Saturday, March 10, 2007

LaTex Test

If you haven't yet sufficient evidence that I'm completely stupid, here's how I spend my Saturday morning: getting upset about people who write how-tos without actually explaining anything. Okay, okay, I'm just a looser with add-ons and I never use Firefox because it just looks ugly. Anyway, here's a test.

Ahm... let's see... hmm.... and now click on the precious button... and...



VOILA!! I did it!! Folks, from this day on, my blog comes with equations :-)

I won't even try to explain how I did that because I for sure couldn't reproduce it. Let me put it like this, it's kind of important you see a monkey in the lower right corner of your eye, for more info go to: Greasemonkey and for one of the annoying how-tos see e.g. here. It won't work for the comments though, sorry, I guess we have kind of a hierarchy problem there.

Great. Now I need a coffee.

Weather report from Waterloo: cloudy and that stuff falling from the sky can't decide whether to be snow or rain. This means spring is coming.

Thursday, March 08, 2007

Temporary Display - contd.

Yesterday's post caused some very interesting comments, one of which I want to promote to a guest post. Not just because I'm as lazy as busy, but because Jörg has raised some important points.




Jörg Ruppert is a German physicist presently working at the physics department of McGill University, Montreal, Quebec, Canada (since Sept. 2006). This job is his second postdoctoral appointment. He has worked at the physics department of Duke University, NC, USA, for two years after graduating from J.W. Goethe-University, Frankfurt, Germany. His research interests are the QCD phase diagram and related to that phenomena occurring in hot and dense nuclear matter produced in heavy-ion collisions at RHIC and CERN. In his spare time he enjoys discovering the wonders of Montreal.


Yesterday, Bee send me a link to the article by M. Lang in Nature. The title (and the subtitle) of the article sounded interesting ("Temporary display: If you look on short-term employment as a way of window shopping, you could get a bargain"). And I am sure one could have written a nice one page essay about it, the actual article fell short of my expectations.

What the author actually did in the first column was contrasting "German" and "American" points of view on temporarily employment. This was followed by his point of view on the advantages of temporal employment for employee and employer in science.

Since the text was published in Nature under the category "inside track from academia and industry" and therefore has been made part of the discussion in a scientific environment, I feel that I have to respond critically to the article as it stands. While I have no problem with the fact that the author (or in general somebody) has a different view on the issue than I have, I would have a problem if the text remained unresponded. That's why I think that it is a good idea that Bee made it an issue in her blog.

I confess I did not have time to do a lot of research about the author and the circumstances in which the text was written. I also confess that I am one of those who are on "Temporary display" and that therefore my opinion might be subjective and perhaps as biased as the author's one (although biased in a different way I hope).

I also decided against analyzing every part and the total of the text in great detail. I just wanted to let you know what came to my mind while reading it:

I think M. Lang misses the point in the German vs. American discussion of temporary employment in scientific research. While the German job market has always been more regulated (in the sense of unions and legal protection of employees) than the American and while Germans (on average) might tend to emphasize job security when considering the benefits of a job more than Americans, this difference in attitudes is not addressing the main issue for people employed in short-term (say <~5 years) research jobs (in many research fields). I actually think this part of his discussion is misdirecting the whole punchline in which the issue should be seen. Obviously job security is a question in research as in any job, but the specific character of research jobs as opposed to many other jobs might make it even more important in research in the long run:
  • Long term projects in fundamental research afford a longer term perspective. That is one reason why (at least (!)) senior scientist should have tenured (or long term) positions. People working on long term position can develop research fields on long term perspectives. People working on short term positions can't do that as effectively.

  • Short term jobs are also enforced by funding agencies: senior scientist get grants for a certain period and have to reapply, they can't offer long term jobs to their (former) postdocs unless a research or faculty position is opened by their university/research institution.

  • If one wants to see the system of postdoc employment from its best aspects, it might be seen as a setup which wants to help young scientists to work with experts in their research field at other places than where they made their PHDs or where they will eventually get a senior science position. It can be interpreted in the sense of "years of travel" where you gain additional experience after having finished your PHD.


Every single postdoc appointment has to be long enough to allow the person (and his/her collaborators) to substantially profit from his/her stay at every single place.

Switching between short-term employments means moving and adjusting to new places and people. While this can be thrilling and keeps you in an active state of the mind, this also takes considerable time, energy and financial resources. One is tempted to point out that even postdocs are not research machines, but human beings with human needs. What does it mean not to be "tied down with family and financial commitments" and friends? It simple means that you shift (because you decide to in order to gain experience and improve your prospects on the long-term appointment job market) during the postdoc years your commitments towards your job away from friends and family. Many people decide to do that also outside of academia -- but it is a decision and for those among us who value close social bonds to loved ones a tough one. In this context I wonder why the author fails to acknowledge that "family values" might be one of the strongest American traditions (stronger than in Europe at least) and that it is actually difficult to move one's partner over the planet -- especially if he or she wants to develop a reasonable career by him-/herself.


For most of us choosing this path also means making not the most reasonable possible choice (judging only on economic grounds): a postdoc position in fundamental research almost never pays off in dollars and cents (even if you get a long term job). Measured financially most of us could seek much more lucrative job options (also in the long term), I guess. In that sense the discussion of the scientist job market in a reduced economical language might in the end prove counterproductive: if we are only economically justifying our choices then a science career definitively is not the best one after all.

That is not to say we shouldn't pursue a scientific career, but people discussing this career path should have in mind that most folks that have chosen to work there don't have money on their highest priority list - which is not to say that a decent salary is necessary to attract good people to science and science careers.

So what's the rational reasoning for making a postdoc experience (and not opting against it and pursuing another career) to my opinion?


  • You love research.

  • You want to learn from/ do research with leading scientists in your
    field and go to where they have long term jobs (which also provides scientific networking later on etc.)

  • You want to eventually get on a tenure track position towards a "senior researcher" with a long term perspective. (As an Ass. professor in the North American system one is on probation for a long term job -- Nobody I know who is German and knows that system doesn't want to have the assistant professor tenure track system copied into the German University system)

  • If the long term perspective is gone (meaning the firm believe that your short term appointment can turn eventually in a long term appointment), than it gets a much tougher journey. And that is the real problem in many fields especially if you have not been clever enough to chose the research topics and places (and last but not least supervisors for thesis/postdoc) that have the full level of publicity in the scientific community. Then it gets tough, even tough to motivate oneself further albeit most people love their research. It is especially hard to keep a positive perspective if you know of other researchers in your field that just fail to get a job because their subject is not on the peak of (temporarily and changing) public awareness of the scientific community -- not because they won't do great research or have a vast knowledge and competence.

  • I also think that short term appointments increase the publication pressure (which can mean more quantity than quality in research output) and the pressure to do short term projects. Furthermore looking for a job every one or two year can make the competition fierce. Again: one should value competition in research (in he sense of providing independent checks and keeping the people focused and on the frontier of research), but I think collaboration in science is equally important. The present system favors competition often over collaboration -- probably copying the free economic market system.
    Science should have a different quality than economic life. While competition is the most important principle in order to provide different competing choices of products for the costumer, science should still seek the unique answers meaning truth and advancement of knowledge -- as its ultimate goal -- and should value collaboration equally high.


To my understanding the prospect of long term appointment can motivate short term appointment (and make it justifiable even if one thinks somewhat in an economic perspective).

The author acknowledges this simple fact also indirectly: "it gives them an opportunity to see the scientist in action, before they make a long-term commitment",

Exactly, nobody argues against a research institute putting somebody on temporary 'probation' to test if the person fits in. In addition nobody says that if people stop doing research or do inappropriate things at their workplace that they should be protected by unreasonable laws or regulations from being fired even if they are on long term position.

All what I argue is that a long sequence of short term positions with a fading perspective of long term jobs in research can drive researchers/postdocs and even worse the quality of their research down: may they be from North America or Europe...


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Wednesday, March 07, 2007

Temporary Display?

"SCENE: A pavement café in a bustling European capital. A forlorn German scientist stares into her coffee. An American friend arrives and sits down.

American: Hey, what's up? You're looking pretty stressed."

That's what I just read an article in the recent Nature issue (Volume 446 Number 7131 p108) by Martin Lang, titled The inside track from academia and industry: Temporary display. The author description says 'Martin Lang is recruitment consultant for Kelly Scientific Resources in Cologne, Germany.'

Essentially, the article elaborates on the allegedly typical German wish for permanent positions (German: [...] But I'd still rather have the stability of a permanent position. I want to stay put until I retire.) In contrast to the allegedly typical American flexibility (American: To be honest, those days are over. It just doesn't happen any more. If the choice is between staying unemployed and trying something different, why not give temping a try? ).

Of course I feel personally offended by that, because I have heard similar arguments for academia, very naively transferred from industry. Martin Lang essentially argues that temporary positions are becoming more common because the job market has changed 'There is no point mourning a job market that has been undergoing dramatic change for several years.' and that we should get used to it 'Both employers and employees are constantly reacting to changes caused by globalization, new technology and shifting scientific and political fortunes. Temporary employment is one reaction to these changes. It is accepted in most sectors as a way to keep staffing levels responsive to fluctuating needs.' And he realizes:

'But to PhD scientists in some parts of the world, the idea of temporary employment can [...] elicit a negative response.'

Now that's really surprising. Well, I can't say very much about industry (actually I can, but would you trust me on that?), so let me stick to academia. The first important point is hidden in the sentence 'So if you're not tied down with family and financial commitments, why not make use of your freedom to exploit the temporary job market?' -- the obvious question is what happens to those who are 'tied down with family'?

Among postdocs the additional problems with this view are:

a) There are just projects you would never start on a short-term employment. And good things take time. If you want your postdocs to do good work, give them a sensible contract.

b) Jumping from one temporary employment to the next is okay for some while. The problem is the absence of long-term positions where you can land. Temping does only work temporarily. It's nothing you want to do for the rest of your life. And being the typical German, I find the spareness of future options genuinely depressing.

c) A long-term contract doesn't mean you are stuck with the people, but you trust in them. That pays off. (It means also you obviously avoid life-time positions, like Professors in Germany, who can't be fired, no matter what.)

d) For the industry, temporary contracts are in many cases just a test run for a possible long-term employment ('For companies that are cautious about bringing in high-level staff permanently, it gives them an opportunity to see the scientists in action, before they make a more long-term commitment.') Where is this option for postdocs?

SCENE: A pavement café in a bustling American capital. A forlorn American scientist stares into his coffee. A German friend arrives and sits down.

German: "Good advice: Never read the 'The-way-I-see-it' column on Starbucks cups. It will most likely spoil your day."



And that's Nemo.



See also the follow-up post: Temporary Display - contd.


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Tuesday, March 06, 2007

Empty Wall

This is a PS to the earlier post Contemporary about the painting that hung in the PI lobby:

After I encouraged as many people as possible to not only tell me they don't like that thing, but to please voice their opinion in the art committee, here is what I found when I came back from LA:



See, every now and then, even a theoretical physicist can help to make the world a nicer place.

I want to ride my bicycle ...


March 6th: Due to heavy winds during the last days, my bicycle has reappeared.


This morning, when I left the house, the outside temperature was -22° C. You know that it is a really cold day when even the Canadians wear gloves on the indoor track. At coffee break I talked to Fotini, who told me it's the month to be away. The funny thing is that every month somebody else tells me it's the month to be away.




@ the anonymous snowboarder in Vermont: I'd be more than happy to ship all the snow over to you. I'll contact Canada Post and ask them for an estimate on the postage fee. I see a huge potential for this procedure. One of you guys in California, could you send some mild sea breezes over here?

Sunday, March 04, 2007

Guest Post: Christine Dantas

Try to conceive nothingness.

It is not the modern physical concept of the vacuum, full of energy, and giving rise to ephemeral virtual particle/anti-particle pairs. Nor it is like a blank panorama, something like a flat space-time devoid of matter, since there is no energy, no time, no space, and no mind -- for whatever definition it is worth --, since even self-conception is not allowed for nothingness.

Nothingness stands more elusive than the concept of God. It reigns separate from any possible concept or entity, it is devoid of any realization -- even of itself; it does not belong to anywhere nor anytime to "this world" (or to any other possible world) -- yet, to our intellect it is "there" somehow.

Why exists everything, instead of nothingness? Nothingness should have been the rule. Or perhaps it is, but we do not realize it. We *do* wonder that, before being occasionally constituted into living forms, we *were* nothing, and when we die, we will be *nothing* again. But is it the same thing?

Perhaps, in fact, nothingness reigns. Perhaps, as paradoxical as it may seem, everything is in fact, nothingness revealed to us. And hence, there is no creation, but some odd, inconceivable delusion.

Those rather metaphysical questions bothered me for a long time since a very young age. Such questions do not belong to physics, but it seemed clear to me that, somehow, I could only understand them through science (and to a certain extent, through philosophy), but not through religion.

I mention religion because I was ten years old when I realized that, after staring, every week, during several years, half an hour or more at the image of Jesus Christ in a church of my school (I studied at a Catholic School), repeatedly and full-heartedly in my mind asking for Him to appear before me -- if he really existed --, and not receiving even a glimpse of response back, I could only conclude He did not exist. My intentions were the purest possible, and He never came. Why He would not come before me? I started to become more and more defiant in my requests, until I decided I would no longer pray before sleeping.

It was a hard time for a little girl, very shy, and scared to talk about these events to anyone else. I was very lonely in this mind endeavor, but it was not so terrible that it happened that way. At least, as I see it now.

I was (and am) exceedingly impressed by the fact that I exist, that the Universe exists, and this fact imparted on me, and perhaps substituted the common idea of God deep inside me for something else that even today I don't know what it is. Perhaps, it is nothing after all, but I do not know for now.

Back, during that time, I discovered science-fiction books, and consequently, popular science books. I would say I had two great teachers during this period: Isaac Asimov and Carl Sagan. From reading their books as a teenager, I decided to be a scientist.

It was and is hard to be a scientist for several reasons, but I will spare the reader from this. I will only mention two things that bothered me most for some time. First it was to find out that not every scientist was turned into a scientist for similar motivations that I had (I mean, the search for a deep understanding about nature). Second, that it is hard, very hard, to get a job as a scientist. Specially if you are too romantic and do not see why a large number of papers is "almost" all that makes a career (being very socially driven also helps a lot). My romantic view of science (that what matters is the value of your work and thoughts) is perhaps the most "misleading" and lasting impression that I carry from my childhood's conceptions and endeavors. We do get old and learn something about the "world out there" and adjust as time goes by. But the most important thing to me is to learn not to get corrupted and remain faithful to your own deep motivations.

So every question in fundamental physics concerns me, intrigues me, and it's unavoidably part of my own questionings. Many physicists would not agree on this and would have a much more impersonal posture and highly different motivations and aims. It is not that I think they are wrong (apart from those that look for stardom), but if I am to be entirely faithful to what I am and think, science goes beyond models, numbers, theories and even brilliant ideas. It is about a deep endeavor -- as Carl Sagan wrote once: it's about atoms thinking about atoms. And although we need models, numbers, theories and ideas to "think" over them, what matters at the end is the fact that nature is understandable at all -- as Einstein would add. To understand nature, even in our tiny human steps, requires exquisite intellectual conditions and a life effort of many minds.

Apart from the difficulties, I cannot think of any other activity as intellectually pleasant as the scientific research, except perhaps for music, to which I had devoted myself for some time (as a soprano). I did not chose a scientific career because I was good at maths and physics (I was average, and did much better in composition and arts: in fact, I wrote many science-fiction short stories and poems when I was younger and a SF book, unpublished, entitled "Laplace's Demon"). I chose it because I know of no other convincing and objective way that I could attempt to *understand* something about the Universe and about myself.

Having "acted mostly" as an astrophysicist until now, I really never contributed to the fundamental questions that so much bother me, since I only had the opportunity to look at some tiny details that nature uses to show us on the sky. All I hope is that I still have the time to put my whole energy into fundamental physics. That is my ongoing lifetime aim, even though I am largely unsure on what I really can achieve.

I did not go very far in terms of what many scientists consider as a successful career. If I had followed some prescribed path or formulae, perhaps I would have gone somewhat "far", but would have reached nowhere in terms of what I was initially motivated. And such a "nowhere" certainly would *not* be any closer to the "nothingness" that impelled me first of all! So, what can I say? I have been more or less faithful to myself and I am happy.

So here it is, a little about why I chose science as a career. This text, I would say, reflects the most abstract and nebulous part of my motivations, and just for this reason, I thought it was more interesting to focus on. Thanks, Sabine, for the challenging invitation.

Christine Dantas is a Brazilian astrophysicist working at the Instituto de Aeronáutica e Espaço. She is interested in foundational questions in physics and cosmology. Recently, she found out that she cannot really escape from the blogosphere, so gave in and set up a new blog, Theorema Egregium. She is married, mother of a lovely boy, and in her spare time, she listens to Bach and walks the dog.


See also the previous contributions to the inspiration-series by

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


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Saturday, March 03, 2007

Gravity Defyer

Your days of shuffling down the corridor to the next seminar are over!

Here's what I found in the Skymall catalogue last week: The Gravity Defyer. Shoes with springs. Even if you're not, you'll walk young and dynamical. As you can see on the figure to the left, if you grin as stupidly as possible, you can jump up all the way up to the moon.

"The energy reciprocating shock of the Gravity Defyer Shoe will spring you forward in life. The shoe is so much fun that the energy reciprocating shock of the Gravity Defying Shoe will actually give you the feeling of wanting to dance and be active. You might just find yourself joining a dance class soon! You will find a renewed enjoyment for walking places. You'll park farther away at the grocery store, shopping mall, and the office just to get extra time walking in your Gravity Defyer Shoes. "


Undoubtedly, you'll feel like it's the spring time of your life.

However, since this is a science blog, a word of caution is necessary. As a smart guy already pointed out, you should be aware that this ingenious invention doesn't actually defy gravity. I.e. you'll have to wait for anti-gravitation to be discovered to actually levitate. The only thing that's really innovative about this product is its name. Besides this, I want to complain that I couldn't find any Gravity Defying high heels (working on my minority issues). What is there left to say except:


If you liked this post, you might also like: Priceless and the Albert Einstein Action Figure.


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Total Eclipse of the Moon

Right now, at 20:18:11 UT to be precise, the Moon is entering the so-called penumbral region of the shadow cone the Earth is casting into space - that's the beginning of a total eclipse of the moon! Clifford has linked to some beautiful photos of the "Red Moon", as it is sometimes called because of the reddish glow caused by light scattered in the Earth's atmosphere that makes in the geometric cone of the shadow.

If you want to know if you can see it, depending on where you live, you can have a look at this map, provided by NASA's eclipse guru Fred Espenak:


(Source: NASA)


In the central, white zone, you can, in principle, see the whole eclipse. The outer lines mark the phase of the eclipse at moonrise (for the Americas) or moonset (for Asia and Australia). The labels P1, U1, U2, U3, U4, and P2 correspond to the different phases of the eclipse, the entering of the penumbra (P1) and the umbra (U1), the begin and end of the total eclipse (U2 and U3), and the leaving of the umbra (U4) and penumbra (P4). So, if you live on the east coast of the US, the beginning of the total eclipse is just at moonrise (U2).


(Source: NASA)


Most spectacular, of course, is the phase if total eclipse from 22:44:13 UT to 23:57:37 UT, with the moment of greatest eclipse at 23:20:56 UT.

Of course, a dense cover of clouds can spoil the show - that's what seems to happen here in Frankfurt am Main. For all of us who cannot see anything, either because of clouds, or because you are living in the "wrong" hemisphere, the German association of amateur astronomers has organised a

from a place in the Siebengebirge near Bonn. So far, they have more luck with the weather than I have. Let's hope that they, at least, will have clear skies tonight!

Friday, March 02, 2007

This and That

Thursday, March 01, 2007

Status Report

My mum is really cute, I love her. Last week she wrote she has seen on TV that NYC has had some snow, and if we also have snow? This was probably the funniest email I've received this year. But interestingly, every week or so, someone asks this question. So. Here's the answer.

Folks. I live in C-A-N-A-D-A. That's the large thing between the USA and the North pole. If I'd mention it every time we have snow, this wouldn't be a science blog, but a snow blog. The people here don't know what to do with all that snow. Before I moved here, I never realized that it can become a problem if the stuff doesn't melt away. I mean, they push it to the sidewalks and into the backyards, but it just piles up. I have seen street signs vanishing in snow hills, no kidding.

Today, the radio announced actually 'snow' and not 'flurries'. This came together with the recommendation not to leave the house, a whole list of closures, and cancellations for events and meetings. Unfortunately, I had to leave the house again. (Well. I was out of Coke, so this was really an emergency.) I forgot to take a photo of the car before I had shoveled it free, just believe me it was covered by at least 20 cm of snow.

Yes, today is March 1st.

If that doesn't impress you, let me add: the car was covered with 20cm of snow - after it was parked in the lot for 1 hour.

Here are some photos taken in front of the groceries store. I know they won't win an award for photographic quality, but it's been something like -15 C, feels like -20 or such, and after 2 minutes my fingers were so numb I couldn't push the buttons any more. Not sure if it's obvious but the second photo shows a bench. A nice place to chill out.







While I was shoveling free my car, a jacket with a toque came by and said: Quite some snow, eh? I know, it's a cliche, but they really do use this 'eh' always and everywhere. I said: Name me one good reason to move from California to Canada! EH? This scared the guy away. But since I know my sarcasm sometimes comes out the wrong way: I just like to complain about the weather. I can't say I exactly know why I decided to move here, but I don't regret it. It's maybe the first time that I like to go to work, and that I don't feel completely misplaced. I didn't expect it to make such a big difference, but it does.

However. I've promised myself and my friends if I have my own institute, it will be on a sunny beach.

Yes, yes, I'm working on it...

Quantum Gravity in the Lab

On Tuesday, we had the first meeting of the discussion group on 'Quantum Gravity in the Lab' that I've set up here at PI. As I've mentioned earlier, I exported the topic to a blog on its own. This is a copy of the entry from the first meeting. Comments are off here, because I want to encourage you to leave comments over there.

I had the intention to briefly summarize all the good reasons for the discussion group, but obviously I forgot half of what I wanted to say. So, if you're reading this you definitely have an advantage.

The reason for me setting up the discussion group was that even for those who are smart enough not to work on it, quantum gravity is the holy grail of theoretical physics in the 21st century. And here we are, standing on the shoulders of giants, trying to make a step without falling down. Luckily, over the last decade, we were able to move the giants a bit, and it's become quite fashionable to work on not derived, but well motivated models that incorporate the one or the other feature of the pursued full theory: like a minimal length scale, extra dimensions, modified dispersion relations, decoherence in a Planck-scale foamy background etc.

However, when I read papers about phenomenological implications of quantum gravity, they most often start with sentences like 'the recently proposed model...' or, 'Recently, it has been shown...', and I'm wondering if there's a decay time for the word 'recently'. E.g. the idea of having the 'true' Planck scale around a TeV dates back about a decade; DSR in it's present version came up around 00/01; early ideas about curved momentum spaces, modified dispersion relations etc. date back far longer.

Yes, it's a new field. But there are more and more people working on it every year, and it's about time that we get an overview about who is doing what, where progress has been made, and what problems have been faced. Part of this discussion group's intention is to summarize these efforts and see how promising they are (though this is surely a subjective judgement that I don't remotely mean to make objective).

The other part of the reason for the meetings is that I, being a particle physicist, find myself a bit lost in the quantum gravity seminars. It is clear that most of these approaches are very strong on the theoretical side, but lack some application. And I repeatedly ask myself if one couldn't investigate this or that feature. So, I would really like to bridge the gap between theory and experiment, to hear your ideas - however weird they might be - how one could test quantum gravity. (On my desk, if possible.)

Roughly speaking, the discussion group is therefore the forum for you to ask all the really stupid questions, and to spit out all the half-cooked topics that you have in mind. I deliberately have not scheduled speakers for the whole term. I want to see what issues come up and be flexible to focus on those that attract the most interest.

In the first meeting, I want to outline what we're going to talk about. Not so much because I don't like vivid discussions, but mostly because I'm not a good philosopher. It's not only that I constantly mix up words that end on -ism, but I generally don't like to argue about words whose meaning hasn't been clarified. So, to begin with, we should try to figure out what we mean with 'quantum gravity' and it's 'phenomenology'.

To me quantum gravity is the try to resolve the apparent disagreement between general relativity and quantum field theory. I say 'apparent' because, well, I'm pretty sure nature knows how to deal with that, so there ought to be a solution to the problem. Since three out of the four interactions in the standard model are quantized, it's natural to expect that also the fourth one - gravity - has to be quantized. In the meaning that the metric is no longer a classical field.

However, I think one should keep in mind that we actually don't know whether gravity is quantized at all. That doesn't solve the problem how it goes along with quantum field theory, but it's nevertheless a possibility. In this case one has a semi-classical theory with an unquantized gravitational field. The question is then how quantum field theory couples to the classical field. This comes with all the issues about renormalization, the vacuum, and as Rafael points out one has to think about what happens to the quantum nature (determinism) of the theory. (This is a topic I've also scratched in the comments at CV here.) Yes, I'm not claiming I know how to deal with that, I just don't a priory see why this is a totally inconsistent try. I don't think anybody knows what happens to the gravitational field of a 'collapsing' wave-function, so there's definitely room to play around there. So, apart from the quantization of the metric, one has the question what happens to the quantization itself.

Further, if one thinks about quantum gravity as stuff that happens when the curvature gets strong, one also has to consider modifications of gravity itself. These might, or might not be motivated by a quantization approach. Issues like singularity avoidance, the cosmological constant, dark matter etc could fall in this range.

One way or the other, as the status is right know, if one starts attacking quantum gravity and wants to investigate phenomenological implications, one makes some more or less motivated approximations, and cooks up an effective model that one can use to make a prediction. I want to point out (if you've read my recent paper you know why) that besides making predictions for new experiments, one shouldn't forget to reproduce all the old and boring stuff in the standard model. You know. Like, apples falling to the ground, photon self-energy, nuclear decay. These things.

The important question is then, what information got lost in the intermediate steps from the 'full theory' to the prediction. That is, we have kind of an inverse problem. Given that we were lucky enough to actually measure something, what could we learn about the full theory? Therefore, questions we should ask about all of the proposed phenomenological approaches are

  • How stringent is the top-down approach (derivation/motivation)?
  • How good works the bottom-up connection (reproduces standard model)?
  • Exactly what is predicted under which assumptions?
  • What could be learned from the outcome of the experiment (positive as well as negative)?


Lee mentions that I'm being too strict and since everything is going so badly we should try something unusual and not set too many requirements to our models. Well, for one I don't think everything is going badly, but more importantly, I haven't set any requirements. These are just the points I think one should investigate about the presently discussed approaches. See, this is just great about being at PI. Here, it's me who's considered being too conservative.

This is obviously a completely biased summary of the meeting, and I've dropped every comment that I didn't like or didn't understand.


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Tuesday, February 27, 2007

Disneyverse

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.


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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'.


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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?





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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'.


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