Age maps
Photographer Bobby Neel Adams splices together portraits of the same person at very different ages (as well as other intriguing work).
Mainstream breakthrough
Let’s get this right out of the way: yes, Cosmic Variance did make its first appearance in the New York Times. We get a passing mention in Dennis Overbye’s article about Lisa Randall, for Clifford’s justified annoyance at Ira Flatow’s remarks on Science Friday about Lisa’s appearance rather than her science.
The NYT profile is a good one, managing to mix the personal with the scientific in a more interesting (and less objectionable) way. And they always do a nice job with the graphics; here is their version of the Randall-Sundrum brane-world construction. (Click to enlarge.)
Randall-Sundrum (versions one and two) is a great idea, one that I hope to discuss at length at some point. The basic notion is to have two three-branes (a three-brane has three dimensions of space and one of time) separated by a five-dimensional bulk that is highly curved. The nice feature is that the curvature acts not only on stuff passing through the bulk itself, but also works to rescale energies on one brane in relation to the other. So, what appears naturally to be very high-energy on one brane can be naturally low-energy on the other. This idea may help to explain the huge discrepancy (fifteen or so orders of magnitude) between the typical energy scales of particle physics (about one trillion electron volts, or one TeV) and that of gravity (the Planck scale, 1015 TeV).
But all the publicity, of course, is currently associated with Lisa’s new book more than with any recent breakthroughs. As predicted, I’ve written a review of Warped Passages, along with Michio Kaku’s book Parallel Worlds, which has now appeared in American Scientist. You’ll see that these are very different books, and it shouldn’t be too hard to figure out which I liked better. The holidays are coming — if there’s nobody in your family you like enough to get them my book or Clifford’s, you wouldn’t go wrong buying them Lisa’s.
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Even scarier
Or if you really want to be scared, visit 3 Quarks Daily to read Abbas’s story of being arrested at JFK airport for beating himself up several years before. It should give pause to people who think that legal representation for suspected criminals is a sign of bleeding-heart weakness. Not, apparently, that being represented by a public defender is any better than simply throwing yourself on the mercy of the court.
The Oval Portrait
A busy Halloween for me, so I’ll shamelessly offer up an excerpt from the master — a bit from The Oval Portrait, by Edgar Allen Poe.
She was a maiden of rarest beauty, and not more lovely than full of glee. And evil was the hour when she saw, and loved, and wedded the painter. He, passionate, studious, austere, and having already a bride in his Art; she a maiden of rarest beauty, and not more lovely than full of glee; all light and smiles, and frolicsome as the young fawn; loving and cherishing all things; hating only the Art which was her rival; dreading only the pallet and brushes and other untoward instruments which deprived her of the countenance of her lover. It was thus a terrible thing for this lady to hear the painter speak of his desire to pourtray even his young bride. But she was humble and obedient, and sat meekly for many weeks in the dark, high turret-chamber where the light dripped upon the pale canvas only from overhead.
But he, the painter, took glory in his work, which went on from hour to hour, and from day to day. And be was a passionate, and wild, and moody man, who became lost in reveries; so that he would not see that the light which fell so ghastly in that lone turret withered the health and the spirits of his bride, who pined visibly to all but him. Yet she smiled on and still on, uncomplainingly, because she saw that the painter (who had high renown) took a fervid and burning pleasure in his task, and wrought day and night to depict her who so loved him, yet who grew daily more dispirited and weak.
And in sooth some who beheld the portrait spoke of its resemblance in low words, as of a mighty marvel, and a proof not less of the power of the painter than of his deep love for her whom he depicted so surpassingly well. But at length, as the labor drew nearer to its conclusion, there were admitted none into the turret; for the painter had grown wild with the ardor of his work, and turned his eyes from canvas merely, even to regard the countenance of his wife. And he would not see that the tints which he spread upon the canvas were drawn from the cheeks of her who sate beside him. And when many weeks bad passed, and but little remained to do, save one brush upon the mouth and one tint upon the eye, the spirit of the lady again flickered up as the flame within the socket of the lamp. And then the brush was given, and then the tint was placed; and, for one moment, the painter stood entranced before the work which he had wrought; but in the next, while he yet gazed, he grew tremulous and very pallid, and aghast, and crying with a loud voice, ‘This is indeed Life itself!’ turned suddenly to regard his beloved:- She was dead!
The Grinch Who Stole Fitzmas
I think this is going to be one of those holidays that I grumble about in an unappealing Scroogish manner, rather than embracing with a childlike innocence. Fitzmas, for those who have been hiding from the Inter Net these past few weeks, is the day when cherubic investigator Peter Fitzgerald hands down his indictments in the Plamegate scandal, sticking a pointy dagger of righteousness into the icy heart of the Bush administration. The day itself was yesterday, as Fitzgerald fingered Scooter Libby for perjury, making false statements, and obstruction of justice; more indictments may be on the way, perhaps including the Prince of Darkness himself Karl Rove. (Although deserving of the moniker, I don’t think many people really call Rove the Prince of Darkness — the label has been appropriate for so many GOP operatives, it’s kind of lost its punch.)
The liberal blogosphere has been gleefully awaiting this day, when they finally get to see some justice brought to the pack of medacious scheming liars currently running the country. Atrios, to pick on him unfairly, has been hoarding bottles of champagne in anticipation.
Personally, I’m not in the holiday spirit. The recent troubles for the White House are not a “positive good” so much as a “minor slowing-down of a tremendous amount of positive bad.” For one thing, indicting a few administration aides, even quite influential ones, on perjury charges is just not that big a deal. For another, putting a crimp in the White House’s style just doesn’t seem like a cause for celebration; it perhaps generates some mild satisfaction, but mostly a melancholy appreciation of the depths to which the country has sunk.
A lot of people, in perfectly good faith, believe that invading Iraq was the right thing to do, for various reasons. That’s fine, we can disagree. But does any reasonable person deny that the Bush administration engaged in a systematic campaign of lies and distortions to get us there? Does anyone in their right mind think that these folks made a careful and conscientious effort to ascertain whether Saddam possessed weapons of mass destruction, and then presented the case to the world honestly as they best understood it? And are there sensible people out there who aren’t deeply bothered by this?
It’s sobering to understand that we are ruled by a group of people who (1) have only a tenuous connection to reality themselves, and (2) have absolutely no hesitation in using lies and intimidation to put into action the policies they want. It’s a dangerous combination, one that should be off-putting to conservatives just as much as liberals. When the current leadership of the Republican party wants something to be true, sincere arguments for or against that thing are completely beside the point. Saddam had WMD’s. Saddam was involved in September 11th. Human-produced emissions have no affect on our climate. Tax cuts reduce the deficit. Life is intelligently designed. The world supported us in Iraq. There’s nothing else we could have done after Katrina. Evidence for or against these propositions has no weight in their calculations.
Yesterday a friend of mine told me a story that she was told by a friend of hers, well-known explorer Sylvia Earle. Apparently Earle found herself at a fancy White House dinner, seated next to Trent Lott of all people. Innocent that she is, Earle thought this would be a great opportunity to explain to him the various ways in which our activities are wreaking havoc with the environment, in the oceans as well as in the atmosphere. After listening patiently to her over the course of dinner, at the end Lott nodded his head and said, But you have to understand that the long-term fate of the Earth doesn’t really matter to us, since everything will be re-arranged when the Lord returns on Judgment Day.
These are not the opinions of some fringe kook — these are the people who are ruling the country.
So I’m not in much of a celebratory mood. (To be fair, neither is Atrios.) We’ve been beaten senseless in a back alley by a group of a dozen thugs, and Fitzgerald’s indictments are like catching one or two of them for jay-walking violations. Even if by some miracle we could see the entire adminstration thrown out tomorrow, my mood would simply be one of relief, not of joy. Since that’s not about to happen, it’s all we can do just to minimize the damage.
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Kansas feels the heat
People who care about science are not sitting quietly as the Kansas board of education eviscerates the state science curriculum. First the American Association for the Advancement of Science and other organizations refused to participate in the sham hearings that had a foregone conclusion. This is a potentially risky strategy, aiming to deny an aura of respectability to the forces of superstition, but running the risk of giving them free rein to spout their nonsense unchecked. It seemed to work in this case, though, as many commentators were forced to take the initiative to point out how non-scientific the testimony was. (Here are more resources from AAAS.)
Now the National Academy of Sciences and the National Science Teachers Association are refusing to let Kansas use their materials in courses.
Two leading science organizations have denied the Kansas Board of Education permission to use their copyrighted materials as part of the state’s proposed new science standards because of the standards’ critical approach to evolution.
The rebuke from the two groups, the National Academy of Sciences and the National Science Teachers Association, comes less than two weeks before the board’s expected adoption of the controversial new standards, which will serve as a template for statewide tests and thus have great influence on what is taught.
Kansas is one of a number of states and school districts where the teaching of evolution has lately come under assault. If adopted, its change in standards will be among the most aggressive challenges in the nation to biology’s bedrock theory.
The copyright denial could delay adoption as the standards are rewritten but is unlikely to derail the board’s conservative majority in its mission to require that challenges to Darwin’s theories be taught in the state’s classrooms.
Again, a risky strategy, but potentially a very effective one. These materials are heavily used throughout the standards, so it will create a major headache for the board to remove them. It’s about time that pro-science groups stood up and started using the weapons at their disposal — the other guys don’t fight fair, we need to put everything we can into this battle.
Update: PZ Myers and Josh Rosenau are upset about the sloppy writing in the article. Fair enough.
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A long time coming
Hey, wasn’t there some sort of baseball game last night? Shouldn’t we be talking about that? National pastime, &c.
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Objectivity
K.C. Cole, moving force behind the Categorically Not! meetings that Clifford has blogged about, has left an interesting comment on Clifford’s post from September on Point of View. It’s provocative (and I largely agree with it), so I thought I would reproduce it here on the front page.
Now that it’s time for our October Categorically Not!, I finally have a moment to respond to objections some people raised about my September blurb on the subject of Objectivity, or Point of View.
As a journalist who writes about science, I thought my colleagues could learn a thing or two about the nature of “objective truth” from physics. Objectivity is a word that journalists use a lot—but in my experience, scientists don’t, because it’s not a very useful term. Journalists believe that it’s possible (and desirable) to have zero point of view—that is, to look at the world from some privileged frame through which they see the unvarnished “truth.” What makes science strong, in my opinion, is that it doesn’t fall into that trap. What scientists say is: I made this measurement, and I got this result. Or, I solved an equation, and I got this solution. To say you have a “result” or “solution” without saying how you got it is meaningless. Even when I say the sky is blue, it’s understood that I am a human being whose retina is detecting certain wavelengths of light which are then being interpreted by my human brain in very specific ways. The sky is not “blue” to a snake or a dog or a bee (or if I look through a red filter).
Similarly, if I say the universe was created in a Big Bang (never mind the details) 13 billion or so years ago, there’s no reason anyone should believe me unless I point out that this particular “objective reality” is based on evidence from several very different points of view (cosmic microwave background, expansion, nucleosynthesis….). Journalists often fail to explain this—which is one reason I believe the whole ID issue has been so badly handled in the press. It’s not enough to say “most scientists think evolution is correct….” That leaves the reader in the position of choosing who to believe—the NAS, or the president, for example. It’s not so difficult, I think, to explain that evolution is an answer to specific questions about the fossil record, morphology, DNA, embryology, etc. But it’s rarely done.
What really seemed to get people’s goat (goats?) was my statement that how you look at something determines what you see. I fail to understand the problem. If I look at light with a certain kind of apparatus, it’s a wave; if I look with another, it’s a particle. Reality is always reality, but how we choose to ask the question does determine the answer. So the only way to get an “objective” answer to is say how you asked the question! (And if I’m viewing the world through the eyes of an educated middle aged white woman living in LA—which I am—then I’d better take that into account as well.)
An astronomer friend told me he was upset because my wording played into the hands of the “relativists” (not that kind); that it was understood as “code” to mean “there’s no reality,” or some such. But I’m really tired of other people telling me what my words mean—whether the subject is objectivity, “family values,” “culture of life,” “liberal,” “feminist,” or any of the rest.
So, yes. Objectivity—meaning looking at a situation from a supposedly privileged frame from which you can see the unbiased “truth” —is, as I said, “not only unattainable, but intrinsically fraudulent and ultimately counterproductive.” Science understands this; it’s journalism that has the problem.
Lorentz invariance and you
Where were we? Ah yes, spontaneous symmetry breaking. When some field takes on a nonzero value even in empty space, and that field is affected by some symmetry transformation, the resulting symmetry is said to be “spontaneously broken,” and becomes hard for us to see directly. The classic example is the electroweak symmetry of the Standard Model, which is purportedly broken by a Higgs field that we have yet to directly detect.
The fields that get expectation values and spontaneously break symmetries are generally taken to be “scalar” fields — that is, they are single functions of spacetime, not something more complicated like a vector field. If a vector field did get a nonzero expectation value, it would have to point somewhere, thereby picking out a preferred direction in spacetime. That means that Lorentz invariance — the physical symmetry corresponding to rotations and changes of velocity — would be broken. Lorentz invariance is a cornerstone of relativity (and thus of all of modern physics), so breaking it is often thought to be bad.
But really, how bad is it? When Einstein put together special relativity on the basis of Lorentz invariance, he was arguing that there was no absolute space nor absolute time in the sense of Sir Isaac Newton. If two physicists traveling freely through empty space passed by each other at a high relative velocity, we couldn’t tell in any universal sense which one was stationary and which was moving — it’s all relative, if you like. If we violated Lorentz invariance by having a vector field get a nonzero value in the vacuum, we could tell who was stationary and who was moving — the vector would define a preferred rest frame.
But that’s not quite the same as going all the way back to Newtonian spacetime. The underlying theory is still Lorentz invariant — if we can’t easily detect this vector field (and we obviously haven’t thus far), Lorentz invariance could be spontaneously violated while remaining in complete accord with all experimental tests.
I was in on the ground floor for this idea — it was the first project I worked on in graduate school (with George Field and Roman Jackiw), and was sufficiently non-mainstream that I worried for my career prospects. Alas, those were more freewheeling times, and you could get a good postdoc without necessarily jumping on a major bandwagon. Subsequently, I was surprised to see Lorentz violation actually become it’s own (relatively tiny) bandwagon! A group of researchers, led by Alan Kostelecky at Indiana, have really pushed the idea of writing down ways to spontaneously violate Lorentz invariance, and have spawned an active experimental program to test these ideas using precision data from astophysics, particle physics, and atomic physics. (Alan has a FAQ on the whole idea of violating Lorentz symmetries.)
So I occasionally return to the idea, as in work with my former graduate student Eugene Lim on the gravitational effects of Lorentz-violating vectors. And now I’ve returned to it again, this time with current student Jing Shu, as we try to understand a fundamental question in physics: why is there more matter than antimatter?
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Hidden symmetries
Symmetries, you may have heard, play a crucial role in modern physics. (Leon Lederman and Chris Hill wrote a whole popular book about the subject, if you’re interested.) But one of the things that makes them so interesting is that they can be hidden — the symmetry is secretly there, even though you don’t easily notice. And sometimes you may be interested in the converse situation — it looks like there is an obvious symmetry of nature, but in fact there are tiny violations of it, which we haven’t yet detected.
To physicists, a “symmetry” is a situation where you can rearrange things a bit (values of quantum fields, positions in space, any of the characteristics of some physical state) and get the same answer to any physical question you may want to ask. An obvious example is, in fact, position in space: it doesn’t matter where in the world you set up your experiment to measure the charge of the electron, you should get the same answer. Of course, if your experiment is to measure the Earth’s gravitational field, you might think that you do get a different answer by moving somewhere else in space. But the rules of the game are that everything has to move — you, the experiment, and even the Earth! If you do that, the gravitational field should indeed be the same.
How do such symmetries get hidden? The classic example here is in the weak interactions of particle physics: the interactions by which, for example, a neutron decays into a proton, an electron, and an anti-neutrino. It turns out that a very elegant understanding of the weak interactions emerges if we imagine that there is actually a symmetry (labeled “SU(2)”) between certain particles; examples include the up and down quarks, as well as the electron and the electron neutrino. (This is the insight for which Glashow, Salam and Weinberg won the Nobel Prize in 1979.) If this electroweak symmetry were manifest (or “unbroken” or “linearly realized,” depending on one’s level of fastidiousness), that means that it would be impossible to tell the difference between ups and downs, or between electrons and their neutrinos.
Of course, in reality it’s not so hard to tell. These purportedly-indistinguishable particles have some similar properties, but they have different masses, and even different electric charges. Nobody would ever mistake an electron for an electron neutrino. (They would mistake a red quark for a green quark or a blue quark, as those are related by an unbroken symmetry — the SU(3) of quantum chromodynamics, for which the Nobel came much more recently.)
The reason is that the SU(2) symmetry of the weak interactions is spontaneously broken (or “nonlinearly realized”). The symmetry is firmly embedded in the laws of physics, but is hidden from our view because the particular state in which we find the universe is not invariant under this symmetry. There is something about the vacuum — empty space itself — which knows the difference between an up quark and a down quark, and it’s the influence of the vacuum on these particles that makes them look different to us.
This idea of spontaneous symmetry breaking has a long history in physics — it was elucidated in condensed matter physics by Philip Anderson (Nobel 1977) and others, and in particle physics by my colleague Yochiro Nambu and erstwhile colleague Jeffrey Goldstone (no Nobel yet, which is a shame). And here’s an interesting thing — if the vacuum is not invariant under some symmetry, there must be some field that is making it not invariant, by taking on a “vacuum expectation value.” In other words, this field likes to have a non-zero value even in its lowest-energy state. That’s not what we’re used to; the electromagnetic field, for example, has its minimum energy when the field itself is zero. But “zero” doesn’t break any symmetries; it’s only when a field has a nonzero value in the vacuum that it can affect different particles in different ways.
The way to do that, in turn, is to imagine that the symmetry-breaking field has a “Mexican-Hat Potential,” as illustrated at right. (Image swiped from The Official String Theory Web Site, which also has a nice discussion at a more technical level.) This is a graph of the potential energy of a set of two fields φ1 and φ2. Fields like to sit at the minimum of their potentials; notice that in this example, the minimum is not at zero, but along a circle at the brim of the hat. Notice also that there is a symmetry — we can rotate the hat, and everything looks the same. But in reality the field would actually be sitting at some particular point in the brim of the hat. The point is that you should imagine yourself as sitting there along with the field, in the brim of the hat. If you were at the peak in the center of the potential, the symmetry would be manifest — spin around, and everything looks the same. But there in the brim, the symmetry is hidden — spin around, and things look dramatically different in different directions. The symmetry is still there, but it’s nonlinearly realized.
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