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Priority battles

As a philosopher of science, I love priority disputes. They invite one to ask “How can it be that brilliant scientists agree that they’ve discovered something, but not when?” The answer instructs philosophers about the nature of discovery – and no true scientist can object to learning more about that. Indeed, the discovery of dark energy has been so contentious that debate over who did what and when still rumbles on a dozen years after the event.

Such were the disputes over the matter that a previous column by me, which earnestly tried to do justice to the topic, went through more than 20 drafts (December 2007’s “Dark Energy”). The most recent resurgence of the squabble was instigated by a seemingly innocuous column in the January 2009 issue of APS News. Entitled “This month in physics history”, it stated that word of “accelerating expansion” emerged after a press conference at the January 1998 meeting of the American Astronomical Society in Washington, DC.

The February issue of APS News carried a letter disputing that remark. It was written by Robert Kirshner from Harvard University, who was a member of the High-Z Supernova Search Team – one of the two teams of supernova hunters that discovered that the expansion of the universe is accelerating. “We should mark the dates of scientific discoveries from the submission of refereed publications,” Kirshner wrote, “not commemorate the extrapolations of reporters who get ahead of prudent scientists in drawing reliable conclusions.” The High-Z team’s submission date, as the reader may guess, was earlier than that of the other discovery team, the Supernova Cosmology Project (SCP).

The April 2009 issue of APS News carried replies. One, by Penn State University astronomer Ruth Daly, quoted her press release for the meeting explicitly stating that her results show that the universe “will expand at a faster and faster rate”. The other was by historian Michael Riordan from the University of California, Santa Cruz, who recalled being present at a still earlier event – a physics colloquium in December 1997 – at which SCP member Saul Perlmutter exhibited data indicating expansion, and hearing an audience member state that “these results implied the previously unthinkable: the need for a cosmological constant”.

Kirshner replied in July. The editors of APS News allowed Riordan a reply, before they declared the discussion closed. I am hoping it will continue elsewhere, for the debate reveals some fascinating insights into the role of techniques and technique-borrowing in discovery.

Perspectives on discovery

Kirshner is the principal warrior in this dispute, with virtually all others in both collaborations willing to share credit. From his perspective, publication is the sole indicator of discovery. The argument in favour of using a paper’s submission date to establish priority is that publication is a time stamp indicating that the results have been carefully checked. It is a sign that the results can be trusted. It is not an absolute guarantee – trust never is – but it is the firmest possible statement that “we did all the checks” by those in a position to make them.

Riordan’s letter, however, suggests that publication is not the sole indicator of discovery. Publication is retrospective; it says, “we already did the checks”. Moreover, a publication date is often artificial; these days, by the time a paper is published a preprint version has already been posted and circulated. Moreover, checks can drag on – when, for instance, you have to wait until supernovae die so that you can get a good background to subtract, and when, as in the SCP group’s case, you have more data to evaluate than other teams.

This can make it arbitrary to pin the complex discovery process solely to date of publication – like saying you only know how to drive when you get your licence. In essence, the dispute is not empirical but conceptual. The issue of exactly when dark energy was discovered will not be settled by more letters about submission dates and priority, nor by further details of when members of the SCP collaboration saw and transmitted news that their data showed accelerating expansion.

At the heart of this episode is an ambiguity in the meaning of discovery. Historians have long known that discoveries are not simple, unitary events made by a specific person or group at a specific place or time. Discovery is often distributed among groups, and in space and time, in a way that makes pinning it down contrived.

The philosopher Thomas Kuhn once described two kinds of discovery cases, “simple” and “complex”. In simple cases, what is discovered is predicted by theory; discoverers know pretty much what to look for and the criteria are clear for knowing when the goal is reached. Here, priority debates tend to be few. (Think of, say, the discovery of Pluto.) Complex cases catch the profession by surprise. Something emerges into scientific awareness slowly and confusedly, like when we first catch sight of something from a bad angle and have to shift position several times before we can confidently recognize it. (Think of the cosmic microwave background.) These cases do not involve confirming a prediction, and signs for completing a discovery can be unclear.

So where on the continuum between these two cases does the dark-energy discovery fit, and why? Part of the answer has to do with the growing role of statistics and systematics in astronomy discoveries. When a discovery emerges slowly from statistics along with uncertainties, as it did in this case, it is particularly hard to pin down the moment of discovery.

The critical point

The dispute invites us to ask one final question: “Why is it sometimes not easy for scientists to share credit, or to follow the adage that, if you really want to get something done, let others take credit?” The answer has to do with the role of prestige and reputation in science. These play a role in getting prizes, and – especially when funding for expensive future projects is involved – securing the resources for doing more and better science. Which true scientist is not interested in that?

• See “Dark energy: how the paradigm shifted” pp32–37, print edition only.

The giant and the thief

In 1696 Isaac Newton made what seems like a bizarre career move. Abandoning Cambridge University and the mathematical pursuits that made him famous, the 53-year-old scientist upped sticks for London to become warden of the Royal Mint. Part administrator, part coining expert, and part criminal prosecutor, this new role would occupy Newton for the remaining three decades of his life.

In Newton and the Counterfeiter, Thomas Levenson explores one of the most intriguing stories from these later chapters in Newton’s career: the great scientist’s dogged pursuit of a master criminal through the streets of London in the late 1690s. London was a toxic, throbbing city in those days, already boasting about 10% of the entire British population. An additional 200–300 new arrivals wandered into its confines every day. Many of them, including Newton, were seeking new lives, careers and fortunes.

Levenson, a professor of writing at the Massachusetts Institute of Technology, establishes the story by first taking readers on a rapid romp through the first 50 years of Newton’s life. He covers the common biographical highlights, including the 1687 publication of Principia. He also touches on some of the more obscure elements of Newton’s life – his alchemy, his mysterious illness of 1693 and his curious friendship with the Swiss mathematician Nicolas Fatio de Duillier.

After these first few chapters, the reader will have enough of a portrait of Newton to appreciate his motivations in pursuing the other main character in the book – a counterfeiter and criminal mastermind named William Chaloner. The son of an impoverished weaver from the Midlands, Chaloner started out as an apprentice nail-maker. However, he soon found that hammering coins was more profitable than hammering nails. He was a master craftsman, known for his skilful counterfeits and forgeries, and in his heyday he became quite rich. He was also notoriously slippery. More than once he was thrown in prison, and more than once he managed to beat the charges and walk out a free man.

Dashing as these actions may seem, readers of Levenson’s book will not likely be left rooting for Chaloner. He was a despicable character. In addition to counterfeiting, he stole property from people and sold it back to them. He also ran a thriving sideline betraying criminals and innocent associates alike. When he lacked a conspiracy to report to the authorities, he sometimes fabricated one. Numerous people went to the gallows while Chaloner bragged openly about his rewards.

As chief prosecutor of counterfeiters, Newton was certain to clash with Chaloner sooner or later. Newton’s appointment came at a critical time for the Royal Mint. Thanks to the efforts of Chaloner and lesser crooks, the circulation of fake coins had reached epidemic proportions: by 1696 Newton himself estimated that 10% of the coins then in circulation were counterfeit.

In his efforts to rectify this, Newton exerted the same sort of profligate enthusiasm that characterized most of his career, wading “hip deep into London’s underworld”, as Levenson puts it. Newton hired undercover operators to trawl pubs and prison cells to gather information. He had himself appointed justice of the peace in seven counties so that he could operate freely in all of them. He arrested, coerced and oversaw the execution of criminals. Perhaps most importantly, he helped persuade the British government to embark on a complete recoining of the realm’s currency. The old hand-hammered coins, which were easier to fake, were taken out of circulation and replaced with the more modern industrially milled coins.

Some counterfeiters might have been deterred by this new technology. Not Chaloner. Instead, the wily criminal hatched one of the boldest criminal conspiracies in history: he petitioned parliament for access to the Mint, arguing that the new coins were insufficiently protected against counterfeiting. He suggested that he, Chaloner, be allowed to inspect the coining machines and make alterations to them as necessary – a ruse simply meant to give him unfettered access to the equipment. He was so convincing that he almost succeeded, and no doubt he would have – had it not been for Newton.

The scientist-turned-civil-servant saw right through this proposal, and Newton began a relentless campaign to bring Chaloner down. As ever, Newton approached his task with a single-minded determination. He spent months deposing witnesses and tirelessly piling up evidence against his nemesis. As Levenson puts it, Newton regarded Chaloner as “someone not merely to be stopped, but crushed”. Even so, he nearly met his match in Chaloner, who repeatedly wriggled out of seemingly impossible legal tangles.

As a backdrop to his main narrative, Levenson presents a grim but compelling picture of London life at the close of the 17th century – from the open sewers in the mean streets to the incomparably brutal Newgate Prison. He also introduces numerous colourful characters along the way. There is Jonathan Wild, who controls the London underworld; and Obadiah Lemon, a street thug who specializes in using a fishing pole to snag hats off rich people passing in the streets below. We meet Kathy Coffee, one of the chief witnesses against the counterfeiter, and the irascible “hanging judge” Salathiel Lovell. And the book is filled with many criminals like Chaloner who came willingly to London seeking their fortunes, and who (also like Chaloner) only left when they were dragged through the dirt to the hangman’s tree.

In the end, the only character in the book who really seems to prosper is Newton. In his later years he is rich, knighted and head of the Royal Society. In London, he keeps the highest company and is surrounded by admirers and fiercely loyal supporters. Chaloner, on the other hand, winds up desperate and poor, and he eventually comes to a sorry end because of the ineptitude and disloyalty of the criminal company he keeps.

Yet Newton’s nemesis remains a colourful figure. Many writers have touched upon him in books covering the end of the 17th century, and of course anyone who has read a comprehensive biography of Newton will already be acquainted with “the man clever enough to challenge Newton”, as Levenson calls him. But this fascinating new book is the first to really explore Chaloner as a compelling character in his own right – and to great effect.

Chasing nuclear rainbows

Expeditions in search of a rainbow’s end never reach their goal. Efforts to solve the problem of nuclear-waste disposal have not had much success either – perhaps because they have been addressing questions the wrong way round. There are two basic challenges of waste disposal. The first is scientific: the waste must be kept somewhere out of harm’s way, where it does not incur major risks to current or future residents of the planet. The second is political: scientists must persuade and reassure the community as a whole that the waste is being handled, stored and disposed of safely. In The Road to Yucca Mountain, author J Samuel Walker gives a historical account of the politics of nuclear waste from the early 1940s to mid-2008. Despite the title, however, the waste-storage project at Yucca Mountain, Nevada, is barely mentioned until the last few pages. Instead, most of the book concerns earlier attempts to arrive at a waste policy. In particular, the machinations that accompanied initial proposals to bury high-level waste in salt mines in Kansas are described in some detail. These mines were supposed to be dry. But even before tests showed that water could transport material within the mined area, such geological questions had become rather irrelevant in the face of the strength of the political opposition.

Walker is the US Nuclear Regulatory Commission’s historian, and within his chosen remit his research is careful and thorough – witness the 35 pages of notes and references in a book where the main text covers only 186 pages. But his book has one great shortcoming: an almost total absence of science. In The Road to Yucca Mountain – as in the waste debate it describes – the science plays a secondary role compared with the interstate squabbling and the jockeying with the US government over where waste should be stored.

In some ways, this is a true reflection of the cut and thrust of the political story. In addition to the Kansas salt-mine debacle, Walker describes other federal initiatives that also foundered, as plans for test drilling in Michigan were aborted, and local objections were raised to sites in Louisiana, South Dakota and Vermont. Even in New Mexico, Washington and Nevada, where there was some public acceptance due to existing nuclear programmes, projects ran into serious local opposition.

Nonetheless, the book would have done a service if it had reflected on the scientific reasons why progress has been frustrated. The truth is that until recently, many important questions surrounding waste disposal could not be answered adequately. Some of these questions were biological. For most of the period after the Second World War, we did not understand the effect of radiation on life well enough to be sure what radiation levels were safe. Only in recent decades have the radiobiology and the epidemiology become sufficiently well established for us to be confident about the risks from low doses – whether acute, chronic or repeated.

This meant that in the earlier years the “experts” were not able to answer with confidence when pressed for firm reassurance on matters of radioactive waste. Politicians and activists pounced on this uncertainty. Consequently, a planned waste repository, though seen as “safe” in one decade, would be deemed “unsafe” before it could be built in the next. The tension that this created between experts and politicians led to claims of deception, which eroded mutual trust. By 1974 the political credibility of the US Atomic Energy Commission had fallen so low that President Gerald Ford disbanded it, dividing its responsibilities between the Nuclear Regulatory Commission and the Energy Research and Development Administration. However, as Walker records, these administrative changes were not enough to avoid the stalemate that then took place.

Now that the epidemiology of radiation is better understood, the most important decisions for nuclear experts concern the reprocessing of the waste and the need to keep it secure after disposal. It is widely acknowledged that nuclear waste should be placed where it is irrecoverable, thus reducing any chance of its use by terrorists. Many deep burial sites would provide natural security over the few hundred years needed – particularly if the waste is reprocessed, since reprocessing reduces both the volume of waste and its decay half-life. However, thanks to its association with the manufacture of weapons-grade fuel, reprocessing has had a bad press, and in 1977 President Jimmy Carter decided to defer it “indefinitely” – a serious backwards step for nuclear-waste disposal.

Ultimately, finding a solution to the nuclear-waste problem requires a degree of political confidence and trust that the right steps are being taken. In the past, these conditions have not been met, as Walker recounts all too clearly. Recently, however, scientists and policymakers have come under increased pressure to solve the problem, thanks to a need for the carbon-neutral baseload energy source that nuclear power provides. Any such solution will require a better appreciation of the science, widespread public re-education and more altruistic decision making.

In its scientifically superficial account, The Road to Yucca Mountain does not really face up to these underlying issues. Fortunately, history does not stop at the foot of the final page of any book. Since it was written, the future of Yucca Mountain and the ban on reprocessing (or “recycling”) have both been thrown into doubt by the new US administration. The matter of nuclear waste has already been on the table for more than 60 years, and its next chapter has yet to be written. But one thing is clear: if the science is put first, the problem can be solved.

Web life: Galaxy Zoo Mergers

So what is the site about?

Many readers will already be familiar with the Galaxy Zoo, a project that allows members of the public to trawl through images of galaxies obtained by the Sloan Digital Sky Survey (SDSS) and classify them according to their shape and features (see “Eyeballing the universe”). The image-processing power of the site’s 150,000 “citizen scientists” has already helped astronomers pick out interesting spiral and elliptical galaxies for further study. Now a new offshoot – dubbed Galaxy Zoo: Understanding Cosmic Mergers – aims to use similar “crowdsourcing” methods to enhance our knowledge of interacting galaxies.

How does it work?

Out of more than 900,000 images in the original Galaxy Zoo data set, volunteers identified about 3000 that showed two galaxies merging or colliding. Now the site’s developers want visitors to compare these real mergers with the results of collision simulations. By selecting the simulations that look most like the actual merging galaxies, and discarding those that appear different, users will be helping astronomers refine their models of how galaxies form. Weeding out “bad” simulations and highlighting “good” ones in this way might even allow researchers to estimate how much dark matter is present in the interacting regions.

What if none of the simulations look like the real thing?

“Getting a perfect result is hard,” acknowledges Chris Lintott, one of the Galaxy Zoo’s co-founders. “But getting close is easy.” If a simulation looks promising, users can “enhance” its outcome by tweaking parameters such as galaxy mass, speed and angle. This is where the real fun begins. For the most part, making a small change in, say, the mass of one or both of the merging galaxies has little effect on the result. Yet with a little tinkering, one can often find narrow regions of the parameter-space where the simulation is finely balanced between wildly divergent outcomes. In some ways, this is just a nifty trick; children of all ages will doubtless enjoy pulling and stretching their simulated galaxies into funky shapes. But it also shows just how important – and difficult – it is to develop models that offer realistic results.

Who is behind it?

The Galaxy Zoo team is a self-described “motley collection” of astronomers, computer scientists, Web developers and outreach specialists based at various institutions in the US, the UK and Europe. Prominent “Zookeepers” include Lintott, who also co-presents the BBC’s Sky At Night TV series; and Bob Nichol, a University of Portsmouth cosmologist and senior member of the SDSS. Most of them work on the site part-time, and as of early January, they are looking to hire new staff for both the technical and outreach-related aspects of the project.

How often is the site updated?

At the moment, the Zookeepers are adding a new merging-galaxy image to the site every day, although older ones will remain available for a short period so that users can revisit their favourites. If you get tired of galaxy-matching, take a look at the site’s official blog and forum, which are great places to learn more about the science behind the project and to share strategies with fellow users.

Can you give me a sample quote?

“For me, this project started 20 years ago when I was in graduate school,” writes Galaxy Zoo member John Wallin, an astronomer at George Mason University in the US. “I wrote a Fortran code to do some of this modelling work. You would set up a run, then wait hours to see the result. If it didn’t match, you had to wait hours for the next attempt…Our understanding of galaxy collisions has been limited by the lack of dynamical models…[But] with your help, we can create the models we need to understand the histories of hundreds of galaxy collisions. These models will be more reliable than any that a single scientist could create.”

Making a Big Bang on the small screen

Stars of the show From left to right, Raj, Howard, Leonard and Sheldon build a robot to enter a fighting-robot competition (credit: Warner Bros Television Entertainment)

By Michael Banks

You may have heard of, or possibly seen, the hit TV sitcom The Big Bang Theory, which features two brilliant postdoc physicists, Leonard and Sheldon, who are totally absorbed by science but fail to fit in with their 20-something non-academic contemporaries.

Now in its third season on the CBS network in the US and with a fourth commissioned, the show has over 13 million US viewers. The sitcom also airs in the UK on Channel 4 and last month E4, Channel 4’s digital network, started showing the third season.

In the January edition of Physics World, Nick Thomas from Auburn University at Montgomery, talks exclusively to the show’s stars and creators about why the series, which has a dialogue peppered with references to physics and mathematics, is such a roaring success with viewers.

Click here to read the full story.

Newton tribute helps ward off New Year blues

Newton celebrated in the latest “Google doodle”

By James Dacey

Welcome back to physicsworld.com for what will hopefully be another exciting year of research breakthroughs and technological innovations. That said, if you’re returning to work after a Christmas break of festivity and overindulgence, the first few days back can be more than a little gloomy. At least the folks at Google are doing their bit to try to lift the spirits of down-in-the-dumps physicists.

Attentive users of the popular internet search engine will have already noticed its tribute to Isaac Newton, the great English physicist who would be celebrating his 366th birthday were he still alive today. The iconic Google logo has been draped with the branch of an apple tree, which drops a fruit when you hover your cursor over it – a tribute, of course, to the incident that allegedly inspired Newton’s theory of gravitation and his Principia Mathematica first published in 1687.

Newton’s much anticipated follow-up Opticks, released to the public 17 years later, also has great resonance this year, as 2010 marks the 50th anniversary of the invention of the laser. physicsworld.com will be joining the celebrations with a series of video interviews with leading laser physicists and engineers, and there will also be a laser special for the May print issue of Physics World magazine.

So whether you’re returning to the office, to the lab, or anywhere else in between, try to ride out those New Year blues, as the celebrations and exciting breakthoughs are just around the corner!

Breakthrough of the year

The first complete ‘quantum computer’

For decades physicists have dreamed of building a quantum computer that could solve certain problems faster than a conventional counterpart. Actually building such a thing has proven extremely difficult, but in August Jonathan Home and colleagues at NIST unveiled the first small-scale device that could be described as a “quantum computer”. The chip can perform a complete set of quantum logic operations without significant amounts of information being lost in transit.

Over the past few years, Home’s team has used ultracold ions to demonstrate separately all of the steps needed for quantum computation. But in 2009, the group made the crucial breakthrough of combining all these stages on a single device, which was, in our view, such a significant piece of work that we felt compelled to pick it as our “breakthrough of the year”.

The device even looks a bit like an early computer chip – but don’t expect it to be running a quantum version of Windows any time soon. Its overall accuracy of 94% is impressive for a quantum device, but this must be boosted to 99.99% before it could be used in a large-scale quantum computer comprising many such processors.

What do the quantum computing experts have to say? “A great step forward and most impressive,” said Hans Bachor, at the Australian National University. “A tour de force,” said Boris Blinov of the University of Washington.

Home was back in the news in November, when he teamed up with David Hanneke and others at NIST to create a quantum computer from two trapped ions. The device can perform at least 160 different quantum-computing operations.

Much more work must be done before quantum computers become a commercial reality – but real progress was made in 2009.

The best of the rest for 2009

Top results from Tevatron

The Large Hadron Collider may have been hogging the limelight in 2009, but physicists on Fermilab’s Tevatron kept churning out a tremendous number of results. Indeed, it seemed that every week, at least one or two papers from Tevatron’s two main experiments (CDF and D0) were published in Physical Review Letters. While it’s tough to pick out the most important result, our favourite is the double act in March when CDF and D0 experiments independently reported unambiguous evidence that top quarks, the heaviest of the six known quark flavours, can be produced individually rather than in pairs as had been observed until now.

Spins spotted in room-temperature silicon

For several decades, physicists have promised smaller, faster and more efficient electronic devices that use electron spin to store and process information. But with the exception of giant magnetoresistance read heads in hard drives, physicists have struggled to create practical ‘spintronic’ devices. In November, Ron Jansen and colleagues at the University of Twente in the Netherlands made an important move in this direction by showing that spin-polarized electrons can be injected into silicon at room temperature. The spins endured long enough to suggest that spintronics circuits could include silicon features that are nanometres in size and operate at frequencies of 10–100 GHz – just like today’s integrated circuits.

Graphane makes its debut

The “wonder material” graphene burst onto the scene five years ago – and the sheet of carbon just one atom thick continues to wow physicists with its growing list of remarkable properties. In January, a team including the UK-based research group that discovered graphene announced a new material called graphane, made by adding hydrogen atoms to their original discovery. As well as being an insulator that could prove useful for creating graphene-based electronic devices, graphane might also find use as a hydrogen-storage medium that could help hydrogen-powered vehicles travel further before refuelling.

Magnetic monopoles spotted in spin ices

Ever since magnetic monopoles were first predicted by Paul Dirac in 1931, physicists have looked in vain for these elusive entities. In September, two independent research groups claimed to have caught sight of monopoles – essentially magnets with only one pole – in magnetic materials called spin ices. The spin-ice monopoles have very different origins from those predicted by Dirac, and therefore are unlikely to help physicists develop grand unified theories of particle physics or string theories. But because the monopoles occur in magnetic materials, understanding their properties could help with the development of magnetic memories and other spintronic devices.

Water on the Moon

The surface of the moon as seen by the Moon Mineralogy Mapper (left), which is on the Chandrayaan-1 lunar mission. (Courtesy: NASA)

We can see the surface of the Moon with the naked eye and some people have even driven on its surface – but until September we weren’t sure how much water is on our nearest neighbour. That’s when scientists working on the Indian space mission Chandrayaan-1 revealed a wealth of data suggesting that there is much more water than previously thought. And then a week or so later, NASA’s LCROSS probe smashed into a crater at near the lunar south pole, throwing up about 100 kg of water. The presence of water makes the long-term colonization of the Moon a little bit easier and such a colony could be a proving ground for a station on Mars – which we know has lots of water. I’m sure we will hear more in 2010 from NASA, ESA and other space agencies about future manned space missions.

Atoms teleport information over long distance

Once the stuff of science fiction, teleportation is now part of the physics lexicon. In January, Christopher Monroe and colleagues in Maryland and Michigan told us how to teleport quantum information between two atoms separated by a significant distance – an advance that could be a significant milestone in the quest for a workable quantum computer. The ions were one metre apart and until this work, teleportation had only been achieved between photons, and between two nearby atoms through the intermediary action of a third. Quantum teleportation is a “spooky” form of transport whereby quantum information such as the spin of a particle or the polarization of a photon can be transferred between particles without the movement of the particles or the transmission of information.

Black-hole analogue traps sound

Technion's Jeff Steinhauer — Jeff Steinhauer hopes to detect Hawking radiation in the lab.

Is there anything that can’t be simulated using ultracold atoms? In June, Jeff Steinhauer and colleagues at Technion University in Israel added black hole to that growing list. The team’s black-hole analogue can trap sound in the same way that an astrophysical black hole can trap light. But instead of a collapsed star, it involves a Bose–Einstein condensate – a collection of atoms so cold that they move coherently in the same quantum state. The next step is to see if the analogue emits something resembling Hawking radiation – particles that are created near to black holes and manage to escape, but have yet to be observed.

Dark matter spotted in Minnesota?

The physics community is still digesting this week’s news that the CDMS-II collaboration has come tantalizingly close to detecting dark matter. The team has found two events that fit a dark-matter constituent known as a weakly interacting massive particle, or WIMP. The probability that these could be radioactive decays or cosmic rays is 23% so much more work needs to be done. Will CDMS-II or perhaps another experiment make a stronger case for dark-matter detection in 2010?

And finally, a big bang at the LHC

No list would be complete with out a mention of the 2.36 TeV proton collisions earlier this month at the LHC – the highest energy ever. You can read about that and lots more in our look ahead to all the exciting physics that could be done in 2010.

2009 in pictures

Back in January, Nobel-prize winning physicist Steven Chu was sworn in as secretary of the US Department of Energy, making him the first working scientist to head the department since it was created in 1977.

Far side of the moon

2009 was the International Year of Astronomy, and with all the festivities came another gallery of awe-inspiring images. In February, a group of researchers in Japan released this gravitational map of the Moon using data obtained from the SELENE mission, which was launched in 2007.

Planets, planets everywhere!

More than 400 exoplanets – that is, planets orbiting stars other than our Sun – are now officially catalogued and new planets are being discovered all the time. In February, the French CoRoT space telescope detected the first solid exoplanet CoRoT-7b. The rocky, and therefore “Earthlike”, nature of the planet was confirmed in a paper published in September.

River dancing algae

2009 was also “Darwin Year” in celebration of the 200th anniversary of the birth of the evolutionary biologist and 150th anniversary of the publication of On the Origin of Species. Biophysics is now a field of research in full blossom as physicists continue to cultivate our understanding of the natural world. These spinning circles are Volvox algae – imaged by researchers in Finland and the UK – that are locked in a dance to increase their chances of fertilization (Phys. Rev. Lett. May).

Hubble bursts back onto the scene

In May, astronauts carried out a series of spacewalks to upgrade NASA’s Hubble Space Telescope. By September the 19-year old instrument had already returned a new bunch of breath-taking images including the Butterfly Nebula 3800 light-years away (left), and the Jet in Carina 7500 light-years away (right).

Hawking honoured at the White House

“From his wheelchair, he has led us on a journey to the farthest and strangest reaches of the cosmos. In so doing, he has stirred our imagination and showed us the power of the human spirit.” These were the words of Barack Obama as he presented the Medal of Freedom to Stephen Hawking at a ceremony at the White House in August. The US president described Hawking as “an agent of change”, and someone who “saw an imperfect world and set about improving it, often overcoming great obstacles along the way”.

Molecules revealed in all their glory

Physicists in Switzerland and the Netherlands unveiled a new form of atomic force microscopy (AFM) capable of identifying individual atoms within a molecule. In a paper published in August they revealed this image of a pentacene molecule where the hexagonal shapes of the five carbon rings are all clearly resolved for the first time.

Engineering the climate

Despite all the hot air, the world’s leaders have failed to cobble together any meaningful climate deal as negotiations broke down at the UN climate conference in Copenhagen earlier this month. If binding emission targets cannot be agreed in the coming year then governments may look increasingly to a “third way” – engineering the climate such as removing carbon dioxide from the atmosphere. In September, the UK’s Royal Society published a report that looks at different geoengineering options, including constructing giant sunshades in space that can reflect the Sun’s rays and introducing iron into the world’s oceans to rapidly increase the amount of phytoplankton that consume carbon dioxide.

Applied physics scoops the Nobel

Nearly half a century after their pioneering work, three optics researchers shared this year’s Nobel Prize for Physics, announced in October. Charles Kao from the Chinese University of Hong Kong won his share for his work on the transmission of light in optical fibres, which has allowed a revolution in telecommunications. The other half of the SEK10m prize money was split between Willard Boyle and George Smith, both from Bell Laboratories in the US, who won for inventing the charge-coupled device (CCD) – an imaging semiconductor circuit that forms the basis of digital cameras.

Cooper pairs do the splits

Working with a cartoonist, a group of physicists in Switzerland and Denmark produced this graphic to represent their new device – a Cooper-pair splitter. They created a “Y-junction” from a tiny piece of superconducting material that can split a pair of entangled electrons – particles that share a much closer relationship than is possible in classical physics. The device should pave the way for tests of the so-called non-locality of quantum mechanics in the solid state.

Big Bang machine bounces back

After beginning 2009 in disrepair, the Large Hadron Collider (LHC) completed a dramatic turn-around this year by becoming officially the world’s most energetic collider. Beams of protons were carefully re-injected in November and the energies were raised. Then, on the evening of 8 December, the LHC achieved for the first time 2.36 TeV collisions thus breaking the record previously held by the Tevatron at Fermilab in the US.

Dark matter detected at last?

For weeks the bloggers speculated feverishly.Then, last Friday the results were finally released – had the CDMS-II experiment made the first bona fide detection of dark matter? . Well, frustratingly, we’re still not quite sure. In a preprint submitted to the arXiv preprint server last Thursday, the US collaboration claim to have detected two “events” that are characteristic of dark-matter constituents known as weakly interacting massive particles, or WIMPs. However, they point out that there is a one-in-four chance that these events could be background noise. This will surely be one of the debates that shapes the landscape of fundamental physics in 2010.

What’s in store in 2010?

As we stand on the threshold of a new decade – the teens, the tens, call it what you will – physics is primed, in the immortal words of Charles Dickens, for the best of times and the worst of times. The good news is that collisions have already begun at the Large Hadron Collider (LHC) – the world’s biggest ever physics experiment – which is back in action following the magnet disaster of 2008.

With the first high-energy (10 Tev) collisions due by the end of the year – and maximum-energy 14 TeV collisions likely in 2011 – the stage is set for a stream of thrilling new discoveries. Before long we could see clear signs of the Higgs boson (or not) or perhaps even supersymmetry, extra dimensions or other “new physics”.

Those findings may have to wait until next year and probably beyond, but you can be sure that the particle-physics world will be abuzz with rumour and counter-rumour. And if the US Congress gives the nod to a request from the Department of Energy, the Tevatron collider may even continue for an extra year beyond retirement into 2011, ensuring that there is a real trans-Atlantic race for the Higgs, for a year at least.

There is also plenty to get excited about in astrophysics and cosmology, particularly following last week’s announcement by members of the Cryogenic Dark Matter Search in the Soudan mine in the US that they had tantalizing hints of the first direct detection of dark matter in the form of weakly interacting massive particles. Although the findings are by no means certain, a clear and convincing sign of the nature of dark matter could be imminent. When that comes – as it may do next year – it will be a huge breakthrough for physics.

Down to Earth

Next year should also see interesting findings from the Fermi gamma-ray space telescope. We can also expect plenty of coverage of the end of the space-shuttle era, which is due to come to a close in September with a final flight form the Discovery craft.

But it is not just in “big science” that exciting new physics is taking place. If 2009 is anything to go by, you can expect plenty of further exciting developments in metamaterials, graphene, spintronics and other areas of condensed-matter physics. Much more progress can also be expected in quantum information.

Indeed, we have selected as our own “breakthrough of the year” work carried out by physicists led by Jonathan Home at the National Institute of Standards and Technology (NIST) in Colorado, US, who created the first small-scale device that can be described as a ‘quantum computer’. The device, which performs a sequence of 15 logical operations with an overall accuracy of 94%, is a key step towards the development of a practical universal quantum computer.

Lasers will also be centre stage in 2010, which marks the 50th anniversary of their invention by Ted Maiman on 16 May 1960 at Hughes Research Laboratories in California, when he generated coherent pulses of laser light from a fingertip-sized lump of ruby illuminated by a flash lamp. In doing so, he beat a number of other physicists to the goal, including Charles Townes, who had earlier developed the maser – the microwave forerunner of the laser.

Key events to mark the golden laser jubilee are taking place around the world, including a special session at SPIE’s Photonics West meeting in San Francisco at the end of January, as well as at CLEO in San Jose in May. As you might expect, we will be marking the anniversary with a special issue of Physics World magazine in May and a series of video interviews with leading laser physicists and engineers as part of the physicsworld.com video series.

Speaking of lasers, 2010 will also see researchers at the huge new National Ignition Facility in the US beginning experiments to focus the energy of its 192 giant laser beams onto a tiny target filled with hydrogen fuel. There is a strong possibility that researchers will be able to reach “ignition” this year – the moment at which the device will produce more energy from fusion than is required to start the reaction. When that happens, it will be the culmination of more than 50 years of research, although releasing that energy in a form that could actually be used by a country’s electricity grid is another thing altogether.

Down down

But despite the great progress in physics, researchers in the UK and Japan are still coming to terms with savage cuts to research programmes. In the UK, the Science and Technology Facilities Council (STFC), which has a shortfall of £40m in its budget, is set to tear into its programmes in astronomy, particle physics and nuclear physics.

The council will be axing its funding for over 25 different projects, including the ALICE experiment at CERN, and slashing studentships by over a fifth. Worst of all, these are cuts to high-profile projects that get the public interested in physics in the first place. For the want of £40m they could do irrevocable damage to UK physics at the worst possible time.

The situation is not much better in Japan, where research funds could be cut in half – or possibly even terminated – following the government’s decision to slash over $35bn from the 2010 budget. The Spring-8 synchrotron in Hyogo and the B-meson factory at the KEK particle-physics lab in Tsukuba are among those facilities that could be hit, as could the Superkamiokande neutrino experiment at J-PARC as well as Japan’s involvement in the Subaru optical and infrared telescope in Mauna Kea, Hawaii. Negotiations will now take place in the ministry of finance with a finalized budget for 2010 set to be made at the end of December.

But let’s not end the noughties on too downbeat a note. Physicists in the US appear set for brighter times, with plenty of funds for energy research in particular following President Obama’s “recovery and reinvestment” bill. Work on two big Europe-based projects – the European Spallation Source and the ITER fusion experiment – continues apace, while the European Space Agency is due to launch its CryoSat2 mission to measure the thickness of the Earth’s ice sheets in February. And with football’s World Cup taking place in South Africa in June, you can be sure that sports physicists will be putting the finishing touches to their latest papers on the aerodynamics of footballs.

Roll on 2010!

Top 10 books for 2009

10. The Physics of Rugby by Trevor Davis (Nottingham University Press).
Unlike cricket and football, which I follow avidly, I haven’t managed to get my head around rugby despite living in the UK for the past six years. The fact that I still really enjoyed this book is a tribute to Davis’ enthusiasm and clear writing. From the kinematics of tackling a gazelle-like fly half to the Brownian motion of a zig-zagging runner, his book offers plenty for dedicated enthusiasts and armchair players alike.

9. First Principles: The Crazy Business of Doing Serious Science by Howard Burton (Key Porter Books).
Written by its founding director, this gossipy account of how Canada’s Perimeter Institute of Theoretical Physics came into being is not without its flaws. The author’s breathless “Who, me? Run an institute?” persona quickly wears thin, and as our reviewer Sir Peter Knight noted, Perimeter is not quite as ground-breaking as Burton makes out. Yet a book that tackles the messy process of scientific management is a rarity, and one that manages to do so in an entertaining way is about as common as a free quark. Kudos to Burton for doing something different.

8. Oliver Heaviside: Maverick Mastermind of Electricity by Basil Mahon (Institute of Engineering and Technology).
Heaviside may not be as well known as his 19th century contemporaries Maxwell and Lord Kelvin, but when we talk about Maxwell’s equations today, it is Heaviside’s tidy vector formulation we mean, not Maxwell’s ponderous 20-variable original. This biography of the brilliant-but-odd electromagnetism pioneer, who gave journal editors nightmares by speckling his papers with libellous attacks on his opponents, is a great introduction to an often-overlooked figure.

7. Atomic: The First War of Physics and the Secret History of the Atom Bomb by Jim Baggott (Icon Books).
There are a lot of books about the atomic bomb. Did we really need another? Yes, argued our reviewer Jeff Hughes: thanks to a flood of specialist histories based on recently released archival material, he wrote, “there is now a place, even in such a crowded field, for a book that brings some of this fresh information together into a good, accessible general history”. Atomic fills this niche admirably, incorporating new revelations about different nations’ atomic programmes to tell a story that felt fresh and engaging despite its familiarity.

6. Lives in Science by Joseph C Hermanowicz (University of Chicago Press).
On the “forewarned is forearmed” principle, anyone contemplating a career as an academic physicist should read this book. Hermanowicz, a sociologist, began following US physicists’ careers 15 years ago, examining how different kinds of academic institutions shape their attitudes and levels of job satisfaction. His latest book – which he summarized in Physics World‘s September careers section – is a dense and sometimes jargon-filled read, but its conclusions are troublingly clear: academic physicists are a dissatisfied bunch, and the more elite their university, the more likely they are to be unhappy at the end of their careers. Not exactly holiday cheer, but food for thought nonetheless.

13 Things That Don’t Make Sense

5. 13 Things That Don’t Make Sense by Michael Brooks (Profile Books).
Brooks caught a lot of critical flak for including homeopathy in his “13 things”, along with the likes of cold fusion, the Pioneer anomaly and dark energy. Interestingly, about half of the people criticizing his book thought he’d been horribly unkind to homeopathy, while the other half savaged him for not being unkind enough. That’s balance of a sort, I guess, but whatever you think about Brooks’ conclusions and priorities, this was one of the most intriguing books of the year.

4. Deciphering the Cosmic Number: The Strange Friendship of Wolfgang Pauli and Carl Jung by Arthur I Miller (W W Norton).
Early in his career, the quantum pioneer Wolfgang Pauli experienced a personal crisis. Like many other troubled residents of 1930s Zurich, he went to consult the city’s most eminent psychiatrist, Carl Jung. The unlikely friendship that developed between these two impressive intellects is the subject of this book: a fascinating and, in places, almost mystical journey through both physics and psychology.

3. Perfect Rigor by Masha Gessen (Houghton Mifflin Harcourt).
The brilliant, reclusive Russian mathematician Grisha Perelman declined a Fields Medal in 2006 for proving the Poincaré conjecture, and subsequently cut himself off from the world. A fascinating subject for a biography, you might think – and, judging from this book, you’d be right. Excellent writing and some fantastic detective work from the author in researching such a difficult subject make this one of my top picks for the year.

2. Plastic Fantastic: How the Biggest Fraud in Physics Shook the Scientific World by Eugenie Samuel Reich (Palgrave Macmillan).
It’s tempting to describe this book as a whodunit, such is the flair of its writing and the suspenseful nature of its story. Yet “howdunit” might be a better word: after all, we learn right away that the culprit was a young physicist called Jan Hendrik Schön, who fabricated data on a massive scale and was eventually fired from Bell Labs as a result. What makes the story interesting is Reich’s description of how it happened – how Schön fooled his colleagues, how competitors struggled to replicate his results, how the review process at prestigious journals failed to stop him. Top-notch stuff.

The Strangest Man

1. The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius by Graham Farmelo (Faber and Faber).
This landmark biography of Dirac has attracted praise from all quarters since its publication in January, and has even made the shortlist for best biography in the UK’s Costa Book Awards, which are among the country’s most prestigious literary prizes. Our reviewer, Sir John Enderby, joined the chorus of commendations, recommending the book “to professional physicists and to laypersons interested in fundamental physics, as well as to anyone who finds the interaction between personality and intellectual endeavour fascinating”. That description sounds like physicsworld.com readers to us, so we’ll second Sir John and wish Graham luck in the Costa awards. He – and we – will find out on 5 January 2010. Meanwhile, don’t forget that you can listen to a physicsworld.com online lecture by Graham Farmelo all about the life and times of Dirac via this link.

Finally, some honourable mentions: 137 Films’ The Atom Smashers and Mark Devlin’s BLAST! are films rather than books, but they’re so good they deserved to be in here somewhere. The Atom Smashers is a compelling and oddly moving documentary about life at Fermilab in the months before CERN switched on the LHC. BLAST! chronicles the bumpy road to success for a balloon-borne telescope that very nearly ended up halfway down an Antarctic crevasse. I watched both of them late last year, and I still can’t get them out of my head.

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