Recently by Margaret Harris

Cartoonist Flash Rosenberg’s drawing of “noise in a magnetic system.”

By Margaret Harris at the APS March Meeting

This year’s APS meeting has been one of the biggest ever, with nearly 11,000 attendees and 54 parallel sessions. It’s impossible to capture the totality of such a huge conference, but here are a couple of snapshots.

One of the most entertaining talks I saw was given by a cartoonist, Flash Rosenberg. Rosenberg makes videos that pair her quick sketching skills with a scientific voice-over: as the scientists speak, she draws what they are saying. Rosenberg spoke during a session on communicating science to the public, and towards the end of her talk she offered to illustrate audience members’ research questions.

Understandably, several of them leaped at the chance. For the first question – “How do bubbles form in nuclear fuel?” – Rosenberg began by drawing nuclear fuel as an unhappy-looking gremlin. I wasn’t quick enough with my camera to capture the hilarious conclusion of her sketch, but another audience member has posted a video of it here (turn the sound up – it’s worth it).

I was better prepared for the second question, which was “How do you measure noise in a magnetic system?”. As you can see in the image above, Rosenberg’s idea of a noisy magnetic system is a couple whose quiet romantic dinner is being interrupted by loud music. Cute.

An over-capacity crowd greeted Leo Kouwenhoven’s talk on Majorana fermions

By Margaret Harris

The hottest talk of the APS March Meeting so far took place yesterday, when Leo Kouwenhoven revealed that his group at TU Delft in the Netherlands may have observed Majorana fermions in one-dimensional nanowires.

Majorana fermions have a curious property – they are their own antiparticles – and particle physicists have been looking for fundamental Majorana fermions for decades. A few years ago, condensed-matter physicists got in on the act too, seeking evidence of Majorana-like behaviour in fermionic quasiparticles such as those formed by electrons in superconductors. But so far, no-one has ever found conclusive evidence that such particles exist – so if this nanowire result holds up, it would be quite the coup for Kouwenhoven and his group.

Unfortunately, Kouwenhoven’s talk was so popular that the crowd overflowed into the hallway outside, and with conference centre staff talking anxiously about fire regulations, it proved impossible for me to squeeze in (Eugenie Reich of Nature was luckier – you can read her summary here). So instead, I headed to the room next door, where Krastan Blagoev of the US National Science Foundation was delivering an inspiring talk on the kinetics of metastatic cancer.

Obesity rates in the US in 2004 and 2008. (Courtesy: Lazaros Gallos)

By Margaret Harris at the APS March Meeting

The data on obesity are pretty unequivocal: we’re fat, and we’re getting fatter. Explanations for this trend, however, vary widely, with the blame alternately pinned on individual behaviour, genetics and the environment. In other words, it’s a race between “we eat too much”, “we’re born that way” and “it’s society’s fault”.

Now, research by Lazaros Gallos has come down strongly in favour of the third option. Gallos and his colleagues at City College of New York treated the obesity rates in some 3000 US counties as “particles” in a physical system, and calculated the correlation between pairs of “particles” as a function of the distance between them. This calculation allowed them to find out whether the obesity rate among, say, citizens of downtown Boston was correlated in any way to the rates in suburban Boston and more distant communities.

It wouldn’t have been particularly surprising if Gallos’ team had found such correlations on a small scale. The economies of Boston and its suburbs are tightly coupled, for one thing, and their demographics are also not so terribly different. But the data indicated that the size of the “obesity cities” – geographic regions with correlated obesity rates – was huge, up to 1000 km. In other words, the obesity rate of downtown Boston was strongly correlated not only with the rates in the city’s suburban hinterland, but also with rates in far-off New York City and hamlets in northern Maine.

This correlation was independent of the obesity rate itself – there are “thin cities” as well as obese ones – and also far stronger than correlations in other factors, such as the economy or population distribution, would suggest. The exception, intriguingly enough, was the food industry, which also showed tight correlations between geographically distant counties.

Gallos isn’t claiming that the food industry is causing obesity. He also doesn’t discount the importance of food choices and genetic factors: what you eat and who you are will clearly play a big role in determining whether or not you, as an individual, will become obese. However, he points out that our genes haven’t changed that much since the US obesity epidemic began in the 1980s, and neither, presumably, has our willpower. The difference, he says, is that on a societal level, increasingly large numbers of us are living in an “obese-o-genic” environment, and “the consensus is that the system makes you eat more”.

Gallos says he’ll post this research on arXiv sometime in the next few days [UPDATE 29/2/12: here’s the link to the paper]. In the meantime, I’ll be testing his hypothesis personally in the obese-o-genic environment of a major scientific conference, complete with multiple breakfasts, receptions and lunches. Pass the pastries, please!

Boston Common and the Park Street Church, part of the city’s “Freedom Trail”.

By Margaret Harris at the APS March Meeting in Boston

The American Physical Society’s March Meeting doesn’t really kick off until tomorrow morning, but with many of the 6000+ delegates arriving a day early, we’re rapidly heading towards a critical mass of physicists here in Boston. Even the good citizens of New England’s largest city are starting to notice the influx; as I was walking along the “Freedom Trail” of historic landmarks earlier today, I met a park ranger who estimated that I was 10th physicist he’d spoken to that afternoon.

Anyway, from tomorrow until Thursday I’ll be swapping sight-seeing trips for talks on a wide range of physics topics. Many of the sessions are devoted to superconductivity, which remains a popular field a quarter of a century after the famous “Woodstock of Physics” March Meeting when the first high-temperature superconductors took centre stage.

Physicists with a keen interest in graphene will face some particularly tough decisions on which talks to attend, with 39 separate sessions devoted to carbon’s newest and sexiest (well, unless you prefer diamonds or buckyballs) allotrope.

There’s also some intriguing-sounding interdisciplinary sessions on the physics of cancer and the aftermath of the Fukushima nuclear incident. And finally, I’m hoping to learn more about the latest nifty experiments in my PhD field of atomic and molecular physics.

First, though, I need to go eat some of Boston’s famous seafood…

By Margaret Harris

I went to the University of Surrey last week for a science careers evening, and as I was chatting to some students afterwards, one of them asked a fascinating question. “We’re always hearing that the UK needs more graduates in STEM fields,” she said, using the ever-present acronym for science, technology, engineering and mathematics. “But if that’s true, why are so many of us struggling to find jobs?”

I’ve been asking myself the same question for some time. As Physics World’s careers editor, I receive many upbeat press releases touting the importance of STEM disciplines in building the knowledge economy, pulling the country out of recession and so on. But I have also watched, with impotent sympathy, as some of my scientifically trained friends search in vain for jobs. So what is wrong with this picture?

By Margaret Harris
One of the highlights on physicsworld.com last week was an online lecture by the University of Surrey physicist and science communicator Jim Al-Khalili, who spoke on the subject of his recent book Pathfinders: the Golden Age of Arabic Science.

If you missed the live version of Al-Khalili’s lecture “On the shoulders of eastern giants: the forgotten contributions of medieval physicists”, you can watch an archived version of the hour-long event here. Be sure to stay all the way to the end, when Al-Khalili tackles some probing questions from audience members – including one asking why these physicists’ contributions have been forgotten in the West, and another wondering why science declined in the Arabic-speaking world after the medieval period.

As usual with these question-and-answer sessions, we ran out of time long before you ran out of questions. On this occasion, several of the ones we couldn’t fit in were so interesting that we asked Al-Khalili to send us written answers so we could share them with you. Below are his replies.

A cricket ball at rest

By Margaret Harris

Late yesterday afternoon, I was pottering around with the BBC’s Test Match Special on in the background when something in the cricket commentary caught my attention. In-between the usual chatter about English bowling (good), Indian batting (bad) and the latest cakes delivered to the TMS commentary box (excellent), the conversation suddenly turned to physics – specifically, to the question of whether a ball could gain speed after nicking the edge of a bat.

The matter was raised after an Indian batsman, V V S Laxman, edged a delivery from Jimmy Anderson, an English bowler. The ball spurted off towards England’s captain, Andrew Strauss, who couldn’t quite catch it. After lamenting the missed opportunity, one of the TMS commentators suggested that Strauss might have mistimed his catch because the ball gained speed after glancing off Laxman’s bat. The commentators then spent the next several minutes talking a load of old rubbish about whether this was physically possible.

Then, shortly after 6 p.m., a secondary-school physics student, Laurence Copson, sent a message to the BBC’s online commentary team claiming that no, it wasn’t possible. “Removing all external forces on the ball, under no circumstance would the ball gain speed after a nick…as [the] bat would be slightly hitting the ball in the opposite direction,” he wrote. However, he did add a caveat: “What may be deceiving is if the batsmen swipes, catches an edge and then the ball gains top-spin and seems to reach the ground quicker than usual.”

This analysis was quickly contradicted by Rob, a university astrophysics student, who pointed out that Copson was neglecting both the elastic coefficients of ball and bat, and (more importantly) “the spin on the ball before it hits the bat which, if very fine, may accelerate the ball…in the direction of spin (like a car with its wheels spinning hitting the ground goes forward)”.

This seemed fair enough, but Rob’s parting shot – ”this is the real world, external forces on the ball can’t be discounted!” – struck me as rather snide, so I decided to do some analysis of my own.

By Margaret Harris

Today is the day when hundreds of thousands of students across England, Wales and Northern Ireland receive the results of their A-level exams, which will determine where (and whether) they go to university in the coming academic year. The subsequent flood of exam statistics will keep education-policy experts busy for the next few days, but it’s already emerged that the number of students taking the physics A-level exam has gone up, rising 6.1% since 2010 and 19.6% over the past five years.

This is welcome news, and it’s the inspiration behind this week’s Facebook poll, which asks:

What is the main benefit of studying physics at university?

As usual, you can cast your vote on our Facebook page.

Now, as for the reasons behind the increase in physics A-level students, several commentators have cited the improving image of physics in pop culture, as evidenced by television shows like Brian Cox’s Wonders of the Universe and the US comedy The Big Bang Theory. Even the IOP’s president, Peter Knight, has suggested that the “Brian Cox effect” and publicity surrounding CERN’s Large Hadron Collider (LHC) may have helped propel physics back into the list of the 10 most popular A-level subjects for the first time since 2002.

But with all due respect to Knight, I’m personally dubious about the influence of pop culture in this case. The UK’s education system forces students to specialize early, so the current crop of A-level students will have begun narrowing down their options at least three years ago. Back then, The Big Bang Theory had only been on UK television for a few months, the LHC was still under construction and the two Wonders programmes were but gleams in Cox’s eye. So it’ll be a few years before we’ll know the true extent of their impact.

I’d place more weight on the second half of Knight’s statement, in which he noted that “Many students are also responding to calls from university leaders, businesses and the government to choose subjects which will provide the skills our country needs.” Campaigns by all these groups to boost science have been going on for years, and economic uncertainty (which, in the UK, dates back to 2007, when the bank Northern Rock collapsed) has probably made students more receptive to them. It’s worth noting that the last time the UK had so many physics students was in 2002, when the world economy was still recovering from the dot-com bust.

Anyway, regardless of the reasons behind physics’ new-found semi-popularity, we wish all students luck with their results – and those who plan to continue their physics education at university should watch this space next week, when we’ll discuss your views on the benefits of studying physics.

By Michael Banks

It had to come didn’t it? With the launch of the last and final flight of the Space Shuttle Programme last month when NASA’s Atlantis shuttle landed back on Earth after an 11-day mission to the International Space Station, the rap video couldn’t be too far off.

So yesterday a tweet from @NASAKennedy – the official Twitter stream of NASA’s Kennedy Space Flight Center – allayed any fears that the rap wouldn’t emerge when it posted a link to the video saying “You know your curiosity will get the better of you so you might as well click.”

Featuring a group of youths dressed in NASA jump suits rapping about the history of the Space Shuttle Programme, I will leave it up to you to decide whether the rap beats the likes of the Climate Change Rap, the Hubble Rap or the Large Hadron Rap.

By Margaret Harris

Last week’s Facebook poll asked a pretty straightforward question:

If you have a physics degree, what do you do for a living?

The options we offered were engineering, finance, IT, research and teaching, and voters could also add their own choices. Among the 161 people who voted, “research” was by far the most popular category, accounting for 45% of the total (N.B. we went ahead and classed the three people who said they were graduate students under “research”). The runner-up was engineering, with 16% of the vote, closely followed by teaching (15%) and IT (13%).

The only user-generated option to attract more than two votes was “science communication”, which picked up six – just shy of 4%. That’s more than finance got, but maybe most physicists in finance are too busy dealing with the financial crisis to vote in Facebook polls.

One final note: could the person who said they were an “inflatable entertainment company owner” please e-mail us at pwld@iop.org? We publish a column in Physics World called Once a physicist that profiles physicists with unusual jobs and, frankly, you’re a shoo-in for a future edition.