Religious kids have all the fun

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From Ernie’s 3D Pancakes, perhaps the best holiday gift ever — the Plush Plagues Bag for Passover!

Plush Plagues
Yes, you can have soft fuzzy representations of each of the ten plagues sent by Yahweh to annoy the Egyptians into letting Moses and his people go. Types of pestilence represented include:

  • A spooky eyed drop of blood
  • A Frog — for frogs, of course
  • A Giant Lice for lice.
  • Cow for cattle disease
  • Black Locust for locusts
  • A white satin lump of hail
  • A black cube of darkness
  • An icky boil on a piece of flesh!
  • A snarling lion’s head for wild beasts
  • and last of all a very sad head – for death of the first born.

Descriptions taken verbatim from the vendor, who goes on to say — “The frog, lice, cow and locust wriggle and roll their eyes, quiver, buzz and move when you pull their string and are apx 4.5″ long.” With toys like this, how come Judaism isn’t the world’s most popular religion?

I mean, seriously. A black cube of darkness! With eyes. Nothing could be more awesome than that.

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Going to California

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Some of you may know that I’ve been on the job market. The good news is that I’ve officially accepted a position at Caltech, starting in September. It’s a fantastic research environment, and they are building up in cosmology at the moment. Also I understand the weather is pretty nice, so I’m excited about the move.

The job itself requires a little explication: I’ll be a Senior Research Associate in Physics. According to Caltech’s classification system, this is a faculty job (“Caltech’s equivalent of a research full professor,” as they put it to me) but not actually a “professor” job. Basically I get to concentrate on doing research — no teaching required, although I’m allowed to volunteer — and can apply for grants and hire postdocs (and even serve on committees!) just like any other faculty member. The downside is that there is no tenure, although it’s not a term-limited job; I can in principle stay forever if the money holds out and they don’t want to fire me. In the meantime, I’ll have the freedom to work on some of the more ambitious cosmology ideas that have been percolating in the back of my mind for a while.

I have to express my gratitude to everyone who has been incredibly supportive during the entire process, from my close friends to strangers on the internet to famous scientists around the world to Marc Kamionkowski and the others who did such a good job recruiting me to Caltech. I’m sure I will miss Chicago at times, but the future looks really bright, and I can’t wait to get it started.

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Dr. Doom

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This story is so amazing/silly/horrifying that it’s taken a few days to sink in. Short version: Dr. Eric Pianka of the University of Texas, an internationally recognized ecologist, goes around giving talks warning that the Earth is in major trouble. We’re headed for an ecological disaster, and human beings in particular are in serious danger of being wiped out by a deadly virus like Ebola, perhaps leading to the death of 90% of our current population. It might even be good for the environment over all (although bad for us, obviously). He’s an alarmist, no doubt about it, but it’s better to hear about such disaster scenarios than to simply ignore them.

And then — and here’s the part that is so bizarre that it takes a while to really believe it — “citizen scientist” and creationist Forrest Mims apparently heard Pianka give a talk, and decided that Pianka is advocating that we release a virus to kill 90% of the Earth’s population. Completely untrue, of course; just a simple-minded and mean-spirited twisting of the guy’s words. Even from the original story, you could tell that there was a serious disconnect between portrayal and reality — the actual quotes from Pianka didn’t measure up to the surrounding alarmist hysteria.

But the right-wing/creationist blogosphere has gone completely nutso over this. I thought my fellow left-wing/scientific friends might be exaggerating the reaction a bit, but it’s true — dozens of posts about the crazy “Dr. Doom” who longs to bring down our civilization through bioterrorism. ID advocate (and tireless defender of academic freedom!) William Dembski has taken the obvious step for someone who is unhinged but nevertheless concerned — he has reported Pianka to the Department of Homeland Security. A good summary of the craziness has been written by Nick Matzke at the Panda’s Thumb; more coverage from PZ Myers (and here), Ed Brayton, Wesley Elsberry (and here), and DarkSyde (and here).

There’s a lesson here, although damned if I can figure out what it is. PZ thinks that these people are just anti-academic, and that it’s part of a campaign to discredit the very notion of expertise. But I suspect that it’s less calculated than that — we’re talking about folks who find it completely plausible to imagine that liberal biology professors are eager to wipe out most of the human race. The basic cognitive short-circuit seems to be an inability to understand the difference between a sentiment of the form “A human population of one billion is more ecologically sustainable than one of six billion” and something like “I would like to personally murder five out of every six living people.” It’s the right-wing equivalent of people who think that the 9/11 attacks were orchestrated by Halliburton and/or the Mossad. Except that it’s not a fringe movement; the buzz is all over the right hemiblogosphere, and was straightforwardly reported by Matt Drudge and others.

Next time I mention that a decay of our vacuum state via bubble nucleation could wipe out life on Earth, I’ll make sure there aren’t any creationists in the audience. I can’t imagine explaining that to the Department of Homeland Security.

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Either/Orchestra

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I’ve been a fan of the Either/Orchestra for over ten years now, since first hearing them on a public radio station in Boston. This Cambridge-based jazz ensemble, a “little big band” in the tradition of the Mingus band, is one of my absolute favorite musical groups. (Whether the name is indebted to Kierkegaard is somewhat ambiguous.) Unfortunately, I moved away from Massachusetts soon after discovering their music, so I haven’t had a chance to hear them live. Until, that is, this last Friday, when they played Chicago’s historic Green Mill. Suffice to say, a decade’s worth of expectations were not disappointed.

Either/Orchestra

The singular genius of the E/O is to simultaneously stimulate the pleasure centers of the right brain and left brain in equal measure. They are a ten-piece group at the moment — bass, piano, drums, six horns, and congas. Past configurations have varied, with personnel changing fairly frequently; distinguished alumni include John Medeski. But the spirit of the group has remained constant: sophisticated arrangements of eclectic music, played with an enthusiastic fervor that carries you along for the ride. Each of the band members is an accomplished soloist, and they work together in intricate configurations that certainly appeal to the intellectual side of one’s musical appreciation — but at no time could they be accused of being stuffy. Each song is generally constructed around a catchy hook, whose possibilities are thoroughly explored rhythmically and harmonically. These guys rock, groove, and swing.

The E/O’s repertoire has always been wide-ranging, from original tunes to classics by Monk and Ellington and Miles to quirky covers of pop songs from the Beatles and Dylan to — wait for it — King Crimson. In the last few years they have been heavily influenced by Ethiopian music, culminating in a recent live album from Addis Ababa. One of the songs performed Friday night will give you an idea of a “typical” E/O tune. It was a suite in two parts, both of which were influenced by the Azmari music of Ethiopia. The first movement originated when saxophonist/leader Russ Gershon became intrigued by the massinko, a kind of one-string violin played in Ethiopian clubs. He composed a Western-style string quartet (“of all things”) inspired by this music, with the playful idea of getting classical musicians with incredibly expensive instruments to try their best to sound like cheap one-string violins you might hear in Addis Ababa. He later arranged the quartet for ten-piece jazz ensemble (don’t ask me how you do that), to form the first movement. The second movement came from bass player Rick McLaughlin, who had taken Thelonious Monk’s classic Well You Needn’t and arranged it with a Azmari-style rhythm. And voila — a suite that only the Either/Orchestra could possibly come up with, or for that matter perform. And it was beautiful.

Besides getting the chance to hear the band play live, I finally had the opportunity to meet Russ Gershon, the founder of the group, in person. A few years ago I sent an email to their record label, asking to be put on the mailing list, and was pleasantly suprised to receive a personal reply from Russ himself. In my response I mentioned that he should let me know if he had any questions about cosmology; this led to a few back-and-forth emails, along these lines:

Date: Mon, 10 Sep 2001 13:00:25 -0700
To: Sean Carroll
From: Russ Gershon
Subject: Re:

So the dark matter is not atoms, protons, quarks – it’s something
else? That’s kind of alarming, what with it being 96% of the whole
thing!

Russ
—
Russ Gershon
Accurate Records
288 Norfolk St.
Cambridge MA 02139 USA

Well, yeah, it is kind of alarming, I have to admit. As you might guess from the date, our conversation was derailed by events. Still, jazz musicians with an interest in cosmology should be rewarded, don’t you think? Maybe someday we will get a Dark Energy Suite. So go buy the records already. My first discovery was The Calculus of Pleasure, so I have a soft spot for that one, but they’re all good.

I arrived a bit early to the show to grab a good seat, since the Green Mill is always crowded. Naturally I grabbed some napkins and started writing equations, as one is wont to do — six cocktail napkins were sacrificed, but for a good cause, as I figured out something important about auxilliary scalar fields. The bartender, Jill, noticed my scribblings and asked me what they were about. As it turns out, she is currently taking a class on differential equations, working toward her Master’s degree to someday be a high-school math teacher. And she gave me a free glass of wine to demonstrate solidarity between we equation-oriented types. The guys sitting next to me also noticed, and between sets I ended up explaining dark energy and the accelerating universe to a bunch of jazz fans. See, another good reason to go to grad school in physics — it opens doors in the most unlikely venues.

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Particle physics marches on

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Physicists (like us) are, with good reason, eagerly anticipating results from the Large Hadron Collider at CERN, scheduled to turn on next year. The LHC will collide protons at much higher energies than ever before, giving us direct access to a regime that has been hidden from us up to now. But until then, a whole host of smaller experiments are interrogating particle physics from a variety of different angles, using clever techniques to get indirect information about new physics. Just a quick rundown of some recent results:

  1. Yesterday the MINOS experiment at Fermilab (Main Injector Neutrino Oscillation Search) released their first results. (More from Andrew Jaffe.) This is one of those fun experiments that shoots neutrinos from a particle accelerator onto an underground journey, to be detected in a facility hundreds of miles away — in this case, the Soudan mine in Minnesota. They confirm the existence of neutrino oscillations, with a difference in mass between the two neutrino states of Δm2 = 0.0031 eV2. The neutrinos left Fermilab as muon neutrinos, and oscillated into either electron or tau neutrinos, or something more exotic. MINOS can be thought of as a follow-up to the similar K2K experiment in Japan, with a longer baseline and more neutrinos.
  2. The previous week, the D0 experiment at Fermilab’s Tevatron (the main proton-antiproton collider) released new results on the oscillations of a different kind of particle, the Bs meson (a composite of a strange quark and a bottom antiquark), as reported in this paper. For better or for worse, the results are splendidly consistent with the predictions of the minimal Standard Model. These B-mixing experiments are very sensitive to higher-order contributions from new physics at high energies, such as supersymmetry. D0 is telling us something we have heard elsewhere: that susy could already have easily been detected if it is there at the electroweak scale, but it hasn’t been seen yet. Either it’s cleverly hiding, or there is no susy at the weak scale — which would come as a surprise (a disappointing one) to many people.
  3. Finally, a little-noticed experiment in Italy has been looking for axion-like particles — and claims to have seen evidence for them! (See also Doug Natelson and Chad Orzel.) The usual (although still hypothetical) axion is a light spin-0 particle that helps explain why CP violation is not observed in the strong interactions. (There is a free parameter governing strong CP violation, that should be of order unity, and is experimentally constrained to be less than 10-10.) The axion is a “pseudoscalar” (changes sign under parity), and couples to electromagnetism in a particular way, so that photons can convert into axions in a strong magnetic field. (Another mixing experiment!) The axion relevant to the strong CP problem has certain definite properties, but other similar spin-0 particles may exist that couple to photons in similar ways, and these are generically referred to as axion-like. Zavattini et al. have fired a laser through a magnetic field and noticed that the polarization has rotated, which can be explained by an axion-like particle with a mass around 10-3eV, and a coupling of around (4×105eV)-1. My expert friends tell me that the experimentalists are very good, and the result deserves to be taken seriously. Trouble is, the particle you need to invoke is in strong conflict with bounds from astrophysics — these particles can be produced in stars, leading to various sorts of unusual behavior that aren’t observed. Now maybe the astrophysical bound can somehow be avoided; in fact, I’m sure some clever theorists are working on it already. But it would also be nice to get independent confirmation of the experimental effect.

Particle physics marches on Read More »

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Unsolicited advice, Part Deux: Choosing a grad school

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Our first installment of unsolicited advice concerned the difficult question of how to get into graduate school; this one presumes that one has successfully leapt the hurdles of GRE’s and ornery admissions committees, and is faced with the perilous decision of which offer to accept. (If one has either one or zero offers, presumably the decision-making process is somewhat easier.) We will not, at the moment, be addressing whether you should be going to graduate school in the first place, or how to succeed once you get there. [Update: see also How to Be a Good Graduate Student.]

This is a much more difficult task than the first installment. Not that it’s more difficult to decide where to go than to get into grad school in the first place; just that it’s much more difficult to give sensible advice about how to do it. When it comes to getting into grad schools, everyone agrees on the basic notions: good grades, test scores, letters, research experience. Choosing where to go, in contrast, is a highly personal decision, and what works for one person might be utterly irrelevant to someone else. Rather than being overly prescriptive, then, I thought it might be useful just to chat about some of the issues that come up. Ultimately, you’ll have to decide for yourself how to weigh the various factors.

  • Why do you want to go to grad school in the first place? Sure, maybe you should have already given some thought to this question — but now is the time to get serious. Is your goal to become a professor or other professional researcher (which is typically assumed)? Or is it just to get a Ph.D., and then see what happens? Or is it simply to learn some science?

    As a general principle, the purpose of grad school is very different from that of your undergraduate college education. At least in the U.S., college serves multiple purposes: training in some concentration, to be sure, but also a broadly-based liberal education, as well as more general exposure to critical thinking, and crucially important social and personal aspects. Grad school is much more focused: it serves to train you how to be a working research scientist (or whatever, although I’ll be speaking as if it is science you’ll be studying, as that’s what I know best). In college it’s good to be a broad person and cast your net widely in the oceans of learning and experience. In grad school, however, there is a lot to be said for focusing as much as you can on the specific discipline in which you are specializing. Not that you should stop having broad interests, but it might make sense to sacrifice some of them temporarily to the goal of becoming an expert researcher.

    The reason for this is that, like it or not, you are entering a competition. Not necessarily grad school itself (where grading and suchlike are notoriously relaxed, although there may be competition for advisors and fellowships and such), but the ultimate job market. Most people who go to grad school want to get jobs as scientists, probably in academia. There are far fewer such jobs than there are grad students, so most people who get a Ph.D. will ultimately not succeed in becoming professors. And the other people who want those jobs are also very smart and dedicated. So, if you are serious about choosing this as your life’s path, it makes sense to really devote yourself to your craft during your grad school years, and give it your best shot. I personally think that the rigorous training provided by a Ph.D. is extremely useful and rewarding even if you don’t become a professor, but you should certainly enter the fray with open eyes.

    If becoming a professor is what you want to do, you should choose your school accordingly. At the same time, I’m a firm believer that your life doesn’t completely end just because you’re in grad school, nor that the process itself should be unpleasant. It should be extremely challenging, taking you to the limits of what you are capable of doing — but the days you spend in school are also days that you are alive, and you shouldn’t completely shut yourself away. That’s the difficult balance to strike. (Told you this wouldn’t be very helpful.)

    • …

    Unsolicited advice, Part Deux: Choosing a grad schoolRead More »

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The Foundational Questions Institute (Anthony Aguirre)

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The Foundational Questions Institute (FQXi) was mentioned in the comments of Mark’s post about John Barrow’s Templeton Prize. This is a new organization that is devoted to supporting innovative ideas at the frontiers of physics and cosmology. It is led by Max Tegmark of MIT and Anthony Aguirre of UCSC, two leading young cosmologists, backed up by an extremely prestigious Scientific Advisory Panel.

Sounds like a great idea, but some of us have questions, primarily concerning the source of funding for FQXi — currently the John Templeton Foundation. The Templeton Foundation is devoted to bringing together science and religion, which may or may not be your cup of tea. I’m already on the record as turning down money from them (see also this Business Week article) — and believe me, turning down money is not part of my usual repertoire. But Max and Anthony and the rest are good scientists, so we here at Cosmic Variance thought it would be good to hear the story behind FQXi in their own words. We invited Anthony to contribute a guest post about the goals and procedures of the new institute, and he was kind enough to agree. Feel free to ask questions and be politely skeptical (or for that matter enthusiastically supportive), and we can all learn more about what’s going on.

———-

I (Anthony Aguirre) have been invited by Sean to write a guest blog entry discussing an exciting new project that Max Tegmark and I have been leading: Foundational Questions in Physics and Cosmology (“FQX”). This program was publicly announced in October, and the Foundational Questions Institute (FQXi) was formally launched as a legal entity in February, as was its first call for proposals. There is a plethora of information on FQXi at www.fqxi.org, but the kind invitation by Cosmic Variance provides a good opportunity to outline informally what FQXi is, why we think it is important, to address some reservations voiced in this forum, and to generate some discussion in the physics and cosmology community.

What is FQXi all about? Its stated mission is “To catalyze, support, and disseminate research on questions at the foundations of physics and cosmology, particularly new frontiers and innovative ideas integral to a deep understanding of reality, but unlikely to be supported by conventional funding sources.” Less formally, the aim of FQXi is to allow researchers in physics, cosmology, and related fields who like to think about and do real research about really big, deep, foundational or even “ultimate” questions, to actually do so — when otherwise they could not. We boiled this type of research down into two defining terms: the research should be foundational (with potentially significant and broad implications for our understanding of the deep or “ultimate” nature of reality) and it should be unconventional (consisting of rigorous research which, because of its speculative, non-mainstream, or high-risk nature, would otherwise go unperformed due to lack of funding.) The particular types of research FQXi will support are detailed in the FQXi Charter and in the first call for proposals, which also features a handy (but by no means whatsoever comprehensive) list of example projects, and their likelihood of being suitable for FQXi funding. In addition to straightforward grants, FQXi will run various other programs — “mini”-grants, conferences, essay contests, a web forum, etc. — focused on the same sort of science.

Why is FQXi important? There are a number of foundational questions that are of deep interest to humanity at large — and are the (often hidden) passion of and inspiration for researchers — but which various financial and “social” pressures make it very difficult for researchers to actually pursue. National funding sources, for example, tend to shy aware from research that is high-risk/high- reward, or speculative, or very fundamental, or unconventional, or “too philosophical”, and instead support research using fairly proven methods with a high probability of advancing science along known routes. There is nothing wrong with this, and it creates a large amount of excellent science. But it leaves some really interesting questions on the sidelines. We go on at length about this in the FQXi Charter — but the researchers FQXi aims to support will know all too well what the problems are. Our goal is to fund the research into foundational questions in physics and cosmology that would otherwise go unfunded.

More money to support really exciting, interesting, and, yes, fun research seems like an unreservedly good thing. Nonetheless, a couple of significant reservations have been voiced to us, both by writers on this blog and others. These are:

1) Some feel research that is very speculative or “borderline philosophical” is just a waste of time and resources — if the research was worth doing, conventional agencies would fund it. We won’t accept this criticism from anyone who has worked on either time machines or the arrow of time (so Sean is out) :), but from others we acknowledge that they feel this way, we respectfully disagree, and we think that many of the giants of 20th century physics (Einstein, Bohr, Schroedinger, Pauli, etc.) would also disagree. Ultimately, those who feel this way are free not to participate in FQXi. We also note that we think it would by great if some private donors were also to support more conventional research in a way that complemented or supplemented federal funding (as they do in, e.g., the Sloan and Packard fellowships); that, however, is not the case here: the donation supporting FQXi is expressely for the purpose of supporting foundational research. Which brings us to…

2) The second major reservation concerns FQXi’s current sole source of funding: the John Templeton Foundation (JTF), an organization that espouses and supports the “constructive dialogue between science and religion.” It is understandable that some people may be suspicious of JTF’s involvement with FQXi, and in today’s political climate in which Intelligent Design and other movements seek to undermine science in order to promote a religious and political agenda, such suspicion is especially understandable. But it is as important as ever to also be open-minded and objective. The salient points, we think, regarding JTF and FQXi are:

  • FQXi is a non-profit scientific grant-awarding organization fully independent from its donors (we are actively seeking other donors beyond JTF, see below) and operated in accordance with its Charter. Proposal funding is determined via a standard and rigorous peer-review process, and an expert panel appointed by FQXi. The structure of FQXi is such that donors — including JTF — have no control or influence over individual proposal selection or renewal. Specifically, scientific decisions are made (as enshrined in the FQXi corporate Bylaws) by the Scientific Directorate (Max & I), on the basis of advice from review panels and the Scientific Advisory Panel. The only condition of the JTF grant to FQXi is that FQXi’s grantmaking be consistent with the FQXi Charter, which, as stated previously, can be viewed in its entirity at fqxi.org.
  • JTF’s stated interest in FQXi is captured in the FQXi Charter: the questions being tackled by researchers funded by FQXi intimately connect with and inform not just scientific fields, but also philosophy, theology and religious belief systems. Answers to these questions will have profound intellectual, practical, and spiritual implications for anyone with deep curiosity about the world’s true nature.
  • While FQXi’s funding is currently all from JTF, we have been strongly encouraged by JTF to seek (and are actively working on finding) additional donors; furthermore, there is no guarantee of JTF funding beyond the first four years — though we certainly hope FQXi will go on long past the initial four-year phase.
  • As for JTF benefiting “by association” with FQXi and the great research we hope that it will support, well, we feel that JTF has been extremely generous not just in giving a large sum of money to science, without strings attached, and with a great deal of support through the complex process of setting up FQXi as an independent institute of just the sort that Max & I wanted. If all this reflects well on JTF, I would submit that they deserve it.

We’ve tried hard to make FQXi’s operation and goals as transparent as possible, so those in the community can make informed decisions on whether they would like to participate in what we are hoping to do. We are very excited by the proposals that are coming in so far, and invite interested scientists to take a look at the call for proposals before it is too late (April 2). For those who are not actively researching foundational questions, we hope to have a very active public discussion and outreach program for both scientists and the interested public; we invite you to periodically check the FQXi website.

Thank you for this opportunity to discuss FQXi at Cosmic Variance.

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Crooked Timber Mooney Seminar

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Crooked Timber is having another of their excellent seminars, where several of the contributors gang up and discuss the work of someone else, who they often persuade to contribute. In this case they are discussing The Republican War on Science by Chris Mooney — well worth checking out. (Although PZ does yelp, with justification, about the inclusion of Steve Fuller. I’m sure that there are respectable pro-science Republicans who could have been brought in to critique the book.)

I never did a proper review of TRWoS myself, as I’ve been reading it piecemeal rather than properly from start to finish. Frankly, it’s too depressing to read too much at once. Like Ted Barlow, I approached the book gingerly, because it certainly is polemical and tells liberals like me what they want to hear. But ultimately I don’t really want to hear it — even if I would prefer Democrats in power rather than Republicans, I still don’t want to think that the current administration is so craven and dishonest as to blatantly distort the scientific process for political ends. But they are, and it’s important to keep our eyes open about it and resist politicization wherever it pops up. Chris’s book is an invaluable contribution to that project.

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Everything I know about the universe I did not learn from newspaper headlines

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The new WMAP results have told us a lot about the universe. The basic findings are:

  • The LambdaCDM model — a universe comprised of about 4% ordinary matter, 22% dark matter, and 74% dark energy — passes yet another test. The data fit quite well, and we have some new constraints on the cosmological parameters.
  • There is some evidence that primordial perturbations, the small ripples in density that later grew into stars and galaxies, did not have precisely the same amplitude on all scales. More quantitatively, the scalar spectral index n was measured to be 0.951 +0.015/-0.019 (updated — see comment below), whereas purely scale-free behavior would be n=1. It’s not as statistically significant as we would like, but it’s something.
  • Reionization, the process in which electrons were ripped from ambient hydrogen atoms when the first stars turned on, happened a little bit later than the first-year WMAP data seemed to indicate. This is an important input to our understanding of the “dark ages” between the early universe and the bright galaxies we see today.

All of this is very exciting to professional cosmologists. But consider the perspective of a newspaper that wants to convey that excitement to a popular audience. The data on LambdaCDM are important, but verifying that a known model is still consistent might not seem like earth-shattering news. The information about reionization is new, but early stars don’t quite have the origin-of-the-universe kind of implications that really seem exciting to the reader on the street. But, intriguingly, the slight scale dependence of the density perturbations fits very well with the predictions of the inflationary universe scenario. In this story, the tiny ripples in the primordial universe have their origin in quantum-mechanical fluctuations during the period when the universe is “inflating” (expanding quasi-exponentially at ultra-high energies). Since the expansion rate during inflation does gradually change with time, the amout of such fluctuations gradually evolves from scale to scale. Inflation traces back to the very earliest times about which we can sensibly speak (and long before we have any reliable data), so that is definitely something that could get the juices flowing.

So a lot of stories focused on the support for inflation as the centerpiece of the WMAP narrative. Which is fine, as far as it goes, but needs to be treated with some caveats. First, of course, even in the most generous reading, the purported detection of scale dependence was only at a level of about 3.3 standard deviations, which is not a reliable discovery by most standards in physics. (In particle-physics lingo, it’s “evidence for,” not “discovery of,” which would require 5 standard deviations.) More importantly, even if there had been incontrovertible evidence for scale dependence, that would by no means prove that inflation was right beyond reasonable doubt; it fits well into the inflation story, but certainly doesn’t preclude the possibility of other stories. And finally, it should go without saying that the evidence being discussed is somewhat indirect; it’s not like we’re looking directly at what the universe was doing 10-30 seconds after the Big Bang. (The cosmic microwave background is a snapshot of the universe about 380,000 years after the Big Bang, quite a while later.)

But those subtleties are hard to get across in a few words, and the resulting stories in the press showed evidence of the struggle between conveying the (undeniable) excitement and getting the story precisely correct. Indeed, the tension was evident right in the press release from Goddard Space Flight Center. There’s principal investigator Chuck Bennett, choosing his words with care:

WMAP polarization data allow scientists to discriminate between competing models of inflation for the first time. This is a milestone in cosmology. “We can now distinguish between different versions of what happened within the first trillionth of a second of the universe,” said WMAP Principal Investigator Charles Bennett of the Johns Hopkins University in Baltimore. “The longer WMAP observes, the more it reveals about how our universe grew from microscopic quantum fluctuations to the vast expanses of stars and galaxies we see today.”

Actually, it’s not the first data that allow us to discriminate between different models, although it is some of the most precise data to date. But the idea of “distinguishing between different versions of what happened” is a very good one, and a nice way to tell the story. Sadly, in the next sentence the possibility that inflation is not right seems to have been abandoned, as he speaks with apparent confidence about the origin of galaxies in quantum fluctuations.

This urge to overstate the case is evident elsewhere, as well. In the New York Times we read:

The reason, Dr. Spergel explained, is that the force driving inflation is falling as it proceeds. The smaller bumps would be produced later and so a little less forcefully than the bigger ones.

That, in fact, is exactly what the Wilkinson probe has measured. Dr. Spergel said, “It’s very consistent with simplest inflation models, just what inflation models say we should see.”

Michael Turner, a cosmologist at the University of Chicago, called the results, “the first smoking gun evidence for inflation.”

Here, David Spergel is being very careful to stress that the data are consistent with simple models, which is quite different from saying that it verifies those models are correct. Michael Turner is much less cautious, as “smoking gun evidence” would lead you to believe that the case was closed, which it definitely is not. It’s just very difficult to simultaneously be a cautious scientist and convey an accurate sense of the very real excitement that cosmologists have when examining these data.

If the quotes are ambiguous, the headlines are worse. Let’s face it, “Satellite Gathers Useful Data” wouldn’t sell a lot of newspapers. So many places went for the idea that we had actually observed the extremely early universe, rather than made some observations that constrained theories of the extremely early universe. So we get:

Really, WMAP did not see the origin of the cosmos, any more than seeing an infant is the same as seeing someone being born. But it’s not hard to figure out where they got the idea — the NASA press release is titled “NASA Satellite Glimpses Universe’s First Trillionth of a Second.”

Interestingly, some of the headlines were misleading in the opposite sense, by being less exciting than the truth:

We already have plenty of evidence for the Big Bang! Some more of that would be anticlimactic indeed. And, needless to say, the fact that the universe is expanding is not exactly hot news. I know what they’re all trying to say, but can’t but feeling that if people had a better general idea about what we already know about cosmology, they wouldn’t be tempted to write headlines like this.

I have great sympathy for everyone involved in the process of bringing a story like this to the public — from the scientists working on the project, to the outside scientists who help interpret the results for reporters, to the journalists themselves, to the headline-writers with the unenviable task of squeezing some subtle thoughts into just a few words. But the readers need to take some of these overly enthusiastic declarations with a grain of salt. If you want the real scoop, you have to go beyond the newspaper headlines. For example, by reading blogs.

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Lunar laser ranging

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Greetings from Toronto, where I’m visiting UofT to talk about dark energy, the arrow of time, and other obsessions of mine. Which has prevented me from as yet writing the long-awaited second installment of “Unsolicited Advice,” the one that will tell you how to choose a graduate school. It is that time of year, after all.

Lunar Radar Ranging In the meantime, check out this nice post at Anthonares on Lunar laser ranging. The Apollo astronauts, during missions 11, 14, and 15, were sufficiently foresighted to bring along reflecting corner mirrors and leave them behind on the Moon’s surface. Why would they do that? So that, from down here on Earth, we can shoot lasers at the lunar surface and time how long it takes for them to come back. Using this data we can map the Moon’s orbit to ridiculous precision; right now we know where the Moon is to better than a centimeter. This experiment, called Lunar laser ranging, teaches us a lot about the Moon, but it also teaches us about gravity. The fact that we can pinpoint the location of the Earth’s biggest satellite and keep track of it over the course of years provides us with a uniquely precise test of Einstein’s general relativity.

You might think that general relativity is already pretty well tested, and it is, but clever folks are constantly inventing alternatives that haven’t yet been ruled out. One example is DGP gravity, invented by Gia Dvali, Gregory Gabadadze, and Massimo Porrati. This is a model in which the observable particles of the Standard Model are confined to a brane embedded in an infinitely large extra dimension of space. Unlike usual models with compact extra dimensions, the extra dimension of the DGP model is hidden because gravity is much stronger in the bulk; hence, the gravitational lines of force from an object on the brane like to stay on the brane for a while before eventually leaking out into the bulk.

The good news about the DGP model is that it makes the universe accelerate, even without dark energy! This is one of the things that I talked about at my colloquium yesterday, and I hope to post about in more detail some day. The better news is that it is potentially testable using Lunar laser ranging! The claim is that the DGP model predicts a tiny perturbation of the Moon’s orbit, too small to have yet been detected, but large enough to be within our reach if we improve the precision of existing laser ranging experiments. People are hot on the trail of doing just that, so we may hear results before too long.

Not to get too giddy, the bad news about DGP is that it may be a non-starter on purely theoretical grounds. There are claims that the model has ghosts (negative-energy particles), and also that it can’t be derived from any sensible high-energy theory (see Jacques’s post). I haven’t examined either of these issues very closely, although I hope to dig into them soon. Maybe if I could quite traveling and sit down and read some papers.

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