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Women in science: a books special

The shows – the first of which you can hear above – are designed to uncover the stories behind the stories, as they will look at the themes present in some of the books recently reviewed in Physics World and on physicsworld.com. Presented by reporter James Dacey, alongside Physics World‘s editor Matin Durrani and the magazine’s reviews editor Margaret Harris, the shows will also include interviews with some of the authors of the books being reviewed, who will discuss the ideas and inspirations behind their latest publications.

Our first programme considers the theme “women in science”. The show begins with an interview with the feminist historian Julie Des Jardins about her book The Madame Curie Complex [running time 1.38]. Des Jardins offers some fascinating ideas about the sort of challenges that women face when considering a career in science, and why Curie is as much a hindrance as an inspiration.

Following on from this, Margaret provides an interesting historical overview of the brother–sister astronomy pairing of William and Caroline Herschel, as told in Michael Hoskin’s book Discoverers of the Universe [running time 8.44]. Harris describes how the Herchels, who hailed from Germany, went to work in England in the late 18th and early 19th century with Caroline helping William to become of one the most influential astronomers of all time. Harris discusses how, historically, this male-leader–female-assistant relationship represented one of the few ways that women could participate in science.

The sexist norms of the period kept Caroline Herschel in her brother’s shadow for much of her life. But can a similar case be made for the early 20th-century physicist Mileva Maric – better known as Albert Einstein’s first wife? In his book Science Secrets: The Truth About Darwin’s Finches, Einstein’s Wife, and Other Myths, Alberto Martinez argues that this assertion, along with many other popular stories in the history of science, is likely to be false. But the truth, he argues, is no less interesting. The Physics World presenters discuss the merits of Science Secrets and whether Martinez could ever be successful in his mission to debunk some of the common myths of popular science [running time 10.55].

The final book under discussion is Soft Matter: the Stuff that Dreams are Made Of by Roberto Piazza [running time 13.54]. The connection to the women in science theme is perhaps less obvious than with the other titles but it is there, and for some reason the book managed to really irritate Matin.

In the next podcast to be released in December, the Physics World team will be discussing a selection of their favourite books reviewed in 2011, and announcing the magazine’s top 10 books of the year. In the meantime, you can continue to read book reviews each month in Physics World and on physicsworld.com.

Nanotube muscles twist and turn

An international team of researchers has invented a new type of artificial muscle that is made from carbon-nanotube threads. The new structures differ from other artificial muscles in that they can twist and turn very quickly.

The new threads could play an important role in technologies that require mechanical movement but where space is limited, says Geoff Spinks from the University of Wollongong in Australia, who was involved in the work. Examples include microfluidics, valves and robotics. The development will be welcomed by nanotechnologists, who have struggled to create nanoscale mechanical actuators. New ideas are required because it can be difficult to build tiny versions of conventional devices – and even when it is possible, such miniature versions often perform poorly.

The muscles, made by a team led by Spinks and Ray Baughman of the University of Texas at Dallas, are composed of thin carbon-nanotube threads, or “yarns”. Carbon nanotubes are themselves hollow cylinders of rolled up carbon sheets, which can be just one atom thick. Key to making the torsional structures is twisting the carbon nanotubes as they are made into a thread, explains Spinks. “The twisting produces a helical structure of intertwined carbon nanotubes,” he says.

Unwinding with a twist

The researchers take lengths of the nanotube thread and partially immerse them in an electrically conducting liquid (or electrolyte). They then hold each end of a thread firmly and connect one end of it to a power supply such as a low-voltage battery. When the power is applied, the thread absorbs some of the liquid and swells. The pressure subsequently produced by the swelling causes the twisted structure to partially unwind, thus creating a rotating action similar to that seen when stretching a helical spring. The structure can be made to rotate in the opposite direction by decreasing the applied voltage.

Diagram showing the carbon-nanotube muscle

Carbon nanotubes in a twist

The team observed the rotation by attaching a plastic paddle to the thread. They found that they could produce rotations of about 250° per millimetre of thread length. This value is roughly 1000 times larger than those observed in previous torsional artificial-muscle systems that are based on ferroelectrics, shape-memory alloys or conducting organic polymers, claims Spinks. And that is not all: the output power per unit mass of the yarn already rivals that of conventional electric motors.

“Carbon nanotubes, which are normally stiff and strong but that have been made more flexible by spinning them into yarns, are ideal for making such muscle-like structures because they have good electrical conductivity,” adds Spinks. “Our work also shows that we can efficiently charge the thread with just a few volts of electricity, and that the threads are strong enough to sustain large weights – for example, the plastic paddle we attached is nearly 2000 times heavier than the thread itself.”

Propelling microrobots

The structures could be useful in applications such as microfluidic pumps, valve drivers and mixers. Indeed, the set-up used by researchers (a plastic paddle attached to the rotating yarns) is a simple mixer in its own right. Mixing fluids on the micro- and nano-scales is difficult but will be crucial for lab-on-chip diagnostics, for example. “Other likely applications are difficult to predict, but we are fascinated by the possibility of using our torsional muscle like a flagellum that would propel a microrobot in the same way it propels a bacterium,” says Spinks.

The team – which also includes scientists from the University of British Columbia in Canada and Hanyang University in Seoul, South Korea – now hopes to study the muscle-like structures in more detail and optimize the yarn geometry. It also hopes to produce even better performing carbon-nanotube torsional muscles by adjusting twist angle and diameter.

The work is reported in Science.

Irish folk meets particle physics

By Matin Durrani

The guys who in 2008 came up with the annoyingly catchy “There’s no-one as Irish as Barack O’Bama” – more than a million hits on YouTube and counting – have re-recorded their song with new lyrics describing the latest mystery in particle physics.

Jumping on the huge interest in claims that neutrinos may travel faster than light, the musicians, known as the Corrigan Brothers and featuring someone called Pete Creighton, have called their new version simply “The neutrino song”.

The song’s not bad if cheesy synths and breezy pop are your thing, although it does that awful thing of going up a key near the end, which is a pet hate of mine.

But as I’ve learned to expect from a string of recent physics-meets-pop disasters, it’s the lyrics that will make your toes curl up.

I won’t spoil the lyrics by reprinting them here in full except to warn you of what is possibly the worst rhyme ever in the history of physics:

Now physics for ever may not be the same
And boffins are gonna be driven insane
If light’s not the fastest
What can this mean-o
And is something faster than the neutrino.

Would you consider not attending a conference because it would involve a flight?

By James Dacey

hands smll.jpg

As you may have just read in Tushna Commissariat’s account, on Monday and Tuesday scientists gathered at the Royal Society’s headquarters in London for a meeting about the Earth‘s climate history. One of the speakers at the event was James Hansen, a highly respected US space scientist, who is also well known for his advocacy of action to limit the impacts of climate change. In his talk, Hansen argued that – based on recent observational data – rapid reduction of fossil fuel consumption is essential if we are to avoid environmental catastrophe.

Following his talk, Hansen was asked the inevitable question of whether he saw any conflict of interest in his taking a transatlantic flight to deliver a lecture on the importance of cutting greenhouse gas emissions. His response was to say that at this stage it is already too late for this sort of minor sacrifice to make a significant difference, and that the more important thing is to communicate the message that urgent government action required. Hansen argued that the key to avoiding further rapid warming is for policy makers to establish high taxes on carbon emissions, which would act as an incentive for the development of green energy technologies.

But we want to know your opinion on this in relation to your professional life. Would you consider not attending a conference because it would involve a flight?

Yes. I would not attend, even if it could hurt my career.

No. My sacrifice would have no useful impact.

Possibly. I try to significantly limit my air travel.

I would take another means of transport, even if it drastically increased my travel time.

Please have your say by visiting our Facebook page and taking part in this week’s poll. And feel free to post a comment on the poll to explain your answer.

In last week’s Facebook poll we looked at the issue of financing large-scale science projects such as CERN’s Large Hadron Collider or the ITER project – the world’s largest experimental tokamak nuclear-fusion reactor, under construction in the south of France. We asked whether, in general, you think that “big science” facilities are value for money? 49% of respondents answered that yes they are worth the money, with just 3% answering no. The remaining 48% selected the measured option of “depends on the project”.

Craig Levin, one of our Facebook followers based in Chicago, Illinois, who voted yes, believes that funding agencies must look beyond the scientific goals of a project when making decisions. He commented that “one also has to take into account the return on investment and economic impact that these programmes can have on the economy, not just the scientific discoveries”. Marios Barlas, a follower based in Patrai, Greece, who also voted yes, takes a more Promethean view of science, commenting that “science never goes to waste. Be it theoretical or applied medical or humanitarian. There is always something to gain even out of utter failure.”

'A different planet'

NASA’s Dr James Hansen (Courtesy: Greenpeace)

By Tushna Commissariat

This Tuesday I was in London meeting some exciting and important people in science. While you will have to wait until tomorrow to find out who I met with in the morning, in the afternoon I went along to the closing lecture at Royal Society’s paleoclimate conference Warm Climates of the Past – a Lesson for the Future?. The lecture was given by Dr James Hansen – the head of the NASA Goddard Institute for Space Studies who has been very vocal on the subject of climate change since the 1980s.

In “Earth’s climate history: lessons for the future” Hansen spoke about how observations of past climates coupled with current-day observations suggest that hard-hitting and immediate measures need to be put in place to avoid further global destruction. Rapid reductions in the use of fossil fuels are the best way to do so, he argued.

Hansen began his talk by saying that our basic understanding of the Earth’s paleoclimate history should depend more on global “real-world” geological observations, rather than climate models and theories. He feels that the Earth’s history provides the information that is necessary to better understand climate change today and that researching “climate sensitivity” at any given point depends on the timescale taken into consideration and the “climate state” at that given time.

Hansen went on to say that when some generally “intelligent people” say that the Earth has been a lot colder or warmer in the past, he is quick to point out that he doesn’t think that the global mean temperature was ever more than a degree higher, as far back as the last glacial period.

He categorized the three main factors affecting the global climate over the past 65 million years and presented the amount of warming change they would cause in Watts/m²:

*external effects (solar irradiance): +1 W/m²

*surface effects (continental location – geological changes): ~1 W/m²

*atmosphere (CO₂ change): >10 W/m²

He pointed out that the natural change in CO₂ has been steady at about 0.0001 ppm/year, whereas the human-generated rate today is at about 2 ppm/year. He also showed that the sea level has been rising at about 3 m per millennium, as compared with the near-constant level it has maintained for the past 6000–7000 years. His hard-hitting statement that “Humans could produce ‘a different planet’” makes it clear that he feels very strong measures need to be put in place to preserve the planet as we know it.

His main suggestion to achieve a more stable climate was a drastic cut in the use of fossil fuels worldwide, by levying high taxes on their use. “We cannot burn all the fossil fuels and yet our governments go along with that,” he said. “A solution has to be a gradually rising carbon tax.” He went on to explain that such a tax would mean that fossil fuels derived from tar sands, for example, would almost immediately stop as it would not make economic sense and that coal would follow soon after. He also feels that such a tax would go a long way toward making clean fuel sources the norm. “Rapid reduction of fossil-fuel emissions is required to succeed in preserving a planet resembling the one that civilization developed,” he said.

On a similar note, a recent Physics World opinion piece, titled “How big is your footprint?” and written by astrophysicist Phil Marshall of the University of Oxford, talks about how physicists carry the responsibility to reduce their own carbon footprints. These can be considerable when you consider the amount of energy that is required to run physics facilities or fly across the Atlantic frequently for conferences. For example, he points to CERN’s Large Hadron Collider energy bill – estimated at about €10m per year – comparable to that of all the households in the region around Geneva. He estimates that US astronomers use an additional 130 kWh per day more than the average citizen.

Marshall also talks about a workshop in Lund, Sweden, this week, where researchers are discussing energy for sustainable science to identify ways to do large-scale physics research with a reliable, affordable and sustainable energy supply that is “carbon neutral”. To read about that and maybe take a look the wiki Marshall runs for green-minded astronomers, take a look here.

Ultrafast interference technique makes a splash

Physicists in the US have developed a new imaging technique that has allowed them to observe the splashing process in great detail. They used the method to look for an air gap that was believed to form when a liquid drop strikes a solid surface, causing tiny droplets to splash out. While they did see such a gap form, they were able to conclude that it is not responsible for splashing – at least in the water–glycerol drops studied.

For more than a century, physicists have used high-speed photography to capture often-beautiful images of the splashes that occur when a liquid drop strikes a solid surface and produces a ring of smaller droplets. However, this beauty belies the complex physics underlying splashing and successive generations of physicists have struggled to understand the process – which is important in practical pursuits as diverse as spray-painting and pesticide application. In 2005 Sidney Nagel and colleagues at the University of Chicago added to the mystery by discovering that a reduction in the ambient air pressure reduces the amount of splashing. This seemed counterintuitive because it had been thought that greater air pressures would tend to hold the drop together, while lower pressures would allow it to break up into a splash.

One proposal put forth by Michael Brenner and colleagues at Harvard University is that air gets trapped under the drop when it nears the surface – and it is this thin layer of air that causes the splash. The lower the pressure, the less trapped air and therefore the splash should be smaller. Others, including Nagel, believe that splashing is driven by interactions between liquid and air at the edge of the drop as it flattens and spreads out on the surface. Now, however, Nagel and Michelle Driscoll have come up with a new technique to monitor how much air is trapped under a drop. Their measurements suggest that trapped air has nothing to do with making the splash, at least for the liquids they studied.

Mind the gap

Their technique is based on an established method for measuring the thickness of very thin films. Monochromatic light from an LED is fired at the drop as it flattens on the surface. Some of this light reflects from the surface and some from the interface between the liquid and the trapped air. The result is an interference pattern from which the thickness of the air gap can be deduced. The challenge for Driscoll and Nagel was to capture this pattern in real time – with particular emphasis on the first few hundred microseconds, which proved to be crucial to understanding the role of trapped air. To do this, they used a high-speed camera that was able to capture the diffraction pattern at 67,000 frames per second. Nagel and Driscoll also had to make sure that they measured the thickness of the air gap and not the thickness of the liquid – which they did by dying the liquid black.

The liquid used by the pair was a mixture of glycerol and water that was chosen because its higher viscosity means that splashing occurs a relatively long time after impact. This makes the process easier to study than the splashing of lower-viscosity fluids such as water. The measurements revealed that a bubble is present under the fluid after about 50 μs after impact. “The behaviour of this air bubble is, to the extent that we are able to investigate in our experiments, consistent with what was predicted in the theory and simulations of Michael Brenner and his collaborators,” Nagel says.

However, as the liquid spreads out, the bubble appears to flatten out slightly, but nowhere near as rapidly as the liquid itself. After about 600 μs a thin sheet of liquid lifts off from the edge of the expanding liquid. It is this sheet that physicists believe will eventually break up to form a splash. However, after 2 ms this thin sheet is still expanding but there is no sign of any splash droplets forming.

Indeed, the main finding of the experiment is that the bubble is completely formed by about 150 μs after impact, whereas the splashing occurs much later and far away from the bubble. As a result, Driscoll and Nagel believe that the splashing is likely to be caused by interactions between the uplifting sheet at the edge of the flattening drop – not by air trapped under the drop.

Brenner told physicsworld.com that the experiments do not rule out the air-layer theory completely because the viscosity of the fluids used are much higher than the fluids considered in the theory. “The air layer was predicted for drops with low viscosity, such as water,” he explained. “It is abundantly clear that when the viscosity increases too much, the assumptions of the calculations break down – and then we have no idea what should happen.”

So it seems that Nagel and Brenner have more experimental and theoretical work to do, respectively, before the mystery of the splashing drops is solved.

These latest results are described in Phys. Rev. Lett.107 154502.

Vacuum Expo hosts a range of technical meetings

Currently the only event of its kind in the UK, this year’s Vacuum Expo incorporates the 2nd Vacuum Symposium, organized by the Institute of Physics’ Vacuum Group and the RGA Users Group, and a one-day meeting on Nanostructured Metal Oxide Thin Films & Integrated Devices. Vacuum Expo also includes a comprehensive exhibition of the UK’s leading vacuum-technology suppliers and will offer opportunities for learning and networking. The two-day Vacuum Symposium will include free technical meetings for the more experienced vacuum user plus free training seminars for those new to vacuum. Day one features sessions focusing on residual gas analysers (RGAs). It will include a presentation from Chris Klepper of the ITER fusion project, who will discuss the development of ITER’s diagnostic RGA. Janez Šetina of the Institute of Metals and Technology in Ljubljana, Slovenia, will describe the challenges of RGA calibration, while Dave Seymour of Hiden Analytical Ltd will explain how RGA durability can be improved.

Day two of the Vacuum Symposium will focus on pump technology and will include an introduction to vacuum pumps and their applications by Clive Tunna of Oerlikon Leybold Vacuum. Consultant Ron Reid will speak about the challenges of pushing the limits of ultrahigh-vacuum pressures and Oleg Malyshev of the UK’s Daresbury Laboratory will talk about non-evaporable getter pumps.

Training seminars

Available on each day of the symposium will be two half-day training seminars run by specialist vacuum trainer Austin Chambers. One session will deal with the basic principles involved in creating and maintaining a vacuum, while the second will focus on vacuum in practice, covering how vacuum is produced and measured.

The Nanostructured Metal Oxide Thin Films & Integrated Devices meeting will be held on Wednesday 19 October and includes three sessions. The first will cover the synthesis, growth and modelling of films and devices, and will include an invited talk from Sarah Thornley of Plasma Quest Ltd on remote plasma sputtering plus a panel discussion. The second session is on characterizing and monitoring the properties of thin films and devices. It will include an invited talk on the direct optical monitoring of advanced metal-oxide films from Alfons Zoeller of Leybold Optics. The final session is on integrated devices and industrial application, and it will feature an invited talk from Martynas Audronis of Gencoa Ltd.

Vacuum Expo will include representatives from many of the vacuum industry’s leading companies and delegates will have access to this extensive pool of vacuum knowledge. New technologies on display at the exhibition will include surface-engineering equipment such as plasma-enhanced chemical-vapour-deposition sources and sputtering systems. Visitors will also be able to get a close look at a variety of pumping technologies, including ion, turbomolecular, rotary-vane and root pumping systems.

A wide range of vacuum-related equipment will be on show, including sample-handling systems, isolation valves and analytical instruments such as mass spectrometers and residual gas analysers. Power supplies and other electronics systems for vacuum systems will also be on display.

The event is held in conjunction with the Photonex exhibition at the Ricoh Arena in Coventry. Photonex is the UK’s largest event dedicated to optics, photonics and vision technologies. Photonex also has a conference programme and it includes sessions on optical metrology, biophotonics and the funding and innovation of new technologies.

Moon’s shadow creates a wake

During a total solar eclipse the Moon comes directly between the Sun and the Earth, casting a dark shadow that moves across land and sea. Now, researchers in Taiwan and Japan have shown that this shadow creates a pocket of high-pressure air that cuts through the atmosphere much like a boat through water – leaving a discernible wake. As well as confirming a 40-year-old prediction, the discovery could have implications for how nuclear tests are monitored.

Along with plunging a region into darkness, an eclipse also causes a sudden cooling of the atmosphere. The effect this has on atmospheric pressure is complicated and not properly understood. Some places cool faster than others, creating regions where the pressure increases and regions where it decreases.

Jianlin Liu of the National Central University in Taiwan and colleagues have used Global Positioning System (GPS) technology to confirm a 40-year-old prediction that “shadow boats” are created in the atmosphere during an eclipse. These are thought to be pockets of high-pressure air directly under the Moon’s shadow that push their way through low-pressure air much like a boat pushing through water.

Bow and stern waves

Indeed, the phenomenon can be understood in terms of a toy boat in a bathtub. If the boat is dropped in the water, ripples will spread out at a fixed speed. If the boat is moved forward, it generates waves at its bow (front) as it pushes water out of the way and at its stern (back) as water rushes in to fill the space behind. If the boat is pushed faster than waves propagate through the water, successive wavefronts will pile up and the waves grow until they become unstable and break.

In 1970 George Chimonas and Colin Hines at the University of Toronto used computer models of the atmosphere to predict that, during a solar eclipse, two pockets of high-pressure air would be created, travelling at over 3200 km/h – one at 30 km above ground level, the other at an altitude of 80 km. Since this is much faster than the speed of sound in air, these “shadow boats” would create bow and stern waves in the atmosphere.

That same year two physicists at Stanford University reported possible evidence of these pressure waves – known as acoustic gravity waves – originating from a solar eclipse. But acoustic gravity waves can be caused by many sources, such as earthquakes, nuclear explosions and even thunderstorms. Therefore a lot of data and sophisticated mathematical modelling are needed to say that a particular set of waves definitely came from a particular source – and over the next four decades scientists had not been able to unambiguously identify acoustic gravity waves from a solar eclipse.

Lucky break

Then, on 22 July 2009, researchers got lucky. Between 10 a.m. and 11 a.m. a total solar eclipse crossed Japan and Taiwan – regions that are covered by dense networks of ground-based GPS receivers. Liu and colleagues were on hand to record the event using about 13,000 GPS receivers and analyse the data collected.

The team used the GPS signals to map fluctuations in the total electron content (TEC) of the ionosphere – the upper part of the atmosphere above about 85 km in altitude. The TEC is related to atmospheric pressure, allowing the researchers to see distinct bow and stern waves from the shadow boats for the first time. They measured an interval of about 30 minutes between the bow and stern waves, which allowed them to calculate that the shadow boats were about 1700 km long.

While bow and stern waves have finally been observed, Liu is cautious about saying that the standard explanation for the effect – pockets of high pressure forcing their way through regions of reduced pressure – is beyond doubt. “Most likely we think it’s regions of high pressure but we don’t have any exact numbers for that. What we observed are the facts; we still need time and effort to work out what really happened in that atmosphere,” he explained.

Jean-Bernard Minster, a geophysicist at the Scripps Institute of Oceanography in California believes that the work’s principal importance lies not in what it tells us about solar eclipses but in its advances in monitoring the ionosphere. “From the point of view of monitoring the nuclear test ban treaty, being able to understand what ionospheric disturbances look like and what their sources may be is really important.”

The work is described in Geophys. Res. Lett. 38 L17109.

How big is your footprint?

Physics, like everything else, has an energy problem. Big science – from huge particle accelerators to massive ground-based telescopes – not only costs big money, but also needs lots of energy to run. CERN’s Large Hadron Collider, for example, has an energy bill comparable to that of all the households in the region around Geneva – estimated at about €10m per year. Telescopes with huge air-conditioned domes churn out terabytes of data that are analysed on thousands of desktop computers worldwide and compared with simulations run on supercomputers housed in air-conditioned centres. As facilities get ever larger they will need more and more energy to run.

The issue of large facilities’ power needs is set to be tackled this month when researchers meet in Lund, Sweden, to discuss “energy for sustainable science”. The meeting’s goal is to identify ways to do large-scale physics research with a reliable, affordable and sustainable energy supply that is “carbon neutral”. Indeed, big science does not have to be a big polluter. Those building the European Spallation Source in Lund, for example, will be able to claim that theirs will be the first carbon-neutral big-science facility when it is completed towards the end of the decade. All of its electricity will come from renewable sources, built as part of the project, and more than half of the heat it generates will be recycled and fed back into the local heating system.

Facilities such as the ESS are becoming more carbon conscious – but what about individual scientists? Are their personal footprints relevant? In 2009, together with colleagues across the US, I carried out an approximate energy audit of US astrophysics for the US 2010 decadal survey (see arXiv:0903.3384). The study reached a surprising conclusion: in astronomy it is not the big facilities that are the most polluting, but the astronomers themselves, as they fly all over the world to observatories, conferences and meetings. We estimated that astronomers were averaging some 23,000 air miles per year during the course of their work, which at 1.8 kWh per mile added up (in our simple model) to about 85% of the professional energy consumption of astrophysics. For comparison, the average US citizen uses about 250 kWh per day on transport, heating, lighting, food, consumer goods and so on; US astronomers use an additional 130 kWh per day doing astronomy.

Fortunately, there are only a few thousand astronomers in the US, so the actual impact of astronomy is very small, accounting for a tiny fraction – about 1000th of a per cent – of total US energy use. But astronomy’s consumption per astronomer is high, about the same as that of a high-flying businessperson – and because it is carbon footprint per capita that needs to be decreased, we have an opportunity to lead the way. Individual physicists can help to solve the energy problem, and not just the ones whose research is in new technologies; we can all contribute by setting the right example.

In it together

Well-established climate science summarized by, among others, the Intergovernmental Panel on Climate Change, has shown that the Earth is getting warmer, and predicts severe consequences for humanity if our greenhouse-gas emissions are not significantly reduced. Fortunately, many countries have pledged to take action, with the UK, for example, passing the 2008 Climate Change Act, which commits it to reducing its emissions by at least 80% by 2050 (compared with 1990 levels). Achieving this, in the UK and across the world, will require mass action, because the bulk of the consumption is done by the bulk of the consumers.

Yet many still seem disengaged with the problem. A recent survey by the information provider Nielsen shows that more than half of Americans are not concerned about climate change. For many people climate change seems distant in either or both of its causes and effects, while some are sceptical about the scientific evidence that links human activity to increasingly high global mean temperatures and extreme weather events.

Physicists need to talk about climate change, and can play a small but important role by putting evidence and numbers in such conversations. Indeed, trusted voices are at a premium at the moment: it matters what physicists say. It matters even more what they do. The staff at the Gemini Observatory South in Chile, for example, are reducing their environmental impact in all areas with their “green initiative”. Calculating and logging the facility’s energy consumption every month, in 2009 alone they reduced their overall number of observatory air miles by 23%.

Many physicists are doing remarkable work tackling climate change, and the least the rest of us can do is to champion their work in support

Significant energy savings such as these are actually not too difficult to make. Some travel is very high value, with some workshops and conferences exponentially increasing research productivity – but some is not, and could be replaced by video conferences without much loss in outcome. The gain in time not wasted sitting in planes may tip the balance: push for video meetings, make them happen and often there will be a net gain in research output.

My experience from attending all-night workshops across the Atlantic by video is that the main thing required to make them work is the will to make them work; the technology is already good enough, and increasingly widespread. Informal discussion is indeed important, but there is no reason why it cannot happen in the presence of a videoscreen – it is not difficult to imagine “teleschmoozing” in meeting breaks.

Everyone is used to cheap travel, but it turns out that its true cost – the environmental one – is high. Currently, one carbon permit in the European Union Emissions Trading Scheme (worth one tonne of emitted carbon dioxide) costs about £20. Just how high this price will need to rise in the future is an active area of research, but the results so far are eye-opening.

The price is right

Last year I attended a seminar at Stanford University by management scientist John Weyant about modelling the world’s ecosystems and economies in various climate-change scenarios. The models, fitted to data and then cautiously extrapolated over the next century, were being used to explore various mechanisms for achieving one future history over another. In the discussion afterwards someone queried the estimated level of the carbon tax in 2050: was Weyant’s value of $2000 per tonne of emitted carbon dioxide an overestimate or would $1000 per tonne be sufficient? As a physicist in the audience, I took away the following message: while the uncertainty in the global modelling was a factor of two, these scientists were discussing a required increase in the price of carbon emissions over today’s value by one to two orders of magnitude. They were talking about a very different world – and one that may take quite a bit of getting used to. Will ships and airships make a comeback, making travel cheap in carbon but expensive in time? Will governments heavily subsidize jet fuel for airlines to allow poorer people to travel? Will research budgets increase to match the rising cost of carbon? Low-carbon research methods seem like a very good investment for the future.

Many physicists are doing remarkable work tackling climate change, which may be the greatest challenge humanity has ever faced. The least the rest of us can do in return is support them by championing their work. We can also act on the ecologists’ warnings by reducing our own carbon footprint, while encouraging those around us to do likewise, and keeping up the pressure on our governments to make and honour global commitments. Some may object to scientists being advocates for action – but anyone who understands the science can see the need for it. As Nobel laureate Sherwood Rowland from the University of California, Irvine, put it: “What’s the use of having developed a science well enough to make predictions, if all we’re willing to do is stand around and wait for them to come true?”

The first joint workshop on energy management for large-scale research infrastructures takes place in Lund, Sweden, on 13–14 October

Discovering the human side of science

By James Dacey

Scientists frequently feature on the radio these days, usually to provide the expert voice on the technicalities of an issue in the public interest – be it climate change, energy issues or the latest medical advance. But these researchers are rarely given the airspace to tell us anything about themselves, such as what first inspired them to pursue a career in science and what motivates them to keep going. A new series on BBC Radio 4 is offering just this.

The Life Scientific, which first aired today, will be a series of 30-minute programmes hosted by Jim Al-Khalili, the nuclear physicist, author and broadcaster based at the University of Surrey in the UK. Each week Al-Khalili will meet an eminent scientist from diverse fields and invite them to talk about their lives and careers in science. Regular Radio 4 listeners will be familiar with the format, which is similar to Desert Island Discs – the show in which celebrities discuss their favourite songs in the context of their life experiences.

In the first episode, which you can listen to here, Al-Khalili meets the Nobel-prize-winning geneticist Sir Paul Nurse, who is also the reigning president of the Royal Society. Despite his lofty status, Nurse comes across as a very open guest. He speaks in earnest about how he reached his current status in part thanks to his humble upbringing in northwest London – Nurse’s dad was a chauffeur and his mum a cleaner. “It wasn’t that I grew up in a bookish family and only got used to speaking to intellectuals – I like talking to people and I like talking to people from all backgrounds,” he says.

Like many scientists of his generation, Nurse says that his passion for science was fuelled by the space age. He recalls the excitement he felt at reading as a boy of eight or nine that Sputnik II would be passing over the UK that evening. When the Soviet spacecraft appeared as a bright star in the sky, Nurse tells of how he ran down the street in his pyjamas trying to keep up as the light vanished over the horizon.

A little later in the programme we hear about how in his 50s Nurse discovered a great revelation about his private life that was to change his view of the past forever. When applying for a Green Card to take up a position at the Rockefeller University in New York, Nurse was informed that his registered mother was the woman he had thought was his sister; and his father was unknown. It transpired that at just 18, Paul’s mum gave birth but the baby was immediately adopted unofficially by her mother (Paul’s actual grandmother). So Paul’s sister suddenly became his mother and his brothers became his uncles.

It all sounds a bit messy but Nurse tells the story in good spirits. “I now have to refer to everyone with a sort of joint relationship like ‘sister–mother’ or ‘brother–uncle’, just to keep things straight in my head,” he tells a surprised Al-Khalili. “Think of the irony of it: I’m a geneticist and here’s my own genetics I didn’t have a clue about.” Perhaps this resilience and wry sense of humour goes a long way to explaining Nurse’s rise to success.

Next week on the programme Al-Khalili will be chatting with the US-based cognitive scientist Stephen Pinker. Other confirmed guests for future episodes include the Northern-Irish astronomer Jocelyn Bell-Burnell, who co-discovered pulsars as a postgrauate student in the 1960s.

Meanwhile, on Thursday 20 October Al-Khalili will also be hosting a special online lecture on physicsworld.com about some of the relatively unknown scientists of the medieval Islamic Empire. In his new book Pathfinders: the Golden Age of Arabic Science, Al-Khalili tells the stories of some of these characters and how their works paved the way for the likes of Newton and Copernicus to revolutionize science. You can register here to attend this lecture.

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