Blogs / Cosmic Variance

From the Atkins diet to the Metabolism diet and the Russian Air Force diet, there’s no shortage of ideas on the correct way to understand the origins of human mass. When it comes to the deeper question of the masses of the elementary particles that make up the ordinary mass of the universe, things aren’t much different.

Most physicists agree that the stunning successes of the standard model of particle physics imply that particle masses must be due to their interactions with a new field known as the Higgs field. At currently accessible energies, it is thought that the Higgs field is a scalar field, and that elementary particles acquire mass because the universe is filled with a condensate of the Higgs field, through which all standard model particles are forced to wade.

One of the hints that the standard model may not be complete comes from the properties of the quantum theory of this Higgs field. For the Higgs field to perform properly, its mass must be around the weak scale (except for in an extremely narrow region of parameter space). However, the masses of scalar fields receive large corrections from quantum effects (so-called quadratic divergences) and, unless one fine-tunes the theory a truly ridiculous amount, the expected mass of the Higgs boson may be as high as the Planck scale - sixteen orders of magnitude higher than the weak scale. This tension, between the required low mass scale of the Higgs field and the ultra-high Planck scale to which it might be driven, is known as the hierarchy problem of the standard model.

Much of the motivation for the next generation of particle colliders - the Large Hadron Collider (LHC) at CERN, and the proposed International Linear Collider (ILC) - comes from the desire to identify the mechanism responsible for the generation of mass (finding the Higgs particle) and to understand the structure through which the hierarchy mentioned above is rendered stable. Other motivations come from the connections between colliders and cosmology.

In the most recent issue of Scientific American, Gordy Kane, a renowned particle theorist from the University of Michigan, discusses these issues in a nicely written article titled The Mysteries of Mass. One of the leading candidates to explain the hierarchy problem is supersymmetry, which tames the quadratic divergences by introducing a new set of particles into the model, related to the standard model particles by, well, supersymmetry. Gordy has been a major player in research into supersymmetry, and understandably this constitutes one focus of the article. It is worth pointing out, however, that there are a number of other ideas floating around (such as extra dimensions, on which JoAnne is an expert), not to mention the perennial favorite - none of the above. Whether you find the idea of supersymmetry compelling or not, the origin of mass is certainly one of the deepest questions facing physics today, and I think Gordy’s article provides an interesting summary of the main questions and challenges.

As we approach the turn on of the LHC, probably in 2007, serious attempts to figure out how to interpret its data to distinguish between the various ideas that theorists have generated have ramped up. To this end, in a few days, CERN will host the LHC Olympics - a sort of blind test of how well such a distinction might be made. They even have a pdf primer. When the results of all this are in, hopefully in a few months, I (or JoAnne if I can persuade her) will report on what happened.

Last week in Paris, I walked along the north-south line connecting the Observatoire de Paris to the Palais du Luxembourg. A line of longitude: in fact, the line of longitude, if the French had had their way a little over a century ago. A politico-scientific battle was being fought in the late nineteenth century over the location of the Prime Meridian. Parisians, thinking only of considerations of nature and philosophy, argued that the line of zero longitude should go through l’Observatoire; the rest of the world, crass materialists that they were, noted that over seventy percent of the world’s shipping was already using Greenwich (nine minutes and twenty-one seconds to the west of Paris) as its standard of longitude. The French lost out to the British, prefiguring a similarly heated tussle over who would host the Olympic Games over a hundred years later.

These issues figure prominently in the book I was reading during my trip, Peter Galison’s Einstein’s Clocks, Poincare’s Maps: Empires of Time. It is a paradigmatic example of a engaging work of intellectual history, as it has a definite theme that is at once simple, interesting, and true. Einstein and Poincare, the obscure German theoretical physicist and the celebrated French mathematician and philosopher, were pivotal figures in the development of the special theory of relativity, whose centenary we are celebrating this year. Relativity has a reputation as an esoteric theory, and Einstein and Poincare are often thought of as abstract thinkers divorced from mundane matters of technology and experimentation. Galison argues convincingly that these thinkers’ practical concerns with the measurement of time — Einstein judging clock designs at his patent office in Bern, Poincare as President of the Bureau of Longitude — were in fact crucial to their recognition of the need for a new understanding of the fundamental nature of time itself.

In a Newtonian universe, time is universal — the amount of time elapsed between two events is precisely and uniquely defined, even if the events are widely separated in space. It may be difficult to actually measure the time between events, and this task was a constant preoccupation of nineteenth-century astronomers, surveyors, politicians, and businessmen. It’s easy enough to use the sun to determine your local time, but the advent of railroads made it necessary (as several unfortunate accidents proved) to sensibly coordinate time among far-flung locales, a program that eventually led to our current system of time zones. In the course of standardizing time across broad expanses of geography, it became clear that synchronization was an operational concept — you had to bounce some signals back and forth between locations, and taking into account the travel time of the signals themselves was of primary importance. Poincare’s work on longitude was intimately connected to precisely this problem, as was Einstein’s experience with novel clock designs. (At one point subterranean Paris featured tubes that would carry pulses of compressed air from a central station to clocks throughout the city, which would use the pulses as reference standards to guarantee as precise a degree of synchronization as possible. Einstein would have seen numerous proposals for electrical versions of such schemes.)

By itself, the need to synchronize time via exchanged signals does not lead you to relativity; it is equally characteristic of Newtonian absolute time. But when combined with the principle of relativity and the invariance of the speed of light, this insight led Einstein to understand that the notion of simultaneity of distant events is not universal, but depends on one’s frame of reference. (In general relativity, in which spacetime is curved, we need to go even further — the notion of simultaneity is not simply frame-dependent, it is completely ill-defined.) Time goes from being an absolute characteristic of the universe to something individual and personal, a measure of the distance traversed by a particular object through spacetime. Poincare (following Hendrik Lorentz) had worked his way to similar conclusions, but it was Einstein who showed how to completely abandon the absolute Newtonian time that other physicists felt still lurked unobserved in the background.

Did someone say that scientists are individual idiosyncratic human beings? Gleaming mathematical edifices like the special theory of relativity can give the impression of having dropped from the sky; it’s nice to be reminded of the messy contingent ways that real people happen to stumble upon them.

My colleagues have already provided very nice introductions to this space, but here’s one more. I’ve been a regular web geek basically since physicists first started
the internets. I’ve also been a political news junkie for as long as I can remember, and have been a blog reader since the early days. It remains to be seen whether I’ll have something interesting to contribute here, but these times seem to require comment and engagement.

Like many scientists, I am extremely concerned about the increasing politicization of science. And, more generally, about what seems like not only an attack on science (from Wait Wait Don’t Tell Me this morning:
“I’m a teacher of high-school science” “Is that still allowed these days?”), but on rationality and critical thinking in general. Perhaps, it was ever thus. But, I have been continuously amazed in the past few years both by the increasing power of voices that seem to want to take America to its mythical pre-Enlightenment days, and by how facts themselves seem ever more distorted by " onclick="javascript:urchinTracker('/outbound/www.nytimes.com/2005/07/15/opinion/15krugman.html?n=Top_2fOpinion_2fEditorials_20and_20Op_2dEd_2fOp_2dEd_2fColumnists_2fPaul_20Krugman_br_/');">political and clerical spin.

So, while I certainly agree with Sean’s visceral distaste of the idea of some monolithic “natural scientist’s perspective” on the world, and with Clifford’s hesitation about the proclivities of physicists to say something about everything, I do think science as a framework has a lot to contribute in combating the belief-based fact-making of these times. And apparently, though, even though 44 percent of Americans think the world was
created in six days, they still have a lot of respect for scientists,
especially astronomers and physicists. So perhaps at least a few people will actually care about what this motley crew of us has to say about the world (well, at least after they read all the blogs by database administrators).

My primary hesitation about starting a blog of my own was the time issue, since I’m already way too overcommitted and one really has to post on a pretty regular basis to develop any kind of audience. Plus, as

I was warned this week in particular, this whole blogging thing is clearly

a very bad idea for someone on the job market. But luckily for you, dear reader, I just can’t help myself (you can ask me in 8 or 10 months how lucky it was for me). The group blog thing (and Sean’s sweet talking, of course) brought me over the edge: hopefully it will be all the fun and only 1/5 of the work and accountability!

Like Clifford, I think there is value in having people know that physicists aren’t all like
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that makes science more accessible (as both a career choice and as a method of thinking). I love what I do for the science itself, but this feeling is one reason that makes me feel like what I do is actually important. Hopefully this blog will make at least a small contribution in that regard.

But don’t worry, this won’t all be science and politics all the time. I don’t have anything insightful to say about Brad and Angelina at the moment, but I will likely subject you to my ramblings on burritos and cheese and sushi, mountains and cities and oceans, gadget lust and music and mac advice, and other assorted uselessness. Anyways, I’m delighted to be doing so with such a charming and renowned group of folks. Welcome, and thanks for reading.

Well let me say right at the outset that rumours that I said I would never blog are exaggerated, but it is certainly true that I expressed serious reservations. Several people kept suggesting that I start a blog -most notably two of my new colleagues in this endeavour, Mark and Sean- and I kept declining. My reasons were simple, and (more…)

Just as I agonized over my first post on Orange Quark, so I am finding this initial Cosmic Variance one difficult.

Probably, the first thing to do is merely to introduce myself. I am a theoretical physicist, working on particle physics and gravity and, in particular, on the roles they play in the evolution and structure of the universe. When asked for a short phrase to describe my research area, I say I’m a particle cosmologist.

I began blogging, initially at Orange Quark, and now here, for essentially three reasons. First, I wanted to make use of this relatively new medium as a way to help non-experts understand scientific questions in which they were interested. Second, I feel that the positive social role of the scientific method is vastly under-appreciated outside of the scientific community (even within academia) and I wanted to try to play my part in addressing this deficit. Finally, it seems to me that science in the United States is, to a certain extent, under attack. In some ways, this attack has been underway for many years and comes, predominantly, from members of the extreme religious right. These zealots persist in beliefs that are directly contradicted by concrete scientific evidence about reality and are bent on twisting and discrediting science to protect their belief system. However, in recent years, the attackers have become much fiercer, better organized and successful, because they are emboldened by a political leadership that is sympathetic to their views and, more practically, depends on their votes to stay in power. I don’t care which political party it comes from, misusing and censoring science to fit ideology does a great disservice to society, and I don’t want to sit back quietly and let it happen.

Science is so much more than the dry accumulation of facts. Rather it is the way we gather meaningful information about the universe in which we live and provides a coherent intellectual framework, based on critical thinking and the demands of evidence, which extends far beyond the boundaries of individual scientific disciplines. As a way of approaching reality, science therefore provides a methodology through which we can tackle difficult topics and decisions with reason rather than with superstition, dogma and irrationality.

I’m sure I’ll also talk about books, humor, gossip, what it’s like to be a scientist, and other intellectual, cultural and, indeed, trivial topics, but I think from the above you’ll get some kind of idea of the topics in which I will mainly be interested. I hope you enjoy Cosmic Variance. I’m certainly excited that we’re getting started and am delighted to be collaborating with Sean, JoAnne, Clifford and Risa - friends old and new. I hope that our group efforts will provide richer and more varied content than any one of us would be able to provide alone. Feel free to comment on our posts and tell your friends.

As an undergraduate I took a delightful course in the Philosophy of Religion from a young lecturer named Tony Godzieba. He was a committed anti-foundationalist, and would discourse passionately on the Hermeneutics of Suspicion — along with Augustine and Aquinas we read Nietzsche and Freud and Ricoeur and had a grand old time.

But Tony had one deeply ingrained habit that used to drive me nuts. He took seriously the idea that there was no neutral vantage point from which we could discuss absolute truths; rather, our lively class discussions were to be thought of as interactions between a variety of perspectives. And he knew that my friend Padi Boyd (who was also taking the class) and I were the astronomy majors in the room. So whenever he would call on either of us, he would (with the best of intentions) inevitably say something like “So now let’s get the natural-science perspective on this.”

Man, that drove me crazy. Putting aside for the moment any disputes between foundationalist and perspectivalist theories of truth, granting that anything I say might necessarily be coming from some perspective, there is still a crucially important difference between my perspective (or that of any other individual scientist) and some abstracted notion of a “natural-science perspective.” When I would argue that St. Anselm’s ontological proof for the existence of God was a load of hooey, I may have been informed by my scientific education, but also by innumerable other influences — random and deliberate, obvious and hidden, justified and irrational. Physical sciences propose crisp mathematical structures in order to model the inner workings of the natural world, but the scientists themselves are human, all too human.

So what we have here is a group blog constructed by some idiosyncratic human beings who also happen to be physicists. Sometimes we’ll talk about science, other times it will be food or literature or whatever moves us — I know I have some incisive things to say about Brad Pitt and Angelina Jolie, for one thing. We’re not a representative collection of scientists, just some engaged individuals curious about our world.

Welcome!