Of Particular Significance

This week and next, I’m very busy preparing and delivering a new class (four lectures, 1.5 hours each), for a non-technical audience, on the importance of and the discovery of the Higgs particle.  I’ll be giving it in Western Massachusetts (my old stomping grounds).  If it goes well I may try to give these lectures elsewhere (and please let me know if you know of an institution that might be interested to host them.)   Teaching a new class for a non-technical audience requires a lot of concentration, so I probably won’t get too much writing in over that period.

Still, as many of you requested, I do hope soon to follow up last week’s article (on how particle physicists talk about the strength of the different forces) with an article explaining how both particles and forces arise from fields — a topic I already addressed to some extent in this article, which you may find useful.

Now — a few words on the flap over the suggestion that math Ph.D. and finance expert Eric Weinstein, in his mid-40s, may be the new Albert Einstein.  I’ve kept my mouth shut about this because, simply, how can I comment usefully on something I know absolutely nothing about?  (Admittedly, the modern media, blogosphere and Twitter seem to encourage people to make such comments. Not On This Blog.) There’s no scientific paper for me to read.  There’s no technical scientific talk for me to listen to.  I know nothing about this person’s research.  All I know so far is hearsay.  That’s all almost anyone knows, except for a few of my colleagues at Oxford — trustworthy and experienced physicists, who sound quite skeptical, and certainly asked questions that Weinstein couldn’t answer... which doesn’t mean Weinstein is necessarily wrong, only that his theory clearly isn’t finished yet.  (However, I must admit my expert eye is worried that he didn’t have ready answers to such basic questions.)

What I do know is that the probability that Weinstein is the new Einstein is very low.  Why?  Because I do know a lot about how very smart people with very good ideas fail to be Einstein.  It’s not because they’re dumb or foolish. (more…)

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POSTED BY Matt Strassler

ON June 3, 2013

Particle physicists, cataloging the fundamental forces of nature, have named two of them the strong nuclear force and the weak nuclear force. [A force is simply any phenomenon that pushes or pulls on objects.] More generally they talk about strong and weak forces, speaking of electromagnetism as rather weak and gravity as extremely weak.  What do the words “strong” and “weak” mean here?  Don’t electric forces become strong at short distances? Isn’t gravity a pretty strong force, given that it makes it hard to lift a bar of gold?

Well, these words don’t mean what you think.  Yes, the electric force between two electrons becomes stronger (in absolute terms) as you bring them closer together; the force grows as one over the square of the distance between them.  Yet physicists, when speaking their own language to each other, will view this behavior as what is expected of a typical force, and so will say that “electromagnetism’s strength is unchanging with distance — and it is rather weak at all distances.

And the strength of gravity between the Earth and a bar of gold isn’t relevant either; physicists are interested in the strength of forces between individual elementary (or at least small) particles, not between large objects containing enormous numbers of particles.

Clearly there is a language difference here… as is often the case with words in English and words in Physics-ese.  It requires translation.  So I have now written an article explaining the language of “strong” and “weak” forces used by particle physicists, describing how it works, why it is useful, and what it teaches us about the known forces: gravity, electromagnetism, the strong nuclear force, the weak nuclear force, and the (still unobserved but surely present) Higgs force. (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 31, 2013

I’ve finished (more or less) a version of the promised article on IceCube — the giant neutrino experiment that may have made a major discovery, as announced last week, and that had an opportunity to make another a few weeks ago (though apparently nature didn’t provide).  The article is admittedly a bit rushed (darn computer trouble) and therefore a bit rough, and it also leaves out some more subtle points that may become important in the future — but I think it’s complete enough to help explain how IceCube made their most recent measurements.  As usual, please send comments and questions, and I’ll work on it further.

Here’s the link to the article.  You may also find it interesting to read more generally about how neutrinos are detected, and about the weird story of neutrino types, and how they can oscillate from one type to another as they travel.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 23, 2013

I was sent or came across a few interesting links that relate to things covered on this blog and/or of general scientific interest.

It was announced yesterday that the European Physical Society 2013 High Energy Physics Prize was awarded to the collaboration of experimental physicists that operate the ATLAS and CMS experiments that discovered a type of Higgs particle, with special mention to Michel Della Negra, Peter Jenni, and Tejinder Virdee, for their pioneering role in the development of ATLAS and CMS.  Jenni and Virdee are both at the LHCP conference in Barcelona, which I’m also attending, and it has been a great pleasure for all of us here to be able to congratulate them in person .

One thing that came up a couple of times regarding weather forecasting (for instance, in forecasting the path of Hurricane Sandy) is that the European weather forecasters are doing a much better job of predicting storms a week in advance than U.S. forecasters are.  And I was surprised to learn that one of the the main reasons is simple: U.S. forecasters have less computing power than their European counterparts, which sounds (and is) ridiculous.  The new director of the U.S. National Weather Service, Louis Uccellini, has been successful in his goal of improving this situation, as reported here[Thanks to two readers for pointing me to this article.]

One of the possible interpretations of the new class of high-energy neutrinos reported by IceCube (see yesterday’s post) is that they come from the slow decay of a small fraction of the universe’s dark matter particles, assuming those particles have a mass of a couple of million GeV/c². [That’s much heavier than the types of dark matter particles that most people are currently looking for, in searches that I discussed in a recent article.]  I didn’t immediately mention this possibility (which is rather obvious to an expert) because I wanted a couple of days to think about it before generating a stampede or press articles.  But, not surprisingly, people who were paying more attention to what IceCube has been up to had recently written a paper on this subject[Here’s an older, related paper, but at much lower energy; maybe there are other similar papers that I don’t know about?]  At the time these authors wrote this paper, only the two highest energy neutrinos — which have energies that, within the uncertainties of the measurements, might be equal (see Figure 2 of yesterday’s post) — were publicly known.  In their paper, they predicted that (just as any expert would guess) in addition to a spike of neutrinos, all at about 1.1 million GeV, one would also find a population of lower-energy neutrinos, similar to those new neutrinos that IceCube has just announced. So yes, among many possibilities, it appears that it is possible that the new neutrinos are from decaying dark matter.  If more data reveals that there really is a spike of neutrinos with energy around 1.1 million GeV, and the currently-observed gap between the million-GeV neutrinos and the lower-energy ones barely fills in at all, then this will be extremely strong evidence in favor of this idea… though it will be another few years before the evidence could become convincing.  Conversely, if IceCube observes any neutrinos near but significantly above 1.1 million GeV, that would show there isn’t really a spike, disfavoring this particular version of the idea.

Regarding yesterday’s post, it was pointed out to me that when I wrote “The only previous example of neutrinos being used in astrophysics occurred with the discovery of neutrinos from the relatively nearby supernova, visible with the naked eye, that occurred in 1987,” I should also have noted that neutrinos were and are used to understand the interior of the sun (and vice versa).  And you could even perhaps say that atmospheric neutrinos have been used to understand cosmic rays (and vice versa.)

In sad news, in the “all-good-things-must-come-to-an-end” category, the Kepler spacecraft, which has brought us an unprecedented slew of discoveries of planets orbiting other stars, may have reached the end of the line (see for example here), at least as far as its main goals.  It’s been known for some time that its ability to orient itself precisely was in increasing peril, and it appears that it has now been lost.  Though this has occurred earlier than hoped, Kepler survived longer than its core mission was scheduled to do, and its pioneering achievements, in convincing scientists that small rocky planets not unlike our own are very common, will remain in the history books forever.  Simultaneous congratulations and condolences to the Kepler team, and good luck in getting as much as possible out of a more limited Kepler.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 17, 2013

IceCube [here’s my own description of the experiment], the big high-energy neutrino experiment cleverly embedded into the ice at the South Pole, announced a very interesting result yesterday, following on an already interesting result from a few weeks ago, one that I failed to cover properly. They have seen the highest-energy neutrinos ever observed, ones that, unlike previously observed high-energy neutrinos, appear not to be generated by cosmic rays hitting the top of the atmosphere. Instead, they apparently come from new sources far out in space. And as such, it tentatively appears that they’ve opened up, as long anticipated, a new era in neutrino astronomy, in which high-energy neutrinos will be used to understand astrophysical phenomena!

[The only previous example of neutrinos being used in astrophysics occurred with the discovery of neutrinos from the relatively nearby supernova, visible with the naked eye, that occurred in 1987. But those neutrinos had energies millions of times smaller than the ones discussed here.  And there was hope that IceCube might see neutrinos specifically from gamma-ray bursts, including the one that occurred just two weeks ago; but that appears not to have happened.]

I don’t understand certain details well enough yet to give you a careful explanation — that will probably come next week — but here’s an early description (and expert readers are strongly encouraged to correct any errors.) (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 16, 2013

I’m still seeing articles in the news media (here’s one) that say that the majority of Americans think the recent sequester in the US federal budget isn’t affecting them. These articles implicitly suggest that maybe the sequester’s across-the-board cuts aren’t really doing any serious damage.

Well, talk to scientists, and to research universities and government laboratories, if you want to hear about damage.

I haven’t yet got the stomach to write about the gut-wrenching destruction I’m hearing about across my own field of particle physics — essential grants being cut by a quarter, a third, or altogether; researchers being forced to lay off long-standing scientific staff whose expertise, of international importance, is irreplaceable; the very best postdoctoral researchers considering leaving the field because hard-hit universities across the country won’t be hiring many faculty anytime soon… There’s so much happening simultaneously that I’m not sure how I can get my head around it all, much less convey it to you.

But meanwhile, I would like to point you to a strong and strongly-worded article by Eric Klemetti, a well-known blogger and professor who writes at WIRED about volcanoes.  Please read what he wrote, and consider passing it on to those you know.  Everyone needs to understand that the damage that’s being done now across the U.S. scientific landscape, following a period of neglect that extends back many years before the recession, will last a generation or more, if it’s not addressed.

These deep, broad and sudden cuts are a short-sighted way of saving money.  Not only do they waste a lot of money already spent, the long-term cost of the permanent loss of expertise, and of future science and technology, is likely to exceed what we’ll save.  It’s not a good approach to reducing a budget.  So tell your representatives in Congress, and anyone who will listen: Scientific research isn’t excess fat to be chopped off crudely with a cleaver; it’s fuel for the nation’s future, and it needs wiser management than it’s receiving.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 15, 2013

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