Recently by Margaret Harris

By Margaret Harris

As the person who (with editor Matin Durrani) compiles letters and web comments for the “Feedback” section of Physics World, I’ve been paying close attention to the flood of comments on physicsworld.com’s various climate-change articles.

A majority of the comments have been negative, as many readers will have noticed, and the same has been true for feedback in the form of letters and emails. On the face of it, this is pretty typical, even for a good magazine: angry readers write letters, while happy readers, by and large, do not.

But I have to wonder what else might be going on that is specific to the issue of climate change. Most people who make negative comments have not read an enormous number of peer-reviewed publications on the subject; at best, they seem to have read an enormous number of websites set up by avowed climate-change sceptics. However, neither do they appear to be in the pay of the fossil-fuel industry, as some environmentalists have charged. So why is there such a huge amount of vitriol out there against the idea that the climate is changing, and humans are (at least partly) responsible?

The answer, it seems, may be partly down to human psychology — at least according to a report from the Center for Research on Environmental Decisions (CRED) at Columbia University. Liz Kalaugher, editor of environmentalresearchweb.org (one of physicsworld.com’s sister websites within the Institute of Physics Publishing) has written a very good summary of the report here . Alternatively, you can download a guide to the CRED report here.

Images from the European Orbiter on the 1987 ESA calendar. Credit: ESA

By Margaret Harris

The question of what to do with old calendars is (literally) a perennial one, but the European Space Agency has an interesting solution: post them on the web.

The agency has created an online gallery of calendars and posters depicting missions from the last 30 years. The images are drawn from archives at the European Space Operations Centre in Darmstadt, Germany, and from a retired employee’s private collection. They include both satellite photos like the one on this calendar — which would have made a great Christmas gift back in 1986 — and artists’ impressions of missions.

It’s not clear why ESOC has chosen to post these images now. There’s no information on the website about any special exhibition, for example, and the nominal 40th-anniversary tie-in seems a little odd, given that ESOC is now 42 years old.

But whatever the excuse, leafing through the various posters is both a nice reminder of the agency’s successes and an interesting glimpse of how it has advertised itself over the years. I particularly liked the city of Darmstadt’s poster, which used a picture of a rocket to promote a week of extended shop-openings back in the 1980s. Unlike the others, it’s not an official ESA image, but I can see why they like it — it neatly captures the public’s enthusiasm for space, and the eagerness to appropriate “cool” space imagery for utterly unrelated purposes. Space-age shopping hours — whatever will they think of next?

The official kilogram. Credit: BIPM

By Margaret Harris

Pick the correct definition of a kilogram:

a) the mass of a body with a de Broglie wavelength of 6.626069311 × 10^-34 m at a velocity of 1 m/s

b) a mass of a body at rest such that Planck’s constant h is 6.626069311 × 10^-34 Js

c) a mass of exactly 5.0184512725 × 10^25 unbound carbon-12 atoms at rest in their ground state

d) the mass of a lump of platinum-iridium sitting under three vacuum jars in a French laboratory

Readers with an interest in metrology will know that the answer is d) — and anyone who didn’t know it could probably have guessed from the photo. But why is the kilogram, alone of all SI units, defined by something so un-fundamental as a lump of metal?

The difficulty, as Bryan Kibble explained this afternoon in a talk at the QuAMP conference in Leeds, is that several of the alternatives have problems of their own. Options a) and b) both rely on pinning down a value for Planck’s constant, and thus might seem like the best way to go; indeed, one of them may actually become the new SI definition, perhaps as early as 2011. However, Kibble argued, both options are somewhat circular, swapping uncertainty in the kilogram for uncertainty in other Planck-derived units, and there’s not really any new science involved in them.

A definition in terms of carbon-12 atoms — or indeed, any kind of atoms — would be more satisfying, Kibble says, but as efforts like the Avogadro project at the UK’s National Physical Laboratory have shown, counting atoms isn’t a trivial task.

Nobody offered any solutions during the question period after the talk, but we did manage to pin down one thing: any fluctuations in fundamental constants (like the fine structure constant, for example) will not affect the kilogram problem — at least not for around 1000 years. So that’s all right then.

Tunneling in action

By Margaret Harris

How long does an electron take to tunnel out of an atom exposed to a strong laser field?

Given the somewhat esoteric nature of the question, you might assume that the answer would lie firmly in the realm of theory. But Ursula Keller, whose talk opened this year’s International Conference on Quantum, Atomic, Molecular and Plasma Physics (otherwise known as QuAMP), is an experimentalist, and she and her group at ETH Zurich have made some interesting progress towards pinning down just how long this fundamental quantum-mechanical process takes.

Using a technique called attosecond angular streaking, Keller’s team found an upper bound for the tunneling time of 34 attoseconds. That’s quick — in fact, Keller claims it is the fastest process ever measured, although some might quibble with that distinction. I’m afraid I only grasped her group’s methodology in small chunks — that’s the trouble with talks sometimes — but you can read more in a paper published in Nature Physics last year.

One development that isn’t addressed in the paper, but which Keller touched on in her talk, is just how controversial their result has been among theorists. The idea that tunneling takes a tiny but finite time makes some intuitive sense, but this is quantum mechanics — intuitive sense doesn’t always come into it. Indeed, some theorists have predicted that the electron’s escape literally takes no time at all, while others suggest that tunneling isn’t even the right way to look at the process.

The arguments on this have become so heated, Keller says — half-jokingly I think — that a few of the people involved aren’t on speaking terms anymore. One thing is clear: the debate on electron tunneling is sure to carry on much longer than the process itself.

Olga Antzoulatos in The Matter of Everything. Credit: Enrico Lappano

By Margaret Harris

This is the last in our current series of film reviews. Send us more films!

The narrator of The Matter of Everything spends most of the film looking puzzled. After all, it’s a puzzling world out there — full of particles that act like waves, matter turning into energy, and all sorts of strange things. Even empty space, it seems, is a lot more complicated than it looks. Such topics can easily ensnare experts in their conceptual knots, so any amateur willing to tackle them deserves a great deal of credit. Here, the brave newcomer is Olga Antzoulatos, a high school teacher who decides to spend some time interviewing particle physicists about their research. To this end, she travels to Fermilab and Toronto’s York University and starts asking questions.

With such a broad subject, and only 100 minutes of film to play with, it’s inevitable that some answers get short shrift. However, that’s not really the point; both Antzoulatos and filmmaker Enrico Lappano are far more interested in the sense of wonder that arises from contemplating nature on such a deep level. Sometimes their efforts pay off — like when Lappano’s camera seeks out a clutch of bird eggs amid concrete slabs at Fermilab, and one of Antzoulatos’ interviewees likens Ernest Rutherford’s experimental knack to “having a red phone to God”.

Still, there’s something missing from this film, and it isn’t a better description of quarks and gluons — it’s a better sense of why Antzoulatos chose to embark on her quest in the first place. What drew her to introduce students in her “Society: Challenge and Change” class to particle physics? How can we encourage more non-scientists to follow in her footsteps? As its title implies, The Matter of Everything is not short of ambition. It’s just a pity it didn’t ask a few more questions.

Image of the European Very Large Telescope credit ESO/Y Beletsky

If the telescope had never been invented, the known universe would consist of six planets, one moon, and a few thousand stars. It’s therefore fitting that one of the “official” products of the International Year of Astronomy 2009 (IYA2009) should be a film history of this astoundingly important device.

Unfortunately, Eyes on the Skies is not so much a film as an hour-long public relations special, with the sheer weight of official approval — it’s a joint production of IYA2009, the International Astronomical Union, the European Space Agency, and the European Southern Observatory — tending to smother its occasional flashes of character. True, there are a few exceptions, particularly in the first two chapters, which cover the telescope’s history from Galileo’s sketches to the 5 m Hale Telescope on Mount Palomar in California. We learn, for example, that legal disputes prevented anyone from earning a patent on the telescope, and that William Herschel’s biggest scope required four servants to operate its complicated system of ropes and pulleys. A little later, presenter Joe Liske of the European Southern Observatory — known here, rather cringe-makingly, as “Dr J” — does a fine job of explaining in simple terms why reflecting telescopes can be bigger than refractors.

Once we reach the modern era, however, the slick artists’ impressions take over. At this point, Eyes on the Skies becomes a visually-stunning laundry list of ambitious projects, and its determination not to leave any of them out detracts from the overall story. The film’s website suggests that it could be shown at “public events carried out by educators, science centres, planetariums, amateur astronomers etc.”, but even with this audience in mind, one suspects that its producers might have been better off just sticking microphones in front of a handful of astronomers and asking them about their work. Indeed, the diverse group of bloggers over at IYA2009’s own Cosmic Diary website would have been a good place to start. In their case, “official” status has not lessened their passion or creativity, and they are far better ambassadors for astronomy than this beautiful but bland production.

Scaffolding on the LHC’s ATLAS detector during construction. Credit: CERN

It may seem odd to think of CERN’s Large Hadron Collider (LHC) as a “time machine”. After all, in its usual science-fiction sense, the phrase refers to a telephone-booth-sized device you climb into before zooming off to explore the future, like the hero of H G Wells’ novel. Yet as filmmaker Yariv Friedman points out in The Time Machine, the LHC should allow physicists to study what happened in the instant after the Big Bang — thereby transporting them, in some sense, through 13.7 billion years of cosmic history.

Friedman’s documentary on this real-life time machine follows a multilingual team of scientists through the final stages of the collider’s construction, where footage taken inside the ATLAS detector offers ample proof of its complexity. Here, even the scaffolding looks complicated, like a giant adventure playground crawling with hard-hatted engineers and physicists. Interviews with scientists offer glimpses of the non-technical challenges; one team leader describes his task as “management by coffee…you have to drink a lot of coffee with a lot of different people to get to the end product”.

The most telling comments, however, come in the run-up to the collider’s gala opening in September 2008. ATLAS’ technical coordinator declares that the LHC will work because “behind every nut or bolt is someone who cares”, while another scientist confesses that he cried when he saw the first particle traces. After this initial success, the shutdown nine days later, “felt like a kick in the teeth,” admits project manager Lyn Evans. Like the project it chronicles, The Time Machine doesn’t quite get off the ground within its hourlong running time, but there’s some great material in this near-miss.

How salaries stack up. Credit: PayScale

By Margaret Harris

Here’s a rare bit of economic good news: people with physics degrees earn more, on average, than their fellow graduates in all but a handful of disciplines.

According to this study by the US website PayScale, physicists are the sixth-highest-earning group of graduates, with a median salary of $98,800 (just under £60k) after at least 10 years in the workforce. Indeed, physics was one of only three non-engineering majors to crack the top ten, along with computer science and economics. Starting salaries for physicists aren’t bad either: $51,100, or a respectable 14th on the same list of 75 different subjects.

In addition to looking at degree subject, the study also ranked 320 US colleges and universities according to their graduates’ salaries. Readers familiar with the US educational system will find some fascinating results in the list; for example, graduates of Loma Linda University, a religious college in southern California, have the highest median starting salary, while Dartmouth College grads earn the most at mid-career.

The CFHT dome at night. Credit: Jean-Charles Cuillandre

By Margaret Harris

We’ve received several more physics-related films in the months since the film review series that appeared on physicsworld.com earlier this year, so we’ve decided to run a new batch of reviews over the next couple of weeks. First up: Hawaiian Starlight by Jean-Charles Cuillandre.

With its sweeping panoramas of galaxies, nebula and the cluster of telescopes perched atop Hawaii’s Mauna Kea volcano, Hawaiian Starlight is the ultimate astronomy screen-saver. At least, that’s how it comes across if you watch it on a computer screen in a brightly-lit office. On a big screen in a dark room — perhaps with a drink, and the right group of friends — I suspect it would be a near-spiritual experience. Throughout the film’s 43-minute running time, images of interstellar objects alternate with time-lapse footage of the telescopes that took them. And that’s it. There is no voice-over, no gesturing science “personality” to ram home the significance of what you’re watching, nor even much text. It is just you, the stars, the scopes, and a curiously hypnotic soundtrack borrowed from the Halo video game series. It’s marvellous.

Part of the marvel is the sheer dedication of filmmaker Jean-Charles Cuillandre, an astronomer at the Canada-France-Hawaii Telescope who spent seven years collecting footage of telescopes and the Mauna Kea landscape. The resulting time-lapse movies make up the bulk of the film, and range from simply beautiful to delightfully whimsical. At 1000 times normal speed, a telescope dome opening and closing bears a striking resemblance to Pac-Man, and “cute” is really the only word for a sequence in which three sub-millimetre telescopes twitch in time with the music.

But for the most part, this film inspires wonder rather than giggles. We all know the official reasons for placing telescopes on remote mountaintops: clear skies, thin atmosphere, and low light pollution make for better images. Watching Hawaiian Starlight, however, one wonders whether more subtle factors could play a role: the awesome environment of Mauna Kea’s summit must surely encourage its scientific visitors to think deeply about the universe.

By Margaret Harris

How do you dramatize the obscure process of funding scientific research for a public audience? If you’re a general-interest publication like The New York Times, one answer is to use cancer as an example.

A thought-provoking article published at the weekend describes how the tendency to dole out grant monies to projects that are limited in scope — and therefore quite likely to succeed within their allotted few-year period — is hurting cancer research. “Playing It Safe in Cancer Research” cites as examples a study of whether people who really like food have trouble following diets (funded), and research that led to the development of herceptin, a ground-breaking treatment for certain types of breast cancer (rejected by mainstream agencies, funded by a special grant from a cosmetics firm).

It occurred to me while I was reading the article that these issues are far from unique to cancer research. Scientists in all disciplines have long complained about how the process of applying for and receiving grants seems to reward “incrementalist” research, and “You have to say what you’ll find before they’ll pay you to look for it” is a common refrain.

It seems I wasn’t alone in thinking the problem could be relevant to physics. Today’s letters section in the NY Times includes one from Lee Smolin of the Perimeter Institute for Theoretical Physics, in which he suggests a “scientific venture capital” fund that would support high-risk, high-reward research using 10 percent of the existing US science budget. Another writer, neurologist Michael Rogawski, suggests funding researchers based on what they’ve already done, not what they’re proposing to do.

What do physicsworld.com readers think of these ideas? Any other suggestions for how we should be rewarding risk-taking research?