Of Particular Significance

Tag: Einstein

I spent the last two days at an extraordinary conference, “Dreams of Earth and Sky”, celebrating the life and career of an extraordinary man, one of the many fascinating scientists whom I have had the good fortune to meet. I am referring to Freeman Dyson, professor at the Institute for Advanced Study (IAS), whose career has spanned so many subfields of science and beyond that the two-day conference simply wasn’t able to represent them all.

DysonPhoto

The event, held on the campus of the IAS, marked Dyson’s 90th year on the planet and his 60th year as a professor. (In fact his first stay at the IAS was a few years even earlier than that.) The IAS was then still a young institution; Albert Einstein, John Von Neumann, Kurt Gödel and J. Robert Oppenheimer were among the faculty. Dyson’s most famous work in my own field was on the foundations of the quantum field theory of the electromagnetic force, “quantum electrodynamics”, or “QED”.  His work helped explain its mathematical underpinnings and clarify how it worked, and so impressed Oppenheimer that he got Dyson a faculty position at the IAS. This work was done at a very young age.  By the time I arrived to work at the IAS in 1996, Dyson had officially retired, but was often in his office and involved in lunchtime conversations, mostly with the astronomers and astrophysicists, which is where a lot of his late career work has been centered.

Retirement certainly hasn’t stopped Dyson’s activity. His mind seems to be ageless; he is spry, attentive, sharp, and still doing science and writing about it and other topics. When I went up to congratulate him, I was surprised that he not only remembered who I was, he remembered what I had been working on in 1992, when, as an unknown graduate student on the other coast, I had sent him a paper I had written.

By the way, it’s somewhat bizarre that Dyson never won a Nobel Prize.  Arguably it is part of the nature of the awarding process, which typically rewards a specific, deep line of research, and not a polymath whose contributions are spread widely.  Just goes to show that you have to look at the content of a person’s life and work, not the prizes that someone thought fit to award to him or her.  Still, he has his share: Dannie Heineman Prize for Mathematical Physics 1965; German Physical Society, Max Planck Medal 1969; Harvey Prize 1977; Wolf Foundation Prize in Physics 1981; American Association of Physics Teachers, Oersted Medal 1991; Enrico Fermi Award 1995; Templeton Prize for Progress in Religion 2000; Henri Poincaré Prize 2012.

The thirteen talks and several brief comments given at the conference, all of which in one way or another related to Dyson’s work, were organized into sessions on mathematics, on physics and chemistry, on astronomy and astrobiology, and on public affairs. All of the speakers were eminent in their fields, and I encourage you to explore their websites and writings, some of which were controversial, all of which were interesting. For non-scientists, I especially recommend Stanford Professor Emeritus Sid Drell’s extremely interesting talk about nuclear disarmament (which he’s been working towards for decades), and a thought-provoking if disconcertingly slick presentation by Dr. Amory Lovins of the Rocky Mountain Institute on what he sees as a completely realistic effort, already underway, to wean the United States of its addiction to oil — with no net cost. Those with a small to moderate amount of scientific background may especially enjoy MIT Professor Sara Seager’s work on efforts to discover and study planets beyond our own solar system, Texas Professor Bill Press’s proposal for how to rethink the process of drug trials and approvals in the age of electronic patient records, Sir Martin Rees’s views on the state of our understanding of the universe, and Caltech’s Joseph Kirschvink’s contention that scientific evidence tends to favor the notion that life on this planet most likely started on Mars.

But really, if you haven’t heard about all the different things Freeman Dyson has done, or read any of his writings, you should not miss the opportunity. Start here and here, and enjoy!

Many happy returns, Professor Dyson; you have been an inspiration and a role model for several generations of young scientists, and may you have many more happy and healthy years to come!

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON September 29, 2013

Done: All three parts of my lecture for a general audience on String Theory are up now…

Beyond the Hype: The Weird World of String Theory (Science on Tap, Seattle, WA, September 25, 2006). Though a few years old, this talk is still very topical; it covers the history, development, context and impact of string theory from its earliest beginnings to the (then) present.

Be forewarned: although the audio is pretty good, this was an amateur video taken by one of the organizers of the talk, and because the place was small and totally packed with people, it’s not great quality… but good enough to follow, I think, so I’ve posted it.

  1. Part 1 (10 mins.): String theory’s beginnings in hadron physics and the early attempts to use it as a theory of quantum gravity.
  2. Part 2 (10 mins.): String theory was shown to be a mathematically consistent candidate for a theory of all of quantum gravity and particle physics, and became a really popular idea.
  3. Part 3 (9 mins.): How string theory evolved through the major technical and conceptual advances of the 1990s.

By the way, if you’re interested in other talks I’ve given for a general audience, you can check out my video clips, which include a recent hour-long talk on the Quest for the Higgs Boson.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON September 6, 2013

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…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 3, 2013

Yes, it was funny, as I hope you enjoyed in my post from Saturday; but really, when we step back and look at it, something is dreadfully wrong and quite sad.  Somehow TIME magazine, fairly reputable on the whole, in the process of reporting the nomination of a particle (the Higgs Boson; here’s my FAQ about it and here’s my layperson’s explanation of why it is important) as a Person (?) of the Year, explained the nature of this particle with a disastrous paragraph of five astoundingly erroneous sentences.   Treating this as a “teaching moment” (yes, always the professor — can’t help myself) I want to go through those sentences carefully and fix them, not to string up or further embarrass the journalist but to be useful to my readers.  So that’s coming in a moment.

But first, a lament.

Who’s at fault here, and how did this happen?  There’s plenty of blame to go around; some lies with the journalist, who would have been wise to run his prose past a science journalist buddy; some lies with the editors, who didn’t do basic fact checking, even of the non-science issues; some lies with a public that (broadly) doesn’t generally care enough about science for editors to make it a priority to have accurate reporting on the subject.  But there’s a history here.  How did it happen that we ended up a technological society, relying heavily on the discoveries of modern physics and other sciences over the last century, and yet we have a public that is at once confused by, suspicious of, bored by, and unfamiliar with science?   I think a lot of the blame also lies with scientists, who collectively over generations have failed to communicate both what we do and why it’s important — and why it’s important for journalists not to misrepresent it. (more…)

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON December 3, 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

In case you haven’t yet heard (check my previous post from this morning), neutrinos traveling 730 kilometers from the CERN laboratory to the Gran Sasso laboratory do arrive at the time Einstein’s special relativity predicts they would.

Of course (as the press mostly seems to forget) we knew that.  We knew it because

So the news from the Neutrino 2012 conference in Kyoto, on new data from May 2012 taken by OPERA and three nearby experiments, is no surprise to anyone who was paying attention back in March and early April; it’s exactly what we were expecting.

One thing that almost no one is reporting, as far as I can tell, is that CERN’s research director Sergio Bertolucci did not give the first talk on neutrino speeds in Kyoto.  That talk was given by Marcos Dracos, of OPERA.  Dracos presented both OPERA’s corrected 2011 results (with corrections based on the detailed investigation shown in March of the problems reported back in February) and also the new 2012 results, which were taken with a kind of short-pulse beams similar to that used in OPERA-2.  (A short pulse beam allows for a neutrino speed measurement to be made rather easily and quickly, at the expense of OPERA’s neutrino oscillation studies, which were the main purpose of building the OPERA experiment.)

Following Dracos’ talk, Bertolucci spoke next, and reported the results of the neighboring Borexino, LVD and ICARUS experiments on the May 2012 data, which along with OPERA are all bathed in the same CERN-to-Gran Sasso neutrino beam, and collected their data simultaneously.  All of the results are preliminary so the numbers below will change in detail.  But they are not going to change very much.  Here they are: neutrinos arrive at a time that differs from expectation by:

  • Borexino: δt = 2.7 ± 1.2 (stat) ± 3 (sys) ns
  • ICARUS: δt = 5.1 ± 1.1 (stat) ± 5.5 (sys) ns
  • LVD: δt = 2.9 ± 0.6 (stat) ± 3 (sys) ns
  • OPERA: δt = 1.6 ± 1.1 (stat) [+ 6.1, -3.7] (sys) ns

(Here “ns” means nanoseconds, and “stat” and “sys” mean statistical and systematic uncertainty.)  The original OPERA result was an early arrival of about 60 nanoseconds, about six standard deviations away from expectations.  You see that all the experiments are consistent with zero early/late arrival to about 1 standard deviation — almost too consistent, in fact, for four experiments.

So there is no longer any hint of any evidence whatsoever of a problem with the predictions of special relativity, and in particular with the existence of a universal speed limit.

A summing up is called for, but I want to write that carefully.  So unless something else comes up, that’s all for today.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 8, 2012

Five out of five experiments agree: neutrinos do not travel faster than the speed limit.

Or more precisely: to within the uncertainties of current measurements, neutrino speed, for neutrinos with energies far larger than their masses, is experimentally indistinguishable from the speed of light in vacuum.  This is just as expected in standard Einsteinian special relativity, which would predict they move just below light speed, by an amount too small to measure with current experiments.

http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html

Based on data taken in May 2012 using a beam of neutrinos sent from the CERN laboratory to the Gran Sasso lab, the four experiments ICARUS, LVD, Borexino and even OPERA (the source of  all the excitement) find results consistent with the speed of light, with uncertainties (at one-standard-deviation) about 10 times smaller than OPERA’s original measured deviation of neutrino speed from the speed of light.  The new results are consistent with ICARUS’s result from 2011 data.  Moreover, OPERA’s mistaken result from September and November 2011 — a claimed six standard deviations away from the expected speed — has now been corrected, following their detective work presented in March.  Even MINOS, a U.S. experiment, has revised their older result, which was previously slightly discrepant from the speed of light by a small amount (two standard deviations), and they find now that their data too are quite consistent with neutrinos traveling with light speed, though with much less precision in the measurement.

And so with a final quintet, sung in unison, this melodramatic comic OPERA buffa comes to a close.  As with all classic operatic comedies, there’s been crisis, chaos, and a good bit of hilarity, all the while with wise voices speaking reason to no avail, but in the end the overzealous are chastened, the righteous are made whole, everyone (even the miscreant) is happy, and all is well with the world.

Curtain!! Applause!!  Science Triumphant!!

Favorable review to follow when time permits.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 8, 2012

One of the strange but crucial features of our world is that every type of atom except hydrogen contains neutrons in its nucleus, even though neutrons, on their own, decay (to a proton, electron and anti-neutrino) within about 15 minutes on average.  At first glance this seems puzzling.  At second glance too.  How can stable matter be made from unstable ingredients?

The reason this is possible has everything to do with Einstein’s special relativity, and the way mass and energy are intertwined there.  A crucial role is played by the energy that is most important for binding things together, which I’ve called “interaction energy”.

I’ve now written an article explaining why neutrons inside of nuclei can be stable, giving the example of the deuteron (one proton bound to one neutron) which is the nucleus of “heavy hydrogen”, or “deuterium”.  If you understand this example, you’ll basically understand the point for other nuclei as well.

[For those of you in the New York City area: I’ll be joined by the wonderfully talented singer-songwriter-pianist Andrea Wittgens in giving a physics/music joint performance/presentation at the storied Cornelia Street Cafe, Sunday May 13th at 6 p.m., as part of their Entertaining Science series.  It’s entitled Rhapsody for Piano and Universe, and intended for the general public.  The place is pretty small, so get reservations in advance.]

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON May 8, 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

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