Of Particular Significance

Category: History of Science

I was busy with some personal issues over the past few weeks, so I hadn’t even really been following the rampant speculation about the Nobel Prize for this year. Apparently a lot of people (including some of my colleagues) thought that the July discovery, at the Large Hadron Collider [LHC] experiments ATLAS and CMS, of a new particle resembling the long-sought Higgs particle would generate a Nobel Prize in 2012 for Peter Higgs and for the other physicists who predicted the existence of such a particle.

Well, I never thought this notion was very plausible; I was confident it wouldn’t happen before 2013. And that is for several reasons.

The first and most important is that although the evidence that a new particle has been found is very strong, the evidence that it is a Higgs particle of some type (which I’ll describe below) is still only moderate. Personally, I’m convinced that the new particle is a Higgs particle, but that is based partly on the evidence from the data and partly on theoretical prejudice — on my knowledge of theoretical physics and of what the alternatives to the Higgs-particle interpretation of the data are. If I’m wrong, too bad for me, but no harm done. However, the Nobel Prize committee is making a permanent, irrevocable award for the history books, and the bar for evidence from the data alone should be very high. Now here’s the key point: by March 2013 at the latest, the data from all of 2012 will have been analyzed. The amount of data that will be available by then will be about three times as much as was available in July 2012 — enough to change the current moderate evidence to strong evidence, if in fact we’re dealing with a Higgs particle of some type. The Nobel Prize committee is surely well aware of this — that by next year the situation is likely to have qualitatively changed, with the evidence beyond controversy.  So it makes sense to wait until 2013, when the case is likely to be closed. (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON October 11, 2012

On Saturday I gave a lecture, newly minted, on how Einstein is perceived in the public eye, and on how the numerous misconceptions about Einstein affect the way many non-experts believe that science is actually carried out.  Doing the research for the lecture involved, among other things, going back to some original sources I’d never read or had only read a long time ago, looking a bit at Einstein’s notebook from the period around 1912 (online here), and re-reading large portions of a wonderful biography of Einstein that I’m afraid was written by a physicist for physicists — and consequently largely unreadable without technical background, but a must-read for anyone who has that background.  I refer here to Abram Pais’s famous biography: “Subtle is the Lord…”, whose title refers to Einstein’s famous quip: “Subtle is the Lord, but malicious He is not.”  (You can read about the origin of this quip in Pais’s book.)

I also enjoyed tracking down some videos online of various physical effects that Einstein explained, or that he predicted in advance.  These included videos (linked below) of (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 18, 2012

A reminder that the transit of Venus across the Sun will be visible a little over 24 hours from now (starting before sunset June 5th in the United States.)  It’s the last of your lifetime, so make your plans now.  Weather forecast across much of the eastern U.S. is pretty bad, I’m afraid. Of course there will be many places to watch on-line.  For more information, I highly recommend http://transitofvenus.nl/wp/ .  Also, though you and I can’t see Venus right now (too close to the Sun), the SOHO satellite can: click here for the latest photo, updated frequently, which shows the sun (at center, blocked out) and the sun’s corona around it, and a white dot approaching the sun, which is Venus (ignore the white horizontal lines, which are an imagining artifact).

The transit of Venus was used, historically, to figure out how big is the solar system (the sun and the planets).  As I’ll explain tomorrow, it wasn’t that hard to figure out how large are the distances between the sun and the planets relative to one another, but getting the overall scale — the absolute distances — was a much harder problem.  The first measurement accurate to a couple of percent came from the transits of Venus in the 1760s.  I’ll explain (roughly) how this works tomorrow; the technique relies on the principle of parallax, a principle which lies behind our own ability to perceive depth, and is used by astronomers to measure distances to (relatively nearby) stars.

[Reminder: two events coming up in which I’ll be speaking: (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 4, 2012

The final panel discussion at the Maryland SEARCH workshop — six theoretical particle physicists talking about the 2011 experimental results from the Large Hadron Collider [LHC] and looking ahead to the 2012 data — has finally been posted online, along with the rest of the presentations at the workshop. I wrote about the workshop, which took place in mid-March, here and here.  In the latter post, I wrote:

The workshop concluded with a panel discussion — the only point during the entire workshop when theorists were formally asked to say something. The panel consisted of Michael Peskin (senior statesman [and my Ph.D. advisor] famous for many reasons, including fundamental work on the implications of highly precise measurements ), Nima Arkani-Hamed (junior statesman, and famous for helping develop several revolutionary new ways of approaching the hierarchy problem),  Riccardo Rattazzi (also famous for conceptual advances in dealing with the hierarchy problem), Gavin Salam (famous for his work advancing the applications of the theory of quarks and gluons, including revolutionary methods for dealing with jets), and myself (famous for talking too much… though come to think of it, that was true of the whole panel, except Gavin.) And Raman Sundrum, one of the organizers (and famous for his collaboration with Lisa Randall in introducing “warped” extra dimensions, and also anomaly-mediated supersymmetry breaking [which was competitive with a paper by Rattazzi and his colleagues]) informally participated too. (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 4, 2012

I’m preparing an article on a very important type of energy that I’ve avoided writing about so far — the energy that comes from the interaction among fields.  I’ve avoided it because it’s tricky to figure out how to explain it.  But it’s important, for this form of energy is responsible for all the structure in the universe, from atoms to galaxies.  The article’s not quite ready yet, so today I’ve just got some good reading material for you, including the heavy, the weird, the amusing, and the optimistic. (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON April 26, 2012

Sometimes I encounter people whose impression is that what Einstein’s 1905 theory of special relativity (the one that said no object’s speed can exceed the speed of light in vacuum, etc.) did in “overthrowing” the ideas of the past was somehow like what the Bolsheviks did to the Czars twelve years later– out with the old order, in with the new, and let nothing remain behind.  The widespread notion, inherited from philosopher and historian Thomas Kuhn, is that a new paradigm arose, and the old was swept away.  The truth is far different.  Important parts of the conceptual superstructure of 19th century physics had to be replaced, but the predictive mathematical core was not replaced, but rather was extended.   It was like tearing the roof and facade off a building while keeping the interior beams and columns, then extending the structure to make it much larger than before, and finally giving it a very novel external appearance.  That’s why the Einsteinian revolution was possible at all! Newton’s equations had already been used to design all sorts of real-world 18th and 19th century technology.  If Einstein’s equations hadn’t contained those of Newton and his descendants as a special case, they would have been in conflict with the real world… a no-no for a scientific theory.

Sine this is so important to understand, I’ve written an article illustrating how Einstein’s equations relating energy, momentum, mass and speed were an extension, not a replacement, of the equations that were previously in use.   It describes how Einstein unified two separate classes of equations, one set that could be used for massive objects moving slowly compared to the speed of light, and the other for light itself, into a single class of equations, one that not only included the two previous classes but made predictions for massive objects moving at speeds comparable to that of light.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON April 16, 2012

It is quite amusing to find that just as I am drafting an article on mass and energy, in which Emmy Noether, one of the important mathematicians and mathematical physicists of the last century, makes a central appearance, the New York Times decides this is the day to make her deservedly famous among the wider public.  A contemporary of Einstein’s, whose respect for her intellect is well-documented, Noether is certainly revered among physicists, but is surprisingly unknown outside of physics and mathematics.

If it’s any indication of her influence on my field, a search of a repository of papers in particle physics, quantum field theory and string theory over the last four decades finds her name in the title of 279 articles, which is pretty darn good for a mathematician who died over 75 years ago; for comparison, Einstein and Feynman’s names appear in over 5000 and over 1500 paper titles respectively, though they were full-time physicists and many things in modern physics were named after them.  What Noether did in mathematics I can’t properly characterize — an expert in modern algebra will have to describe that — but within physics, Noether’s name is most commonly associated with a profound mathematical theorem of great importance for physics.  It is the theorem that clarifies why some quantities in nature (such as energy and angular momentum) are conserved (physics language for “preserved”, or “unchanging over time”.)   We’ll be celebrating the centenary of this theorem in 2015 (it was written down in 1915, though only published in 1918).

I’ll be putting up my mass and energy article up in stages; some part of it should go up tomorrow.  In the meantime, enjoy the well-written and apparently correct New York Times article, whose only flaw, perhaps, is that it slightly over-states  Noether’s role in physics (she wasn’t as important as Einstein, but that’s hardly a criticism) while almost completely neglecting her important achievements in pure mathematics, some of which also had a later role in physics.  And also enjoy Einstein’s memorial tribute to her, which is likely the first time that her name appeared in the Times, and which gives perhaps a more properly balanced description of her achievements.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON March 27, 2012

Well, ICARUS flies even higher, and so far shows no sign of losing its wings.

Remember OPERA, the experiment that claimed neutrinos sent from the CERN lab in Switzerland to the Gran Sasso lab in Italy arrive earlier than they were expected to? And that a couple of weeks ago had to admit they’d found a couple of problems that were large enough to scrap their result for the moment, and that require additional investigation?

And remember ICARUS, OPERA’s neighbor in the same Gran Sasso lab in Italy, which measured the energies of neutrinos from the CERN neutrino beam, and showed they were not altered in flight? And thus proved that if the neutrinos really were traveling faster than light, they did not exhibit anything like the variant of Cerenkov radiation that was suggested by and calculated by Cohen and Glashow?

Now, ICARUS’s result from the fall didn’t directly refute the OPERA experiment (despite some claims, even by them) but it certainly added to the aura of extreme implausibility that surrounded the whole story.

Well, this time ICARUS refutes OPERA. Essentially, they did the same measurement as OPERA-2, as I called the short-pulse variant of OPERA’s original experiment.  They took data at the same time as OPERA-2, in the same neutrino beam, in the same laboratory.  It took them a while to do all the distance and timing calibrations that OPERA had done many months ago, but they’re finished now. And whereas OPERA-2 gets the same result as OPERA-1— an early arrival of 60 nanoseconds (billionths of a second) — ICARUS finds a result consistent with an on-time arrival. Same measurement, different answer. At least one experiment made a mistake; and one result is vastly more plausible than the other, so I think the consensus is pretty clear in the matter.

ICARUS's 7 neutrinos (dark blue histogram), measured in October and November, arrived as expected to within 10 nanoseconds (billionths of a second). OPERA's result (but not its neutrinos) is shown at right, at approximately 58 nanoseconds early arrival.

(more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON March 16, 2012

Why does the sight of the Moon draw our gaze and silence our voices? What is it about the planets, those exceptionally bright points of light that wander among the stars, that we instinctively find so beautiful?  Is it perhaps that they make us dream of faraway, unreachable places? Is it that they are beacons in the night, nature’s candle flames, helping keep fear at bay, and offering us hope amid darkness? Or is it perhaps that they seem to float — we do love things that float, whether they be autumn leaves, balloons, clouds or birds — suspended in the sky, in apparent defiance of the force of gravity which keeps us pinned to the Earth?

This last thought offers a certain delicious irony… for in truth the planets and the Moon, in their procession above our heads, obey gravity’s dictates.

The next few days, weather permitting, will give us a chance to contemplate these questions. Our planet’s natural satellite, on its monthly trip around the Earth, will pass three of the brighter planets in the sky, creating one lovely spectacle after another. Of course, the Moon really passes nowhere near the planets, just as your outstretched hand, when it blocks your view of the Moon, is nowhere near the Moon itself. It is all a matter of perspective — of geometry, of cavernous spaces, of the play of light, and of the elegant choreography of the solar system.  But this perspective is not something we sense easily.  Our eyes can perceive no depth for objects so far away, and so our brains form a two-dimensional picture from the three dimensions of the universe, projecting the Moon, the planets and the stars, at extraordinary distances from one another, onto a psychologically flat black screen of the night sky. It takes great mental effort to see things as they are, and not as they appear. This, too, is worthy of contemplation.

First, on the night of February 22nd, just after sunset (don’t be late!), one of the most delicate of nocturnal sights awaits:   Click here to read more…

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 21, 2012

I’ve already mentioned in some earlier posts that the international nature of high-energy physics is one of its great pleasures.  And occasionally the opportunity for travel arises in the context more of celebration than of pure work. In 2008, Professors Makoto Kobayashi and Toshihide Maskawa won the Nobel Prize, (sharing it with Yoichiro Nambu, who was awarded for a separate topic.) The award was for work they did together  in 1973 predicting [more or less] the existence of the “third generation” of quarks (the top and bottom quarks — the first two generations being (1) the up and down and (2) the charm and strange quarks.)   (You can read about the known quarks here.)  (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON October 25, 2011

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