So you don’t enter the new year completely unprepared, here are my most secure predictions for 2012. Unlike other prognostication websites, these predictions are based on Science!

1. Freely-falling objects will accelerate toward the ground at an approximately constant rate, up to corrections due to air resistance.

2. Of all the Radium-226 nuclei on the Earth today, 0.04% will decay by the end of the year.

3. A line drawn between any planet (or even dwarf planet) and the Sun will sweep out equal areas in equal times.

4. Hurricanes in the Northern hemisphere will rotate counterclockwise as seen from above.

5. The pressure of a gas squeezed in a piston will rise inversely with the change in volume.

6. Electric charges in motion will give rise to magnetic fields.

7. The energy of an object at rest whose mass decreases will also decrease, by the change in mass times the speed of light squared.

8. The content of the world’s genomes will gradually evolve in ways determined by fitness in a given environment, sexual selection, and random chance.

9. The entropy of closed systems will increase.

10. People will do many stupid things, and some surprisingly smart ones.

Happy New Year, everyone.

‘Tis the season when bloggers, playing out the string between Xmas and New Year’s, fill the void with greatest-hits lists from the year just passed. But a question inevitably arises: how does one decide which posts to include? There are many different criteria, and preferring one to another might lead to very different lists. This is what’s known as the measure problem in blogospheric cosmology.

This year I’ve decided to confront the problem pluralistically. Thus: here we have five different Top Five lists, chosen according to completely different criteria. Let us know if your favorite Cosmic Variance post of the year somehow managed to not be on any of the lists.

First, the most crude and common measure, the posts with the most page views this year.

• Ten Things Everyone Should Know About Time
• I’m Too Smart to Understand Human Beings
• Faster-Than-Light Neutrinos
• Dark Energy FAQ
• Physics and the Immortality of the Soul

Next up, an equally quantitative and misleading measure of popularity: the top five posts by number of comments. Read the rest of this entry »

Merry Christmas, or whatever holiday you choose to celebrate, everybody. And if you don’t choose to celebrate for any particular reason, feel free to celebrate for no reason at all.

Here’s a legitimately touching Xmas song, Tim Minchin’s White Wine in the Sun (indirectly via Balloon Juice). As an Australian, he has a warmer image of the season than we Northerners. This isn’t the one that got censored from British TV, which is more amusing than heartwarming, but also worth a listen.

I’ve been meaning for a while to do a post on “Books You Should Read,” but I put it off until the last minute (of 2011), so now it’s a shopping list. I’m sticking to books that came out in the last year or two, on subjects vaguely related to what we often talk about here on the blog, since I know people get grumpy when we deviate from the prescribed topics of conversation. And I’m trying to highlight books that aren’t already bestsellers, but deserve to be; I’m assuming you don’t need me to tell you about recent books by Lisa Randall, Steven Pinker, Richard Dawkins, or Brian Greene. (Or me, or my lovely wife.) Note for late shoppers: Amazon will get you all of these in plenty of time for Christmas. And pre-emptive apologies to anyone whose book I didn’t include — probably because I haven’t had a chance to read it yet.

	How I Killed Pluto and Why It Had It Coming, by Mike Brown. My Caltech colleague Mike Brown is the person most responsible for getting Pluto demoted from planetary status, by discovering Eris and other Kuiper-belt objects. For a long time I thought it was silly to go to such trouble to re-classify a celestical body, but this book convinced me otherwise. Part of the reason is that Brown (or plutokiller on the Twitter) is an enormously engaging writer; few quasi-autographical science books have managed to mix the personal side with the science so effectively.
	Science Ink: Tattoos of the Science Obsessed, by Carl Zimmer. My sleeper pick for book of the year, Carl Zimmer’s compendium of science tattoos is a real delight. I’m not especially fascinated by tattoos or their own sake, but the beautiful photography here is matched by Carl’s fascinating descriptions of the science behind each one. This would make a great gift for just about anyone.
	The Bodhisattva’s Brain: Buddhism Naturalized, by Owen Flanagan. Western atheist/naturalists are occasionally criticized because we speak disapprovingly about traditional Western religions, while not paying attention to Buddhism and other Eastern philosophies. Here’s the book that redresses the balance, but in a very sympathetic mode. Flanagan is a thoroughgoing naturalist, but appreciates some of the insights into human nature that Buddhism has to offer. In this book he offers a careful philosophical examination of Buddhist beliefs and practices, in the light of modern scientific understanding of humanity and our universe.
	The Infinity Puzzle: Quantum Field Theory and the Hunt for an Orderly Universe, by Frank Close. “Quantum Field Theory” is the scientific concept that, in my opinion, features the largest ratio of “people should be familiar with” to “people are familiar with.” Frank Close looks at the historical development of the subject, one of the great intellectual triumphs of the 20th century. I could nitpick (Ken Wilson isn’t even mentioned once?), but this book is full of great insights.

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The holiday movie season brings us The Girl With the Dragon Tattoo, David Fincher’s English-language version of Stieg Larsson’s bestseller, which has already been made into a Swedish movie. Ordinarily you might not want to make a new movie when one based on the same book came out just two years ago, even if it was in a different language; but Larsson’s Millenium Trilogy is more than popular enough to carry the load, with over 27 million books sold worldwide.

That popularity really bugs some people. Sales figures notwithstanding, Larsson’s books fall pretty dramatically short on several conventional metrics of literary quality, such as “elegance of writing” and “plausibility of plot.” Early in the first novel, before we really know what’s going on or have been properly introduced to most of the characters, we are treated to a scene that consists of one character telling another about a long series of complicated and shady European business deals, complete with obscure acronyms and names that will never be mentioned again. This keeps up for what seems like pages. And it’s just a hint of the various stylistic crimes Larsson will gleefully commit throughout the series. He loves piling on meaningless details, especially about what his characters are eating and the clothes they are wearing. The prose is clunky and often wearying. The series effectively evokes the brooding coldness of Scandinavian winters, but that’s not always a good thing.

And yet — the books are impossible to put down, as approximately 9 million readers will testify. (I haven’t seen the American movie, although I did see the Swedish one, which wasn’t anywhere near as gripping as the original novel.) So we have a fairly common occurrence in publishing: books that are fantastically popular, but nevertheless are not very “good” by many agreed-upon criteria. In very different ways, think of Dan Brown, JK Rowling, or Stephenie Meyer.

Faced with such a puzzling phenomenon, one can go two ways. Read the rest of this entry »

For any remaining mind/body dualists out there: neuroscientist Patrick Haggard builds magnetic coils that he can hold close to your head, and use them to control your body via signals to your brain. “Transcranial magnetic stimulation” would be the technical term. (He thinks it means you don’t have free will, because he’s a neuroscientist and not a philosopher.)

The machinery can’t force Prof Haggard to do anything really complicated – “You can’t make me sign my name,” he says, almost ruefully – but at one point, Christina is able to waggle his index finger slightly, like a schoolmaster. It’s very fine control, a part of the brain specifically in command of a part of the body. “There’s quite a detailed map of the brain’s wiring to the body that you can build,” he tells me.

We sometimes say “the Large Hadron Collider is the most complex machine ever built,” but I’m not sure how it would directly compare to a human being. All part of the great bootstrap up to greater complexity, which will continue for a while until it all inevitably deteriorates into empty space.

Perhaps best known in the field of particle physics as the co-author of the Higgs Hunter’s Guide, Jack Gunion has been in the theoretical trenches of the search for the Higgs boson for several decades now. He is a senior professor and leader of the theoretical particle physics group at UC Davis, where he has been a member of the faculty for over 25 years. Here is a guest post from him on today’s big news from CERN.

Tuesday December 13 has been a very exciting day for particle physics. The ATLAS and CMS experiments at the Large Hadron Collider (LHC) announced today that they are both seeing hints of a Higgs boson with properties that are close to those expected for the Standard Model (SM) Higgs boson as originally proposed by Peter Higgs and others. While the “significance” of the signals has not yet reached “discovery level” (5 sigma in technical language) the two experiments both see signals that exceed 2 sigma so that there is less than a 5% chance that they are simply statistical fluctuations. Most persuasively, the signals in the channels with excellent mass determination (the photon-photon final decay state and the 4-lepton final state) are all consistent with a a Higgs boson mass of around 125 GeV IN BOTH EXPERIMENTS. This coincidence in mass between two totally independent experiments (as well as independent final states) is persuasive evidence that the photon-photon and 4-lepton excesses seen near 125 GeV are not mere statistical fluctuations.

Observation of the Higgs with approximately the SM-like rate suggests that to first approximation the Higgs is being produced as expected in the SM and that it also decays as predicted in the SM. Many theorists, including myself, have suggested that a Higgs might be produced as in the SM but might have extra decays that would have decreased the photon-photon and 4-lepton decay frequencies to an unobservable level, making the Higgs boson much harder to detect at the LHC. The level of the observed excesses argues against such extra decays being very important. The photon-photon and 4-lepton detection modes were originally proposed and shown to be viable for a SM-like Higgs boson by myself and collaborators (in particular, Gordy Kane and Jose Wudka) way back in 1986-1987. It has taken a long time (25 years) for the technology and funding to reach the point where these detection modes could be examined. I often joked that I was personally responsible for forcing each of the LHC collaborations to spend the 30 million dollars or so needed to build a photon detector with the energy resolution required. Fortunately, it seems that the money was well-spent and the ATLAS and CMS detectors both found ways to build the needed detectors, a real triumph of international collaboration and technical expertise. Also key is the very successful operation of the LHC that has produced the enormously large number of collision events needed to dig out the Higgs signal from uninteresting ‘background’ events. Until this summer produced the first very weak signs of the Higgs, I was beginning to wonder if the Higgs would be discovered during my lifetime. Fortunately, simplicity (i.e. a very conventional SM-like Higgs boson) seems to have prevailed and ended my wait.

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The news from Geneva this morning is in. Essentials: what we’re seeing is pretty consistent with the existence of a Higgs boson around 123-126 GeV. The data aren’t nearly conclusive enough to say that it’s definitely there. But the LHC is purring along, and a year from now we’ll know a lot more.

It’s like rushing to the tree on Christmas morning, ripping open a giant box, and finding a small note that says “Santa is on his way! Hang in there!” The LHC is real and Santa is not, but you know what I mean.

Here are the technical write-ups from ATLAS and CMS. For stories and some live-blogs, check out Philip Gibbs, Matt Strassler, Aidan Randle-Conde, Ken Bloom, or Jester. Or if you just want the bottom line sigmas, Jim Rohlf provides them. ATLAS gives 3.6 sigma local significance, 2.3 sigma global significance; CMS gives 2.6 sigma local significance, 1.9 sigma global significance (although CMS points to about 124 GeV, while ATLAS points to about 126, which might be important). The difference between “local” and “global” is that the first asks “if I were only looking at this one point in parameter space, how surprising would the result be?”, while the latter asks “what is the chance I would find this kind of deviation somewhere in parameter space?” Nominally the global significance is obviously more relevant, although one could argue that we have good reasons to expect that the Higgs is actually lurking right there, so the local significance isn’t completely cheating.

Let’s put it this way: if we were testing a theory that everyone thought was wrong, rather than one that everyone thinks is right, nobody would take these results as strong indications that the idea was correct. We have a strong theoretical bias that the Higgs exists and is somewhere close to this mass range, so it’s completely reasonable to think that we are seeing hints (tantalizing ones!) that it’s there, but wait-and-see is still the right attitude.

Here are the simplest plots I could find. First the full analysis from ATLAS (zoomed in on the interesting region), via Philip Gibbs’s blog.:

Then from CMS, via Ken Bloom:

These plots are complicated because they’re trying to tell you two things at once. The black curve is the data, the green/yellow bands are the expected ranges of the data at 1 sigma and 2 sigma. If all you want to do is ask whether we can exclude the Higgs in a certain range, just check whether the black band is below the value 1. But if you want to say you have evidence for the Higgs, you need the black line to wander above the yellow band (or higher, if you want more than 2 sigma [and you do]). So ATLAS sees something at 126 GeV, CMS is at least consistent with 123-124 GeV (although it doesn’t see much at 126).

As Sarah Kavassalis puts it, the real message today is that the LHC is working great. 2012 will bring another year of data, hopefully at even higher luminosity (so many more total events). The Higgs has been around for 13.7 billion years, it will still be there tomorrow.

Tomorrow, Tuesday 13 December, there will be a couple of seminars at CERN presented by Fabiola Gianotti and Guido Tonelli, speaking respectively for the ATLAS and CMS collaborations at the LHC. They will be updating us on the current status of the search for the Higgs boson. The seminars will be webcast from CERN, and there should be a liveblog on Twitter that you can follow by searching for the #higgsliveblog hashtag (no Twitter account required). The seminars start at 14:00 Geneva time, so that’s 5:00 a.m. Pacific time if I do my calculations correctly. Of course there will be plenty of news coverage immediately thereafter, so don’t feel too bad if you sleep through it. Many places with LHC physicists (including Caltech) are also having their own local seminars. Should be exciting!

If you want to know why it’s exciting, after you’ve read John’s description of life in the trenches and Matt Strassler’s post about the multiple stages of hunting the Higgs and mine about why we need something like it, see even more recent posts by Matt, Jester, and Pauline Gagnon. Reader’s Digest version: not only are we being updated on the status of the search, there are believable rumors that the searches are actually seeing something — hints of a Higgs near 125 GeV, with better than 3-sigma significance from ATLAS and better than 2-sigma significance from CMS. But obviously rumors are no match for what actually happens.

All I’m here to tell you is: you should not expect to hear anyone announcing that we have discovered the Higgs boson. This will, at best, be a hint — “evidence for” something, not “discovery of” that thing. The collaborations realistically can’t claim to have actually discovered the Higgs, even if it’s there — they don’t have enough data. (CERN even issued a press release to drive home the point.) And in the real world, hints are sometimes misleading. That is: the experimenters will give us their absolute best judgment about what they are seeing, but at this stage of the game that judgment is necessarily extremely preliminary. If they say “we have 3.5-sigma evidence, which is quite suggestive,” do not think that they are just being coy and what they really mean is “oh, we know it’s there, we just have to follow the protocols.” The protocols are there for a reason! Mostly, that many 3-sigma findings eventually go away. This is one step on a journey, not the culmination of anything. (For Americans out there: it’s like a bill has been passed by the House, but not yet passed by the Senate, and certainly not signed by the President. Much can go wrong along the way.)

The journey of a thousand miles begins with a single step. It’s possible that tomorrow’s announcement means that we’re nearing the end of the journey, say at the mile-990 marker. But we can’t be sure, and there are no royal roads to particle physics. Patience! The excitement of not knowing for sure is what makes science one of the most compelling human stories.

For the past year, physicists at the LHC experiments CMS and ATLAS have been analyzing ever–increasing data samples from the huge machine. Rumors are now circulating about what the experiments might announce at next week’s presentations at CERN regarding the search for the Higgs boson. Next Tuesday there will be a joint seminar from the two experiments at CERN in which the latest results are shown. And though I cannot tell you everything that we will say next week (and nothing about the ATLAS results, which I have not seen), from the public statements made by the CERN Director General you already know that an unambiguous discovery is not yet in the offing.

But, following on Matt Strassler’s excellent post about the physics, I thought it might be interesting to tell you what it’s been like this past year getting to this stage in this search. As you probably know, each of the two big experiments has over 3000 physicists participating, from all over the world. Many, but by no means the majority, are resident at CERN; most are at their home institutions in Europe, North America, and Asia and elsewhere.

The main thing that allows us to collaborate on a global scale like this is video conferencing. We used a system called EVO, developed at Caltech, which allows us to schedule meetings and connect to them from a laptop or desktop computer, or even dial in by phone. Sometimes it’s clear that people are connected by phone from the oddest places: once I heard the clear sounds of someone participating in the meeting from a train ride in Italy, oftentimes you hear people speak while they are driving the (hopefully with a hands-free device), and often one hears the sounds of children in the background (including my own). The issue is that meetings can be at any time of day for different people in different continents. Fortunately the experiments have gravitated toward having meetings in the late afternoon, Europe time, which makes it early morning for people like me in California.

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