Table of contents

One of the big challenges in cosmology is to top down the amount of "dark matter" in the universe. But how can astronomers be sure that dark matter exists if as its name suggests, it cannot be seen? The answer is that dark matter, like ordinary matter, exerts a gravitational influence on both light and matter – and this influence allows it to he detected. Now four teams of astrophysicists have detected a phenomenon known as weak gravitational lensing – in which dark matter distorts the light from distant galaxies – for the first time. Three of the groups published their results on the Los Alamos preprint server first (xxx.lanl.gov/abs/astroph/0002500, 0003008,0003338), while the fourth opted for the more traditional route (D M Wittman et al. 2000 Nature 405 143).

For the first time, physicists have reproduced in the laboratory the fluid-dynamo mechanism that is thought to generate the Earth's magnetic field. The experiment was carried out by researchers from Latvia and Germany at the Latvian University in Riga. The magnetic fields measured by the team match the predictions of fluid-dynamo theory (A Gailitis et al. 2000 Phys. Rev. Lett. 84 4365).

The best resolution in most imaging techniques is limited by the wavelength of radiation used. This so-called diffraction limit can be overcome by illuminating the sample through a sub-wavelength aperture.

The UK's best research in physics and astronomy is as good as any in the world, according to a report by an international panel of physicists. However the panel says that the UK "continues to suffer from a low level of funding [and] is currently in a state of slow recovery from a long period of chronic underfunding". The panel was set up at the request of the UK government's Office of Science and Technology to report on the "standing, balance and potential of physics research in the UK".

The standard of physics education in England is very high, according to the review of higher education by the Quality Assurance Agency (QAA). The results from all 41 departments in England and Northern Ireland are now in, and 80% of departments scored between 22 and 24 points out of a possible total of 24, higher than in many other subjects. Ten departments scored 24 points (see table).

Some 17 years after President Reagan approved the ill-fated strategic defence initiative more commonly known as Star Wars, the issue of defending the US against foreign missiles has re-emerged. In a few weeks time the Pentagon plans a critical test of the National Missile Defense system, the so-called "son of Star Wars". The test should help the Clinton administration to decide whether to deploy the system – which, when fully assembled, will consist of 100 anti-ballistic missiles, steered by ground radar and satellites.

"Our vision is a world where every person, place and thing is connected and communicating via the Web," says Dick Lampman, director of HP Labs – the research arm of the giant Hewlett-Packard corporation. His vision might seem either exciting or terrifying depending on your enthusiasm for the Internet, but it is a vision that sets the agenda at the company's six research laboratories around the world. The company wants to make the Internet "mo"re useful, more accessible and more reliable" by developing everything from new scanners, printers and imaging devices to advanced software, networking and security products.

UK government is to sell off 75% of the Defence Evaluation and Research Agency (DERA) by the summer of next year. It plans to split the agency which is one of the largest research organizations in Europe, into two. One part, currently dubbed NewDERA, will he privatized, and a smaller core agency will remain within the Ministry of Defence (MOD). DERA has an annual turnover of about £ 1bn and employs some 11700 staff, including about 2600 physicists, most of whom are expected to become part of the privatized Firm.

"Science is more controversial than art can ever be." Strange words for an artist, perhaps, but Cornelia Parker has been inspired by science for many years. Indeed, Parker's "Cold, dark matter" – the suspended remains of a garden shed that the army blew up on her behalf – is currently on show at the recently opened Tate Modern gallery in London.

A new generation of facilities for the treatment of cancer with carbon-ion beams from particle accelerators is being planned for Europe. A new hadron-therapy centre at Heidelberg in Germany will treat its first patient in 2005 and a similar centre is expected to open in Lyon, France, in 2007. Meanwhile, a proposed new centre in Milan is waiting for approval by the Italian Ministry of Health and other partners, and the Karolinska Institute in Stockholm is also considering plans for such a facility. The investments follow promising results from the Chiba hadron-therapy centre in Japan.

For a 77 year old who has just given about 50 interviews to the media on both sides of the Atlantic, Freeman Dyson shows no sign of tiring. We meet at Claridge's hotel in London, the day after the Duke of Edinburgh presented him with this year's Templeton prize for progress in religion. Sitting quietly in the corner of the hotel restaurant, Dyson is disarmingly honest when I ask him why he has won the $600 000 prize. "The answer is I don't know Clearly it has something to do with my books. I have written hooks that have some religious overtones – they're not hooks about religion but books of a personal kind that describe the way I look at the universe."

American astronomers have produced a roadmap that charts their priorities for the next ten years. The report outlines the key scientific challenges over the next decade (see box) and identifies a series of new initiatives that will help to advance our understanding of the universe. The roadmap was produced by a committee of 15 astronomers and astrophysicists set up by the National Research Council. It is the successor to a similar report from 1991 that led to many advances in astronomy during the 1990s.

"As one newspaper said, I've had the longest political apprenticeship in history." laughs Phil Williams, professor of physics at the University of Wales in Aberystwyth and shadow Welsh secretary for economic development. Until last summer Williams was strictly an amateur politician, but at the age of 60, when many an academic starts to think about retiring, he fought and won an election to the Welsh National Assembly.

News in brief articles for June 2000

Every four or five years a panel of wise men – and, occasionally a woman – assesses the quality of the research in all the physics departments in the UK. The panel awards marks that can range from 1 (the very worst) to 5* (the very best). The results of this research assessment exercise (RAE), which covers all subjects, are invariably met with a mixture of pride, relief, disappointment and threats of legal action.

Exchanging messages in absolute secrecy is an age-old problem. In classical physics, there is nothing, in principle, to prevent someone from eavesdropping on a message without being found Out. Fortunately, in quantum mechanics, the uncertainty principle dictates that every measurement disturbs an unknown state. So if a message is encoded using quantum signals – such as photons polarized at various angles – then any eavesdropping will almost surely be spotted. This is the principle that lies behind "quantum cryptography".

The principal speaker at the dedication of the main accelerator at Fermilab on 11 May 1974 professed bewilderment. "Until the call which commanded me here," physicist Leon Lederman told the audience, "I hadn't even known that the protons we had been studying were coming from an undedicated accelerator." He claimed to be out of his element. People who run dedication ceremonies are not scientists, he said, but "older persons, or statesmen or philosophers".

The article "Dark-matter dispute intensifies" (April p21) reported a presentation by the DAMA collaboration at the recent dark-matter conference m Marina del Rey, in which they claimed to have observed a signal for weakly interacting massive particles (WIMPs). Such particles have been predicted by various extensions of the Standard Model of particle physics, and their discovery would represent a major breakthrough in both particle physics and astrophysics.

In her forum article "Collaborating with the enemy?" (April pp1 7–18), Gina Hamilton presented the results of her classroom investigations, which appear to show that girls do better at physics if they study together with boys, rather than on their own. Hamilton says that girls are afraid to argue with one another and need boys to challenge their thinking While thought-provoking and interesting, Hamilton's conclusions on the relationship between gender and achievement in science remain dubious.

As a schoolteacher and an active member of the Women in Physics group of the Institute of Physics, I am becoming increasingly aware that a significant proportion of girls who study physics at university go on to have a career in medical physics. Sadly I find that medical physicists are almost invisible to the general public. If we wish to encourage more girls to take up physics, surely we should be promoting the careers in which they are successful?

The geometry of the universe is Euclidean and space is flat. This has now been confirmed from detailed measurements of the cosmic microwave background – the radiation left over from the big bang – by an international team of astronomers from Italy the UK, the US, Canada and France. The Boomerang collaboration, led jointly by Paolo de Bernardis of the University of Rome and Andrew Lange of the California Institute of Technology has measured the angular distribution of temperature fluctuations in the microwave background with unprecedented accuracy Such fluctuations contain information about the energy density and curvature of the universe (P de Bernardis et al. 2000.Nature 404 955).

Every year around 596 million tonnes of rice are grown around the world, and some 30 million tonnes of this – approximately 2×10¹⁵ grains – are inspected by food-sorting machines before being sold. By identifying and removing defective foodstuffs and contaminants, producers can recover more of the end-product and control its quality. Indeed, the sorting process adds so much value to the final product that the initial cost of purchasing and setting up a sorting machine can often be recouped in a matter of weeks, rather than months.

Once upon a time, a devil decided to build a mountain. As the pyramids had already been built, he elected to try a different approach with the 1018 or so cube-shaped stones that he had at his disposal. In the end he opted to make the surface area of the structure as small as possible, which resulted in a mountain that was almost hemispherical. After stopping to admire his work, the devil noticed that the surface looked like many staircases leading to a large flat terrace at the top, so he decided to climb the mountain.

The concept of a refractive index is familiar to every physicist: wine glasses sparkle, deep pools appear shallow and camera lenses focus sharp images. As every physics student knows, Snell's law relates the angles of incidence and refraction in materials with different refractive indices. However, my complacency was recently given a jolt by Sheldon Shultz, David Smith and co-workers at the University of California at San Diego who have made a material with a negative refractive index (D Smith et at. 2000 Phys. Rev. Lett. 84 4184).

Nanotechnology is predicted to spark a series of industrial revolutions in the next two decades that will transform our lives to a far greater extent than silicon microelectronics did in the 20th century Carbon nanotubes could play a pivotal role in this upcoming revolution if their remarkable electrical and mechanical properties can be exploited.

Solid-state devices in which electrons are confined to two-dimensional planes have provided some of the most exciting scientific and technological breakthroughs of the last 50 years. From metal-oxide-silicon field effect transistors to high-mobility gallium-arsenide heterostructures, these devices have played a key role in the microelectronics revolution and are critical components in a wide array of products from computers to compact-disk players. From a more parochial perspective, the study of electrons in two-dimensional systems has also been responsible for two Nobel prizes in physics – to Klaus von Klitzing in 1985 and to Robert Laughlin, Horst Störmer and Daniel Tsui in 1998. This is testimony to the basic as well as applied interest of such devices (see Heiblum and Stern in further reading).

In 1991 Sumio Iijima used a high-resolunon transmission electron microscope to study the soot created in an electrical discharge between two carbon electrodes at the NEC Fundamental Research Laboratory in Tsukuba, Japan. He found that the soot contained structures that consisted of several concentric tubes of carbon, nested inside each other like Russian dolls.

In the past ten years or so, the remarkable electrical and mechanical properties of carbon nanotubes have captured the attention of researchers worldwide. This is largely because these novel structures are of significant fundamental interest and could lead to a huge range of potential applications worth billions of dollars. These range from nanoscale electronics and tools to manipulate individual atoms, to exceptionally strong materials, flat-panel displays and hydrogen fuel cells.

The numerous extraordinary properties of carbon nanotubes are now well known – as the other articles in this special issue emphasize – and it is clear that nanotubes differ from ordinary molecules and solids in many respects. In fact, nanotubes have an ambiguous identity: they have reasonably well defined structures – albeit a large variety of them – like molecules, but their relatively large length and width means that they also resemble solids. Indeed, nanotubes can be extended to macroscopic lengths and Widths to ultimately merge With bulk graphite, which has a familiar layered structure.

Interdisciplinary research is currently in fashion, and no interface is more in vogue than that between physics and biology But whereas the subject matter of, say, chemical physics or materials physics is relatively well defined, there is no such agreement on what constitutes biological physics, and no broad research programme to follow.

"Science without religion is lame; religion without science is blind."

I approached this latest collection of Abraham Pais's reminiscences with the unworthy suspicion that it might consist of scraps from the many notes the author must have made for his previous biographical and historical works. The opposite is true: these are well crafted, varied, charming and fascinating essays. The 17 physicists and mathematicians from the last century are ordered alphabetically, rather than chronologically or by the importance of their discoveries: how invidious that would be. They are selected on the basis that Pais knew them as friends or colleagues. (Most are dead.)

Not everyone can be a rocket scientist or a brain surgeon. In fact, to young physicists who have decided to continue actively using their science, career decisions can sometimes seem surprisingly limited – a stark choice between the traditional career paths offered by industry and academia. However, there is an alternative that allows physicists to make an impact on technologies as diverse as rocketry and medicine, while at the same time encompassing many of the advantages of working in pure research. That alternative is scientific consultancy.

Ever since the American theoretical physicist Alan Sokal had his spoof paper published in the Post-Modern journal Social Text, I have been trying to figure out what exactly Post-Modernism is. You may recall that Sokal – having noticed that articles in Social Text manage to fill up large areas of white paper without apparently doing much else – decided to submit a more-or-less arbitrary collection of Post-Modernist buzzwords to the editors as a kind of hoax. The paper was published.