuum mobile meant for the dependence of various quantities such as the melting point of ice on the external parameters such as temperature.
In 1848, Thomson finally proposed the existence of absolute zero and defined an absolute temperature, currently measured in Kelvin degrees.
It took one more year or so before Thomson understood why the caloric theory was wrong, Joule's equivalence of heat and work was correct. He made some basic steps towards the second law of thermodynamics. The language of thermodynamics was a bit religious at that time: heat was work that was "lost to man irrevocably; but not lost in the material world". A compensation would require a "creative act".
In the 1850s, he started to build the first transatlantic internet cables. They were referred to as telegraph cables. By having argued about the most economical design of the cable in the media, he became a publicly known figure. He joined the board of directors of the Atlantic Telegraph Company but was largely ignored - including his project that could send more than 1 bit of information per second ;-) - until he started to claim that copper was a superior choice for the cable. At that moment, he became important. In 1858, he participated in the cable installation, already as a manually skillful guy.
The mainstream design of the cable system due to Wildman Whitehouse, the real boss, collapsed and had to be replaced by Thomson's galvanometer. Thomson had some respect for Whitehouse but later he was sorry that he didn't attack Whitehouse's proposals more intensely. Whitehouse was fired and Kelvin became the new boss. His cable-laying expeditions of 1865 and 1866 were ultimately successful and Thomson was knighted in 1866.
After a long illness, his wife died in 1870. He bought a schooner, a sailing vessel to entertain his friends and colleagues. He married again in 1874, using telegraphic signals to agree about the wedding with Fanny Blandy who was 13 years younger. Thomson was also an enthusiastic yachtsman. He contributed a lot fo the technology of compasses, ancient global positioning systems on the sea, promotion of the Morse code, and other things.
But it may be equally important that between 1855 and 1867, he co-authored the Treatise on Natural Philosophy with Peter Guthrie Tait, a thousands-of-pages-long two-volume textbook that defines classical physics as we know it or, more precisely, as the contemporary engineers know it.
Back in the 1840s, he started to settle the operational methods to measure electric units, especially with the current balance (Ampere balance or Kelvin balance) that defined 1 Ampere.
In 1893, Thomson was the leader of an international committee that designed the Niagara Falls power station. Even though Kelvin was a fan of direct current, Nikola Tesla convinced him about the advantages of three-phase alternating current power transmission. Thomson surrendered and in 1896, he described Tesla as the greatest contributor to electrical science ever. Have you taken a picture of yourself with Tesla's sculpture near the Niagara Falls?
Throughout his life, Kelvin was a devout Christian who attended church on a daily basis. It may have influenced some of his opinions. For example, he believed that the Earth had to be a few dozens of millions of years old. Charles Darwin and some geologists already knew that the age should be counted in billions of years. Frankly speaking, I don't think that Kelvin's error was a result of the religious influence. Millions of years were incompatible with the Bible just like billions of years. Kelvin just made some wrong calculations here and there and underestimated the uncertainty about various quantities such as the useful energy stored in the Sun.
In 1884, he gave cute lectures at John Hopkins University about mechanical models of the aether. These lectures were creative but their lasting value for physics is zero. The mechanical model of the world collapsed pretty soon and the aether was moved to the dumping ground of the history of physics.
However, I would say that Lord Kelvin was perfectly aware of the real defects of the image of the world as painted by classical physics. In his famous talk in 1900, he described two clouds floating about physics of his time. Physics, he argued, couldn't explain two phenomena: the Michelson-Morley experiment and the black body radiation. These two clouds led to relativity and quantum mechanics, respectively: two major revolutions in the 20th century that would start one year later.
Kelvin has made some wrong predictions about engineering and marketing. In 1895, he said that flying machines that are heavier than air were impossible. It only took 8 years to prove him spectacularly wrong. In 1897, he said that radio had no future which would be rather accurate except for the 1920s-1960s when radio was very popular. OK, it is still popular with some people under certain circumstances but today many of us might agree with Lord Kelvin's statement that radio has no future once again. ;-)
Kelvin belongs to a different era, a pre-quantum, pre-relativistic epoch. Still, we may recognize that he was simply an important guy in an industrial society similar to ours.
Jan Švejnar, a professor of economics at University of Michigan and a U.S. citizen, decided that he wants to be the next Czech president who will be elected by the Parliament in February 2008. Václav Klaus remains the likely winner but with the support of the Czech Social Democratic Party and the Green Party, Švejnar becomes a serious contender.
I have nothing against him personally but I find it somewhat strange for a person who has no idea about the life in the Czech Republic to become its president. He has lived in the U.S. since 1970 or so.
A TV program today showed very clearly how detached Švejnar is from the Czech history, Czech culture, and Czech reality. He was asked several questions from the Prague Castle's quiz addressed to children and youth. For example, he was asked:
He had no idea. But the faux pas continued. Another question wanted him to say the motto on the official presidential flag. As all children know, it is
Truth prevails (actually "Pravda vítězí" in Czech, which is "Veritas Vincit" in Latin)
He had no clue. What do you mean by a presidential flag? Did you say that truth prevails? I will have to inform myself, he said. One more question was about the famous sculptures or allegories of Virtues and Vices by Matthias Braun.
Where are these sculptures located?
This was a tougher one. The correct answer is the Kuks Castle and he didn't know, of course. He happened to know that Charles University was founded in 1348 and Bedřich Smetana composed "My Country". However, he was also asked
Which ancient tribe that used to live on our territory gave the name to Bohemia?
It was also a hard one. The answer is that these guys were Boii which is a Roman name of an old Celtic tribe, and a Germanic word "boio-haemum" designates their home. Mr Švejnar, of course, didn't know.
Now, I don't think that these particular questions are the most essential ones for a president. But I suspect that he is out of touch with many more important questions associated with the citizens of the country in which he wants to become the president.
I feel that these are vices that go beyond any ideology and it is simply a bad idea to promote such candidates.
The highest temperature today in Pilsen was -3 °C and there are some small snow residuals around.
But in Ontario, Quebec, the U.S. Northeast, and, to some extent, the U.S. Midwest, they have more fun. At some places, they received a foot of snow which is not bad even though it is less than forecast. But Southern Ontario still has a chance to see a record snowstorm.
In Boston, the one-foot snowstorm has set a new record for December and exceeded the average amount of snow for the whole December. 400 flights were canceled at Logan.
By the way, the global sea ice area anomaly is slightly positive right now (graph, more): it means that the total area is higher than the average for mid December. I am afraid that you won't read about it in the media.
Google News finds about 47,000 articles from the last month that contain "global warming" and 16,000 articles that contain "snow storm" or "snowstorm" or "winter storm". But only 70 articles include both "global warming" as well as one of the three versions of a "snowstorm". It seems that these things have nothing to do with each other. However, whenever you have a "warm" event, most of the articles about it refer to global warming. Where does this asymmetry come from?
Fritz Walther Meißner was born on December 16th, 1882. In the early 1920s, he built the third largest Helium-liquifier which allowed him and Robert Ochsenfeld to discover the Meissner (or Meissner-Ochsenfeld) effect, the superconductors' magnetophobia, in 1933. How did he do it?
He simply took a German train and placed it on tracks with superconducting magnets in Shanghai, China (click the picture above to see more details). The superconducting magnets don't allow the magnetic field to penetrate too deeply: it is exponentially dropping as you go deeper. The photon effectively becomes a massive particle and it is no coincidence that the electroweak symmetry breaking is sometimes referred to as electroweak superconductivity because the mathematics is isomorphic even though, in the case of the normal superconductivity, the broken phase is not a vacuum but requires some atoms to be present.
At any rate, the train was flying or at least levitating - the maximum speed is 430 kilometers per hour - and people started to call it maglev. The story has been improved a little bit but the physical essence is painted faithfully. ;-) I think that Meissner has been one of a small number of condensed matter physicists who deserved a Nobel prize but never got it.
The participants of the conference in Bali, Indonesia agreed to spend the following two years with an intense schedule of similar meetings.
When I look at the picture above, I wonder why they agreed about such a plan. It is conceivable that even Marc Morano agreed with this great idea! :-)
In December 2009, they plan to replace the Kyoto treaty with the Copenhagen consensus in the Danish capital. If you haven't heard of it, the Copenhagen consensus is a consensus of economists that the money spent to fight climate change are wasted, much like the money spent for similar conferences of social parasites such as those who have gathered in Bali.
Antoine Henri Becquerel was born on December 15th, 1852. How did he become famous? Well, in 1896, he was verifying Röntgen X-ray experiments and studied fluorescence, too. So he wrapped a fluorescent substance (potassium uranyl sulfate) in thick black paper that was inserted in photographic plates. And he saw images of the fluorescent material and the Maltese Cross (and later coins) on the photographic plates: see the picture below. It followed that there had to be a spontaneously emitted radiation that can penetrate the black paper.
Radioactivity was born - one of two Lord Kelvin's dark clouds floating above classical physics. These were times when making important discoveries in physics was rather easy. Becquerel received the 1903 physics Nobel prize.
Physics has made substantial progress since 1896. What he observed is no longer just some mysterious structureless radiation. We know alpha-, beta-, and gamma- radiation, dominated by the strong nuclear, weak nuclear, and electromagnetic interactions, respectively. The gravity radiation has not yet been measured, not even at the classical level, as the previous posting explains. Each of the three observed types of radiation has been described by a very specific, crisp but mathematically profound gauge theory and we seem to know how two of these theories must be unified and all three of them might be unified.
Freeman Dyson celebrates his 84th birthday today, congratulations!
Rolf-Dieter Heuer will head CERN in its LHC era, starting from 2009. Robert Aymar, the current Director General, described the LHC progress as excellent and mentioned an intensity upgrade in 2016.
What do great theoretical physicists do with experiments that contradict their crisp theories? Well, they laugh at them, of course. ;-)
Gell-Mann, who is in a great mood, explains that a colleague of his, Albert Einstein, was often asked by journalists: What about the experiment of D.C. Miller that contradicts relativity (whoever is D.C. Miller)? Einstein said: it will go away.
Well, Feynman and Gell-Mann were better: they had a theory that contradicted seven experiments. It was a pretty theory and it had to be right. Of course, Feynman and Gell-Mann were right and the experiments were wrong.
Gell-Mann explains that the laws of physics are mathematically beautiful and universal. Symmetry is important but there are more refined reasons why beauty is important in physics. One of them is the similarity of the mathematical description of different layers of the onion of natural laws.
Inekon Group, a modern upgrade of Škoda Pilsen, has previously sold some trams to Portland and Tacoma. In Seattle, they were choosing the best vehicles for Paul Allen's South Lake Union project - he is building a modern biotechnology center nearby - and the same Czech company just happened to win, too. Washington D.C. should join the family soon.
Andrei Sakharov was born in 1921 and died on December 14th, 1989. His grandfather was a successful lawyer in the Tsarist Russia. But his father was an atheist, private school physics teacher, and an amateur pianist. So Andrei has had all kinds of influences.
Politics
His political development is amusing. A triple hero of socialist labor (a communist award for work) from 1953, 1955, 1962, the winner of the 1953 Stalin prize (the most valuable Stalin prize in 1953 was, however, that Stalin died), and the 1956 Lenin prize became a leading Soviet dissident which is why he received the 1975 peace Nobel prize.
Because the Soviet communists behaved much like the climate alarmism apparatchiks who shamelessly censor the ICSC and other skeptics in Bali these days, Sakharov was not allowed to travel. His wife at that time, who was another dissident, was however able to pick the award and give the speech. These were somewhat hard times when totalitarian regimes were crippling a third of the world but on the other hand, the rest of the world, including the Norwegian Nobel Committee, was rewarding true heroes who risked their well-being for truly respectable goals. These days, the Norwegian Nobel Committee rewards hypocritical jerks who fight for despicable ideas and who have already earned hundreds of millions of dollars for these ideas, by brainwashing loads of dopes in the world.
Sakharov's conversion from a hero of communist labor to a heroic warrior for freedom started because of fears of a nuclear war but his political focus became much more comprehensive during the years.
The Soviet megaton-range hydrogen bomb used a designed referred to as "Sakharov's Third Idea" and it was surely no coincidence. Moreover, with Igor Tamm, Sakharov co-fathered the tokamak, the most standard torus-shaped device to confine plasma for thermonuclear fusion.
Baryogenesis
By far the most famous theoretical physics paper by Sakharov is a 1967 paper on baryogenesis. Sakharov formulated the three necessary albeit somewhat counterintuitive conditions for baryons to be created out of nothing during the very early cosmological eras, namely
Baryon number B violation
C- and CP-symmetry violation
Interactions out of thermal equilibrium.
Induced gravity
What may also be interesting for fans of theoretical physics is that Sakharov was a father of the concept of superconductivity-like model of emergent gravity, the so-called induced gravity, also in 1967. The exact scenario he had in mind has been safely falsified: it violates the Weinberg-Witten theorem, and even if you forget about the wrong spins and masses of the excitations, it leads to a huge and calculable cosmological constant.
The real reason why I write about it today is to show that these and similar ideas have been around at least for four decades even though some people try to sell them as "hot" today. The Wikipedia article on "induced gravity" correctly hints that the closest realistic sibling of Sakharov's idea occurs in the AdS/CFT correspondence but there are many more things beyond gravity that are emerging as well, for example a whole non-compact dimension of spacetime.
Because a recent TRF text might suggest that I think that no blonde can possibly know whether France is a country, let us talk about a blonde who probably knows the answer. ;-)
Even though TRF remains the third Google hit for "Garrett Lisi", the fraction of TRF visitors who came because of this particular "new Einstein of particle physics" has fortunately dropped from 80% during the peak day to approximately 2%.
On the other hand, it's a pleasure to see that a more meaningful wave appeared. People are searching for the "Isaac Newton of biology", as
calls her. TRF is the second Google hit for her name (after her lab that only achieved its PageRank because of a redirect from her previous Harvard FAS page) and about 10% of the readers get here because of
Without much exaggeration, I think - not just because of this Esquire article - that Esquire has a more sensible and science-friendly reporting of science than the Telegraph and the Wall Street Journal. I would still say that it is Charles Darwin, not Franziska Michor (sorry, FM!), who is the Isaac Newton of biology but Esquire's approximation is simply better than others. ;-)
By the way, the title "Isaac Newton of biology" is not quite an invention of the journalist because in our interview, Franziska said that "biology without maths [was] like physics before Newton." Now, she is certainly not the first scientist who introduced maths to biology but again, it can be painted this way and Esquire does it.
The Esquire text was still more politically correct than what I would have liked but it could have been worse if they e.g. decided to emphasize her ala-111 SLC24A5 BF - whom I know as well and he is a great guy, of course.
Sorry for my being busy but constructing and installing this kitchen unit (Iza Hruška=Pear plus a packet not shown on the picture) takes some time, hundreds of screws, and so forth. ;-)
Kellie Pickler may win 25,000 dollars for a charity but there is a big hurdle on her way. Budapest is the capital of what European country?
Buddha's - Booduh Pest? I've never heard of that. I thought that Europe was a country, one that speaks French! OK, so I would think that Budapest might be in France except that France is not a country. What, hungry is a country? I've heard of turkey but hungry? :-)
I listen what you're saying but I only hear what I want to, Kellie clarifies. That's what being a woman means. (PC cows start to boo.) Kellie thinks that the show could be called "Are you smarter than a man?" because she surely is, she thinks. :-) Because the host can't pronounce "Hungary" either, she might be right. And women don't want to hear men's opinion but just their opinion in a deeper voice, Jeff Foxworthy explains. :-)
Incidentally, the Czech edition of this contest ("Are you smarter a 5th grader?") has been aired on Czech TV, too (jingle). I found it very funny. Just like Nathan, the kids are smarter than the contestants - I suppose it is partly by design to make the show funny.
This weekly dose of peer-reviewed skeptical literature about the climate will be rather short because we have talked about similar issues many times. In the International Journal of Climatology,
show, in their article "A comparison of tropical temperature trends with model predictions", that the previously discussed "fingerprint" predicted by 22 greenhouse-dominated models disagrees with the observed data summarized in 10 datasets.
Figure 1: Models said "Good bye" to reality. At the key altitudes, reality is about 6 uncertainties of the mean (measured as the standard deviation of the model ensemble divided by the square root of 22-1) away from the models. If you include "submodels" or "realizations", there are 67 of them and the discrepancy jumps to 10 sigma (this is why copying a model many times, as in the "consensus science", will be used against you by the rules of science). If you count the discrepancy in the experimental standard deviations, they will exceed 5 sigma, too. Regardless of these numbers, the picture above says a lot by itself.
The models and observations are compatible near the surface. However, about 5 kilometers above the surface (where the greenhouse effects starts to become relevant) in the tropical zones, models predict between 2 times and 4 times higher warming trend than what is observed. Above the altitude of 8 kilometers, the theoretical and empirical trends have opposite signs.
The insights strongly indicate that the true mechanisms driving the changes of temperature are not understood and the overall effect of greenhouses gases is being overestimated - between 2 times and 4 times - by all existing models. Note that with this reduction, IPCC's sensitivity between 2 and 4.5 °C gets reduced to the standard 1 °C climate sensitivity which means that the additional greenhouse-induced warming by 2090 will be less than 0.5 °C.
On December 11th, 1882, two well-known people were born: Fiorello LaGuardia and Max Born. LaGuardia, nicknamed the Little Flower (a translation of his first name combined with his being a kind of dwarf), was a mayor of the New York City, nicknamed the Big Apple (several explanations of the nickname exist). He was a popular GOP supporter of the New Deal and an early critic of the Nazis and an airport was ultimately named after him. He lived in the Big Time when the Little Flower was a Big Cheese in the Big Apple. :-) See a video.
But because my nerd score was just measured to be 96 (click to get yours), we will obviously spend more time with Max Born.
Max Born was born in Silesia, Greater Germany, to a Jewish family. His father was a biologist while his mother was a daughter from an industrialist family who unfortunately died when little Max was four. He spent some time in Breslau, Heidelberg University, and the University of Zurich. But he came in touch with many great minds in Göttingen, including Felix Klein, David Hilbert, Hermann Minkowski, Carle Runge, Karl Schwarzschild, and Woldemar Voigt (please don't forget the "g"). His ties with Minkowski and Hilbert were very close. Hilbert decided that Max Born was an exceptional guy so Max received the honor to write up the class notes. ;-)
Max Born was able to defend a PhD on elasticity - a favorite subject of Klein - despite some elastic relationships between Klein and Born.
Even though Born's wife was Jewish as well, he converted to the Lutheran Christian belief. The prettiest and most famous granddaughter of Max Born was Olivia Newton-John, a prominent British-born Australian California-based pop singer, drummer, actress, high-school dropout, moral warrior against breast cancer, and ecoactivist. She's been depressed since 2005 when her partner Patrick McDermott went missing during a boat trip. While Olivia's mother was Irene Born, a daughter of Max Born, her father was Prof Brinley Newton-John who wasn't related to Isaac Newton but who took Rudolf Hess into custody when he parachuted into Scotland in 1941. ;-)
"Physical", the aerobic anthem and the most popular song by physicist Max Born's granddaughter (1981). As a kid, I liked the song especially because I could understand one word - it was about "fyzika" (physics). :-) Compare with Kylie Minogue's remake (2000). Unfortunately, both Newton-John and Minogue know what it means to have breast cancer. You may have heard of "Grease" (1978) and "Xanadu" (1980), too. Only the Xanadu song, not the movie, was successful. I was thinking whom her hot energy reminded me of and I think I got the answer: Obama Girl.
Incidentally, Ms Libuše Barková, an enterpreneur, a boss of a brothel, and a friend of former Czech prime minister Gross, became the only international producer of "Grease" (the Czech version is called "Pomáda") who hasn't invited Newton-John.
Between 1915 and 1919, while at the University of Berlin, he became a life-long friend with Albert Einstein. Once Born became a boss at Göttingen, he figured out that Arnold Sommerfeld of the University of Munich shared his experiment-based approach to theories. Equally importantly, Arnold Sommerfeld sent Max Born a pretty good student to become Born's assistant. His name was Werner Heisenberg. ;-)
Max Born was kind of leading his junior colleagues such as Werner Heisenberg and Pascual Jordan in their research of matrix mechanics. Heisenberg was 60 days faster than the other two but before the year ended, these three men published a paper together.
In 1928, a former patent clerk called Albert Einstein nominated Heisenberg, Born, and Jordan for the physics Nobel prize. However, it didn't work that way. Heisenberg had to wait until 1933 when the 1932 Nobel prize was finally announced and he received the whole amount even though he insisted that Born and Jordan had deserved to share it. Max Born waited until 1954 when he received the full prize for the statistical interpretation of quantum mechanics.
Pascual Jordan never received a Nobel prize, largely because he became a Nazi party member and a storm trooper in 1933. It was the same year when Max Born - a Jew and a pacifist combined - left Germany for Britain.
Although Max Born has written a lot of things about physics, we associate him with the probabilistic interpretation of quantum mechanics. The function "psi(x)" is not a classical wave analogous to the electromagnetic field or a diluted electron as Schrödinger and others used to think. Instead, it is a gadget whose only role is to predict probabilities that a particular outcome will be observed. For example, "psi*(x)psi(x)dV" is the probability that a particle is gonna be observed in a small volume "dV" near the point "x".
See the 1927 Solvay conference 0:55 when Max Born leaves the conference room. Einstein told Born that God didn't play dice.
This insight due to Born may seem to be a very modest one but it is one of the main symbols and results of the quantum revolution, the most profound conceptual breakthrough in the 20th century science. It is very likely that Max Born was able to articulate this principle so crisply because his thinking about physics was rooted in experiments. By thinking about the actual experiments, he could easily and efficiently falsify various "materialist" interpretations by his less empirical and more philosophically prejudiced colleagues.
Carl Gustav Jacob Jacobi was born on December 10th, 1804. This ancient Jewish Prussian string theorist was one of the greatest mathematicians of all times and one of the most inspiring mathematicians of his times.
As a classical liberal, he was active in the 1848 revolution. Also, he suffered a breakdown from overwork at the age of 39 but he lived for 8 more years.
Jacobi was a true champion of special functions. Jacobi polynomials are those hypergeometric series that actually terminate. Jacobi showed that his elliptic functions are omnipresent as solutions to many equations in mathematical physics such as the pendulum, a symmetric top in a gravitational field, and a freely spinning body. Jacobi also liked to compute the motion of planets. Jacobi's integral gives a limited solution to the three-body problem. The Hamilton-Jacobi equation relates the time-derivative of the classical action with the Hamiltonian and is one of the key insights of modern abstract classical mechanics.
He also applied elliptic functions to number theory. For example, he proved a couple of "simpler" theorems due to Fermat. In a different paper, he introduced the Jacobi symbol, a generalized Legendre symbol involving prime factorizations of numbers. All mathematicians and physicists know him for the Jacobian, the determinant of a matrix of partial derivatives of new coordinates with respect to old coordinates, and for the Jacobi identity relating three double commutators of operators which is a defining formula for Lie groups. Some people remember his iterative Jacobi method to solve sets of equations in linear algebra. The Carathéodory-Jacobi-Lie theorem allows one to patch-wise define coordinates and momenta on each symplectic manifold.
String theorists know him as a colleague primarily for his Jacobi theta functions, appearing in partition sums and correlators of worldsheet fields at one-loop level (toroidal worldsheets). He has demonstrated the Jacobi triple product, the identity that allows you to re-express infinite sums as infinite products. A modern elegant proof of this formula uses a simplified model of the Dirac sea, probably pioneered by Richard Borcherds, and random partitions as defined by Andrei Okounkov, a fresh Fields medal winner and a string-theoretical mathematician.
In 1841, Jacobi reintroduced the modern symbol for the partial derivatives, originally invented by Legendre. It became standard.
But I chose the most string-theoretical result of Jacobi's life as the ultimate punch line. In 1829, he proved a "rather obscure formula" ("aequatio identica satis abstrusa") involving three terms that are fourth powers of a Jacobi theta function which verifies the spacetime supersymmetry at the level of partition sums in the Ramond-Neveu-Schwarz formulation of superstring theory. Mankind had to wait for nearly 150 years, until the late 1970s, to see what is the true physical reason why this fascinating identity holds and to make the formerly obscure formula transparent.
Loehle's article was the first published climate reconstruction that has only used proxies that had already been independently calibrated in peer-reviewed literature. It has eliminated tree rings because they don't seem to be good temperature proxies: it seems that the growth of trees is more affected by humidity, precipitation, and directly by the concentration of carbon dioxide, the food for trees. The main result of Loehle's paper was that the Medieval Warm Period did exist, after all.
Gavin Schmidt correctly lists five important issues that a good reconstruction must properly address:
Dating: correct chronology for your proxies is essential and its accuracy of the "age" must be sufficient to answer your questions
Fidelity: the assumed relationship between temperature and your proxy should be pretty much time-independent; temperature must be the main thing that influences your proxies
Calibration: the coefficient between the changes of the proxy and the changes of temperature must be correctly determined
Compositing: when you study global mean temperature, local data must be properly combined to be representative of the globe
Validation: you must check that your method works by comparing some of its results with another method that has already been established
As far as I can say, Gavin Schmidt learned these principles from McKitrick & McIntyre and other independent climate experts because they have been carefully checking these things in the context of older climate reconstructions such as the infamous Mann et al. hockey-stick reconstructions for quite some time.
If you remember Richard Feynman's "Cargo Cult Science", he talked about the sloppy experiments with the rats running through labyrinths. Later, a guy called Young actually made some careful experiments and found what kind of information the rats actually use. He therefore found the rules that one must respect in order to find anything new about the rats. Young's work was ignored by the rat pseudoscientific establishment in the 1930s. Needless to say, the generic rat scientists play the same role as Mann et al., Young is McIntyre, and the issues one must be careful about are mentioned above.
Unfortunately, Gavin Schmidt didn't learn these rules too well. For example, his very first sentence says:
Many people hold the mistaken belief that reconstructions of past climate are the sole evidence for current and future climate change.
His suggestion that climate reconstructions may be completely avoided is, of course, untrue because of the point "5. Validation". The very existence of climate change is a tautology and you don't need any special methods to say that climate is changing and will be changing. But if you want to say anything beyond this tautology - how much it will change and what factors may influence it - you can't live without climate reconstructions.
It is because every theory or model in science must be validated and the validation must ultimately involve a comparison to reality. If a theory predicts how the temperature will change at the centennial scale, it is simply inevitable to have some data about the centennial changes of the temperature. Because of the arrow of time ;-), we can only have such data from the past.
In order to figure out whether the 20th century warming was outside the natural variability, you may create a lot of theories but you won't know whether the theories are true and accurate - or whether you have missed some additional low-frequency processes - until you will compare their description of the past climate with the corresponding information extracted from the history of Earth, at least in some of its aspects. Think about it: it simply can't work otherwise, especially because we know that the partially unknown natural causes are stronger than the man-made causes, at least for 30-year-long periods (such as the 1945-1975 cooling).
Now, I am the last one who would think that it is essential to know whether the year 1005 was warmer than 2005. These are two relatively warm years and which of them was warmer is pretty much a matter of chance. If 2005 were warmer than 1005, it is still far from a reason to panic. On the other hand, if we can show that 1005 were warmer or 1005 and 2005 were very close, it shows that the recent temperatures are not unprecedented but it still doesn't quite guarantee that all temperatures in the future will be safe. At any rate, it would be foolish to build global policies on a random question whether 1005 was warmer than 2005. On the other hand, you can't throw away all the data from the centennial paleoclimate reconstructions because they are the only empirical source that tells you which effects actually matter in reality at this timescale.
Gavin's criticism
It is a standard policy at RealClimate.ORG that the authors of the articles don't offer the criticized article itself to their undemanding readers. Gavin's recent text is an exception - a link to Loehle's paper was later added to Gavin's article but it is still difficult to find it. What's important for the readers is not to learn something or compare arguments for various statements and their robustness. Instead, what they expect is their daily prayer, Oh the global warming, you're so great and holy, and oh the climate skeptics and the climate traitors, they are oh so evil. Gavin Schmidt and others are optimized to write this inexpensive material for this kind of people.
Gavin tries to indicate that Loehle makes errors in all the five issues mentioned at the beginning. Unfortunately, his criticism is somewhat vague and in the cases when it is not vague and where I could try to check his statements, they seem to be demonstrably wrong.
So for example, we learn that Craig Loehle has confused the symbols "BP" and "BP (2000)". The former symbol means "before the year 1950" while the latter means "before the year 2000". I don't see any trustworthy evidence for this accusation by Gavin. If you go to the first sentence and download the PDF file with Loehle's paper, you may check that the paper doesn't use any of these "BP" symbols at all. This symbol should only be used for very long timescales, not timescales comparable to centuries, anyway. Moreover, Craig Loehle has thanked the very same Eric Swanson for finding dating errors as Gavin Schmidt.
I just find it unlikely that Loehle's paper contains these well-defined dating errors that Gavin could find so easily but express so vaguely. And frankly speaking, whether the warmest years of the medieval warm period occurred around 930 AD or 980 AD is not such a big deal anyway. Such a possible error can't be compared with a fabricated shape of a hockey stick, can it?
Some of the other statements by Gavin seem even more obviously incorrect. For example, Schmidt writes that the proxy Loehle #12 is also off by 50 years (???) but this proxy shouldn't have appeared at all because it only starts in the year 1440. If you actually look what the proxy is, it is from the paper Calvo, Grimalt, Jansen (2002). Click at the link and read at least the abstract. You will see that these authors don't go 550 years into the past but as much as 8,500 years into the past: "ka" means a "kiloannum", 1,000 years. This is what some of the cores from the seas are normally used for. As far as I can say, what Schmidt writes is a downright lie and he relies on the assumption that no one will be searching for the actual papers and check his statements. Preventively, he didn't link to the paper by Calvo et al. either.
OK, maybe it wasn't a lie. Maybe he just "confused" Calvo et al. (2002) with Zhao et al. (2000): it is indeed an analysis of sea cores that covers the interval 1440-1940. However, Zhao et al. (2000) was not used by Loehle (2007): just check the list of references in Loehle's paper. At any rate, Gavin's criticism is incorrect.
There might be some legitimate criticism in Gavin's text but I couldn't find any. The comparison of Gavin Schmidt and Steve McIntyre as "auditors" couldn't be more startling. While McIntyre always analyzes the finest detail of the reconstructions, he reruns all relevant programs (and does some reverse engineering when necessary), Schmidt builds on superficial, Woit-like defamations and pseudocriticism that he often makes up in which he doesn't even link to the relevant papers or sources because he probably knows himself that what he writes is not true and it only designed to manipulate with gullible readers.
If you realize that charlatans such as Gavin Schmidt are paid for their work while Steve McIntyre must work as an outsider, the state of affairs in the present climate science seems sad, indeed.
Loehle's paper has also been criticized because he didn't specify any error bars. Now, I obviously agree that it is better to specify errors bars if you can. On the other hand, detailed audit of older papers about these topics has demonstrated that the error bars in most paleoclimate papers are more or less unjustifiable numbers that are either determined by incorrect calculations or by randomly chosen Bayesian priors. If the only error bars one can determine are of this kind, I think it is better not to calculate any error bars at all.
Figure 1: Moberg 2005 (up) compared with Loehle 2007 (down). While Moberg is viewed as a "mainstream" scientist, Loehle is being sold as a skeptic. However, if you look at the figure above, you may see that their reconstructions are almost identical. This is of course partly because they use similar sources of data. But it is very conceivable that paleoclimate reconstructions will eventually converge to charts similar to those above - or other charts that someone will draw in the future. In one of them, the medieval warm period may win and be warmer than out times, in the other reconstruction, it may be the other way around. But you can easily see that the actual difference is small. I am unimpressed by the people who oversell the difference between the two graphs - on either side of the global warming debate.
The graphs above substantially differ from some older reconstructions that are thought to be very inaccurate these days (especially because the graphs above show much greater natural variability) but I do think that at a certain moment, the reconstruction business can only do progress when methodologies and proxies compete and scientists propose their positive work and remove errors that were identified as important ones, one by one. In this sense, I disagree with Steve McIntyre who celebrates that Gavin Schmidt has joined the international coalition of auditors. Nevertheless, if you're interested in audits of these papers, you should definitely read what Steve McIntyre has to say.
But it would be even more constructive to try to use your criticism to create a better reconstruction than Moberg and Loehle. No reconstruction will ever be perfect but the goal should be to reduce methodological errors and keep on increasing the accuracy. It was very important for someone - M&M - to point out some of the popular mistakes in the reconstruction but we should eventually assume that the top paleoclimatologists have had the opportunity to learn their lesson and they should be allowed to return to positive work. Every proxy or method that people can use involves a certain tension with one or more points in the list of 5 issues from the beginning of this article. The real difficult question is how to optimally overcome them to learn as much as possible.
Videos with "physics" in their title may have 365,000 visits in a week, too. Lots of boxes, tossed around in real time. The song is Aberdeen City, Pretty Pet.
Originally published on December 3rd. At the end of this text, I added a textbook example of a postdiction, showing that the whole controversy hides in the Bayesian priors once again.
Certain physicists keep on promoting the arrow of time - a scientific question that was settled between 1850 and 1872 and that became standard material of college physics (and maybe high-school physics) - as an area of active research in 2007.
Because most of the 21st century debates about the arrow of time are profoundly irrational, I will try to reveal and clarify several inherently religious (more precisely, anti-religious but equally metaphysical) myths underlying this debate.
The previous blog articles about this topic or closely related topics were:
The arrow of time is the arrow pointing from the past to the future. This concept is a symbol of the macroscopic asymmetry between the future and the past. Eggs break but they never unbreak, chicks get older but they never get younger, the heat always flows from the hotter object to the cooler one, the friction force slows things down. The reverse processes don't seem to exist. The origin of this asymmetry might be confusing for beginners but it has been well understood for a long time.
After each myth written in italics, I will describe the reality. The first myth will be about the history but I will jump to the essence of the problem right after that.
Arrow of time according to beer physics.
Myth:The arrow of time became very important or confusing in recent years.
The arrow of time has been understood in terms of physical quantities for more than 150 years: Rudolf Clausius formulated the second law of thermodynamics in 1850 even though the idea goes back to Sadi Carnot's paper from 1824. Lord Kelvin, James Clerk Maxwell, Ludwig Boltzmann, Josiah Willard Gibbs, and others have shown that the origin of these phenomena is microscopic (not cosmological!) in nature. Boltzmann proved his H-theorem, a quantitative and rigorous form of the second law, in 1872. Gibbs introduced the key notion of an "ensemble" of microstates (or "points in phase space", using his old classical setup): we will talk about "indistinguishable microstates" later. There have always been people who misunderstood statistical physics but there are no recent scientific results that would justify a qualitative revision of Boltzmann's, Gibbs's and related answers.
Discussions about the arrow of time are not the core of the research of well-known scientists and no papers in which the arrow of time plays a crucial role are famous. There are no experiments and no non-trivial calculations in recent literature that would justify a new kind investigation of this concept and if you are a sponsor of science and a scientist tells you something else in order to get funding, you are being had.
The arrow of time belongs to the basic material of physics that is not affected by any known modern results in particle physics or general relativity or string theory or cosmology and the well-known particle physicists and string theorists have nothing to say beyond what good physicists in broader groups, including those outside high-energy and gravitational physics, should know anyway.
The term "arrow of time" was coined by Arthur Eddington in 1927. Although I have criticized his numerology from the 1930s, of course that he knew basic physics - at least in the 1920s - and correctly said that the arrow of time "can be determined by a study of organizations of atoms, molecules, and bodies" and in physics, "it is a property of entropy alone": see Wikipedia.
Myth:The time asymmetry of macroscopic processes contradicts the time-reversal symmetry (or, more precisely, CPT symmetry) of the underlying microscopic dynamical laws.
This myth - also referred to as the "irreversibility paradox" - is the main driver behind the irrational debate about the arrow of time. Most people who present the arrow of time as a "hot" topic believe this myth although they never state it clearly. They only give you "hints" about a "subtle tension" and they hope that this fog will make you think that there is a contradiction. Of course, they can't replace this fog by a particular well-defined contradiction because no such contradiction exists. Whether they feel some tension is a problem for their physician, not a physicist. And there exists no verified principle that would imply that this kind of "tension" should be rationally viewed as a problem by a physicist.
Why is there no contradiction? Well, the microscopic laws are time-reversal-symmetric - or at least approximately time-reversal symmetric and exactly CPT-symmetric. But as we will discuss in detail, the microscopic laws are not "everything" one needs to make physical predictions. While the microscopic laws or "dynamics" contain pretty much all the non-trivial information about the physical system and all the difficult maths, one also needs another part of the structure that I will generally call the "interpretation of physics" in order to connect the formulae with reality. This interpretation includes basic logic, inference, and it gives meaning to words used for various macroscopic concepts, objects, and phenomena.
We have known for 80 years that the world obeys the laws of quantum mechanics and the "interpretation of physics" therefore mostly means "interpretation of quantum mechanics". However, even classical physics needs some "interpretation" even though it is less subtle. The arrow of time always hides in the "interpretation of physics" component of a physical theory, especially in the definition of words from the "macroscopic vocabulary" and in the basic logical rules to work with them, and whether the theory is classical or quantum is pretty much irrelevant for this qualitative question.
There is of course no contradiction between our "dynamical microscopic laws" and the "interpretation of physics". Only the latter structure breaks the symmetry between the future and the past but it is of course enough for macroscopic physics to be time-reversal-asymmetric. We will see more details later.
Myth:The arrow of time is a consequence of quantum mechanics.
It is quite easy to see why this sentence is incorrect: even when the world was thought to be classical, people knew that eggs were breaking but not unbreaking. Quantum mechanics changed many qualitative facts about the real world but the arrow of time is not one of them.
Classical statistical physics (with its Maxwell-Boltzmann distribution and other insights) was replaced by quantum statistical physics (with its Bose-Einstein and Fermi-Dirac distributions and similar wisdom). But both of these disciplines imply pretty much the same large N limit called thermodynamics. In the quantum case, the large N limit also includes the classical limit. The qualitative relation between thermodynamics on one side and statistical physics on the other side is pretty much identical in the classical and quantum world.
Another simple way to debunk the myth is to notice that the strength of all quantum phenomena is controlled by Planck's constant which is very tiny in "everyday units" while the manifestations of the arrow of time - such as friction - are clearly macroscopically large. So they can't be proportional to Planck's constant: their essence can't depend on quantum mechanics.
Myth:The arrow of time is a consequence of gravity.
This myth was promoted by people such as Roger Penrose (who has also combined this myth with misinterpreted collapses of wave functions and psychology). Roger Penrose is an original thinker, a hero of mathematical physics, but his belief in his myth represented a profound breakdown of very basic scientific intuition and rational reasoning in general.
Why is the sentence a myth? Well, some astronauts can tell you that even in spaceships with no gravity, eggs break but never unbreak. In fact, they could offer as many examples as you find necessary. All effects of gravity are controlled by Newton's gravitational constant. Can the arrow of time be one of them?
Well, one of the nice, quantitative examples of the arrow of time is friction: it slows objects down but it never speeds them up. It is trivial to see that the arrow of time associated with friction (or diffusion or many other phenomena that add first time derivatives into classical equations of motion) is identical with the arrows associated with eggs and chicks. If someone says that the arrow of time is due to gravity, he also says that friction is due to gravity. I think that such a statement would be embarrassing even for many smart pupils from elementary schools.
Friction is something very different than gravity.
The magnitude of friction is clearly controlled by atomic physics and electromagnetism; gravity has obviously nothing whatsoever to do with it. Gravity is irrelevant. The friction force is not proportional to the tiny Newton's constant. A good enough student should be able to make an order-of-magnitude estimate of the size of friction from the first principles. Collide atoms and calculate the elastic and inelastic cross sections. The inelastic scattering will control dissipation, friction, and consequently the strength of the arrow of time.
Myth:Cosmology is the source of the arrow of time.
Cosmology is a discipline that studies certain solutions to general relativity, a theory of gravity, relevant for the Universe at the longest time scales and distance scales or the Universe near its beginning. If gravity is not behind the arrow of time, it actually follows that cosmology can't be behind it either. Thinking that the friction force or the aging processes are due to the phase transition of a young Universe or due to the Sun or something else in the vast Cosmos is obviously a form of astrology.
Let me say a few more words anyway. When it was born, the Universe probably had a very low entropy. We should really expect it was zero; for example, the Hartle-Hawking wave function is a unique state and the entropy of a unique state is "ln(1)=0". The vanishing entropy of a young Universe is consistent with the second law of thermodynamics that requires the entropy to increase as the Universe gets older. But the low initial entropy is not equivalent to the second law. Why?
Myth:A small or vanishing entropy of a newborn Universe is a sufficient condition that explains all effects of the arrow of time.
But the vanishing entropy of a newborn Universe is surely not a sufficient condition that is enough to derive the applications of the second law of thermodynamics that we normally care about. If the total entropy were zero at the beginning, it would be natural for it to be increasing afterwards, at least for some time, because the entropy can't be negative.
But it could still be true that the total entropy of the Universe increases but in 40% of the Universe, eggs are unbreaking. The remaining 60% of the Universe where the eggs are breaking would overcompensate this anomaly. Believe me or not but the eggs are breaking in the whole observable Universe and regions with opposite arrows of time simply can't co-exist. I will try to discuss this fact later.
The "strength" of the processes that break the time-reversal symmetry, such as friction, is controlled by dissipation and the calculations of inelastic processes we mentioned previously. These calculations are completely local and they apply to every small piece of spacetime. The friction seems to be universal across the Cosmos; you could never derive the universality of the friction force across the Universe from a global or cosmological assumption. In fact, some cosmological details about the Universe a few billion years earlier are absolutely irrelevant for the size of a friction force. Every student who has actually understood where the friction force comes from - and it is the electromagnetic interaction between many elementary particles that makes it work, not gravity - should feel certain about this simple fact.
Myth:A low entropy of the early Universe is a necessary condition for the second law of thermodynamics to hold today.
An "opposite" statement, namely that a vanishing total entropy of the newborn Universe is a necessary condition for the second law of thermodynamics, is also incorrect. The entropy could have been nonzero and the second law would still hold. In fact, many people believe that the total entropy was always nonzero. And Boltzmann himself even believed that the entropy in the distant past could have been very high, higher than today - exactly the opposite than what Sean Carroll considers necessary - and we were born from an unlikely low-entropy fluctuation (recall the Boltzmann brain). The assumptions about the distant past have nothing whatsoever to do with the assumptions we need to make to scientifically derive things like the Boltzmann equation and other macroscopic violations of the T symmetry.
The correct assumptions we need are local ones and they are effectively equivalent to the molecular chaos, namely the absence of correlations between positions and velocities of individual molecules of the gas in the initial state. The assumption of strictly vanishing correlations simplified Boltzmann's calculations considerably. Now, these quantities are not really 100% uncorrelated but what is important is that it is insanely exponentially unlikely that their correlation is exactly the right one to change anything about the result of the calculation of diffusion and other time-asymmetric processes, for example they are insanely unlikely to make the entropy decrease for a macroscopic amount of time.
Myth:The arrow of time is a manifestation of quantum gravity.
This statement is as sexy as the previous myths about quantum mechanics and gravity combined. Unfortunately, it is also as stupid and manifestly wrong as these previous two myths combined. Equivalently, we may formulate the myth as follows: "There would be no arrow of time if the Universe were not quantum or if it didn't include the gravitational force." Check that this is equivalent.
This is doubly incorrect because the arrow of time (e.g. a friction force) clearly exists in a classical world (there is also inelastic scattering in classical physics) and it also exists in a non-gravitational world (ask the astronauts).
It is plausible that in a hypothetical future description of quantum gravity that may unify dynamics and interpretation of physics in a very surprising way, it will be possible to "derive" the arrow of time by a novel procedure. But it would still be true that the arrow of time would follow from those ingredients of the new theory that would supersede the "interpretation of quantum mechanics" as we know it today. The arrow of time does not and cannot inherently depend on any insights of quantum gravity because if it did, it couldn't hold in theories simpler than quantum gravity.
And it cannot have global, cosmological reasons. Boltzmann, Gibbs, and their colleagues have derived nothing else than that the origin of the irreversible processes is microscopic and local. Whoever says that it is cosmological and global should have been failed in high school physics.
I think that to associate concepts of cutting-edge research such as "quantum gravity" with mundane notions of 19th century physics such as the "arrow of time" is a form of intellectual porn that builds purely on human ignorance and rudimentary misunderstandings of the real world.
Myth:The arrow of time is a consequence of CP-symmetry violation.
The weak nuclear interactions violate the CP symmetry which is equivalent to saying that they violate the T symmetry. Is it the reason why eggs don't unbreak? Of course not. There are two basic ways to see why. First, the weak interactions much like all other interactions preserve the CPT symmetry - there is extensive theoretical as well as experimental evidence supporting this assertion. And the CPT symmetry would be enough to show that eggs break as often as unbreak. More precisely, eggs break as often as mirror anti-eggs unbreak. ;-)
That's not the case. However, there is another argument that doesn't require you to find any mirror anti-eggs. If the CP violation were responsible for the time asymmetry of eggs and of the friction force, friction would have to be proportional to the small numbers that encode the CP violation by the weak interactions (a small angle from the CKM matrix, if you care). Again, this is clearly not the case because the friction force is much stronger and it is controlled by electromagnetic collisions - collisions caused by a force whose microscopic description is time-reversal-symmetric.
Myth:The time-reversal symmetry of microscopic dynamical laws implies that the arrow of time shouldn't exist.
For the sake of clarity, let us represent the arrow of time by the friction force again. The incorrect statement above would imply that the friction force has to vanish because zero is the only number that is equal to minus itself. Obviously, the friction force doesn't vanish. We can observe this fact empirically but a good enough theoretical physicist should also be able to show theoretically - from the first principles - why the friction force doesn't vanish. And to roughly estimate it.
How is it possible that the time-reversal-invariant microscopic laws allow us to calculate a non-zero friction force? Well, as we have already mentioned, it is because the microscopic laws are not everything we need to make physical predictions. We also need an "interpretation of physics" to relate the mathematical symbols to our observations.
So how do we make predictions? We always have to approximately know the state of the physical system (or the Universe) at one moment "P" and to use the evolution encoded in the microscopic dynamical laws to calculate some (not all) pretty much macroscopic features of the physical system at a different moment "F". Predictions in science always follow this template. In English, the moment "P" is referred to as the past while the moment "F" is called the future. "F" must come after "P". More precisely, we define the word "after" (and the logical arrow of time) in such a way that "F" comes after "P".
Note that the role of "P" and "F" in the previous paragraph is asymmetric. It is important that in the past, we know the state of the physical system approximately. And it is equally important that in most cases, we are only interested in some questions about the system in the future: we are not interested in some "environmental" degrees of freedom or some very convoluted microscopic correlations at the moment "F".
This is the whole source of asymmetry that drives the friction force as well as decoherence (these two arrows are guaranteed to agree; all the older arrows except for the decoherence arrow were proven to be equivalent by Enrico Fermi in his 1936 book "Thermodynamics" although he was certainly not the first guy to understand the reason).
If you have systems where you either know the configuration at "P" exactly or you are able to study all degrees of freedom at "F", the arrow of time indeed disappears: microscopic or structureless objects are the best examples. But it doesn't disappear for eggs, chicks, and friction. In the case of complex or macroscopic objects, it is very important that our incomplete knowledge of the physical system and the environmental degrees of freedom - that are associated with "P" and "F" asymmetrically - introduce an asymmetry to the whole calculation that allows the entropy to increase.
Even in particle physics, we know about these asymmetries. For example, we often calculate inclusive cross sections where we sum over many different final states if we don't care about their differences. On the other hand, we don't sum over initial states. The closest thing we do is to average over N initial states when we don't know the initial state accurately. (Think about summing or averaging over projections of spins.) But the additional factor of "1/N" from the averaging is a key example of a time asymmetry in our "interpretation of physics". Why do we add the "1/N" for the initial states but not the final states? Think about it - it is about pure logic. You don't need to understand any particle physics to know why. And this logic doesn't respect any symmetry between the past and the future.
And by the way, caring and knowing are two different things, too. Sometimes we don't know the exact initial state even if we would care about it. On the other hand, we often don't care about the details of the final state even though it would be possible to know it. ;-) "Not knowing" is associated with averaging and the past but "not caring" is associated with summing and the future. There is no symmetry here.
Myth:Postdicting the past from the present follows the same formulae as predicting the future from the present, with "t" replaced by "-t".
I am convinced that most talented 12-years-old kids know that this belief - a belief of Sean Carroll and lots of other deeply confused people - is not true once we talk about macroscopic objects, concepts, and phenomena. Five minutes ago, the friction force was slowing objects down just like it is doing now. The procedure sketched above would imply that five minutes ago, the friction force was speeding objects up. I think that you have a damn serious problem with your physical theory or a physical approach if it implies that five minutes ago, the friction force was speeding things up!
It is much more serious a problem than some subtle cosmological deviations that can be measured after billions of years or by analyzing memories from the Big Bang. It is a problem that completely destroys the agreement of your theory with pretty much every local event that has ever occurred anywhere in the Universe.
Because it seems that there is a lot of experimental evidence that the friction force was slowing things down just like it is doing now and much like in the future, I dare to say that their theory or their approach is falsified, it is dead, and we should no longer try to revive it or organize silly conferences about such an approach. And be sure that "my" old-fashioned method to predict the sign of the friction force implies that the friction forces were always slowing things down. ;-)
It is incredible but this is really what the debate is all about. Some people just think that the laws of physics imply that the friction force was speeding things up five minutes ago and only a profound discovery in quantum gravity could bring the world back to normal. :-)
Well, I beg to differ. In fact, "my" approach to physics respects the time-translational symmetry (up to tiny corrections implied by cosmology). That means that if the friction will be doing something in 5 minutes, it was inevitably doing pretty much the same thing 5 minutes ago. When a physicist calculates the probability of the configuration A at time T1 evolving to another configuration B at time T2, it doesn't matter what the "current time" is, whether it is before T1, T1, after T1, before T2, T2, or after T2. Physics doesn't and cannot depend on "current time" because it is a subjective notion. Physical laws and methods are constant and eternal. On the other hand, it is important to know whether T1 is before T2 or the other way around.
What's wrong with the approach of the people who believe this myth is their "interpretation of physics". They don't understand the difference between the assumptions and the assertions, between the future and the past, between the cause and the effect. It's probably because they never deal with any complex systems - only with time-reversible orbiting planets or elastic scattering.
Even in mathematical logic and probability theory, the role of assumptions and assertions is highly asymmetric. To see it, let me describe the Bayes' theorem. It is a prescription to correct your idea about the probability of a hypothesis "H" after you see evidence "E". The corrected probability, the so-called posterior probability which is really the conditional probability of the hypothesis "H" given the evidence "E", is calculated as
P(H/E) = P(E/H) P(H) / P(E)
On the right-hand side, P(H) is the prior probability of the hypothesis "H" that you knew before you saw evidence "E": the "primordial" priors before you collect your first evidence are of course the main sources of controversies in the Bayesian approach but this subtlety has nothing to do with the topic we discuss in this article. "P(E)" is the so-called marginal probability of evidence "E" in all contradicting hypotheses, equal to the sum of "P(E/H_i) P(H_i)" over "i".
Finally, "P(E/H)" is the conditional probability of seeing evidence "E" assuming the hypothesis "H". The main point of this discussion is to emphasize that the conditional probabilities "P(E/H)" and "P(H/E)" are two very different animals. There is no symmetry between assumptions and assertions in conditional probability calculus. The additional factor of "P(H) / P(E)" that distinguishes them is a more general version of the "1/N" factor in the averaging over the initial states that we discussed previously, in the comments about particle physics.
At the end of this article, I added a textbook example of a Bayesian postdiction in which it is very clear that the controversy hides in the "prior", as expected.
The very same factor must also be added when you are postdicting the past, as we discussed in the article dedicated to this subtlety and linked above. One can use physical theories to say something about the past but the formulae for the probabilities are different from the formulae controlling the predictions for the future. If you didn't include the extra factor, you would incorrectly postdict that the entropy in the past was probably higher than today and the friction were negative (accelerating). The additional factor of "exp(-entropy)" that prefers low-entropy postdictions for the past configurations has the very same origin as the "P(H) / P(E)" factor in the Bayes' formula.
The people who believe the myth think that all these factors are equal to one. Logicians have a part of their brain occupied by the Bayes' formula; ordinary people store their common sense in the same piece of their brain. The believers in this myth have a hole in that region instead. A related myth caused by this hole is the belief that the high-entropy configurations are the natural, primordial state of all objects. Quite on the contrary: high, maximized entropy is the feature that physical systems only acquire in the future, once they have enough time to reach the equilibrium. Completely different (and, in fact, opposite) observation applies to the past: it is not only acceptable but really natural (or necessary) for objects to have a low(er) entropy in the past.
These differences between the past and the future are not facts related to cosmology or quantum gravity or string theory but rather very universal facts associated with elementary logic. The people who say that the arrow of time is due to cosmology or quantum gravity or global warming misunderstand elementary logic. They will tell you that the arrow of time is due to cosmology or even their more or less bizarre version of it. They will tell you "trust me". But even if you don't get the explanation above, trust me, they are just being incredibly silly. ;-) They are not saviors who will protect you and science from seemingly absurd predictions. The reason is that science, when used properly, was never making any absurd predictions of this kind.
Even many regular people who don't know the Bayes' formula and similar things realize that there is a difference between our thinking about the past and the future and this difference is a fundamental ingredient of any rational thinking about the real world that other laws of physics must be compatible with. And they are consistent, of course. The other laws of physics such as Maxwell's equations are just being added to the basic logical framework - the "interpretation of physics" or "interpretation of science" in general - that deals with knowledge, memories, and predictions.
Let us try to localize the problem again for the case of a breaking egg. For the microstates of atoms of an egg, the dynamical laws are time-reversal-symmetric and reversible. But this fact doesn't allow us to deduce that "an egg was unbreaking in the last 5 minutes". The reason is that the very sentence "an egg will break" or "an egg will unbreak" implicitly includes the averaging over the initial microscopic states of the macroscopic object called "an egg" and summing over the final microscopic states of "an egg" and its environment. This is because of the very definition of "an egg" and of "breaking". An egg as a concept is not a particular microstate: it is a macroscopic state that can be represented by each of many microstates. And this union is and must be treated asymmetrically with respect to the time reversal. The summing vs. averaging above is the reason why the entropy is (almost) always higher for the final states of the macrosopic objects. It is the reason why we may derive that an egg - like other macroscopic objects - breaks but (exponentially) almost never unbreaks.
Slogan: All statements, questions, and probabilities of processes involving macroscopic objects include averaging over indistinguishable initial states in the past and summing over indistinguishable final states in the future. The previous sentence is manifestly past/future asymmetric and this is where the whole asymmetry comes from. The macroscopic systems thus prefer to evolve from macrostates with a few indistinguishable microstates in the past (because they're being averaged over, adding the "1/N" factor) to macrostates with many more indistinguishable microstates in the future (because the probability is summed over all of them). Therefore, the entropy increases and the second law holds. No extra explanations are needed and no extra explanations exist.
Some people talk about "preparing" initial and final states. But those who have heard about the causal arrow of time realize that controlling the future, or causing something to happen, creates correlations between the doer and the effect, and these can only be created as we move forwards in time, not backwards. After all, similar correlations between the effect and its environment that increase as we move forwards in time are also the reason behind decoherence and its arrow of time.
If you want a book that explains that the "irreversibility paradox" has been solved a very long time ago and the solution is fully based on a careful logical analysis of the differences between the microscopic and macroscopic descriptions of a physical system, see e.g. Michael Bushev 1994 (at amazon.com: Synergetics) or Jack Hokikian 2002 (The Science of Disorder, also includes quotations of Richard Feynman). See also a book by Peter Harman (1982), Cyril Domb (1996), and Derek York (1997). York is the only person who includes some cosmological speculations but he still presents Boltzmann's conventional picture. Susan Friedlander and Denis Serre (2002) argue, in Handbook of Mathematical Fluid Dynamics, that the rigorous definition of the conditions in which the Boltzmann equation holds was given by Grad in 1949.
OK, so I actually think that most people have enough common sense to know that the past is fundamentally different from the future and there exists no meaningful logical, predictive framework in which this difference between assumptions and predictions, and between cause and effect, is absent. In this sense, the time asymmetry can't be due to a "spontaneous symmetry breaking" because there exists no logical framework in which the symmetry between assumptions and assertions holds. So why do some people defend the undefendable equivalence between the future and the past?
Shockingly enough, the answer is political correctness. Sean Carroll, one of the staunchest champions of this totalitarian ideology, writes very seriously: "We human beings are terrible temporal chauvinists." So it is really politically incorrect to point out that his opinions about the origin of the arrow of time are silly - because you would become a chauvinist! ;-)
Well, I am not only a "temporal chauvinist" but I happen to think that those who can't admit a fundamental, logical asymmetry between the past and the future in any world qualitatively resembling ours lack basic knowledge of logic as well as common sense. Denying the difference between the past and the future is even worse than not seeing the cognitive differences between the two sexes. It is insane.
Myth:The cosmological arrow of time must always coincide with the thermodynamic arrow of time.
The cosmological arrow of time is the arrow from the moment when the Universe is small to the moment when the Universe is large. Because the Universe is expanding right now, this arrow agrees with the thermodynamic arrow of time. But it is always the case? Stephen Hawking used to argue that the answer was Yes. He used an incorrect continuation to the imaginary time to derive this hypothesis.
The Yes answer is clearly wrong: if you considered a Universe that ends with a Big Crunch, the eggs can't start to unbreak once the Universe reaches the maximum volume and begins to shrink. One can't even calculate the exact moment at each point of the Universe when the Universe is just beginning to shrink. But the eggs and chicks would need to know the moment very accurately. These two arrows obviously don't have anything to do with each other - eggs are controlled by accurate and fast local physics while the expansion of the Universe is about some global, slow properties of the Universe - and their directions may, in principle, be independent. Hawking has agreed that his previous statement was wrong.
Myth:Inflation is a sufficient condition to explain the arrow of time.
During an inflationary era, the cosmological arrow of time is "almost always" coincident with the logical arrow of time - because the Universe is "almost never" found in the fine-tuned state that would lead to a long, exponential shrinking or "deflation". But other kinds of shrinking of the Universe don't depend on any such "fine-tuning" and they can therefore occur in both ways, as explained in the previous paragraph.
Moreover, you can't say that inflation "explains" the arrow of time. Inflation during which the Universe accelerates its expansion is just another example of the arrow of time in which the rules of the game "look" kind of opposite than those controlling the friction force. But as we have already argued, inflation or any other cosmological evolution is insufficient to explain why invidividual eggs break but don't unbreak. In fact, the Universe after inflation (more precisely, after re-heating) already has a pretty high entropy. If a low-entropy beginning was your strategy to "derive" the second law, inflation will make your task harder, not easier.
Long after inflation, matter starts to clump. Gravity differs from non-gravitational gases in one respect: non-uniform configurations - such as those with black holes - are actually the highest-entropy ones. In fact, black holes have the highest entropy that you can squeeze into a given volume. This fact allows the seeds of galaxies to emerge without violating the second law. Gases are normally getting increasingly more uniform but gravity can change this conclusion.
But this is just a technicality about the geometric shape of generic and special configurations. If you only care about the second law - about the increasing entropy - there is no qualitative difference between inflation, post-inflationary cosmology, breaking eggs, or other processes in the Universe. The entropy always increases and it increases because of a fundamental logical arrow that must exist before one learns additional scientific laws.
Conclusions
Let me summarize: there exists some knowledge about the arrow of time and the second law of thermodynamics that is not being taught sufficiently clearly at schools but those physicists who actually understand how the real world is connected with the formulae of physics have understood for more than a century while those physicists who try to connect the arrow of time with some esoteric details of their cosmological models are the slower ones, if I have to be completely polite.
And that's the memo.
Update...
Bonus: a textbook example of a postdiction
Imagine that your system has N microstates. We will study the evolution from time T1 (earlier) to T2 (later). At T1, we will distinguish two macroscopic states A1, A2. A1, A2 include M1, M2 microstates, respectively. Analogously, we will distinguish macroscopic states B1, B2 at time T2 whose corresponding number of microstates is N1, N2, respectively. We have M1+M2 = N1+N2 = N.
What about the dynamics? N11 microstates from A1 evolve into states in the set B1. N12 microstates in A1 evolve into states in B2. N21 microstates in A2 evolve into something in B1. N22 microstates in the A2 set evolve into states in B2. We have N11+N12 = M1, N21+N22 = M2, N11+N21 = N1, N12+N22 = N2. Among these four relations, three are independent because M1+M2 = N1+N2.
Imagine we know that at T1, we have measured the macroscopic state to be A1. What is the probability of getting B1 at T2? Among the M1 microstates representing A1, N11 and N12 give us B1 and B2, respectively. So the probabilities to get B1 and B2 (from A1) are N11/M1, N12/M1, respectively. These two probabilities add up to one. Everyone agrees with this paragraph.
But now imagine that we know that we have the final macroscopic state B1 at T2 and we want to postdict the macroscopic state at the earlier time, T1. The unbreaking-egg people will just interchange the role of T1 and T2. They will tell you that the probabilities that you had A1, A2 at T1 were N11/N1, N21/N1, respectively.
But this time-reversal-symmetric result is not the correct answer because this would imply a high entropy in the past. The correct answers have nothing like N1, N2 (associated with B1, B2 and time T2) in the denominator. Instead, it is always M1, M2 (associated with A1, A2, and T1) that appear in the denominator: recall that we should always average over the initial microstates. Because postdictions are a special case of inference, a proper formula may be obtained from the Bayes' formula blockquoted above if we identify the "hypotheses" with the "initial conditions" A1=H1, A2=H2, and the "evidence" with our assumed "final state", E=B1. We therefore have
P(A1/B1) = P(B1/A1) P(A1) / P(B1)
The conditional probability P(B1/A1) is N11/M1, as explained three paragraphs ago. As always in the Bayesian reasoning, the "prior" probability P(A1) is the main quantity that encodes the whole controversy while the "marginal" probability P(B1) in the denominator is a normalization factor that guarantees that the probabilities P(A1/B1) and P(A2/B1) add up to one.
Prior, a standard Czechoslovak shopping center from the age of socialism. "Prior" stands for "Přijdeš Rychle I Odejdeš Rychle" which means "You arrive quickly and you leave quickly." :-)
OK, so what's the result?
The key player is the "prior" probability P(A1) of a macroscopic state A1. If you chose it to reflect the number of microstates, as the unbreaking-egg people always do, i.e. P(A1) = M1/N, you would end up with probabilities N11/N1, N21/N1 for having A1, A2 at T1, respectively (assuming B1 at T2). However, it is not correct to punish initial states for having a low entropy in this brutal way. There is no a priori reason to assume that the initial state should have a high entropy.
The correct method to postdict the initial state dictates that you treat all your different hypotheses about the macroscopic form of the initial state as a priori equally likely. In our case it really means that P(A1) = P(A2) = 1/2. Consequently, your postdicted probability of A1 at T1 is
By construction, the probabilities add up to one. Anyway, that's quite a different result than N11/N1, isn't it? For example, when M1/N goes to zero while M2/N, N11/N1, N21/N1 are kept finite somewhere between 0 and 1, the probability above goes to one: a low-entropy initial state A1 is heavily preferred in this case which would surely not be the case of the wrong N11/N1 formula. This Bayesian method of postdiction can be easily generalized to arbitrary physical systems, both in classical and quantum physics.
Note that I didn't have to add an additional assumption about a low entropy of the early Universe or something like that: it wouldn't be useful to quantitatively calculate the probabilities anyway. I only needed to drop the wrong assumption that the initial state had a high entropy. The contrarians who probably think that my prior is "obviously" wrong or "unnatural" should realize that they are choosing a prior, too. If there are two competing theories in physics, we should make observations to decide. Observations unanimously show that my prior is pretty much correct and the contrarians' prior is hugely wrong.
If you are irritated that the result depends on how finely we clump microstates into macrostates - i.e. on a somewhat arbitrary choice of the prior - you are correct: they do depend on it. For example, if we were suddenly able to distinguish two macroscopic states A2, A3 that used to be grouped under the same (old) A2 umbrella, the natural prior would be P(A1)=1/3, P(A2+A3)=2/3. We could have changed the priors even without this justification. However, there exists no "canonical" or "more rigorous" or "unique" way to postdict in physics that would be independent of any priors. In a sense, the well-defined predictions are irreversible - something that becomes intuitively clear when we deal with irreversible processes that make it difficult to determine the past because the information is getting lost. If you know that both 1 ton of banknotes and 1 ton of books burns into the same pile of ash that you see, there is no canonical rule to tell you whether the initial state contained banknotes or books. You need to use other wisdom to make a qualified guess. I think that the (inconvenient) books are more likely than the (convenient) banknotes but the reason has nothing to do with the entropy of books vs banknotes. :-) Common sense and the context is crucial; physics of the phenomenon itself is not enough.
This discussion is another example of discussions we have had in the context of the stringy landscape. Does a much larger number of vacua in a set (KKLT vacua, for example) make the corresponding scenario much more likely? Because the details of the stringy vacuum may be viewed as a feature of our past (the early Universe), the discussion about the likelihood of classes of vacua is really a special example of the considerations from this article.
My answer has always been that the different classes of vacua or different ideas (a special case of the macroscopic states) must be treated as a priori comparably likely, regardless of gigantic differences between the numbers of vacua (or microstates) in the set, and the general case we discuss now is no different. At the same moment, there is no "canonical" way to assign the priors which is why we cannot settle the question about the initial state of the Universe, including the preferred scenario in string theory, by a well-defined and trustworthy calculation of probabilities. Priors always play a role in any postdiction or inference.
One of the qualitative consequences of "my" resulting formulae is that all the postdictions of a high entropy in the past disappear. We have really inserted this outcome to the Bayesian formulae as an assumption, as the "prior". But it is a correct assumption because there is no rational reason to think that the high-entropy states in the past should be preferred, as observations clearly demonstrate. It would be completely absurd to punish the states in the past for having a low entropy.
Imagine that you have two hypotheses: for example, man evolved from a monkey vs. man evolved from a tulip. The initial state of the Earth with tulips preparing to evolve into human beings would have a higher entropy, by "10^{30}" or so, which is very plausible. Does it mean that you should a priori assume that the tulip theory of evolution is "exp(10^{30})" times more likely? It's completely ludicrous. Warm enough tulips with a high enough entropy could then beat the dynamical difficulty of getting one human DNA from one tulip DNA as a mutation and you could end up claiming that the tulip theory of human evolution (including a massive violation of the second law of thermodynamics) is more likely. Even though it was explained above that there are no correct God-given priors (1/2 or 1/3 for P(A1) is comparably reasonable), we see that Sean Carroll's priors are wrong by a factor of "exp(10^{30})" or so which is a pretty large number.
Physics as understood by your humble correspondent should agree with observations and the observations show that eggs were not unbreaking five minutes ago and high-entropy tulips didn't evolve into humans; the unbreaking-egg people disagree because the primary player of their physics is a stubborn (albeit nonsensical) metaphysical dogma that everything we say about physics must be time-reversal-symmetric.
One of the groups that have been discriminated against at universities are chimpanzees. Many white, black, and yellow people have a lot of prejudices against the chimpanzees even though we share 96% of genes.
Figure 1: Click the picture for a FoxNews story. Mr Ayumu who is a 5-year-old Chimpanzee Japanese can memorize the position of nine Arabic numerals in ascending order. You can't do that. Mr Ayumu gets raisins and apple cubes for his performance.
RSS MSU satellite data (graph, more graphs) for the lower troposphere show that November 2007 was the coldest month since January 2000. Other major teams that measure the global mean temperature have not yet published their November data.
Update:HadCRUT3 data (the first column is global mean temperature) confirm that November 2007 was the coldest month in this century but only since December 2000. The rest of the article focuses on RSS MSU.
The temperature anomaly was -0.014 °C. It means that the whole month was actually cooler than the the average recorded November. It was the first month in this century that was cooler than average.
The previous record low temperature anomaly in this century occurred in July 2004 when the anomaly was +0.053 °C. In other words, the record low for this century was improved by 0.07 °C. The continuing La Nina is the main reason behind the recent cold months; La Nina is expected to disappear in Spring 2008. January 2000, a month that was even cooler than November 2007, witnessed a La Nina, too. November 2007 was also a whopping 0.915 °C colder than April 1998.
Another reason could be an inactive Sun. We are expecting the solar cycle 24 to begin soon but it takes a longer time than expected and there are still almost no sun spots. Via a crucial mechanism, it means that we should be getting more galactic cosmic rays that should create more clouds.
The year 2007 is now very likely to become RSS MSU's 9th warmest year on record which really means one of the coldest years of our times. It will end up colder than all other years in the 21st century so far as well as 1998 (by 0.4 °C) and 1995. We explained that 2006 was very cold but 2007 will be shown as 0.1 °C colder.
This extraordinarily cold conclusion of RSS MSU occurs partly (but certainly not completely) because RSS MSU omits the polar regions north of 82.5°N and south of 70.0°S latitude. The former region that occupies less than 0.5% of the surface of Earth was recently getting substantially warmer.
Other teams (HadCRUT3, UAH MSU) except for GISS will also report 2007 to be between the 6th and 9th warmest year. Dr James Hansen's GISS deviates substantially - it may even announce that 2007 was the second warmest year after 2005 (or third, after 1998) - and their method to measure temperature based on stations is probably dominated by urban heat islands and the results are most likely complete rubbish.
Based on 11 months, HadCRUT3 should say that 2007 was the 8th warmest year (like RSS but warmer than 1995).
Because GISS was able to accumulate a 0.5 °C error (in the difference between 1998 and 2007 temperatures) during one decade and because the older measurements of temperature resembled those of GISS, it is conceivable that the whole 20th century warming by 0.6 °C is due to similar errors. Ross McKitrick and Patrick Michaels have just argued that the warming since 1980 is due to a similar contamination of data. That's still better than the sea level data that were completely falsified according to Nils-Axel Morner, an ex-head of Earth Sciences in Stockholm.
Click to get to a new Wikipedia page that I just created.
Every time I returned to Czechia for a month in the summer, I could see some new things around. But the changes were not too fast: one year is not such a long time, from the viewpoint of the eternity. However, when they demolished the old exhibition center where "Ex Plzeň", a gastronomical fair, took place during socialism, I was kind of stunned.
It only took a few years for a new huge shopping mall combined with an entertainment center to emerge here. The location couldn't be better. When you say a "center of the city", it is often a vague concept. Not so in Pilsen: the center of Pilsen is defined to be the Cathedral of St Bartholomew in the middle of the Square of the Republic.
And the new Plzeň Plaza shopping mall is just 250 meters from the central square. They opened the mall at 5 p.m. and it is very luxurious and impressive. Certain western nations may seem a bit tired by capitalism. I think it is safe to say that the Czechs are not yet tired by it. ;)
The project - 20,000 rentable squared meters (and 27,000 in total) was built almost in time. The speed is kind of amazing. To make it more exciting, the Israeli developer Plaza Centers sold the center to Ségécé a few days ago. It costs about CZK 1.2 billion (EUR = CZK 26.50).
Update:Phun (click!) might be a better software doing the same things. I've tested it, it's cool.
This impressive show was created with the help of Working Model 2D or maybe a related program described by Zephir (!) in the fast comments. It can figure out what you are drawing, idealize it, and simulate what will happen in the real world of classical mechanics with it.
He sketches some basic facts about the physics research that is expected to be relevant for the observations at the new collider. So you are offered some basic knowledge about the Standard Model and physics beyond the Standard Model, especially what has become stringy physics such as supersymmetry, grand unification, large extra dimensions, and warped extra dimensions. But he also talks about technicolor, CP violation, dark energy, and other things. You may read a pretty decent basic explanation of the concept of moduli and the character of the stringy landscape as well as the new tools to predict physical phenomena that it has led to.
One of his goals is to correct massive misinformation about a "gap" in particle physics that is being produced by the blogosphere and by the media that are close to the blogosphere. One basic thing that the "critics of science" haven't told their undemanding readers about high-energy physics is that among the theorists, there are two comparably large groups of people: pure theorists and phenomenologists. Phenomenologists who like to post on their favorite hep-ph archive are always interested in experiments that are doable in a foreseeable future, regardless whether their understanding is fully accurate, justified, and complete, while pure theorists who like to post on hep-th focus on ideas that are firmly rooted theoretically, regardless of their immediate relevance for doable experiments.
These are two theoretical approaches to high-energy physics that have been competing for quite some time but there is no inpenetrable gap in between them: it is rather a kind of continuum and many physicists are often switching from one mode of thinking to another. Michael Dine himself is a living example of this fact because he is one of the most solid bridges between hep-ph and hep-th.
The fuzzy border between pure theory and phenomenology is penetrable and the equilibrium between these two approaches is determined by the invisible hand of the market of ideas where scientists are both producers and consumers, not by media campaigns, intimidation, public votes, or undereducated but loud science-haters from the blogosphere. The opinion that one could social-engineer the ratio between different approaches to pretty much the same scientific topics "from above" is an artifact of an ultracommunist mode of thinking and doesn't belong to science.
And how does the equilibrium look like?
As Michael Dine makes very clear, the phenomenological approach usually ends up with random ideas and speculations that are not justified by any deeper fundamental reasons: many papers from the hep-ph archive are random constructions that someone just found interesting enough. This approach may lead to successes at many points of the development of physics but it is just a fact that in the last 20 years, the purely theoretical - one could say "Einsteinian" - approach has been much more successful because of the constant stream of solid and exciting conceptual results as well as new ideas for model building that have been coming out of string theory.
There is nothing universally better about one approach or another and when we are overwhelmed by new confusing data - and the LHC may lead to exactly this situation - the relative importance of phenomenology over pure theory may increase. But that's not where we stand at the end of 2007. Right now, it is extremely important for an idea about new physics to be reconciled with the solid cutting-edge picture of reality that is available, namely with string theory. In the absence of doable tests, this is pretty much the most important criterion that decides whether an otherwise conceivable idea is worth research or not.
The Czech song "Bude mi lehká zem" (The soil will feel light to me) by Mr Petr Hapka (a Czech composer) and Ms Jana Kirschner (a Slovak singer) is from 2001 or so.
If you think that Jana Kirschner is too young for Petr Hapka, try "Levandulová" (Lavendery), a love song of Hapka with Ms Hana Hegerová. She happens to be Slovak, too. Both women sing in perfect Czech.
Shinya Yamanaka of Kyoto University (Japan) and James Thomson of the University of Wisconsin in Madison (U.S.) have announced that their teams have independently found a promising method to transform fibroplasts (generic skin cells) to iPS cells (induced pluripotent stem cells) that were so far only obtained by killing embryos.
Congratulations to both teams. Although, truth to be said, those who have opposed killing embryos, including Christian groups and politicians in different countries, could perhaps take a part of the credit. It is rather likely that the discovery will lead to an expansion of stem cell research in the future. There are already hints that the method could be helpful to cure cancer.
It's 
Radioactivity was born - one of two Lord Kelvin's dark clouds floating above classical physics. These were times when making important discoveries in physics was rather easy. Becquerel received the 1903 physics Nobel prize.
Because a recent TRF text might suggest that I think that no blonde can possibly know whether 
On December 11th, 1882, two well-known people were born: 
