December 2008 Archives

By Matin Durrani

What’s the biggest challenge in physics? What was the biggest breakthrough in the subject over the last 20 years? And do you like the fact that physicists are unpopular parties? Those were just three of the serious and not-so-serious questions in our special survey that we launched in October on this website to mark the 20th anniversary of Physics World.

The survey was just meant to be a bit of fun and we had no idea how many people would reply. But in the end 522 people had their say before we closed the survey in early December. We reckon those numbers are high enough to draw some reasonably secure conclusions. Even if not, here are the results anyway and you can draw your own.

1. What was the most important discovery in physics over the past 20 years?
From the ten choices made by the Physics World team, the clear winner — with over a quarter (26.6%) of the vote — was evidence for dark energy, discovered in 1997/8 by two teams of researchers looking at the properties of certain exploding stars called type 1a supernova. In second, was the discovery of nanotubes — rolled-up sheets of carbon atoms, the discovery of which is often (controversially) attributed to Sumio Iijima from NEC in 1991. In third, with 11.9% was Bose—Einstein condensation — the long-sought-after low-temperature state in which a cloud of atoms all fall into the same quantum state. Its discovery in 1995 led to Eric Cornell, Wolfgang Ketterle and Carl Wieman sharing a Nobel Prize for Physics six years later.

2. What was the most significant popular-science book over the last 20 years?
No surprises here, with Stephen Hawking’s seminal A Brief History of Time scooping 42.7% of the vote. His book was published in April 1988, just six months before Physics World magazine started life. In second was Brian Greene’s The Elegant Universe (12.3%) followed by the late Richard Feynman’s What Do You Care What Other People Think? in third (11.2%). Bad news though for Britain’s Astronomer Royal and head of the Royal Society Martin Rees — his Just Six Numbers came tenth, picked by only two people.

By Hamish Johnston

Sorry for the delay on this entry, but the 15 December issue of the New Yorker just landed on our doormat about a week late.

In that issue there is an article by David Samuels about an American truck driver called John Coster-Mullen, who has spent the past 15 years or so trying to understand how Little Boy worked.

Little Boy was the atomic bomb that destroyed much of Hiroshima in 1945 — and not surprisingly, its design has remained a secret.

Coster-Mullen, who is 60, described his quest as “nuclear archeology,” and doesn’t seem too concerned that his book, Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man could be of interest to those intent on wreaking mayhem. Defending Coster-Mullen, Samuels writes “Surely, hostile powers could easily obtain the kind of information that Coster-Mullen has acquired, however painstakingly, in his spare time”.

Indeed, after reading the New Yorker piece, I was left with the chilling thought that just about anyone with about 60 kilograms of uranium-235 could build a bomb like Little Boy. And the key to success, according to Coster-Mullen, is realising that the bomb was “female” in design rather than “male” — something that previous historians had missed completely.

The New Yorker also has a slide show called Secrets of the Bomb

Physics of Medicine Institute in Cambridge

I’ve just spent the last couple of days in Cambridge for the opening of the new Physics of Medicine Institute (pictured right) at the Cavendish Laboratory. The new institute will serve as home for scientists who are essentially bilingual in biology and physics. The Grand Opening was part of the Physics of Living Matter conference, which displayed the rich variety of problems that biophysicists are trying to tackle: medical imaging, new materials for medical purposes, systems biology, the role of mechanical processes at the cellular level. This is stuff that could bring biology to the next level.

It’s interesting to notice that this Physics+Biology is only a one-way street. The physicists are bringing their quantitative tools to biology, not the other way around. Biologists are not quantitative scientists, and this, in the long run, is a recurrent problem in the field. Descriptive tools can only take you so far, and applied mathematics are fundamental to bring out the big picture on fundamental scientific questions. A biologist at the conference confessed to me that physicists are always needed when there is the impending need to renew the paradigm in biology.

By Hamish Johnston

On Thursday mornings I drop my children off at school and walk to work listening to the BBC Radio 4 programme “In Our Time”, presented by Baron Bragg of Wigton — or Melvyn as he likes to be known.

Bragg is one of those rare intellectuals who seems completely at ease as a broadcaster and every week he somehow manages to get a panel of three academics into a lively discussion about just about anything from “St Hilda - the life and times of the Abbess of Whitby”, to “The Multiverse - the universe is not enough”.

This morning the subject was “The Physics of Time”, and the panel was Jim Al-Khalili, Professor of Theoretical Physics and Chair in the Public Engagement in Science at the University of Surrey; Monica Grady, Professor of Planetary and Space Sciences at the Open University; and Ian Stewart, Professor of Mathematics at the University of Warwick.

You can listen to the programme here and you can find an archive of all programmes here.

By Hamish Johnston

Anyone who has lived in the UK for more than a few months knows that the British are obsessed with exams.

Indeed, this morning one of the lead items on the news was the resignation of “exam watchdog chief” Ken Boston (yes, the UK has an exam watchdog!) over the chaos that ensued earlier this year when many national tests called Sats were incorrectly marked and the results returned late.

A common theme in the discussion of exams is the “dumbing down” of the tests that some allege has occurred over the years — an allegation that often comes across as a variant of the familiar “youngsters have it so easy today”.

Now Cambridge Assessment, a firm that was set up 150 years ago to administer exams, has shed some light on this crucial national debate by releasing a study of physics exams for 16-year olds from 1867 to 2007.

Interestingly, there actually was no “physics” paper before 1927 — up until then a candidate’s knowledge of physics was covered in tests on topics such as “natural philosophy” and “mechanics”.

I wonder if the new topic “physics” was greeted with the same derision that “media studies” garners today?

By Hamish Johnston

I was trained as a physicist, many of my friends are scientists and I believe that science has made the world a much better place.

But, would I trust my economic well being to “a group of good scientists…some who know a lot about economics and finance, and others, who have proved themselves in other areas of science..”

Probably not…

I suppose I’m old fashioned in the sense that if water is pouring from my ceiling, I would call a plumber, not a physicist — even though the physicist would probably have a better understanding of how gravity and fluid dynamics had conspired to ruin my day.

The above quotation comes from the introduction of an article called Can science help solve the economic crisis? that has been published on a website called Edge, where clever people expound on various topics of general interest to society.

The article is written by four intellectuals — including the physicist Lee Smolin of the Perimeter Institute — who argue that scientists should be given chance at “developing a scientific conceptualization of economic theory and modeling that is reliable enough to be called a science”.

The article goes on to identify several failures of neoclassical economics, which has been the guiding philosophy for markets and economies worldwide. Many of these criticisms seem to deal with how principles of science — such as the concept of equilibrium — have been naively applied to economics with dire consequences.

Then, it suggests a way forward — applying the concept of self-organized critical systems to economics.

Hmm, better call for that plumber!

By Hamish Johnston

Imagine my surprise when I turned on the radio this morning to be told by the BBC that astronomers have “found” a supermassive black hole at the centre of the Milky Way…

Didn’t we know this already, I thought?

A quick trawl through the physicsworld.com archives revealed that yes, we have long known about this black hole, roughly where it is, its mass, and that it is probably spinning.

I pointed this out to the BBC, which has since changed the headline from “Black hole found in Milky Way” to ” Black hole confirmed in Milky Way”. However, the home page still carries a supermassive banner using the word “found”.

I find it slightly worrying that one of the world’s most respected news outlets has decided that the most important thing we should know about today, is something that has been accepted by many physicists and astronomers for some years.

By Hamish Johnston

No, at least according to a paper published yesterday in Nature Nanotechnology by researchers in the US and Singapore.

The team discovered that people who live in countries with a relatively high level of “religiosity” are less likely to agree that “nanotechnology is morally acceptable”.

Their study on public attitudes towards nanotechnology involved surveys of over 30,000 people in the US and 12 European countries. Americans topped the religiosity scale with a score of about 9 out of a possible 10, and also had the highest percentage of respondents (25%) who did not agree that nanotechnology is morally acceptable.

At the other end of the scale were countries such as the Netherlands and Sweden (5 and 4 on religiosity respectively) where far fewer respondents had negative moral issues with nanotechnology.

On the surface, this study seems to go against the popular notion of Europeans as Luddites, and Americans being keen to embrace new technologies.

The study is also interesting in relation to another paper published in the same issue of the journal but by a different team. This concludes that, “people who had more individualistic, pro-commerce values tended to infer that nanotechnology is safe”.

In terms of national stereotypes, that sounds more like your average American than your average Swede. Indeed, the UK and Ireland — which are usually thought of as individualistic and pro-commerce — also tended to be less morally accepting of nanotechnology than many of their more “socialist” neighbours.

The BLAST team. Credit: Mark Halpern

By Margaret Harris

Things are not going well for the astrophysics “balloonatics” at the bottom of the world. After weeks spent waiting for decent weather, their Balloon-Borne Large Aperture Submilimeter Telescope, or BLAST, has hit a stumbling block. Fairly literally, in fact: the fragile, sensitive instrument has just slammed into the truck being used to launch it. “Oh, you’re (expletive) kidding me,” someone cries in the background, as the stricken telescope sways gently beneath its balloon in the still Antarctic air.

“Step by tedious step, we stumble away from abject failure,” says Barth Netterfield, a Canadian astrophysicist and co-star of the feature-length documentary BLAST, which chronicles the 18 rocky months leading up to the equally rocky launch of the telescope. “And that’s on a good day.” It’s a statement that will bring grimaces of recognition to many an experimentalist’s face, and as a summary of the film, it’s as good as any. If you’re reading this as a PhD student, and your experiment is not going well, take heart: at least it isn’t scattered over a 120-mile stretch of frozen wilderness, with the bulk of it halfway down a crevasse.

By Michael Banks

Whilst trawling the web this morning I came across a few blog posts showing the first pictures of the damage caused by the magnet failure at CERN’s Large Hadron Collider (LHC) on 19 September.

The pictures were apparently shown during a presentation by the lab’s director general Robert Aymar on Friday at a meeting of the European Committee for Future Accelerators held at CERN.

The US/LHC blog posted a link to slides of Aymar’s talk. However, within an hour of the post (on 1 December) access to the talk had been restricted. Fortunately, particle physicist Stephanie Majewski from Brookhaven National Laboratory, who is at CERN for a year, posted the pictures from the talk on her blog.

From the two images, probably the more striking picture is the one that shows the region between the magnets that was crunched due to the pressure as the helium escaped into the tunnel. The other image shows a magnet unattached from its mount, which is secured to the concrete floor in the tunnel.

CERN is planning to release a full report in early December about the damage to the LHC, outlining the repair schedule and plans for operation in 2009.

Ebb and Flow by P Mininni et al

By Matin Durrani

Two silent round flashes on a dark screen. That was the image witnessed by researchers crowded into the control room of the Large Hadron Collider (LHC) at the CERN particle-physics lab near Geneva on 10 September that heralded the successful passage of the first beam of protons around the 27 km collider. Later that day physicists watched as one of the LHC’s main experiments - the Compact Muon Solenoid - generated its first images from the debris of particles produced when the proton beam was deliberately steered into a tungsten collimator block.

Particle physics has long been a rich source of iconic images - from the tracks in the bubble chambers of the 1950s to the particle collisions that signalled the detection of everything from the W-boson to the top quark. But visualization has a proud history in other areas of science too. Ever since Galileo turned his telescope to the heavens in 1609 and saw mountains on the Moon and spots on the Sun, researchers have sought to see beyond what is possible with the naked eye. Indeed, astronomers now claim to have directly observed extrasolar planets for the first time.