Tuesday, February 27, 2007


Last weekend, I was really fed up with snow and literally jumped on the next plane to somewhere. Somewhere turned out to be LA, and if I had looked at a calendar in advance, I probably wouldn't have chosen the week between President's day and the Oscars.

Anyway, my hotel reservations were messed up in every place that I had booked (even though I had already payed for), and after some random walk I ended up staying in a really weird place at the Ocean Front Walk in Venice Beach. The whole room was painted in dark blue, furniture all in chrome, and all from IKEA (with the tags still on). Even the bedsheets were IKEA (I have the same). There was no toilet paper, but a huge flat-screen on the wall. There was no heating, but a fridge large enough to store a whole cow. There was no hair dryer, but a high speed WLAN. There was no key, but a touch pad. I never saw anybody who worked at that place. I just called a number and the guy said: go to room 17, code is 1717 (I was very tempted to try next door with 1818).

I didn't do so very much that week, except maybe reading papers on the beach instead of my office, and scribbling on Starbucks napkins among palm tress instead of scribbling among toque-wearing maple-syrup addicts. Oh, yes, and I went to Disneyland. Here are some photos from an almost causally disconnected part of the multiverse

Disney's World never worked for me. It's too illogical, there are too many open ends that don't meet (and Donald's eternal struggles are too frustrating). But it's just amazing how much attention they have payed to the smallest details. For some hours, it's a very nice fantasy world. But it's a bubble. And when you ask what keeps this world together, you'll notice the laws of this universe don't allow it to exist for very long. Maybe a Harry Potter World would work better. I'm not a large Potter fan, but one has to give it to Rowling that she's payed a lot of attention to keeping her imaginative world consistent. At least to some degree.

Regarding virtual realities and parallel worlds you might also like to read Terence Tao's post about Quantum Mechanics and TombRaider. Regarding leaving towns and bubbling landscapes, see also John Baez' review of Lee Smolin's book.

I had been hoping when I come back all the snow would have been gone, but unfortunately Toronto is still covered with white stuff. It's gotten considerably warmer though, the temperature rose to a stunning -2 C, and I feel almost like spring time.


Rosetta Mars Fly-By

What's this?

No, that's is not a still from a new Science Fiction movie, but a photo taken from aboard the ESA space probe Rosetta, when approaching Mars to fly-by at an altitude of 250 km with a velocity of 36 000 km/hour.

Rosetta is on a long and intricate journey to a comet, called 67P/Churyumov-Gerasimenko. It is supposed to join the comet close to its aphel, beyond the orbit of Jupiter, and travel along with it on its elliptic path towards and around the Sun. The idea is to study in detail the stuff the comet is made of, and to follow the changes in the comet as it approaches the Sun. There is even a small lander which is planned to descend on the surface of the comet!

It seems to be not so easy to bring the space probe in the orbit of the comet - there are three Earth fly-bys and one Mars fly-by necessary to meet the comet in 2014. The successful Mars fly-by was in the night from Saturday to Sunday - it made it in the news on German TV on Sunday! That's in part because ESA mission control is located in Darmstadt, Germany, a town just 20 miles south of Frankfurt.

The ESA site has more pictures taken during the fly-by, including this photo of clouds high in the atmosphere of Mars - they all look quite spectacular!

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Sunday, February 25, 2007

Guest Post: Anne Green

Why did I become a physicist? My usual answer to this question, especially after a few beers, is either "the career opportunities are far better for second rate physicists than third rate musicians" or "the film Top Gun" (the female lead has a PhD in astrophysics and I've got a bit of a thing about Tom Cruise....). The serious answer is a combination of the usual curiosity about how things, in particular the Universe, work and a somewhat unhealthy obsession with doing difficult things just to prove that I can.

Physics definitely wasn't something I just fell into. I grew up on a farm in rural Somerset in the south west of England. Neither of my parents have a degree (or even studied maths or physics beyond the age of 14), and only a small handful of the people at my not particularly academic school made it to University. By the time I was 15 I was spending most of my spare time playing various musical instruments and singing. Although I loved music, and lots of people assumed that's what I'd do with my life, I never really considered it seriously as a career choice. It took hours of practice for me to be even half-way competent and I didn't actually like listening to classical music.

The other obvious option was maths. For a theoretical physicist I'm not a great mathematician, but at school I could easily do anything the teachers threw at me. I was reasonably good at physics too, but didn't really enjoy it; it was too practical and too boring. Thanks to a number of television documentaries and the one popular physics book in Shepton Mallet town library, I began to develop a fascination with cosmology and astrophysics though, and convinced myself that physics at University would be more exciting. I toyed briefly with the idea of studying maths and astrophysics, or physics with music, but the "come and have a go if you think you're hard enough" appeal of straight physics at Oxford eventually won.

I've got mixed feelings about my time at Oxford. I unwittingly ended up at one of the posher colleges and, with my country bumpkin accent, Dr. Martens boots, purple hippy clothes and very short orange hair, really didn't fit in. The main college physics tutor, Ian Aitchison, was great though and I became good friends, and had a healthy academic rivalry, with the other physicists in my year.

Physics did get a lot more interesting, and by my final year I'd decided, thanks largely to a Scientific American article on inflation, that I wanted to do a PhD in early Universe cosmology. I had, however, heard about Part III of the Cambridge maths degree and, given it's reputation for being tough and egged on by my friends, I wanted to do it. At that time students from outside Cambridge could get funding to do part III, at the discretion of the education authorities where their parents lived. Somerset happily provided discretionary funding for people to go to agricultural college and study small animal care, but not, I discovered, to go to Cambridge and do part III. My tutors also tried to gently convince me that highly mathematical theoretical physics
wasn't what I was best at and that me doing part III wasn't a great idea. The decision was sealed though when I got offered a PhD place at Sussex University to work with Andrew Liddle. Sussex was initially fairly low on the list of places I wanted to go, and back then Andrew wasn't yet particularly well known outside of the early Universe community. But having visited Sussex and met Andrew I was certain it was what I wanted to do.

At the end of my PhD I was fortunate enough to get a three year PPARC postdoctoral fellowship, which gave me the opportunity to follow my scientific nose and, slowly losing my pure theory obsession, I wandered from inflation to WIMP detection, via primordial black holes and micro-lensing. I then spent two very happy years as a postdoc in Stockholm before returning (semi-reluctantly) to the UK on a five year advanced fellowship.

Sabine suggested that I also write about the things which trouble me about physics, and I can't resist the opportuntity to stand on a virtual soap box and rant about two of my favourite (physics related) topics.

The first one is the "harder the better" obsession of many theoretical particle physicists. At the risk of sounding like an evangelical born again Christian or a reformed alcoholic-there's more to physics than doing hard-core theory at the most famous institution possible! Which brings me to some pieces of (unsolicited) advice for PhD students and postdocs. Studying and working at "good" places is important if you want a long-term career in research. But the definition of "good" should include "where there are people who you can learn from and collaborate with" and not, necessarily, "a famous place which will impress your non-physics friends". And rather than following the herd, charging around writing papers on whatever is this month's hot topic, try and find your own niche working on problems that interest you and which you can make a significant contribution to solving. Not only is this more fun (and if physics isn't fun, why bother when you can get paid far more working in the city?) it's probably better for your long term career prospects too.

The second is the "diversity" issue. Most physicists are male, white and middle class. A lot of time and energy is spent on the first of these issues, a (very) little on the second and virtually none on the third. While I realize that things were very different in the relatively recent past, I firmly believe that being a woman hasn't hindered my career to date at all (in fact it's the possibility of being the unwitting recipient of positive discrimination which keeps me awake at night). My family and school background, on the other hand, have made the path to becoming a physicist slightly more tortuous than normal. I had to fight a to be allowed to study "Further Maths" as an additional subject at school (a fairly standard thing for would-be theoretical physicists in the UK to do, but pretty much unheard of where I came from). My parents were always very supportive with practical things (for instance taking time off work to take me to
University open days) but physics and academia are a complete mystery to them. I once mentioned studying mechanics. My mum's bemused reaction was "but I can't imagine you with your head under the bonnet of a car"! And the postdoc job search is stressful enough without having to explain to concerned parents that a series of short term positions is the standard career path, and not the beginning of a road to nowhere. Like many other physicists I'm involved in various outreach activities, but I think all too often we end up "preaching to the converted"; giving talks at "nice" schools, where going to University is the default choice. There's a large fraction of the population for whom this isn't the case. We should be doing more to try and make contact with them, and get over the message that studying physics is not only fascinating but also opens the door to a range of careers.

Anne Green is an astro-particle physicist and has a faculty position in the Particle Theory group at the University of Nottingham. At the moment she is particularly interested in the dark matter distribution on sub-galactic scales and its experimental and observational consequences. She currently spends her spare time ironman training, playing the piano, listening to nu-metal and emo and traveling to interesting/unusual places.

See also my previous post about Anne's colloq, her work with Stefan Hofmann about the small scale structure of dark matter, and of course the previous contributions to the inspiration-series by

and my related guest post at Asymptotia 'Sabine Hossenfelder: My Inspiration'.


Saturday, February 24, 2007

The Principle of Finite Imagination II

See also: The Principle of Finite Imagination.

Happy Birthday!

Today, Backreaction celebrates its first anniversary!

One year ago, I was sitting in my office in Santa Barbara, shifting problems back and forth, not getting anywhere except towards a huge headache. A friend sent me a link to a post at the ReferenceFrame, and I figured that's what they call a 'blog'. Interesting, I thought, looks like a good trashbin for all the unifinished ideas and random stuff. I can do that as well.

So, I signed up at blogger, and after I was done messing up templates, the first sentence read 'Okay, that is my 3rd try to set up a blog. Be patient. My world is a fuzzy sphere and my English reliable only at the 95% confirmation level.'

Over the year contributors came and go. The only one who stayed reliably at my side is the guy I married last summer (as he likes to put it, I scared the others away with my writing).

This is a small thank you, first of all to my husband for not getting scared away, but also to all the fellow readers: for your feedback, the interesting comments and for clicking our but which is getting fatter and fatter (see sidebar).

Very special thanks go to Arun, Quasar, Plato, RaeAnn, and UncleAl, for always being around.

Here is the visitor statistic from the last year (status Feb 23rd)

(not only did I move in August and was offline for some while, but also was blogger constantly down. The peak in January was due to a link by CosmicVariance to our KATRIN post, followed by a link from Seed, and a whole bunch of secondary links.)

Some of my favorite Google searches that lead people to this blog include

This is also your opportunity to let us know what you'd like to read about more often. Or less often. Can you cope with the disorganization of this site? Do you like the template? Every opinion and criticism is welcome!

(Should add, I am not myself satisfied with the template as it is right now, but I don't currently have the time to do something about it).

Friday, February 23, 2007

Supernova 1987A

23 February 1987,
7:35 UT
Anomalously high neutrino counting rates observed in the Kamiokande, IMB, and Baksan neutrino detectors
23 February 1987,
10:30 UT
Robert McNaught photographs the Large Magellanic Cloud. When he develops the plate, a bright new star shows up.
24 February 1987,
5:30 UT
Astronomer Ian Shelton at the Las Campanas Observatory, Chile, sees with his naked eyes a new star in the Large Magellanic Cloud.

Do you remember the Supernova in the Large Magellanic Cloud in February 1987?

Last weekend, I climbed down into the cellar of my parent's house, and it was still there, in a pile of yellowed magazines: The old copy of the March 23, 1987 TIME magazine with the long cover story about Supernova 1987A, which had exploded four weeks before, on February 23, 1987.

Just having finished school, I did my military service at that time, and was casually reading TIME to work on my English. The Supernova news had fascinated me, I knew it was the first in our cosmic vicinity that could be seen with the naked eye since the days of Kepler, and I was deeply disappointed that it was visible only in the Southern Sky. But this four-page story compensated my quite a bit - it was well written, and you can still read it online. The thrill of this exciting event was one of the reasons I started to study physics later that year...

I hope at least some of our readers have a conscious memory about things scientific that happened 20 years ago ;-) I'll be glad to read your memories of SN1987A!

Plenty of fascinating physics and great photos are related to Supernova 1987A - see e.g. here:

By the way, what has happened to the neutrino signal of 02:52 UT from the Montblanc detector?


Thursday, February 22, 2007

A Tribute to Heinrich Hertz

Cell phones, radio, television, satellite communication, WLAN - it is hard for us today to imagine a world without the technology of electromagnetic waves. And yet, the man who first created, detected and studied them was born just 150 year ago today, on February 22, 1857.

Heinrich Rudolf Hertz (February 22, 1857 - January 1, 1894),
the discoverer of electromagnetic waves.

Heinrich Hertz grew up in Hamburg, Germany, where his father was a lawyer and senator of the city of Hamburg. After school, he prepared to be a civil engineer, but he was fascinated by mathematics and physics, and after his first year at university, he changed from engineering to physics. He studied in Munich and Berlin, got his PhD at the age of 22 with Kirchhoff and Helmholtz - very young even at that time - became a postdoc at Berlin and Kiel and professor in Karlsruhe and, finally, Bonn - quite a typical meandering path for a German scientist in the 19th century.

In Berlin, Helmholtz got him interested in the status of electromagnetic theory. At that time, Maxwell had formulated his equations already 20 years before, but in Germany, the action-at-distance theories of Weber and Neumann still hold strong. In these theories, electromagnetic phenomena were described by augmented versions of the Coulomb electrostatic law, with velocity-dependent terms added. Helmholtz had intensively studied all these different theories, including Maxwell's, and proposed a unified formulation - the only problem was that all of them were completely compatible with the then-known experimental facts. So, he suggested that his student Hertz may have a closer look at this issue, and maybe find an experimental clue.

The experimental apparatus used by Heinrich Hertz to produce and detect electromagnetic waves. The coil in the background on the left produces a high voltage, which feeds an antenna, the two rods with the big spheres at the end, via a spark discharge between the two small spheres at the centre of the rods. This antenna is the prototype of what we call today a Hertzian dipole (Source: Deutsches Museum, Munich).

Indeed, in a series of experiments in 1887, building on work with resonant circuits fed by spark discharges, Heinrich Hertz managed to create electromagnetic waves. He could detect them with a small wire loop, he could determine the wavelength and calculate from the known frequency that they propagate with the speed of light, he could demonstrate interference and polarisation. After these experiments, it was clear that Maxwell had formulated not only a beautiful, but also a true theory, and that light is indeed an electromagnetic wave, as are the "Hertzian" waves we know today as radio waves.

Creating electromagnetic oscillations of a sufficiently high frequency was an essential prerequesite for the detection of electromagnetic waves. Hertz' initial apparatus produced oscillations of about 500 million cyles per second, corresponding to a wavelength of 60 cm. To commemorate the discovery of electromagnetic waves, the official SI unit for frequency in cycles per second is now the Hertz.

In his work with spark discharges to create high-frequency oscillations, Hertz remarked that electric charges could get "lost" from his apparatus when illuminated by the bright flashes of the spark. As a by-product of his work on electromagnetic waves, he discovered the photoelectric effect!

The configuration of the electromagnetic field around a dipole, as calculated by Heinrich Hertz. This plot from his 1889 paper "The forces of Electric Oscillations, treated according to Maxwell's theory" features in every text on electrodynamics. It was drawn by his wife Elisabeth. (From the collection "Electrical waves".)

Hertz was not only an ingenious experimentalist, but also an excellent theorist. For example, he gave Maxwell's equations a form similar to that we know today (well, not too modern: no vectors, no forms), and made them popular and well-understood in Germany. He applied the theory to calculate the field configuration of electromagnetic waves around a dipole, the "Hertzian dipole". You can speculate what he could still have achieved, had he not died young, at age not even 37.

It is sometimes said that Hertz did not think that the electromagnetic waves he had discovered would have any practical consequence. This is probably a misinterpretation of a mail exchange he has had with a civil engineer named Huber in 1889, who had asked him if he thought it possible to transmit acoustic oscillations via electromagnetic waves. Hertz replied that this would not work since the wavelengths corresponding to such low frequencies are just to big and not possible to handle. Indeed, it still took more than 30 years until the first transmission of voice and sound via radio waves was achieved.

Whatever Hertz may have thought about the later use of "his" waves: If we listen to the radio today, or talk to someone via cellphone, or watch TV, it is a good idea to toast to Heinrich Hertz, and to follow Albert Einstein's suggestion made in a speech at the opening of the 7. Deutsche Funkausstellung in Berlin in 1930, broadcast via radio:

Ladies and Gentlemen who are present and who are not!

When you hear the radio think also about the fact how people have come to possess such a wonderful tool of communication. The origin of all technical achievements is the divine curiosity and the play instinct of the working and thinking researcher as well as the constructive fantasy of the technical inventor. [...] Think also of Maxwell who showed us the existence of electric waves by using a mathematical way, of Hertz who as the first person generated them with the help of a spark and thus proved them. [...] And everybody should be ashamed who uses the wonders of science and engineering without thinking and having mentally realised not more of it than a cow realises of the botany of the plants which it eats with pleasure.

  • A huge compilation of references about Hertz can be found here. However, there seems to be not too much literature easily available online.

  • While his experiments leading to the discovery of electromagnetic waves, Heinrich Hertz has kept a detailed notebook. Moreover, there are many letters he (or his wife) has sent to his parents during this period, so that historians know a lot about how the discovery has happened. A detailed account is given in Jed Buchwald: "The creation of scientific effects - Heinrich Hertz and Electric waves". General background on Electrodynamics in the 19th century can be found in Oliver Darrigol: "Electrodynamics from Ampère to Einstein".

  • Differences between Weber and Maxwell electrodynamics are discussed, e.g., in this paper by A K T Assis and H Torres Silve, "Comparison between Weber's electrodynamics and classical electrodynamics", Pramana 55 (PDF)

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Wednesday, February 21, 2007

The LHC Game

Wonder what all the LHC magnets are good for? Dream of finetuning them by hand?! Ever wanted to push The Red Button? Then the LHC Game is for you!

Sunday, February 18, 2007

Guest Post: Peter Steinberg

Why I Am A Physicist

As a child, many people noticed that I had aptitude in mathematical things, and even I noticed a persistent fascination with all things mathematical and technical. This was despite being surrounded by a family much more into art, design, and all that (my grandmother collected art, my father was an art history major turned city planner, my mom is a licensed architect, and my sister a trained painter, etc.). Ultimately it was a combination of two people, my grandfather and my father, who nudged me towards what would be my career. My grandfather was a businessman, but one with a tinkerer's disposition (keeping a functioning woodshop and darkroom in a Lake Shore Drive apartment) and longtime fascination with most things physics, e.g. Einstein's relativity, and math/logic, e.g. chess, for which he unsuccessfully tried to get me to sit still long enough to play against him. My father had some early success with math and science in school, but followed a different career path. And yet, he was always dropping interesting things in my path, be it my first computer at age 9 (after I consumed all of the computer magazines he left around the house), or trips to Fermilab as a teenager to see the accelerator. Somehow the mystique of being a physicist ended up as part of my DNA (both physical and mental).

That said, the path from age 11 to age 18 was one of budding math/ physics/computer geek, to puberty, and thus a channelling of said geekiness into musical pursuits (piano, then guitar, then bass, then recording with friends, playing in bands etc.) to the utter neglect of my technical abilities. In the pursuit of, well, the attentions of the opposite sex, I somehow decided that music, art, and other creative endeavors were my way out of a somewhat annoying adolescence.

So I end up at college at Yale, all set to tackle the big questions of western civilization. But, I had no idea what the western canon really was (my school was excellent but a bit disorganized, or maybe it was just me that was a bit disorganized...) and somewhat overblown views of my abilities to express it. So, like all intellectually precocious, but completely pretentious, young men, I gravitated towards philosophy and literature as my way to encounter those big questions. And I was terrible at it, at least relative to my better-prepared, and generally more urbane, peers.

And then the pivotal event: a week after starting classes freshman year, my grandfather passed away after several years in and out of hospitals. Not only was he the grandfather who taught me so many things (from the concept of relative motion to how to twiddle with a color print) and whom I could spend all day with -- and did throughout my youth -- but he was the first person in my family to die. That is to say, up to that point death had been something very abstract for me, despite friends having lost parents and grandparents along the way. It was always something that happened to other people, so I had no sense of what it meant to feel loss. That wasn't a problem anymore after that, since I found myself heartbroken for the next several months (and it didn't help to think that I was performing at a mediocre level, at best, in most of my classes!)

But what was a problem (but an amusing one in retrospect) was that I had stumbled into taking an introduction to Greek philosophy, more or less by accident as the result of a passing remark by my faculty advisor, who was more or less randomly assigned to me upon entering college. R.I.G. Hughes turned out to be a well-known philosopher of Quantum Mechanics, but I had no idea at the time, when he seemed more like a well-meaning but somewhat oblivious old English guy with a beard (and who taught the second semester philosophy overview, and terribly, if i remember right). Anyway, don't give a 19-year old in mourning the Phaedo to chew on, with all of Socrates' ruminations on body and soul, life and death. While I was hooked on the the subject matter and the intricate arguments, I was getting genuinely obsessed with mortality and its discontents, both pertaining to my grandfather, whose disappearance I had a hard time accepting, and to myself, for obvious reasons.

Unfortunately, freshman philosophy classes are great on questions, and are not so great on answers. I had a sense that I was never going to get what I needed. Thus, I remember a conversation my grandmother in her kitchen a couple of months after my grandfather died. She taught me a clever way to clean my glasses (I had just gotten my first pair after realizing that I couldn't see the blackboard from the back of the room) and probably chatted with me about her firm belief that our souls were some kind of "energy" that moved on to "dimensions beyond our ken" (I always loved that phrase). This was a conversation we'd had many times as I was growing up, as she wasn't at all bashful about her more mystical beliefs. But this time, something hit me. I had to know where my grandfather went, and thus where I would go when my time came. And I instinctively felt that this was a *scientific* problem. OK, I had some fairly desperate ideas: to become some sort of scientist that would actually observe what happens to our "energy" after we die (not exactly an original idea, e.g. Innaritu's "21 Grams" ). But I at least decided that I had to try and understand what was known, so I could get a better grasp on what wasn't known, or perhaps what could never be. So that was my Moment, the precise space-time event where I decided to become a physicist.

From there it wasn't a straight path, to be sure. But that's another, much longer and more complicated story.

Anyway this sounds like a somewhat childish, and even non-scientific, reason to become a scientist. But I know I'm not alone in finding that Death is a powerful thing to wrap one's mind around, and something which can drive one in unexpected directions in life. Just consider Ronald Mallett, whose memoir Time Traveler was also done as a fantastically-gripping radio piece on This American Life. Here's a kid who loses his father (a TV repairman) at age 10, and spends the rest of his life trying to build a time machine a la H.G. Wells -- and does, in a fashion, after becoming a professional physicist along the way. I was riveted while listening to that radio piece, when I connected with the same yearning, and the same sense that there was a way to deal with the issue that was not based on religious faith, but on actually looking around and engaging with the physical world. Maybe it's not surprising that I do particle physics, often described (inaccurately) as a "time machine" to the early universe. I certainly know that if my work didn't at least *feel* fundamental to understanding the nature of space, time, and how matter experiences it, I would probably be doing something else. Probably at a bank.

But in writing this, I'm torn between deciding that my Moment was the end product of a series of chance events (even R.I.G. Hughes suggesting I take that philosophy class), or something more like a directed random walk (i.e. I somehow knew all along that I'd end up the way I did). Maybe chance favors the prepared mind, indeed, so I can't help feeling glad for all the nudging from my dad and grandfather (and my mom too, who kept reminding me of my childhood aptitudes). I like to think they would be glad about it too, if they were around to chat about it.

Peter Steinberg is a Physicist at Brookhaven National Laboratory. When not working on current and future experiments involving colliding nuclei at BNL and CERN, he blogs at Entropy Bound, documenting his continuing efforts to understand sprawl of urban life, and to find the perfect dumpling, and maybe some bookshelves.

See also the previous contributions to the inspiration-series by

and my related guest post at Asymptotia 'Sabine Hossenfelder: My Inspiration'.



Disclaimer: No, I don't believe in horoscopes, this is just for entertainment. Get your Chinese Horoscope here.

The Chinese Zodiac - Dragon

Idealistic and proud, the Dragon is someone you want around when something big needs to be done. They think in large terms and dream big dreams. They are direct and up front, always letting you know what is on their mind. Dragon is a karmic sign, which means they will experience more than a few extreme highs and lows in their lives. The downside to the Dragon is that some are quixotic, i.e., wildly unrealistic with their big plans, while others are simply all talk or show and no action. Flattery will get you nowhere with the mighty Dragon; they expect worship. Nevertheless, the Dragon is the sign of luck, and we certainly want them on our side.


This 2007 sees a good bank account for you, Dragon - you will be able to save more, therefore keep your money stowed in a bank or safe investment. But, if you find yourself spending all this extra cash, your Wealth luck will come to nil.

Ah. So I can save money, but if I spend it, it won't get me anywhere. Now that's really quite a surprise


Support from colleagues will really spur you to greatness this 2007, Dragon, if you keep productivity on a constant high year-though. If you have been mulling over plans to start off your own business, the Pig year 2007 will be an especially auspicious year for you to do so! Solo and collaborative ventures are both good for you.

Hey, folks, watch out!


You are truly blessed this 2007, Dragon - of all the twelve animals in the Chinese Astrology pantheon, you will enjoy the best Love luck this Pig year! The married or attached Dragon will enjoy an idyllic, almost perfect relationship with their other half. If you have been dreaming of having a child lately, the year 2007 is a good year for you to do so. Aside from this, relationships with superiors and subordinates will go swimmingly for you. Congrats!

Just so you know.


Dragons will enjoy a generally sunny disposition health-wise, but elderly Dragons may have to be a little more careful with their health. Practice good judgment when eating out, and do address any minor sicknesses you may have instead of brushing it under the carpet.

Well, they could have been a bit more inspired, eh? I can write horoscopes like that as well: Dragons are generally unlikely to be run over, but should take care when crossing the street. The coming year will bring an event of great joy but it will be followed by an inevitable disappointment. Be careful whom you trust, and don't forget to file your income tax return.

Saturday, February 17, 2007

Broken Symmetry

Symmetry breaking is one of the most fundamental concepts in theoretical physics. It is what gives rise to all the diversity that makes our live so rich and surprising. How boring would it be if everything was perfectly symmetric - and massless on top of that.

Here is an example of the breaking of rotational symmetry into a discrete symmetry - you might have seen it in your own sink! These are photos of water flowing down vertically and being distorted into a horizontal direction. The first photo shows rotational symmetry. The following photo shows a distortion by which the water is spread out into 14 discrete beams.

These photos have been published in

Hancock, M.J. and Bush, J.W.M., 2002. Fluid pipes, J. Fluid Mech., 466, 285-304.

See also Fluid Polygons and Polyhedra.

Friday, February 16, 2007

NASA launch of THEMIS Satellite

Launch Date: Feb. 16, 2007
Launch Window Time: 6:05 p.m. - 6:23 p.m. EST
More info at the NASA website

The five NASA THEMIS satellites wil explore the dynamics of the magnetophere, the extended region around Earth of the Earth's magentic field. This should help to understand better when and how auroras are created. (Credits: NASA)

The THEMIS satellite's task is to measure details of the Earth's magnetic field, which is responsible for the phenomenon of the Aurora. If you've never seen it, have a look at this stunning time lapse movie, filmed in British Columbia, Canada.

While the basic physics of Auroras is more or less understood - electrons trapped in the magnetic field of our planet hit and ionise the gas of the upper atmosphere around the magnetic poles - these great phenomena still pose some riddles. For example, how come about all the different appearances of Auroras, and why can they change dramatically from gentle waves of light to wildly shifting streaks of colour?

An auroral display at the Peterberg Observatory at 49.6° northern latitude. Aurorae are quite rare at that distance from the poles, and you have to be very lucky - or have a good forecast - to see them. (Source: Sternwarte Peterberg)

Answers to these question are supposed to be found in a better understanding of the detailed dynamics of the magnetosphere. This dynamics will be explored by five satellites in an experiment called THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms". Substorms here relates to strong, turbulent fluctuations in the Earth's magnetic field. Such substorms kick around the electrons, which then ionise oxygen or nitrogen in the atmosphere, which again, when recombining, emit the beautiful green and red lights.

If you think it's quite an idle project to work on improvements of Auroral Activity Forecasts, keep in mind that such predictions are extremely useful for those of us living at comfortable distance from the poles not to sleep on the rare occasions when we can witness these fantastic lights at low latitudes.

Further reading:

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Thursday, February 15, 2007

Maps of Mars

As a souvenir for myself when travelling, I used to collect topographical maps of the of the places that I had visited. In the era before maps.google, this offered a great opportunity to continue the trip after coming back home.

Now, I guess I will never travel to Mars. But at least, I may have soon the opportunity to get detailed topographical maps of the red planet - that's what I learned today when browsing the German news magazine Spiegel-Online.

A sheet of the smallest-scale topographical map available for Mars. It shows a region called Iani Chaos on the scale 1:50 000 with contour lines only 50 meters apart. (Source: ESA)

This map was created by a team of planetologists at the Freie Universität Berlin and cartographers at the Technische Universität Berlin, using data from the High Resolution Stereo Camera HRSC on board the ESA probe Mars Express.

Mars Express is in orbit around Mars since December 2003. The camera has been designed by the FU Berlin group and developed by the German Aerospace Center (DLR), and it is mapping the entire planet in full colour and with a resolution of about 10 metres, going down to a resolution of two metres for selected regions. Since it has a stereoscopic view, it also allows to reconstruct the profile of the surface. Here, you can find much more details about the camera and how it works.

When this cartography project will be finished, the "Topographic Image Map Mars 1:200, 000" will cover the complete surface of the red planet in 10,372 individual sheets. At least, the future astronauts exploring Mars won't get lost!

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Big Bang Bubbles

More beautiful fractals on the websites of the exhibition series The Frontier between Art and Science.

Tuesday, February 13, 2007

The World's Largest Microscope

One of the most amazing things about nature is its diversity. The amount of structures, shapes and colors is just fascinating if you consider that everything is build up from only some few ingredients that we call the particles of the standard model. For a long time in the history of science, progress in physics has been accompanied by an increase of resolution - a fascinating journey in negative powers of ten.

The search for the building constituents of our world has come a long way. Democritus, sometime around 500 BCE1 was the first to theorize that there is a fundamental indivisible entity which he called átomos - the 'uncuttable'. Today we know that what was later termed 'atom' isn't uncuttable at all, but actually mostly empty, the rest being a small core of protons and neutrons, orbited by electrons. And even the protons and neutrons aren't fundamental particles.

The invention of magnifying glasses, and the light microscope was the first step. Roughly spoken, a microscope uses photons that are focused with lenses. These photons are either reflected on, or transverse a sample.

The photons are then caught on a screen, or a film, and give you a picture. The resolution that one can achieve with light is limited by its wavelength. It is impossible to resolve structures finer than that. Using light of higher frequency (gamma rays) increases the resolution. The average microscope allows us to see cells, or the structure of crystals (for some stunning images see here) .

More efficient than using photons is to use focused beams of massive particles. Due to their quantum properties, massive particles also have a wavelength which considerably smaller than that of massless particles like photons. In addition, charged particles like electrons, can be nicely directed by electromagnetic fields. Indeed, magnetic fields can be used for beams of charged particles like lenses. The electromagnetic fields can also be used to accelerate the charged particles. The advantage of this is that faster particles have a higher energy, or equivalently, a smaller wavelength. Therefore, the faster one accelerates a particle, the better the resolution.

Modern electron microscopes can roughly resolve distances as small as an Ångström - that is about the size of an atom.

However, if you hit the sample with particles of higher and higher energies, you'll eventually alter what you want to observe. If the energy gets sufficiently high, electrons will not only elastically scatter from the sample, but the beam will react with the sample to form new particles. Needless to say, the faster the particle, the more complicated it then becomes to reconstruct an image.

A particle accelerator is nothing but a giant microscope.

Particle beams are accelerated to highest energies, and then either crash into a sample (fixed target) or head on into another beam (collider). The particles that come out of the collision are detected. And here the physicist enters the stage and reconstructs particle's trajectories to understand what has happened. The outcome of such collisions depends on the structure of the elementary matter, and from detecting the particle traces one can confirm, or falsify, models about the stuff that we are made of.

It is quite a detective work. Extracting information about the structure of matter from hundreds of scattered particles whose initial motion is only know to a certain precision is like examining the outcome of a car crash, and trying to find out where the driver had dinner the night before. But over the last decades, physicists have become quite good at this. They've even grown a subclass of the species called: high energy physicists.

The outcome of their detective work is a list of identified objects at the crime scene, published annually in the particle data book, which recently celebrated its 50th anniversary. This essential reading for the high energy physicists also lists the usual suspects for physics beyond the standard model, and it has a very useful table with the technical data of accelerators of the past, present and future.

The February issue of the Discover Magazine has a very well written and researched article 'The Big Bang Machine' by Tim Folger about one of the most interesting currently running experiments, the Relativistic Heavy Ion Collider (RHIC). The article explains the properties of the hot plasma of quarks and gluons that is investigated there, why these findings are so exciting, and what this has to do with string theory and the AdS/CFT correspondence2 (see also our previous posts about the Quark Gluon Plasma and what string theory has to say about it).

If you're to lazy to read, on Wednesday we lucky guys here at PI had a very nice colloqium by Brian Cole from Columbia who will tell you what we can learn from the experiments. You find video and audio at this website.

The world's largest microscope is currently under construction at CERN and is called LHC - the Large Hadron Collider. It looks like this

The LHC is scheduled to start in September. Its main task is the collision of two proton beams with an energy of roughly 10 TeV, that corresponds to a resolution of 1/1000 femtometer. It will allow us to look closer into the structure of matter than ever before. With this, we hope to finally find the Higgs-particle that is our current explanation how particles get mass. But we also have the possibility to find evidence for supersymmetric partners of the standard model particles, and who knows - maybe quarks turn out to be not elementary particles after all?

Besides the proton-proton collisions, the LHC will also run collisions of heavy ions similar to the ones at RHIC, but with higher energy. Though the single particle's collisons have less energy that in the proton-proton collisions at LHC, using larger clusters of colliding particles with the heavy nuclei one can create blobs of matter with extremely high density and temperature. In such a way, LHC is able to re-create conditions that have not existed since the beginning of the universe. The above mentioned Discover article quotes Bill Zajc from the PHENIX experiment at RHIC:

    'One question that screams out to be answered is whether we'll see the same sort of perfect fluid that we see at RHIC'.

For more info about the LHC's heavy ion program, see e.g. the websites of the ALICE experiment.

If you're not yet totally fascinated by the LHCs prospects you're probably German, so you can have a look at this nice video about the LHC (thanks to Andi). Among other things it shows how the detective's work looks like - and what's essential for it :

However, the protons that are collided at the LHC are themselves made out of three (valence) quarks that are bound together with gluons, also called the 'partons' of the system. So, the detective needs to know something about the distribution of the proton's constituents that is called as the 'parton distribution function'. This complicates matters and increases uncertainties. In addition, this also means that the total energy of the accelerated beams doesn't fully go into the elementary parton collisions, but the energy is actually distributed over these partons. And the energy of the single collisions of these constituents is consequently less.

The easiest way to get rid of this annoyance is to use elementary particles and examine their collisions. The planned International Linear Collider e.g. would collide electrons with anti-electrons. Clifford at asymptotia explains brilliantly why this matters, and JoAnne at CV tells you how to design the next big thing.

However. Having told you why this is fascinating and exciting stuff, I'd also like to bring up an issue that is usually not discussed in design reports, and which I was recently reminded of through this article 'Wer soll das bezahlen' - Who's supposed to pay for that? (again in German, unfortunately)
    "The only things physicists always have are problems. At least when they try to understand the world. They don't get the most obvious stuff: Why do things have weight? Are there really only three dimensions?"

(if you can, I encourage you to read the comments) whichs bring up the question whether it's justified to spend such an amount of money, while there are still people starving elsewhere in the world.

It is of course a tough question, one that I ask myself repeatedly, being aware of my privileged position in Somewhere, North America. Wouldn't all that money be better used otherwise (like, you could give it to me ;-)). One can ask that about every possible investment a country makes, and to begin with I am perfectly sure there are better places to doubt the wisdom of these decisions. However, taking money and - in a mood of generosity - just giving it to those in need, whether in your own or other countries, sounds like a good idea, but isn't going to help on the long run. The reason is simply that we still can't eat money. Investments are only sensible if they permanently affect the infrastructure. It's not as easy as just scraping some billions here and giving them to the homeless. Whether or not we like the current government, the very purpose of politics is to optimize the use of tax money.

This might sound obvious, but I think it's necessary to point out every now and then, so this is now. Yes, experiments in high energy physics are a luxury of our societies, and we are very lucky that we can afford them today. The world is not a system in equilibrium. It has never been. I doubt it will ever be, but we might be able to get closer than we are now. Working towards equilibrium however isn't done by scraping money here and giving it to somebody else over there. It requires, well, a thoroughly investigated plan as to whether the investment is sensible, and not just a feeling of guilt.

No, building large particle colliders isn't necessary for the survival of our species, but it is the way to answer questions that men have asked since thousands of years. There will always be parts of this world ahead of others. But to close with a quotation by Isaac Asimov:

    'There is a single light of science, and to brighten it anywhere is to brighten it everywhere.'

Footnote 1: Before the Common Era, Christ! - There goes another 'E'.
Footnote 2: I can really recommend the article, it also tidies up with the myth of the man-made black hole that swallows Long Island.

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Sunday, February 11, 2007

This and That

Research has been moving slowly the last weeks, but the blog is developing a life on its own. Some random things:
  • Last week I received an email from Martin Griffith with a pdf version of his article in the January issue of Physics World: "Talking physics in the social web", which quotes me with a remark about spots on noses, and which prompted me to write this earlier piece about physics blogs. The pdf version has an entertaining side box with quotations of scientist's opinions about blogging etc. that I must have missed previously. E.g.

    “Physics blogs will explode in popularity, but rather than replacing science publishing, they will be used for informal communications between researchers, and as a way to interact with the public.” ~ Sean Carroll, California Institute of Technology

    “Generally, I don’t trust the physics I read in blogs at all, and I don’t think it was a good idea to put trackbacks connecting them to arXiv.org.” ~Lee Smolin, Perimeter Institute in Canada

    “There are a bunch of string-theory-oriented blogs out there, but I’m fairly disgusted with their antics at the moment, so I’m not currently reading them.” ~ Chad Orzel, Union College, New York

    “No. I’m 47.” ~ Gary Hinshaw, NASA’s Astrophysics Science Division, when asked whether he uses 'social tagging' sites
    In this regard, see also Mark's yesterday's post at Cosmic Variance How Can We Best Use Blogs?

  • Some days ago I received an email from Jennifer Ouellette who asked whether I'd give permission to use my post Water in Zero Gravity in the monthly newsletter of the APS. I was of course very flattered and said yes. I have to admit though that I've never ever read more of the APS news than the first page. So, last weekend, I actually opened one, and voila, they have indeed a column called 'Zero Gravity' - The Lighter Side of Science.

    I expect that from now on people don't only greet me with 'AAAh, you're the one with the bloo-oo-og!' (the three syllables in the last word seem to be kind of essential there), but probably with 'Oooh, you're the one sleeping on the ceiling!' I am considering handing a copy to my landlord though. And of course I promise to read the APS news from now on. If only the lighter side of it.

  • The inspiration-series which we've posted every Sunday evening for a month now is going very nicely. We have a couple of upcoming contributors that include: Yidun Wan, Anne Green, Peter Steinberg, Clifford Johnson, Simone Speziale, Bill Zajc, JoAnne Hewett, Amruta Mishra and Huang Mei. So, stay tuned.

  • And just in case you haven't yet noticed, this blog has one of the most popular buts in the internet - see sidebar.

  • Update: The Globe and Mail has an article about Nima Arkani-Hamed's last week's public lecture here at PI

    Physicist's guiding star put universe at his feet

    [...] the long-haired physicist, in his black pants and black untucked shirt, took the stage to deliver a mind-bending public lecture called The Future of Fundamental Physics.

    "I realize this is a rather modest title," Dr. Arkani-Hamed said to laughs from an audience dotted with scientists from Waterloo's Perimeter Institute for Theoretical Physics, which played host to the event [...]

Guest Post: Kerstin Paech

God, I love science Fiction!

"Why did you become a physicist?" That was the quite simple question from Bee that I find very hard to answer. But I will try my best to do so. Probably answering this question is so hard for me because I feel an entirely different person started making this decision about 10 years ago.

The first occasion I remember today that may have set me on track (or maybe just foreshadowed it) becoming a physicist was when I was about 10 years old. I started wondering what made the world going and why things happened. For my grandmother - I spent a lot of time with her as a kid - the answer in the end would be "God". Unfortunately, when I was around 10, this answer did start not making sense to me anymore. Even worse, it was the source for even more questions and confusion that I found to be very troubling back then and none of the grownups would really answer. Over the next years I looked for an answer in a lot of places and from a lot of people, but I didn't get an answer that would satisfy me.

Some years later, my curiosity found a great playground: science fiction. Although it didn't answer anything, it asked questions that were not so different from my own. Good science fiction is as much about the science part for me as about the fiction part - where here fiction for me means to explore existential questions about our existence and the very limits of our existence. Not all science fiction does that, but my favourite ones do.

And with science fiction there came an interest science. So I went listen to public talks about Astronomy and Astrophysics, started to read popular science books. It started with Special Relativity went on to the Standard Model.

However, this fascination with fundamental physics didn't translate to my interest in physics I was supposed to learn at school. Sure, it was kind of interesting how a refrigerator works, but what was about the really interesting stuff? In 11th grade then, everything changed - I got a new physics teacher - Alfred Schmitt. He showed us a hint of what physics is like, he showed us the structure of it all and it actually started all making sense. So, although I was an average student in physics at best, I chose it to be one of my two majors for the final to years of my high-school education (In the last minute I changed from majors English and Sports to Math and Physics).

And with the end of high school came the question: What's next? Although I was really thrilled about physics and the entry in our final yearbook read: "Greatest dream: Working at CERN" I was not sure at all if this was what I really wanted. I had the two options laid out for myself: Should I become a Physiotherapist or study Physics? I was absolutely uncertain if I could take up this challenge, but my curiosity won (my husband would probably say that this is not surprising at all, because I am the prototype of a nosy person).

The first years as a student at Frankfurt University was like life on the fast lane. I found that my high school teacher had prepared me extremely well for what I would find at the university - at least physics wise, it didn't keep me from wondering if I could really make it.

I soon started peeking in to research, I went to CERN (can you believe it???) in the summer after the second year to get some hands on experience with the NA49 experiment. I was overwhelmed with all the new impressions I got. I found it real mind-blowing. After that summer I decided to go for theoretical physics, I felt it to be my real calling.

Unfortunately, there is no real fundamental theoretical physics division in Frankfurt. You can either decide for theoretical solid state physics or for something that is called "structure of elementary matter", but effectively is heavy ion physics. Maybe an interesting field of research, but for sure not a very fundamental one. Leaving Frankfurt to go to another University was not an option back then. So I stayed and chose heavy ion physics, because at least there were quarks and gluons involved. And a lot of people there gave me the really strong impression that fundamental physics is not really worthwhile and heavy ion physics is as good as it gets in physics. Over the time I lost my calling, I settled for less than I had started for. And it was only much later I realized it and that is when I became the person I am today. I don't feel the kind of
curiosity in my daily work anymore. I still like my job, but it is not my passion anymore. It's a little like growing up and with growing up the wonders slowly fade away.

But then... I found new wonders, sometimes in unlikely places. I found that Physics was not the only path I would choose - why do I have to choose anyway? If I had met different people, had stumbled upon different impressions, I maybe would have found a fascination for Anthropology, maybe for Philosophy, maybe for Computer Linguistics, maybe for Psychology, or maybe - if my grandmother had had different answers - Theology. After all "We create the meaning in our lives. It does not exist independently"*.

Kerstin Paech graduated 2005 in Frankfurt/Main (Germany). Currently she is a postdoc at MSU, working on Heavy Ion Physics. She is a great fan of Hobbes (the tiger, not the philosopher), in her free time she enjoys to cook and she hates fast food with a passion. Her favourite SciFi TV Shows are "Babylon 5" and "Farscape", her favourite SciFi books currently are "Altered Carbon", "The Swarm", and "The Sparrow".

Footnote: Quotation from a B5-episode, full text e.g. on this website.

See also the previous contributions to the inspiration-series by

and my related guest post at Asymptotia 'Sabine Hossenfelder: My Inspiration'.


Saturday, February 10, 2007

Saturn in Opposition

Today, at 18:42:05 UTC, to be precise, planet Saturn is in opposition. This means that as seen from Earth, Saturn and the Sun are at opposite points on the celestial sphere, as is the Moon at Full Moon. So, Saturn is visible in the sky all night long, reaching the highest point of its path around midnight. Since the orbits of Earth and Saturn around the Sun are nearly circular, opposition also means the closest approach between Earth and Saturn. Today, the distance to Saturn is roughly 8.20 Astronomical Units, or 8.2 the distance from the Earth to the Sun. Thus, Saturn is also brighter right now than at any other phase of its orbit.

Planet Saturn in November 2006 as seen from Earth.
(Credits: Jeff Barton and Josh Walawender, via JPL/SOC).

In fact, if you look at the Eastern sky two or three hours after sunset, it's very easy to spot Saturn: Follow the line from the right hand stars of Ursa Major, the Big Dipper, away from Polaris to the head of Leo, the Lion: There is Saturn, the brightest light in this region of the sky, outshining even Regulus. Technically speaking, Saturn's magnitude is 0.0 today.

View toward the Eastern horizon from 49°36' North 7°East, on Saturday, February 10, 200, at 20:30 UTC (Credits: fourmilab.ch). Saturn is the brightest object in this region of the sky.

Opposition is the best time to observe the outer Planets, and even with a very small telescope, the rings of Saturn make an impressive view. I remember well the feeling of surprise and awe when I first spotted them through my Kosmos 68 mm refractor. Of course, there are now the breathtaking photos from the Cassini/Huygens mission, but to see the planet and its rings with your own eyes is something different again.

The NASA/JPL in Pasadena has used the current opposition of Saturn to launch the public outreach "Saturn Observation Campaign", where observatories and associations of amateur astronomers all over the world offer public talks and opportunities to have a glimpse at Saturn through real telescopes. The idea is to convey the fascination for astronomy and the science and facts behind the beautiful pictures from Cassini. Check out the list of events - maybe there is also something nearby to your place?

The Peterberg Observatory (Credits: Sternwarte Peterberg)

Yesterday night, I went to the "Night of Saturn" at the Sternwarte Peterberg - that's a small observatory run by the Association of Amateur Astronomers in Saarland, next to the place where my mother comes from. An uncle of mine still lives there. He is a member of the Association and gave me a private tour of the observatory and its instruments while one of the talks was running.

The main telescope in the dome of the Peterberg Observatory.

Unfortunately, weather yesterday night was quite typical for February in Germany - it was overcast. There had been some open spots between the clouds early on, and I could see the bright light of Saturn in the sky for an instant. But when the dome of the large telescope was supposed to be opened, even a slight drizzle had set in. So, we had to be content with a great presentation of stunning Cassini photos instead...

But here is the good thing about oppositions: It's not a big deal if you miss the date. Observing opportunities will be equally good over the weeks to come, and so I hope I will have more luck spotting Saturn soon again...

Clear Skies, as they say :-)

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Friday, February 09, 2007

Fire Water Burn

Found as a wallpaper at fantasyartdesign.com.

One day

Okay, here is a very delayed answer to Arun's question what I actually do over a day. Let's take yesterday which makes a good example. Starts like this: BlackBerry beeps at 8 am with an invitation to a workshop. I accept, and spend the following 1/2 hour trying to open a window and get some fresh air into my apartment. Which turns out to be impossible because the window (sliding glass) is frozen shut from the outside. I have the ingenious idea to use a hair dryer, which involves first finding the extension cord (I find it in a box together with the book on vector analysis I've been searching for some months now). Reaching for the the upper rim of the window however, I fall from the bed, drop the dryer, and topple over the night desk. Which crashes the hair dryer. I tell myself it was a stupid idea anyhow. If the window is frozen shut better it's closed than open, no? Another email beeps in with a referee request from a Canadian Journal I've never heard of.

Since the outside temperature fell below -20 C last weekend, I've retreated to indoor running which is thoroughly depressing. After warming up with scratching off several layers ice from the car, I run some miles on the 'fast'-lane which means, well, faster than all the people from the retirement home who take their morning walk in circles. On the way back I stop at Starbucks, which provides quality time scribbling on napkins, and I convince myself that an idea I thought was dead isn't so dead after all. At 10:30 am the BlackBerry begins beeping frequently, that being about the time when comments on the blog start coming in. I remember there's a seminar at 11 am by Nima Arkani-Hamed where I meant to go. So, I rush home, take a shower. And realize to late I can't dry my hair because the stupid dryer is broken.

I arrive at PI 3 min to 11 with ice hanging from my head, grab a cup of coffee and go hear Nima's talk. Something about compactifying the standard model down to 2+1 dimensions with an argument why this implies the standard model also has a landscape problem. If someone could explain me why electrodynamics in 2 dimensions makes sense, and are the large dimensions stable? During the confusion drop, the dead idea that wasn't so dead at Starbucks dies again. I make some sketches for a new painting, and take a note to get coelin blue. Lunchtime: we discuss a colleagues almost finished paper - well, actually the problem whether it's too long, or too messy, or what is the correct use of the words 'proved' and 'proven'.

I squeeze in 15 minutes blogging which results in yesterday's plot about the apparent seminar duration, and check the new papers on the arxiv. At five to 2pm an email beeps in telling me there's a quantum gravity seminar where I should go, so I grab another coffee. While the speaker is explaining something about spin networks, I read the recent Discovery magazine, which has an interesting article about RHIC. After the seminar, I answer the emails that have accumulated during the day, even find some minutes to read my favourite blogs, and to leave more or less intelligent comments. I try to figure out how I best transfer a conference fee in Euro from Canada to Poland, and end up asking my mum.

At 4 pm there is the discussion group on foundations of quantum gravity, speaker yesterday Lee Smolin about the problem of time. As you should have noticed by now, time is a serious problem. But the seminar turns out to be one of the most interesting ones I've heard lately, despite or maybe because the somewhat unfinished and confused argumentation. In 90 minutes Lee raises enough questions to keep me occupied for the rest of my life. I still can't make up my mind whether or not the universe is just a mathematical machinery, but I settle on the opinion of time not being fundamental. At least temporarily.

On the way back from the seminar room, I bump into Simone who I meant to talk to regarding my workshop proposal for October. It turns out we agree on the important points, so I'll just submit the text as it is. I notice Simone is probably the only person in the world who can wear a bright green T-shirt in Canadian winter without looking either nuts or silly or both. Returning to my office I find the door shut and realize a) my key card is inside, and b) my office mate is in NYC, so I have to c) get the security guy to open the door - on the way to whom I d) come by my snail-mailbox where I find an enormous amount of past due bills for the BlackBerry (argh), and a note from the German Science Foundation in reply to* my email from last May (only 8 months processing time, that's progress). Back in my office, I eventually have time to read papers, look up some details, and take notes. Interrupted by phases of staring out of the window in a mode of California dreaming, and answering incoming phone calls on skype.

Thursday evening there's pub night at PI, where I go and have a glass of wine. Lucky me, I end up sitting with Lee and Nima. After one hour my not-so-Boltzmannian brain feels like a bubble of nothing and I leave early. Gee, there's a limit to the amount of new information I can process in one day! Back in my office I notice it's too late to stop by the artist store and get the blue I ran out of, but at least I buy a new hair dryer. While in the store I get an email regarding my last paper, which 'kindly draws my attention' to somebodies interesting (but completely unrelated) work, and would I please add a citation?

Back home I manage to burn dinner so completely the fire alarm goes off. Hey - this is a first, at least I know now that the alarm actually works. Unfortunately, I still can't open the window, so I open the door which prompts my neighbor to comment something about my cooking skills. The rest of the evening I push back and forth the undead idea, replying to an email every now and then, and fall asleep on the couch.

Summary: 50% accumulating input, 20% processing input, 10% administration, 10% complete waste of time, 10% quality working time

I should add though that thre sminars pr day is th xcption, this was a prtty busy day. Hy Arun, I'm still waiting for my supply of vowls. but I hop this answrs your qustion ;-)

Footnote: They have finally realized I'm not coming back.