December 2010 Archives

By Matin Durrani

Season’s greetings to all physicsworld.com readers.

The Physics World staff are all on a well-earned Christmas break right now.

While they’ve all got a few days off, there’s plenty to keep you amused over the holiday period.

If you haven’t seen it already, don’t miss our breakthrough of the year, which went to research into antimatter, as well as our top 10 physics books from the last 12 months.

We’ve also included a selection of the most stunning pictures of 2010 as well as our favourite quirky stories that made us laugh throughout the year.

Finally, there’s our look forward to 2011, which promises so much. That’s the thing about physics – it just never ceases to amaze us.

See you all in the new year, and thanks for your dedicated interest throughout 2010.

P.S. For all materials-science lovers out there, we’ve also just posted a couple of videos from the Materials Research Society fall meeting in Boston earlier this month. There’s a vox-pop with delegates as well as as an interview with Ian Robertson, incoming head honcho at the National Science Foundation’s division of materials research.

By Hamish Johnston

My old friend John Shymko has posted some lovely photos of a very red eclipsed Moon that he took early this morning in southern Ontario.

The Earth is blocking direct sunlight from reaching the Moon, which is instead illuminated by sunlight that has scattered through the Earth’s atmosphere. This is what gives the Moon its lovely red colour.

Indeed, consulting NASA’s entry on the Danjon scale I’d say that John’s Moon scores full marks at L=4. This means that John saw a full umbral eclipse.

Courtesy: Paramount Pictures

By James Dacey at the AGU in San Francisco

A number of strange events including bizarre weather patterns and mass migrations of birds have led people to fear that something is going seriously wrong with the Earth’s magnetic field. In the US, a brilliant though dishevelled geophysicist believes the situation is due to a slowing in the rotation of the Earth’s core, the site where the field is generated.

When the US government caught wind of these claims, they had the scientist escorted to a secret meeting location where he delivered a short lecture on the fundamentals of geomagnetism. He warned that if the field vanishes entirely, the Earth will lose its protective shield and be exposed to a torrent of lethal radiation from the Sun.

Once they were sufficiently convinced by the passionate but uncooperative scientist, the government concluded that there is only one viable solution: they will drill down to the centre of the Earth and nuke the core into moving again.

Don’t worry. This is not a serious news story.

This is the plot to The Core, the 2003 disaster film, which grossed more than $70 million at the box office. On Tuesday night, The Core’s director, Jon Amiel was talking at the American Geophysical Union (AGU) Fall Meeting here in San Francisco in a session about the representation of science in blockbuster films. In an entertaining presentation, Amiel discussed Hollywood’s obsession with geo disasters, from freak hurricanes to giant space rocks on collision paths with the Earth. He described how the idea of something going seriously wrong in the Earth’s interior appealed to him as another interesting spin on this theme.

After showing us some very funny clips from The Core, Amiel went on to discuss the question of whether Hollywood should try to represent science and scientists in an accurate way. Unsurprisingly, he believes that the success of a film comes from its ability to stir the emotions, and the aim of staying faithful to the science always comes second.

Amiel did, however, talk about his passion for the underlying science and all the geology he learned in making the film. “The Core articulates a good mystery story, like all great science,” he said.

Amiel was joined in the discussion by other speakers including Bruce Joel Rubin, who wrote the screenplay for Deep Impact, a film about a comet heading towards Earth, released in 1998. Rubin shared the same view about the importance of narrative but he believes there is no reason why film makers should shy away from including good science, so long as it is not to the detriment of the story. He described the extensive talks he carried out with geoscientists in predicting how a comet-impact with the Atlantic Ocean would trigger a tsunami that would wash away large parts of the US eastern seaboard and the low-lying areas of Europe.

“I really worked hard trying to make this film scientifically accurate,” he said. He contrasted his efforts to those of the makers of Armageddon, which was released in the same year and followed a similar plot. In this case, however, Bruce Willis is sent up to the approaching space rock to drill a bore hole and implant a nuclear device. He detonates the bomb, splitting the comet in half, and the world is saved.

Also on the panel was Sidney Perkowitz, condensed-matter physicist at Emory University in the US, who wrote this interesting article for Physics World back in 2006 about the way physicists are portrayed on screen.

By Hamish Johnston

If you type the word “invisible” into the search engine on arXiv.org you get a very curious result. Two papers with nearly identical titles, uploaded three days apart.

A quick scan of both papers, which are by separate groups, reveals that they are both about roughly the same thing – the first invisibility cloak that works on large objects illuminated with visible light.

This promises to be a major breakthrough in the world of cloaking and I understand that one paper is destined for a prestigious journal; I’m not sure about the other.

We have a crack reporter looking into it. More later…

In the meantime you can read the papers here and here.

By James Dacey at the AGU in San Francisco

NASA satellite images have revealed that the biosphere is being placed under increasing strain as rising population on a global scale is accompanied by increased consumption of crops and animals per capita. If population and consumption continue to grow at present rates then by 2050 more than half of the new plant material generated on Earth each year will be required for humans. These findings were presented on Tuesday by NASA scientists at the American Geophysical Union (AGU) Fall Meeting here in San Francisco.

Marc Imhoff of the NASA Goddard Space Flight Center presented the results of a global survey for 1995–2005. Using data from NASA’s AVHRR and MODIS satellites, Imhoff and his colleagues tracked the amount of plant material produced on Earth. These satellites scan the Earth at 600 km per second, monitoring the colour of light emitted from the surface. Light near the green part of the spectrum is taken to indicate the presence of vegetation. A MODIS image of some of North America is shown above (image courtesy of NASA).

To create a “currency” for natural consumables, the researchers considered plants and animals in terms of the amount of carbon that they draw from the atmosphere – referred to as “net primary-production (NPP) carbon”. They discovered that between 1995 and 2005 the amount of NPP carbon used for human consumption rose from 20% to 25% of the total generated on land.

“These images tell us very dramatically that we do need to look at what kind of impact human consumption rates have on the ability of the biosphere to generate the supply,” said Imhoff.

He believes that the need for more plant products will have big implications for land management. As more land is required for agriculture, planning authorities will be faced with difficult decisions as they try to protect important ecosystems, such as boreal forest.

Rama Nemani, another member of the NASA team, is keen to stress that it’s not the role of Earth-monitoring programmes to suggest what should be done with global land use. He believes, however, that the next generation of Earth-monitoring satellites will play a key role in informing these discussions. These will include NASA’s National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project and ESA’s Sentinel satellites.

Nemani told me that he would also like to see the creation of an international body to monitor global biodiversity, in the same way that the climate is assessed by the Intergovernmental Panel on Climate Change (IPCC).

Do these concentric circles offer a glimpse of before the Big Bang?

By James Dacey

Roger Penrose is defending his claim that our universe did not begin with the Big Bang but instead continually cycles through a series of lifetimes, or “aeons”. He makes his latest case in a paper submitted to the arXiv preprint server yesterday.

The recent excitement began in November when Penrose, a University of Oxford physicist, made the sensational claim that he had glimpsed a signal originating from before the Big Bang. Working with Vahe Gurzadyn of the Yerevan Physics Institute in Armenia, Penrose came to this conclusion after analysing maps from the Wilkinson Anisotropy Probe (WMAP). These maps reveal the cosmic microwave background, believed to have been created just 300,000 years after the Big Bang and offering clues to the conditions at that time.

After scrutinizing over seven years’ worth of WMAP data, as well as data from the BOOMERanG balloon experiment in Antarctica, Penrose and Gurzadyn say they have identified a series of concentric circles within the data. These circles show regions in the microwave sky in which the range of the radiation’s temperature is markedly smaller than elsewhere. According to the researchers, the patterns correspond to gravitational waves formed by the collision of black holes in the aeon that preceded our own, and they published these claims in a paper submitted to arXiv.

The paper was quickly picked up by physicsworld.com and, in no time at all, the story was causing a big stir in the blogosphere. But not everybody agrees with Penrose’s outlandish claims and to date at least two other groups have published their own independent analyses of the same CMB data, and both have taken issue with the original conclusions. The first is a paper by Moss et al and the second is written by Wehus et al – both published on arXiv.

The disagreements are subtle – and I won’t pretend I fully understand them – but in essence both groups are saying that we should not be surprised by the circles, which can easily be explained by anisotropies in the CMB. The patterns, claims Wehus’ group, are fully consistent with the accepted inflationary model of cosmology: that the universe started from a point of infinite density, expanded extremely rapidly for about a second, and has continued to expand much more slowly ever since.

But not to just sit and sulk, Penrose and Gurzadyn have already hit back with a follow up paper, published yesterday on arXiv. In the short article, they agree that the presence of circles in the CMB does not contradict the standard model of cosmology. However, the existence of “concentric families” of circles, they argue, cannot be explained as a purely random effect given the pure Gaussian nature of their original analysis. “It is, however a clear prediction of conformal cyclic cosmology,” they write.

The battle, it seems, is set to go on.

DNA being pulled through a sheet of graphene. Courtesy: Robert R Johnson

By James Dacey

High achievers who commit their working life to fundamental research do not tend to be driven primarily by money. But the chance to win a slice of a $10 million prize must at least bring a bounce to the step of a scientist as they whizz around the lab. That’s the situation for researchers developing DNA sequencing technologies who stand a chance of sharing the Archon Genomics X Prize, which will pay this money to the first privately funded company that can accurately sequence 100 human genomes in 10 days.

Earlier this week, researchers at the University of California reported an important breakthrough in one of the promising techniques that could scoop this prize. Kate Lieberman and her colleagues are seeking to develop a system known as nanopore sequencing. The basic idea is that by feeding DNA through pores in thin films that are so small that the molecules almost fill the gap, the DNA could alter the electronic properties of the film. If researchers can also develop a highly sensitive way of monitoring electronic currents passing across the gap, they could in theory identify individual bases – A, C, G and T.

The idea was first mooted in the mid 1990s, but naturally there have been a number of challenges along the way. Lieberman and her colleagues have addressed one of these, which is to find a controlled way of passing DNA strands through the gap. They manage to pass a single strand of DNA through a nanopore in protein by coupling the DNA with a polymerase enzyme, which can then pass smoothly through the gap and be detected in the presence of an electric field.

The researchers, who report their findings this week in Journal of the American Chemical Society, intend to develop their technology by working with their industrial partners, the UK-based company Oxford Nanopore. “The ‘strand sequencing’ method of DNA sequencing using a nanopore has been studied for many years, but this paper shows for the first time that DNA can be translocated by an enzyme using methods that are consistent with a high throughput electronic technology,” said Gordon Sanghera, CEO of Oxford Nanopore.

If you are a member of the Institute of Physics, you can read more about nanopore sequencing and the incentive of the X Prize in this recent feature article from the print edition of Physics World.

By James Dacey

If you are a regular follower of this blog, you may remember that a few weeks ago I went to see the Pope’s astronomer, Brother Guy Consolmagno, who was giving a talk at the British Science Festival in Birmingham.

Here is a video of that talk in full in which Brother Guy discusses many things including science, religion and the Catholic church’s view on extraterrestrial life. On serious topics such as how he squares his belief with his rational scientific thought, Consolmagno was a lot more candid than I had expected. For instance, if you skip to just over 7 minutes in you can hear how his decision to become a Jesuit just before his 40th birthday was based on a botched calculation regarding his age.

The loudest laugh of the night came when Consolmagno dismisses the idea that Catholics read the Bible as if it were a literal truth, as if it were a science book. “That’s not a Catholic idea… that’s a protestant idea,” he says with a mischievous grin on his face. (See 11 min 30 sec in.)

Video credit: David Evetts from the Birmingham Astronomical Society

“Glass” (Courtesy: Neville Greaves/Aberystwyth University)

By Michael Banks

Make sure you do not miss a new exhibition at the Didcot Cornerstone Arts Centre in Oxfordshire, which starts today and runs until 9 January.

ISIS: Super Microscope features pictures of the ISIS neutron source taken by photographer Stephen Kill as well as images from some of the science performed at the facility.

The exhibition is aimed at raising the public’s awareness of the neutron source, which is at the Rutherford Appleton Laboratory in Oxfordshire and operated by the UK’s Science and Technology Facilities Council.

Completed in 1984, ISIS remains Europe’s only source of pulsed neutron beams. In 2008 the facility completed the construction of a second target station, which will see the number of instruments double to over 40.

Every year hundreds of researchers come to ISIS from around the world to study a range of materials from magnetic materials to biological samples.

One of the images on display is called “Glass” (shown above), which shows the atomic structure of glass as inferred from data collected in neutron experiments.

The image below, which has the appearance of a petal, is taken from raw data collected by a neutron camera at ISIS.

The “flower” (Courtesy: Steve King/ISIS)

Flower

ISIS researcher Stephen King explains how the image was made using neutrons

By Hamish Johnston

Much of Britain is under a thick blanket of snow – and there is even a light sprinkling of the stuff here in normally balmy Bristol. So it’s not surprising that our thoughts have turned to the physics of winter sports.

Louis Poirier is one physicist with both a practical and theoretical understanding of that subject. Poirier spent more than five years on Canada’s national bobsleigh team before starting a PhD in physics at the University of Calgary.

Poirier still has an academic interest in the sport and last year he published a paper in the journal Sports Engineering on “Optimization of handheld gauge sizes for rocker measurements of skate blades and bobsleigh runners”. That’s Louis pictured above with a gauge (photo courtesy of U of Calgary/Ken Bendiktsen).

Now, Poirier has turned his attention to making bobsleigh runs safer for athletes – an important issue for the sport after the death of a competitor in this year’s Winter Olympics. Tomorrow, Poirier will be at an international bobsleigh, skeleton and luge competition near Calgary armed with a radar gun.

Poirier told the Toronto Star that current models used to design tracks are not very accurate because they only consider the time the sled passes about six points along the run.

Using his radar data, Poirier hopes to work out the acceleration on the competitors as they whiz around bends in the track.

Interestingly, he says that speed isn’t always the problem – and that slow tracks can sometimes be more challenging (and dangerous) than faster ones.

Poirier hopes to be able to publish his findings but admits that it may be impossible to perform controlled measurements in a competitive event. You can read about his work here.

By Matin Durrani

The Royal Society – one of the oldest scientific societies in the world – has been spending all this year marking its 350th anniversary.

The society was founded on 30 November 1660 and its outgoing president is the Cambridge University cosmologist Martin Rees.

Rees, whom I interviewed earlier this year (see video above), stepped down yesterday after five years in the hot seat, to be replaced by the Nobel-prize-winning geneticist Sir Paul Nurse, who was lured back to the UK after a stint in New York.

It takes a certain polished charm, coupled with a clear vision, to get appointed as Royal Society president – a quality that Rees has for sure, as you’ll see from the interview.

Nurse no doubt has those qualities too, insisting to the Observer in a recent interview that “scientists have to earn their licence to operate and that means getting out there to talk to people and explain what we do.”

To mark Nurse’s appointment, the Royal Society has also just released a new report entitled Science Sees Further: How Science Will Answer Some of the World’s Biggest Questions containing 12 articles on the “most exciting areas of science today”.

The topics are quite general – ageing and Web science being among them, with the most closely related to physics probably being those on, greenhouse gases, geoengineering and extraterrestrial life.

As for Rees, I doubt his life will get much quieter – he’s still president of Trinity College Cambridge and the UK’s Astronomer Royal after all.