Friday, May 30, 2008

Crime Scene Investigation

Missing Energy! Whodunit?I recently talked to a friend who is all into crime novels and he continues to recommend books despite my obvious disinterest. I keep telling him I'm not much into whodunits, yawn, I spend my whole day investigating suspects and trying to figure out why they disagree and what the real story is. True, the suspects are the assumptions I've used and not the gardener and the wife's lover, but anyway. Then he goes on, yesyes, but did you read...?

Then I coincidentally came across an article titled "Even Scientist's Can't Decide". The crime committed in this title is the word 'even'. What it signals to me is that scientists are expected to present unchangeable facts. Fundamental truths. Possibly it has been the case for centuries that indeed when scientific research reached the public it was the already well established knowledge. Scientists have found. And what the scientists say is not to doubt. Reliable. Does not change from one day to the next. At least not generally. And if it does we call it a revolution and put it on the front page.

What is the image of the scientist that is distributed in the media today? A white haired man in a lab coat explaining you'll be happy for the rest of your life if you only eat two apples a day and brush your teeth three times, at least two minutes. And don't forget to floss. And btw, of course you shouldn't just take any toothpaste, but dentists recommend. Clinically proven. Trust him. He's a scientist. I encourage you to do a Google image search for 'scientist' - tells you all you need to know.

But look now, what ever happened to science? Nowadays, even the scientists can't decide! What is the world coming to! We can as well go back to superstition or religion. At least then we have fundamental truths. Unchangeable facts. It's so disturbing if the rules change over time, let's look them up in a book that's at least 2000 years old and not question them. What does the bible say about brushing your teeth?

So, look now, what ever happened to science? Nothing. But presenting only the outcome leaves out the process. And today when every piece of discussion is documented and reaches the public almost immediately, I'd think it's about time that people begin to understand how science works, and that investigation takes time during which there is uncertainty.

Of course scientists disagree with each other. They argue about the interpretation of facts, they argue about data analysis, they argue about the assumptions in their calculations, they argue about which approach is more suitable for which problem, or which conclusion more plausible, who said what first, and which place to go for dinner. You should be worried if they didn't argue, because that's what keeps science alive and healthy. And while scientists investigate the evidence and look for missing pieces their opinions might differ and change.

These processes take time. Questions can be around for decades and they get settled only gradually, until they become established knowledge.

Take for example neutrino oscillations. In first experiments starting with Raymond Davis in 1968 it was found that neutrinos from sun were only measured to be about one third of the prediction, which became known as "The Mystery of the Mission Neutrinos". It was proposed the observations could be explained with neutrinos decaying, or oscillating, or maybe there's something we don't understand about the sun, or maybe the measurement is just wrong. People discussed back and forth. Even I recall that the situation was far from clear and there was a lot of argumentation. More experiments were done. It was shown the effect can occur also for neutrinos from reactor sources and not from the sun. It was observed for neutrinos of different energies. It was shown that not only neutrinos of one flavor go missing, but instead they change into different flavors. The measurements were reproduced numerous times in dozens of experiments. The theory about neutrino oscillation became gradually more established. Today it's textbook stuff. (For a very nice introduction, see John Bahcall's Nobel Lecture - is it a coincidence he chose detectives as illustration?)

Another more recent discussion is the GZK-cutoff, a sudden drop in the spectrum of ultra-high energetic cosmic rays when the energy of the incoming proton exceeds a certain threshold energy. Predicted in the late sixties, it has been claimed to be there, to not be there, then to definitely be there, but there's still people who discuss it as I saw in a paper that was on the arXiv yesterday.

Is there a CMB background or is it pigeonshit?

Or take the Pioneer anomaly. Is it a real effect? Or a systematic problem in the data analysis? Is the situation settled?

Following these discussions and being part of the search is without doubt one of the most exciting aspects of being a scientist. It's quite addictive to hear what's going on, what came out of this experiment, who has a new argument, how does it fit in and what does this mean. And in the age of infotainment when busy bloggers pass on gossip from the corridors to the whole wide world, this search can pretty much be followed by everybody who is interested.

There's two way one can deal with topics that are currently under investigation. One option is to just not talk to the public about anything before there is an established scientific consensus. Problem is, this would make many science journalists unemployed, cause bloggers and their readers withdrawal symptoms, and besides this a public interest in recent scientific research is beneficial for both sides. There would also be the problem to decide when the dust has settled enough, and whether or how that could be decided. This sounds very unappealing to me.

Then the remaining option is learning to live with arguments and uncertainties that come with transparency. That means dropping the idea that scientists are judges instead of crime scene investigators, or have to decide for either side when they instead are collecting the evidence.

“We are faced with all kinds of questions to which we would like unequivocal answers […] There is a huge pressure on scientists to provide concrete answers […] But the temptation to frame these debates in terms of certainty is fraught with danger. Certainty is an unforgiving taskmaker. […] If we are honest and say the scientists conclusions aren’t certain, we may find this being used as justification for doing nothing, or even to allow wiggle room for the supernatural to creep back in again. If we pretend we’re certain when we are not, we risk being unmasked as liars.”


Anomalous alignments in the CMB - who ordered that? Hole the size of the univserse missing! The Cosmological Constant: Wanted - Dead or Alive.

Wednesday, May 28, 2008

Bumblebees can't fly?

Bumblebees are quite impressive insects: They make a nice humming sound, they cause a small stir when flying over patches of dusty ground, and with a mass of nearly a gram, they are heavy enough to bend clover flowers under their weight when landing to feed nectar.



And, of course, bumblebees cannot fly according to the laws of aerodynamics, or so goes the myth. This story, often invoked by people wanting to dismiss results of scientific reasoning, seems to go back to the 1930s, to students of Ludwig Prandtl, a pioneer of aerodynamics at the University of Göttingen in Germany.

As so often, there is some truth also to this myth: If one starts from the assumption that the uplift force comes about as for an airplane wing, this is fine to understand the flight of large birds. But this assumption works much worse for small birds and bats, and it fails for insects such as bumblebees. Obviously, bumblebees have found clever way to fly very different from that of airplanes.

But they don't defy the laws of aerodynamics anymore: The issue of Physical Review Letters of September 4, 2000, besides discussing Prospects of Detecting Baryon and Quark Superfluidity from Cooling Neutron Stars and Magnetic-Octupole Order in Neptunium Dioxide, had a paper by Z. Jane Wang with the unassuming title "Two Dimensional Mechanism for Insect Hovering". But as the abstract explains Resolved computation of two dimensional insect hovering shows for the first time that a two dimensional hovering motion can generate enough lift to support a typical insect weight. The computation reveals a two dimensional mechanism of creating a downward dipole jet of counterrotating vortices, which are formed from leading and trailing edge vortices. [...]". (Phys. Rev. Lett. 85 (2000) 2216-2219).


Snapshots of the vorticity field of the moving wings (black). The illustration, taken from Phys. Rev. Lett. 85 (2000) 2216-2219, shows the formation and dynamics of a "dipole jet" of vortices, which creates the uplift force that allows the insect to hover.


It seems that the rapid motion of insects wings creates tiny vortices in the air that keep them aloft. This is especially important when hovering around a clover bloom. Luckily, bumblebees can fly without reading the PRL.











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Monday, May 26, 2008

Solid State Physics in the Garden

This spring, a nice little gadget is popping up in the yards and gardens of villages and suburbs in Germany: Small lanterns, with lids equipped with solar cells that collect sunlight during daytime and give it back at night.

  


Here is how such a lantern looks like:



The lid not only bears the solar cells, it contains also a rechargeable battery, a bit of electronics, and a white light-emitting diode (LED) that produces the light at night.



The LED is actually quite tiny, but it gives off a very bright and concentrated spot of light. This light is refracted and dispersed by the corrugated casing of transparent plastic.

Photons of sunlight hitting the semiconducting material of the photovoltaic solar cell can promote electric charges from the valence to the conduction band, where they can move and create a small direct electric voltage, if the material is suitably engineered. This voltage is used to charge the battery. When no light falls on the solar cells, the electronics allows the battery to discharge via the LED; where just the inverse process takes place: Electric charges recombine across the band gap, thereby emitting photons. LEDs that can give off white light are a relative recent development, and rely on quite sophisticated recipes to combine different semiconducting materials.

The solar constant, the flux of energy from the sun hitting the Earth, is 1.37 kW/m² at the top of the atmosphere, but there is of course absorption, clouds blocking the light, the constant change of day and night, the height of the Sun varying with the seasons... - as a result, the annual average of solar power arriving at ground level is about 120 W/m² for Germany (or 1 MWh/m² per year). The solar cell of the lamp has an area of roughly 50 cm² (7 × 7 cm²), so it can harvest roughly 0.6 W. Assuming an efficiency of 15% for a standard multicrystalline Si solar cell, the solar panel produces a power of about 10 mW on average over the year. During the summer months, this power may be higher by a factor of two or so, but it is still quite small - yet big enough to light steps in the garden path all night long.








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Sunday, May 25, 2008

Text + Equations = Clarity ?

I want to pick up a discussion that emerged out of my previous post "The Illusion of Knowledge" in which I mention that I dislike the fear of using equations in pop sci books, and that I also very much appreciate further references to follow up on a topic. Equations make a verbal explanation much more precise, and if possible I think one should at least provide the basic relations or definitions.

Dany expresses his scepticism about this and argues maths is too complicated:
"I think that the average professional in the theoretical physics need at least five years to learn the math which I consider directly relevant to formulation of Relativistic QM (QFT). After that he needs to develop the necessary supplementary math on his own."


I explain that one can extract some knowledge from equations even without understanding the full context: First, there is the benefit of knowing how a system is quantified to begin with. But more importantly, there is some information that can be rather easily extracted, like what fields couple to which other fields, or how sources affect the field. General parameter dependence of solutions e.g. how the number of dimensions affects Newton's law. Questions of definition, like what is the cosmological constant, or what are the dimensionalities of quantities, scaling, and so on.

Let me call that 'reading maths', in contrast to 'speaking maths' in which you'd have to find a mathematical description for a system you want to investigate which is considerably harder. I think with a bit practice most people could learn to 'read' maths if they get used to it. If I open a newspaper I also wonder how many readers actually understand the details of the business part. But they are just used to the terms, and after a while they get some notion of what's going on. Using equations in the science part wouldn't be all that different.

Dany then argues that using equations and further references isn't nice for the reader because

"after first reading one remains with the feeling that it is interesting but only illusion of understanding and knowledge"


And yes, that's exactly the impression I want the reader to have. If you've had to argue with people who believe the Hawking effect is nonsense because in 'The Brief History of Time' it's written that it requires the existence of anti-gravitating particles, you'll understand what I mean. In fact, this was one of the aspects I meant to emphasize in that previous post: It has noticeable drawbacks to leave readers with the 'Illusion of Knowledge'. This drawback esp. in the science area is that readers come to believe it's all trivial and obvious and they don't even need to take a physics class to conclude that String Theory is nonsense, the LHC piles dogs, Special Relativity is wrong, and the tenth dimension is where the consciousness lives. After all, equations are unnecessary.

Example: I am still waiting for somebody to point out if you believe Lisa Randall's explanations for why mini-black holes at the LHC evaporate very fast: "just as a small drop of coffee evaporates more quickly than a big one" (Warped Passages, p.380, US Hardcover) then the temperature doesn't increase when black holes get smaller as is the case with Hawking's radiation. The problem isn't with the reader who just swallows this, but with the reader who takes such a metaphor literally and then tries to build upon it. I am not against using such verbal explanations, I would just wish the limitations of their usefulness would be made clear. (The actual mass-loss rate is the surface times the fourth power of the temperature, and the temperature grows with the inverse of the radius).

Dany further argues:
"I would not provide you any tools “to dig a bit deeper” since I honestly respect my reader"


If a book doesn't come with further references to dig into a topic this a) lowers the usefulness of a book dramatically, b) is an indication the author either doesn't know the literature well, or didn't take the time to scan it so limits his/her credibility and c) it's just unscientific. If you write about a topic without explaining all details you should at least provide a reference to look them up. If pop-sci books don't do that how can you expect millions of people on the internet to appropriately references their sources?

I agree with Andrew who mentions:
"You can have equations in a pop science book as long as you also include a written description so people can avoid the equations if they so wish. But people who want to dig a bit deeper could consider the maths. So it appeals to the widest audience. At the very least, they should have references to arXiv papers."

Yes, some references at least to arXiv papers or so are very useful - just that not every field (yet) has something like the arXiv. See, if I read a pop sci introduction into a field I don't know very well but I find interesting, I just want to have some recommendation for where to continue reading, preferably by somebody who has an overview on the literature and not by a Wikipedia article.

To add another aspect: when I was a kid I read several pop-sci books on Special and General Relativity. There is a huge abundance of literature that will tell you a lot about rockets and elevators and trains and twins and flying angels and signals and clocks and again the rockets, the rockets are everywhere. It's not that I totally didn't understand these explanations, I just didn't know what to make out of all the extra baggage. And some of these explanations are not very insightful.

I recall there was an explanation in a book which was a construction meant to 'proof' length contraction. Unfortunately, I assume now it was a construction done with the knowledge of what the outcome should be, but not meaningful in itself. So I went and 'proofed' it nonsense and showed it to my physics teacher hoping for some insight. All my teacher said was 'We know Special Relativity is correct'. Which didn't help me anything. However, today I can kind of understand his hesitation to take apart somebody's fancy construction of flying rockets and clocks and so on.

Special Relativity began to make sense to me the moment I learned what SO(3,1) is. No more rockets. What a relief. Okay, it is maybe a matter of taste but I found the maths underlying Special Relativity more insightful than all the thought experiments. It's not that I would want to throw verbal explanations out, just I'd prefer to use them as a motivation instead of a substitute. (And no, understanding what a orthonormal transformation is isn't all that hard and can nicely be explained with some pictures. The part with the Lorentzian signature is a bit more tricky. To the German readers I warmly recommend Ulrich Schröder's book on Special Relativity.)

I got a lot out of the magazine Spectrum (the German version of Scientific American) and Bild der Wissenschaft (which is a very similar German magazine), both of which usually provided at least one or the other equation and some references. (At this time however it was for me almost impossible to get a hand on the mentioned references. This would be considerably easier today.)

On the philosophical side it is quite interesting to which importance thought experiments (Gedankenexperimente) have grown since Einstein.

Anyway, what is your opinion on having equations in pop-sci books?

@ Dany: I didn't mean to pick around on your comments because they are so outrageous, they just made for a nice pro/con situation.

Friday, May 23, 2008

Nuclear Power, Return Of

Just a quick commentary on something I said previously several time, e.g. in this post on Global Warming. If extracting energy from natural gas and oil resources becomes increasing difficult, countries will look for alternative solutions. The most convenient thing is to fall back to already existing technologies. Power from nuclear fission stands on top of the list. It is except for a little waste problem environmentally fairly clean, and has a reasonable energy-return-on-investment (EROI), somewhere around 10:1 - at least considerably better than biofuel. Though people disagree on the details. This site (which is a quite good resource) offers a plot of the EROI estimates for Nuclear Power plants vs. year of analysis. (The estimates are not all for the same technologies, which explains part of the deviations. Either way, one would wish for some clarification on the issue.)

It's not that I am advocating nuclear power, I just want to mention this is likely where things are going. There hasn't been a major accident for a while and those who've demonstrated against nuclear power plants some decades ago are now worrying about hemorrhoids and their children's tuition fees. What I am waiting for is some 'educational' advertising campaign for how great nuclear power is to overcome the NIMBY problem, or possibly BANANAs. Nuclear power plants are cost intensive, so to get things started governmental backup is helpful. Here as in many other areas however, the question is eventually not whether it is cost intensive, but how much more cost-intensive other alternatives would be.

Over the last years you could collect more evidence for this trend. Since 2002 the Department of Energy is running a program called Nuclear Power 2010:

"New baseload nuclear generating capacity is required to enhance U.S. energy supply diversity and energy security, a key National Energy Policy (NEP) objective. The Nuclear Power 2010 program, unveiled by the Secretary on February 14, 2002, is a joint government/industry cost-shared effort to identify sites for new nuclear power plants, develop and bring to market advanced nuclear plant technologies, evaluate the business case for building new nuclear power plants, and demonstrate untested regulatory processes[...]

The NP-2010 program is focused on reducing the technical, regulatory and institutional barriers to deployment of new nuclear power plants based on expert recommendations [...]"

And President Bush can be heard saying (Washington Post, May 22nd 2008):
"Our problem in America gets solved if we expand our refining capacity, promote nuclear energy and continue our strategy for the advancement of alternative energies, as well as conservation."

Every once in a while there appears some article like e.g. this one in Scientific American from September 2007
Nuclear Power Reborn
New Jersey-based NRG Energy applies to build the first new nuclear power plant in the U.S. in more than 30 years


"It is a new day for energy in America," David Crane, NRG president and chief executive officer, said after making the application. "Advanced nuclear technology is the only currently viable large-scale alternative to traditional coal-fueled generation to produce none of the traditional air emissions," including the greenhouse gases responsible for climate change.

Armed with the backing of the White House and congressional leaders—and subsidies, such as $500 million in risk insurance from the U.S. Department of Energy— the nuclear industry is experiencing a revival in the U.S. As many as 29 new reactors may be added to the current U.S. fleet of 104, according to Bill Borchardt, director of the Nuclear Regulatory Commission's (NRC) office of new reactors. "It is going to be significantly different than it was in the 1970s," he says.

This is not an US-only trend. In Physics Today, February 2006 it is summarized

Stronger Future for Nuclear Power
Nuclear reactor builders are jostling for business as energy utilities take another look at nuclear power.

Some two dozen power plants are scheduled to be built or refurbished during the next five years in Canada, China, several European Union countries, India, Iran, Pakistan, Russia, and South Africa. In the US and the UK, governmental preparations are under way that may lead to 15 new reactor orders by 2007.

CBS reports (April 2007)
"France: Vive Les Nukes

With power demands rising and concerns over global warming increasing, what the world needs now is an efficient means of producing large amounts of carbon free energy. One of the few available options is nuclear, a technology whose time seemed to come and go and may now be coming again.

For the first time in decades, new nuclear plants are being built, and not just in Iran and North Korea. With zero green house gas emissions, the U.S. government, public utilities and even some environmental groups are taking a second look at nuclear power."

Reuters discusses the waste problem (Jan 2008). USA today comments on the "nuclear rebirth" 131 days ago (can somebody find a date on this site?):
With nuclear rebirth come new worries
Global warming and rocketing oil prices are making nuclear power fashionable, drawing a once demonized industry out of the shadows of the Chernobyl disaster as a potential shining knight of clean energy. [...]

Of the more than 100 nuclear reactors now being built, planned or on order, about half are in China, India and other developing nations. Argentina, Brazil and South Africa plan to expand existing programs; and Vietnam, Thailand, Egypt and Turkey are among the countries considering building their first reactors.
And today the New York Times reports that Italy Plans to Resume Building Atomic Plants.

The only thing that surprises me is that there hasn't yet been a more furious outcry.

Finally, here is a special bonus for the Germans from today's Spiegel Online

With the new Italian government saying it wants to pave the way to construct new nuclear power plants, Germany's chancellor says its time for Berlin to rethink its energy policies. It "doesn't make sense," Merkel argues, to take Germany's nuclear plants offline.

Wednesday, May 21, 2008

The Blog Universe

As a PS to my recent post on Science and the Web 2.0, here are some results from a survey among "more than 400 communication experts from all over Europe" that studies "the way weblogs and social software are changing organizational practice". The survey, called EuroBlog 2007, is a follow up of a 2006 survey. You can download the details from their website


One of the lead researchers, Swaran Sandhu from the University of Lucerne, Switzerland, said

"We did not expect the field to mature so quickly. Four out of five participants of the survey read Weblogs regularly, two out of five daily. A year ago Weblogs were spoken about, but they were not integrated into the daily media consumption of communication professionals. Today they seem to be indispensable.


85% of the participants think that Weblogs and Social Software are revolutionizing the way we communicate. 89% believe the new communication platforms such as Weblogs and Wikis are becoming accepted communications platform in the same way as website. 20% sees Weblogs as overhyped and not very relevant for their daily operations.

As the most relevant factors limiting the use of weblogs or social software in companies/institutions is a lack of return on investment (42% up from 31% in 2006), as well as a lack of personnel capacity to handle the new communication challenges (69% up from 22% in 2006).

Also interesting is this question, the answers to which I think apply to the academic world as well:

What are the biggest challenges using weblogs brings for your organization?

83% (10% in 2006): Having time to blog regularly
83% (37% in 2006): Reacting to comments/feedback by the audience
80% (39% in 2006): Creating Content and Ideas for posts
88% (40% in 2006): Integrating blogs into communication strategy

And they also provide us with an interesting graphic on the 'virtuous circle of blogging':


A graphic that I however can't make very much sense of. I fail to see why a) blogging is necessarily about environmental scanning and why b) reaching new audiences leads back to environmental scanning.

The pdf of the survey results contains a 'suggested citation' for quotes from their study. Unfortunately the pdf is copy protected and I'm in no mood to retype their suggestion, so here just comes the link.

Tuesday, May 20, 2008

Vampire Devices

This press release from the White House is almost seven years old, but I think it is worthwhile to mention that the President of the United States explained he does not wish to break basic laws of Nature like conservation of energy, and therefore wants to support vampire slayers.

"The President will challenge American businesses, both in their manufacturing decisions and in their purchasing decisions, to look to the vampire slayer as a means of conserving energy and saving money."

"Conserve your energy. That's the message I'm sending to Congress today," stated president Bush.

Sorry, couldn't resist. And yes, of course I'm all for energy saving, so stop laughing, it burns calories.

Monday, May 19, 2008

Flying Over Mars

Next Sunday, on May 25, the Phoenix Mars Mission is supposed to land on Mars.

In the meantime, here is fancy animation of a flight over the Columbia Hills on Mars, via the Astronomy Picture of the Day:



The animation, by Doug Ellison, Randolph Kirk (USGS), MSSS / MER / NASA, combines real topographical data from the Mars Reconnaissance Orbiter with information about the Spirit Mars Rover, making its appearance at 1:45 in the movie...

More about the Mars Exploration Rovers (MER) Spirit and Opportunity and Phoenix at the Planetary Society. The Planetary Society Weblog also has links to QuickTime versions of the movie.


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Sunday, May 18, 2008

The Block Universe

I was just about to throw away Petkov's paper "Is There an Alternative to the Block Universe View" when I realized I totally forgot to let you know my conclusions about it.

In my earlier post Every Now and Then I explained why I think the most plausible explanation for our perception of the now being different from the past and the future is due to the ability of our brains to store memory. I thus believe in the 'block universe' in which there is nothing special about the now, and the past and the future exists in the same way as the present moment.

Nevertheless, I want to point out this isn't more than a believe of mine that I personally find plausible. Especially, I do not think it follows from Special Relativity, as some comments indicated - and as also Petkov argues in his paper. Here, I want to explain why I don't think his argument holds. I will pick around on Petkov's paper not because I dislike it so much, but because it is actually a useful summary that also contains a brief historical introduction on the previous work on the issue, most notably the Rietdijk-Putnam argument [1,2].

Please note that the following does not take into account quantum mechanics, with which everything becomes much more complicated.



Preliminaries

The following should be familiar to everybody who has opened a textbook on Special Relativity (SR), so excuse me for being somewhat brief with the basics. In SR one can construct the surface of simultaneity of an inertial observer, Bob, in a straight-forward way. One puts two lights in equal distances into the restframe of the observer (meaning their relative velocities vanishes). If Bob measures signals from both lights to arrive at his worldline at the same time, he says they were emitted simultaneously. Doing this for lights of all possible distances creates a surface, called the 'surface of simultaneity' on which all events lie that happen at the same time according to Bob. One can repeat this for all instances on the world-line of the observer, which gives a slicing of simultaneity. For the observer in rest, these are just parallels to the x-axis in Minkowski-space.

If one considers a second observer (Alice) moving with a relative velocity to Bob, she can do the same construction. It turns out however, her notion of simultaneity is a different one, and her slices of equal time are not identical to those of Bob. The reason for this is that the speed of light is constant in SR and the same for all observers. If Alice's and Bob's world lines cross at one point (e.g. the origin), the events they consider simultaneous with this meeting are on two different lines that form an X.

This is illustrated very nicely in this figure from the Wiki-commons. Here, event B is simultaneous with A in the green reference frame, but it occurred before in the blue frame, and will occur later in the red frame.



The argument then goes as follows: if everything exists that Bob calls simultaneous but there is nothing special about Bob, then everything that Alice calls simultaneous exists the same way. You can repeat this for all observers that cross either of these already existing surfaces anywhere and you'll fill up the whole space. Thus, everything in the four-dimensional plane exists, because everything lies on somebodies surface of simultaneity.

There was a criticism of this argument by Stein [3] which I didn't read so I can only tell you what Petkov says about it. Apparently Stein's criticism is that the notion of present but distant events does not make sense, since one can not say anything about the 'now' that is not also 'here', so one should talk only about the 'here-now'. To reformulate this into Bee-speech, I'd say the argument is you can't have information about the 'existence' of anything that is not (yet) causally connected to you, like everything on your space-like slice is. Thus, concluding it 'exists' just because you measure it later is not possible. (This is probably a very fanciful interpretation of mine about a paper I didn't read, apologies.)


Claims

Petkov wants to show that

1) The block universe view, in which the universe is regarded as a timelessly existing four-dimensional world, is the only one that is consistent with Special Relativity.

2) Special Relativity alone can resolve the debate on whether the world is three-dimensional or four-dimensional.

I will in the following argue that 1) is wrong and 2) is correct. For being able to conclude anything at all, I will start with explaining what I am talking about. There is a possibility I am not using the terms as your philosopher next door does, but at least you know what I am talking about
  • a) The block universe is a 3+1 dimensional space time with Lorentzian signature in which there is no present moment that is special in some regard.

  • b) Presentism means there is a notion of 'now' and it is only the 'now' that exists. This can be further sub-divided in to categories

    • b1) Presentism in which time is a parameter.

    • b2) Presentism in which time is not a parameter.


For maximal carefulness I want to point out that another assumption which also goes into the argument is

A) Time is either a parameter or a dimension and there is no other possibility.

If that wasn't the case one could never make a claim like 'is the only option consistent with' as done in 1). To call upon the Principle of Finite Imagination, one should however keep in mind that this is an unproved assumption and an alternative option can't be outruled. I will understand SR as the relativity of all observations in all inertial frames. Sorry for nitpicking, but I want to throw out all merely philosophical baggage that isn't observable - you'll see later why.


In Media Res

For the reader who has taken a class in SR the rest of the argument is now actually trivial.

Let us start with claim 2): We know that time can't be a universal parameter because we have experimental prove the passage of time depends on the state of motion and path of an object. Thus, presentism b2) is falsified, which means with A) time is a dimension. It follows 2) is correct.

Now to claim 1): The first observation is that one should be skeptical about this claim because it involves the notion of 'existence' which doesn't appear in SR altogether. So how can one possibly say whether some sort of 'existence' is compatible with SR?

I'll give you an analogy. I could ask you whether my invisible friend is compatible with complex analysis. At the very best, you could say the question doesn't make sense, or to make it sound somewhat more sophisticated, it is ill-defined. Unless I tell you something about my invisible friend, there is nothing incompatible because in complex analysis there are no invisible friends. If I now told you my invisible friend is an entire function that is bounded but not constant, you could go and prove this is incompatible with complex analysis (via Liouville's theorem).

So how come Petkov as Rietdijk and Putnam can and do say anything about claim 1)? Well, the reason is that they don't actually explain anything about 'existence'. Instead, they say the 'now' does 'exist', thereby exporting 'existence' into a concept that can be defined in SR: the 'now'. Since I do not want to define 'existence' either, I too want to export it into the 'now'. This then however doesn't allow us solve the problem addressed in 1), for there is no reason why the 'existence' should be bound to the 'now' in the way one can define it in SR.

Let me make that more precise. The 'now' in SR can be constructed using surfaces of simultaneity in the usual way as mentioned in the prelimiaries. This is a definition of now. It doesn't say anything about existence. If you however use this definition of now, and say what is 'now' according to this definition 'exists', then you suddenly have a definition for existence. Cool, eh?

However, this is a definition and not a conclusion, as you can't say anything about whether something exists on your surface of simultaneity elsewhere, you can only say something exists if it's not only 'now' but also 'here'.

That, so I gather was also the argument by Stein mentioned above.

So, the flaw in the argument is that you can very well have a notion of a 'now' that 'exists' that is not in disagreement with any measurements confirming SR because there is no reason to define 'presently existing' with the surfaces of simultaneity in SR. In fact, everything that can be said about 'existence' in SR is a completely empty statement.

To see this, put an 'existence - slicing' with a time parameter τ on Minkowski-space [4] and say for each τ it is only the respective slice that 'exists', or is 'now' - according to this definition of 'now'. This can't be in conflict with experiment, for you never measure 'existence' anywhere than where you are. What you measure are signals from elsewhere and/or elsewhen. Yet on which 'now' slice these signals sat with you at emission is completely irrelevant. All that matters is that the propagation takes place according to the laws of SR because that's what we have measured. This is not a block-universe because it has a notion of a present moment, but is not in disagreement with any predictions by SR.

Thus, 1) is wrong.

Below an illustration to this.



Anyway

There is however two more things to be said here:

One is that this option is compatible with all our measurements, but it does of course break observer-independence as a matter of principle for singling out some slicing means singling out preferred restframes.

The other one is that this option is compatible with Special Relativity and all measurements because it doesn't have any observables whatsoever and is not falsifiable. To make this an interesting scenario, you'd have to tie some observables to the 'existence-slicing' (if you think GR that could e.g. be the restframe of the CMB).


[1] Rietdijk, C.W. A Rigorous Proof of Determinism Derived from the Special Theory of Relativity, Philosophy of Science, 33 (1966) pp. 341-344
[2] Putnam, H. (1967) Time and Physical Geometry, Journal of Philosophy, 64, (1967) pp. 240-247
[3] Stein, H. On Einstein-Minkowski Space-Time, Journal of Philosophy, 65, (1968) pp. 5-23
[4] You would want to make sure it fulfils some nice-ness features of slicing like that the slices don't cross, are space-like, and cover all of space etc.



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Friday, May 16, 2008

Science and the Web 2.0

I recently came across an interesting article by Davit Crotty from Bench Marks: Why Web 2.0 is failing in Biology about a talk he gave at the American Association of Publishers Professional and Scholarly Publishing (AAP/PSP) meeting in Washington some time in February. He has a couple of interesting slides discussing the potential merits and hurdles in webifying science, and draws our attention to this last year's article from The Register
Scientists shun Web 2.0

[...]

A panel of science web publishers said scientists had consistently shunned wikis, tagging, and social networks, and have even proven reticent to leave comments on web pages.

The refusnik stance presents a puzzle in light of arguments in favour of Web 2.0 services which are more compelling for science than for trivia - the biggest web 2.0 market to date.

[...]

The penetration problem seems to stem from the extremely competitive and rigorous funding process. Research projects have to justify every penny and minute spent by their scientists, presenting a catch 22 for web 2.0 as a tool for science. Researchers won't use the tools until they justify their worth, but they are worthless unless researchers use them.


David's examination of this problem is somewhat more insightful than the article at the Register, and he mentions a couple of good reasons why scientists do not use the Web2.0 all that extensively, and I find myself agreeing with him.
  • First of all, there is the issue of time. We're all busy already anyhow, and since there seems to be a correlation between lack of time and what is commonly considered a successful career, there is the effect that those with more expertise shy away from doing anything not directly career related.


  • Then there is the problem of lacking incentives. Why spend time on something for which you receive no credit? When one can passively benefit from other's activities, why be active oneselves? I.e. when you read a commentary on a paper and you disagree on the opinion put forward, is there a benefit of starting an argument, or were you just interested in hearing other peoples thoughts?


  • Further there is the overabundance of offers. There are loads of sites that do more or less the same. I am a curious person, and I sign up for many things just to have a look and then wait and see where it goes. In such a way I must have a dozen of accounts I never use and can't even recall. NatureNetworks is presently one of the Web2.0 offers that looks quite promising to me. But I guess most people just choose not to choose until peer pressure gets high enough. In a conservative community this can take a while.


  • And then there is the most obvious factor in which sites need to be appropriate for the community, and no, a MySpace for science probably doesn't sound very convincing for most of my colleagues. (Yes, I do have a MySpace account. No, I never use it.) As David puts it "Scientists interact in very different ways than teenager and their peers, or rock bands and their fans. Scientists don’t find collaborators by chatting online with strangers."


When it comes to science blogging, Sean Carroll is quoted with saying that way scientists communicate is already efficient and thus physics blogs are unlikely to play a more prominent role. I do mostly agree with him, but this statement depends so some extend on the infrastructure of your workplace. If more people come through your institution than you can possibly talk to anyhow, you certainly have no need to find like minded people online, but not everybody everywhere is thus lucky.

As I explained in my last year's post Physics Blogs, I further do also not think that blogs are a good medium for scientific discussions simply because of the organization (the host being able to edit and censor, the journal-like structure, the background noise).

Blogs are however useful to provide readers with an impression of how the work and life of scientists looks like, and they thus contribute to making the 'ivory tower' a little less detached. They further fulfil a social networking function within the community in that one frequently find advises on how to give talks, prepare presentations, deal with complicated coworkers, write applications or proposals and other topics of that category where people exchange experiences.

Sean further is quoted with
“A blog raises your profile, but it raises your profile for something other than research. [E]ven if you are extremely productive as a scholar, some professors may view a blog as sign that you could be spending more time in the laboratory or library, engaged in traditional research.”


Well, this doesn't seem to go very well with the above assertion that very few scientists notice the existence of the blogosphere altogether. Though the fraction of people in the community who have heard of one or the other blog is increasing. Anyway, some might say the same about other activities, like engaging in interest groups or surfing. This concern also isn't at all confirmed by my experience. Blogging or not, as long as I got my work done in a timely manner to the satisfaction of my supervisors and/or employers they didn't care very much how, where or when I worked, or what else I was doing. That is one of the few features (possibly the only one) that makes the academic world attractive for me.

A colleague (who shell remain unnamed because he doesn't like his name to appear in the blogosphere) recently mentioned he stopped reading this blog because he finds it scary I'm writing so much. Well, I on the other hand find it scary other people talk so much! The science blogs I read I find very different in the composition of topics (and in the quality of writing), but the one thing I guess all bloggers share is that they like to write.

Wednesday, May 14, 2008

This and That

Back in Waterloo. The visitor who was sharing my office left today, after dutifully producing this paper with Yidun and having covered the blackboard with loads of equations that however seem to be completely unrelated to that paper. So possibly there's more to come. Kinda scary, people who are so productive while I chew pens (so much about my New Year's resolution).

Either way, Waterloo is rainy today, but considerably greener than when I left two weeks ago. Here's some infotainment that I came across recently

Sunday, May 11, 2008

The Illusion of Knowledge

Isn't it funny how one sometimes uses words with the honest believe it's a well known term, but then comes to realize nobody understands it? Like, when I was a kid, the 'grandma-button' was a very well known concept to me. My grandma, being farsighted, used to accidentally tune the TV's brightness and color instead of the volume. Luckily, the remote control had a 'grandma-button' to reset the now very odd looking appearance on the screen. Since 'reset' didn't mean anything to me, the corresponding feature on various technical devices became grandma-buttons. Needless to say, except for my younger brother nobody knew what I was referring to.

I was thinking about this recently when Michael mentioned that the 'Illusion of Knowledge' I kept talking about and that even made it on our conference poster (it's no longer there), isn't anything he'd ever heard of. Thus, I guess I made that up and came to believe I heard it elsewhere. So here is the missing explanation.

The Illusion of Knowledge refers to the following quotation by Daniel J. Boorstin
    "The greatest obstacle to discovering the shape of the earth, the continents, and the oceans was not ignorance but the illusion of knowledge."

~ Daniel J. Boorstin


Illusion in the 21st Century


In the 21st century we are faced with an incredible amount of information, and it is in many instances impossible to read and judge on all of the available information on a given topic. If under pressure to put forward an opinion it is often necessary to use shortcuts to arrive at a conclusion fast, most notably relying on trusted sources. The illusion to then have knowledge about a topic makes the world much easier classifiable in good and bad, right and wrong, friends and enemies.

The internet supports the Illusion of Knowledge in various ways
  • Because many sites are publicly available, but poorly referenced, unrevised, and present unbalanced and severely biased information whose scientific quality possibly isn't immediately clear to non-experts. Yes, one would think people should be critical, but sites with high ranking in search engines are widely read, and I suspect there are many people who don't judge as critically as necessary.

    Take as an example the discussion about the alleged danger that the LHC destroys the earth. It is tale-telling how many people believe such catastrophe stories notwithstanding the fact that literally everybody working on the field patiently explains why the accusation is completely unjustified. The question here is not who has the better arguments, but which side receives larger attention in the media (and catastrophes always go well).


  • Because with the advent of infotainment there seems to come the believe that learning must be easy, and if a topic is complicated, it must be the fault of the person explaining it. Everything can be explained easily on only five powerpoint slides, in a blogpost not exceeding three paragraphs, or on a YouTube video, right? This consumer-attitude is an unjustified expectation.

    Possibly "in the year 3535 everything you think, do or say is in the pill you took today" - but we're not there yet. To learn something in the year 2008, it still takes time, one has to sit down and think about it. It doesn't help reading 30 websites in the hope to find the one explanation that immediately makes sense. This explanation just might not exist.


  • Because of the increasing believe that knowledge which isn't on the internet doesn't exist, or if there's only ununderstandable explanations to be found, nobody can explain something understandably.

    It's not only that Stefan and I, we've both come to notice that there is sometimes no useful reference that can be linked to. It's also that many of the best and most useful sources of information are still books, carefully researched, revised, and written by people who know how to write (it makes a big difference, at least to me). And many of these books are possibly decades old, and don't even appear on Amazon search inside. I have also repeatedly come across statistics or data that weren't available online, even if I knew the institution who did a survey. There are also large differences in coverage depending on the country. Yes, one would think that the knowledge base on the internet grows, but the question is very much one of demand. I am afraid that the pieces of knowledge that are likely to receive little attention (like not very well known books in the history of science or so), will just never make it.


  • Related to the above, the increasing believe that newer information is better. E.g. if there is a newer book/article on some topic, omit the older one because it isn't up to date. As things are, many of the really insightful science books were written long before the first website went online. (A side effect of this attention-for-newness is that pieces of information have a recurrence time after which they can be warmed up again and reappear.)


  • Because of the believe that relevant information which is online can be found easily, which I suspect leads people to not search very closely for information.


  • Because of the general problem of information overflow, and the effects of constant time pressure combined with the fear of missing something and not being up to date. It causes a generally short attention span, and lacking patience. The constant fear to miss something and to not be up to date supports very much the tendency of people to expose themselves to more information than they can possibly accurately judge on in the time they take.


  • Because online one can find support for whatever point of view one holds, one just has to chose the social network appropriately and stick to the right forums, blogs or interest groups. As I mentioned in this earlier post "Can technology make us happy?", online networks can much easier be kept 'clean' from undisturbed influence and thus support confirmation bias.



Consequences

  • The distribution of opinions about science without any quality control leaves people with a great confusion about the reliance of today's scientific research, and with the suspicion that science is a waste of time and money, and people in the 'ivory tower' don't care or don't understand what is important in the real world out there. This is an excellent base for superstitious believes.


  • A raise of pseudoscience distributed by people who have the erroneous believe they've solved some urgent problem without knowing exactly what the problem is to begin with.


  • Blurring of the boundaries between Fact or Fiction for the sake of entertainment, on which I previously commented here.


  • And eventually an erosion of the facts that progress can be build upon. There can be no scientific progress without it being appreciated by the public, since research has to be funded and eventually needs to be incorporated into every day life.


You can witness today the consequences of such a gap between scientific research and its incorporation in the case of social sciences, politics, economy and ecology. It's been decades that scientists have warned our political and economical systems are inappropriate to deal with global environmental problems, yet people have continued to argue with faith based approaches - and they still do so. If you are among those who believe in 'invisible hands' or that 'it will all work out somehow' you probably sleep better at night than I do, but there is no scientific basis for your faith. I don't want to see the same thing happening in the natural sciences - there being a case in which incorporation of knowledge into our society is stalled by opinionated influential lobbies and insufficient education. I therefore think we need to keep track on how technological developments influence the way we pursue and communicate research, and what the impact is of these changes.

Bottomline

The internet is a tightly coupled network that reacts on very short timescales. It is not a coincidence that 'hypes' have been gaining more momentum with the advent of online media, and it is unsurprising this also affects the scientific community. Such hypes are brilliant examples for positive feedback loops, in which attention causes more attention - and nowadays everybody craves attention. Information that has been repeated many times gains some sort of importance notwithstanding its actual value. The result are bubbles of nothing that waste time, energy, and resources.

The problem is not lack of knowledge. The problem is the Illusion of Knowledge that comes with an overabundance of unstructured information. It fosters the public manifestation of unfounded believes, stalls scientific arguments, and hinders progress.




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Friday, May 09, 2008

The Other Side

Some months ago I was at a friend's wedding and volunteered to give a speech. Me! Later, some guests said "What a nice speech, I could never talk in front of so many people." Yeah, I thought, that's what I too used to say. "It comes with the job," I told them.

Indeed, had I known being a physicist involves speaking in front of people that frequently, I probably would have become a landscape designer or something. But I didn't know. Anyway, one gets used to it. On Wednesday, Stefan took some photos during my talk in Duisburg. Unfortunately the photos are all rather blurred and he's decided he needs a new digital camera. I found the photos aren't soo bad, and maybe some of you are interested how that talk-giving looks from the speaker's side.

So here's me during the introduction (Sabine made her PhD in soandso, spent a year here and a year there and currently works in X on Y. We're very happy to have her here today, and she'll speak on, ooohm...). What this photo demonstrates very nicely is the first-row-gap. The unwritten first law of scientific talks that says nobody ever sits in the first row, unless the density exceeds one person per seat.



The next photo was taken shortly before the talk began, while the audience was entering the room. What you see here demonstrated is the second law of scientific talks, saying people cluster towards the back and/or close to the exits so they can leave without causing much attention. The speaker always notices if somebody leaves, believe me. There's nothing as depressing as people leaving during a talk, even if you tell yourself they probably have an appointment or have to change into superman clothes and save the world or so.

I didn't notice anybody leaving on Wednesday. They were all very nice and polite, and also didn't interrupt me to ask questions that would have been answered the next slide. (A very annoying habit that is fairly widespread).



I don't particularly like if the room is much too large for the audience, like in this case. Because of the second law people tend to sit in the back meaning I have to shout, and that can be quite exhausting. Besides this, one has to talk to many empty seats which makes you feel as if the tickets didn't sell or so. The talk in Duisburg was actually well visited, esp. if you consider it was a beautiful late spring afternoon. I count 47 people on the photo above. The last two rows filled somewhat more than on this photo, and some where sitting to the right. In total there were maybe 60 people or somewhat more, 3 of which were women. Yeah, sorry, I always count the women share, and that's another thing that is always depressing. Now here's a more funny aspect



Stefan tells me the guy who is waving with his hands didn't chase mosquitoes but was asking a question (forgot about what). Two other people are scratching their heads while the guy in the front is... hummm... cooling his forehead on the table? I've seen people sleeping in this position during flights. I've tried but instead of sleep I only got a backache. Anyway, it's sometimes very funny to watch the audience and how people linger around in their seats, picking their noses, or make funny faces.

If you're interested, here are the slides of the talk (watch out, it's ~12 MB)

Thursday, May 08, 2008

PI Director Announcement

PI's new Executive Director will be announced tomorrow 9:30 am EDT.

[And no, I don't know who it is.]

Update Friday 7:45 am: Click here to view the webcast.

Update Friday 9:45 am: PI's new director is (drums please!) Neil Turok!!

Update Saturday 3:30 am: Here is the official blahblah


Waterloo, Ontario, Canada, May 9, 2008 - The Board of Directors of
Canada's Perimeter Institute for Theoretical Physics (PI) is pleased to announce the appointment of Dr. Neil Turok to the position of Executive Director. The appointment, effective October 1st, comes with the unanimous endorsement of the Institute's Board following an extensive search and the unanimous recommendation of the Search Committee composed of Perimeter Institute researchers, members of its international Scientific Advisory Committee and members of the Institute's Board of Directors.

Mike Lazaridis, the founder of Perimeter Institute and Chairman of the Board, personally led the successful search and says, "We are extremely pleased to welcome Professor Turok to Waterloo, Ontario, Canada. He is a world-renowned scientist of the highest calibre and provides tremendous research and leadership experience. He is ideally suited to build upon Perimeter Institute's considerable international achievements to date in scientific research and educational outreach as we move forward in our next, ambitious phase of development."

Commenting on his appointment, Dr. Turok says, "I am thrilled and honored to serve as the next Executive Director of Perimeter Institute, or PI. The Institute's innovative approach, its flexibility and its determination to tackle the most basic questions are already attracting the world's most brilliant students and researchers to Canada. Working with the excellent PI team, I hope to strengthen these developments so that PI becomes a world epicenter for theoretical physics, catalysing major scientific breakthroughs."

Professor Stephen Hawking, the internationally acclaimed scientist at the University of Cambridge and a close colleague of Dr. Turok, says, "Neil Turok will make an excellent Director of the Perimeter Institute which has established itself as a world leading center of research in theoretical physics. He has been a colleague of mine for a number of years and I have been very impressed by his insight and originality. The combination of Neil and PI is brilliant and holds great promise for the future."

About Dr. Neil Turok

Dr. Neil Turok currently holds the Chair of Mathematical Physics at Cambridge University, where he is also the Director of the Centre for Theoretical Cosmology. He earned his PhD at Imperial College and, in 1994, became a Professor of Physics at Princeton University. Among his many honours, he was awarded the 1992 James Clerk Maxwell medal of the U.K. Institute of Physics.

Dr. Turok has worked in a number of areas of theoretical physics and cosmology, focusing on observational tests of fundamental physics. In the early 1990s, his group showed how the polarization and temperature anisotropies of the cosmic background radiation would be correlated, a prediction which has been confirmed in detail by recent precision measurements. The team also developed a key test for the presence of the cosmological constant, also recently confirmed.

With Stephen Hawking, he later developed the Hawking-Turok instanton solutions describing the birth of inflationary universes.

Most recently, with Paul Steinhardt at Princeton, he has been developing a cyclic model for cosmology, according to which the big bang is explained as a collision between two "brane-worlds" in M-theory. In 2006, Steinhardt and Turok showed how the model naturally allowed the cosmological constant to relax to very small values, consistent with current observations. Steinhardt and Turok co-authored the popular science book "Endless Universe: Beyond the Big Bang." A full online multimedia talk about this subject may be viewed online by clicking on Perimeter Institute Public Lectures and reviewing Dr. Turok's presentation "What Banged?".

Born in South Africa, Dr. Turok founded the African Institute for Mathematical Sciences (AIMS, www.aims.ac.za). Based in Cape Town, this postgraduate educational centre supports the development of mathematics and science across the African continent. For this work and his many contributions to theoretical physics, Dr. Turok was recently awarded a prestigious TED
Prize
(www.ted.com) and a "Most Innovative People" award at the 2008 World Summit on Innovation and Entrepreneurship (WSIE).

About Perimeter Institute

Canada's Perimeter Institute for Theoretical Physics is an independent, non-profit, scientific research and educational outreach organization where international scientists cluster to push the limits of our understanding of physical laws and develop new ideas about the very essence of space, time, matter and information. The award-winning research centre provides a multi-disciplinary environment to foster research in areas of Cosmology, Particle Physics, Quantum Foundations, Quantum Gravity, Quantum Information, Superstring Theory, and related areas.

The Institute, located in Waterloo, Ontario, also provides a wide array of educational outreach activities for students, teachers and members of the general public in order to share the joy of scientific research, discovery and innovation.

In partnership with the Governments of Ontario and Canada, Perimeter Institute continues to be a successful example of private and public collaboration in science research and education. A full history is available at www.perimeterinstitute.ca.


Update Saturday 4:30 am: Globe and Mail: Cambridge scientist takes Canada to cutting edge of physics theory

TagCrowd



bee being believe black blog case comments communication describe different earth effect emergence example exists field future german holes however information interaction labels lhc links magnets matter model moment number past people physics planck possibly post present quantum question results science since stefan system theory think understand world years
created at TagCrowd.com



Fun! Make your own TagCloud out of any text :-) Via Bob O'Hara.

Something completely different. As some of you know, we have a new site tracker 'Statcounter' because the other one triggered a wrong virus alert. Since then I'm having fun checking the recent search queries that lead people here. Here is the sample from a minute ago. I swear I'm not making this up, it's just copy and paste (I've highlighted the more amusing ones).


    why are the spiral arms dangerous in our galaxy
    pascal puy de dome
    html/infected.webpage.gen
    hydrogen fine structure balmer h line
    lhc black hole
    backreaction blackholes
    lee smolin physicist bad
    curie temperatur ising model 2d
    below planck scale
    other interviews
    janiszewski and uy
    temporary display
    light behaves like a wave slit plane
    to express idea is difficult in writen form
    the trouble with physics
    information for dwarf planet eris and photos
    ups quantum view request number
    backreaction.blogspot.com
    gravity defyer
    lhc blogs black holes
    is brane world dead if lhc finds the higgs
    maple to count times digits of pi appear
    only force that can enter extra dimensions
    mobius tranformation
    dimensions we experience
    casimir effect
    'html/infected.webpage.gen' [virus] was found
    lee smolin physicist bad angry
    dont step on the cracks photo essay
    indigo purification by sublimation
    what the moon looked like on may 30 2008
    eris the planet
    nabla stringed instrument
    optical illusion bicycle
    beyond the standard model: nineteen things we understand and four we don't
    back reaction
    lisa randall brookhaven physics experiment
    html/infected.webpage.gen [virus]
    smolin, the trouble with physics: the rise of string theory, the fall of a science, pdf
    blue led nobel prize
    unparticle physics
    historical aspect of the number pi
    broadcast yourself
    nostradamus lhc
    joao magueijo big bang preview science channel
    power spectrum cmb
    lubos motl
    easay of all kinds of gambling should be bended
    ceres and eris pics
    analysis of the hydrogen spectrum
    the hadron-muon branching ratio
    kind of calendar
    lhc black hole risk
    sabine hossenfelder
    nature look who's doping
    warped passages
    einstein quotes, honey bee,
    dangerous ideas physics
    klaus von klitzing stefan hüfner
    cristian stelea
    i want to ride my bicycle
    review extra dimensions
    water phase diagram
    heidelberg vs frankfurt life quality
    micro blackholes
    anne green of oxford
    scanning bagage when entering the usa


According to Google analytics the keywords that presently lead most people to this blog are (in order):

1. backreaction
2. sabine hossenfelder
3. sexed up atheism
4. lhc black hole
5. lubos motl

Tuesday, May 06, 2008

Fun with Magnets

Last week, my brother had started to tidy up a cupboard at our parent's place where we had stored away toys and other stuff from our childhood. In between chemistry and electronics kits, he dug out a small orange box I had completely forgotten about, but which I had loved when I was a small boy: A kit with a few magnets.

There was a magnet with a grip that can be used to lift coins and paper clips, two funny plastic spheres with bar magnets hidden inside, and two rings of magnetic material. The only thing missing was the little jar with iron filings to map out magnetic field lines - but I remember that my mother once had removed it from the kit, because she had become fed up with this stuff ending up either distributed all over the kitchen or sticking to the magnets.




These ring magnets were especially fascinating because one of them could be made hovering above the other on a pole, and oscillate along the pole when dropped.

The most surprising effect I could create with the oscillating magnets I had discovered by chance: I could use the magnets to switch off our new, remote-controlled TV set. Physics was cool!




Here are more Cool Experiments with Magnets. Unfortunately, understanding the origin of the "itinerant ferromagnetism" of the classical permanent magnets, iron, cobalt, and nickel, is not that easy, but interesting nevertheless.


Monday, May 05, 2008

German Interlude

With apologies to those who don't speak German, here's my Ph.D. advisor Prof. Dr. Horst Stöcker (presently scientific director of the GSI) who demonstrates very nicely how to just ignore the interviewer and continue talking (in this case about black holes at the LHC and the GSI FAIR project)



Horst, I'm so proud! You didn't say anything utterly wrong! Just what you said about supersymmetry doesn't quite make sense.

But seriously, very nice interview, well done :-)

Stefan tells me the video was recorded last October at the Frankfurt book fair and was broadcasted yesterday evening on SAT1. The interviewer is Alexander Kluge. The above YouTube video is part 1 of 5 (you find link to the other parts on YouTube).

Hello from Germany

So, I made it to Germany. To my big dismay, Air Canada messed up my seat reservation (that's the third time this happened). So no cloud watching from above, but instead a middle row middle seat with a neighbor who uninhibitedly stared at my scribbled equations.

After the first days I have now almost gotten through the phase when I turn around frequently and think "Hey, they speak German!", am amazed by the blue highway signs (not green!), and can't pass by any bakery without buying something. In a case of severe jetlag I spent a full minute staring at my mother's cotton pads where it reads 'weich und fusselfrei', wondering what it means, and ordered a-glass-of-water-without-ice-please forgetting that a) no need to speak English b) they don't usually put ice in it anyhow, at least not as long as the outside temperature is below 30°C and c) the water isn't for free.

What's new in Germany? Not much actually.

Despite what I've been told, they still don't give you cashback at the register ("Nee, da kommt ka Geld raus").

The topic of the month is apparently sex. Yeah, I mean, what else. It's all Germans ever talk about, right? Just read this blog. But seriously, apparently a women called Charlotte Roche wrote a book, titled "Feuchtgebiete", which made it on the top of the amazon.com worldwide bestseller table. I find myself unable to translate the title (it's a pun). And now all of Germany talks about female secondary sexual characteristics.

Besides this, optimism is reaching unimaginable hights because the unemployment rate apparently has been dropping further, and spring is everywhere. Stefan says I missed the cherry tree bloom, but here's some apple trees:











Btw, I coincidentally came across this text about the American-German interaction

"Table 2. Politeness: American Friendliness.
  • Not broaching controversial issues like politics or religion when desiring to maintain a friendly atmosphere
  • Using politeness formulae (routine formulae) with strangers or acquaintances: Hi, how are you? It was nice meeting you. Have a nice day. Let's get together sometime. It was nice talking to you
  • Maintaining "the customer is always right"
  • Not saying anything negative, especially to a stranger (usually)
  • Expressing some willingness to talk to strangers about family situation
  • Saying "excuse me" when touching or bumping into a stranger in public
  • Using first names right away
  • Talking "informally"
  • Using chitchat, small talk


Table 3. Politeness: German Respect.
  • Broaching controversial issues like politics when desiring to get to know a person better
  • Using routine formulae: saying Guten Tag or some variant when greeting strangers, saying Auf Wiedersehen or some variant when leaving
  • Often considering salespeople experts
  • Using last names only with an earned title or Frau or Herr ("Ms" or "Mr.") when addressing strangers and people one doesn't know well
  • Using the respectful form of "you," Sie
  • Expressing willingness to talk with tourists on the train; topics may vary across cultures
  • Expressing honesty and directness
  • Showing distaste for small talk


Problems occur, however, when Germans and Americans meet, for Germans often interpret American "friendliness" behaviors as the beginning of deeper friendships, which the Americans may not be intending at all. Americans, even if unconsciously, tend to know these distinctions exist. They know when friendliness is meant, and they know when a different relationship--a deeper, more enduring friendship is developing. More than once the German-speaking interviewees in this book talked about their first reactions to Americans' statements like "Hi, how are you?" and "Let's get together sometime," which the Germans took literally. They were quite disappointed when the Americans looked shocked at their detailed explanations about how they were, or when they never did "get together" with them.

Conversely, Americans can interpret German "respect" as distance or aloofness, or negative honest assessment as rudeness. If a supermarket clerk were not to say anything to many Americans upon reaching the cashier, it would be perceived as a problem, most probably unfriendliness. Similarly, telling a friend how bad she looks would also be construed as rude.

The American and German behaviors may be interpreted within the framework of Helga Kotthoff's hypotheses that Germans stress "honesty" in such encounters, while Americans wish to maintain an agreeable attitude and do not want to "disappoint" their interlocutors.

Thus, when they meet, if they are expecting behavior from the others that they find in their own cultures, Americans and Germans often do not have their expectations met, and they become disappointed in the members of the other culture.

Sometimes the stories are funny; at other times they are disturbing, when interviewees have had experiences that depressed, angered, or enraged them. German readings of Americans and vice versa cause many of us to have the following negative and positive opinions of each other, aptly summarized by Hall and Hall:

Germans often describe Americans as being overly familiar, intrusive, historically and politically naive, poorly educated, narrow in viewpoint, undisciplined, lacking in taste, profligate, unmindful of the proper care of property, vacillating in decision making, shallow, boastful, and overly self-confident ....

On the positive side, Germans often see Americans as friendly, open, resourceful, energetic, innovative, and, in general, capable in business ... [with] greater freedom, generally happier, ... more productive and creative than many other people ...; [and having] opportunities to succeed ....

[Americans find Germans] highly disciplined, well educated, neat and orderly, ... systematic, well organized, meticulous, ... efficient .... Some Americans find them hard to get to know--not unfriendly, but reserved. On the negative side, ... Germans are pushy in service lines ... and often insensitive to the feelings of others."


For more details, read this interesting article. I am very relieved that I can hencethereforth blame my distaste for smalltalk on my place of birth.