Philip Ball
Can the tevatron steal the LHC’s thunder?
Recently, I went on a visit to Cern (the European Organisation for Nuclear Research) in Geneva, site of the Large Hadron Collider (LHC). The LHC, whose much heralded opening last September ended in tears just nine days later, is due back in action this September. The LHC could transform scientists’ understanding of the particles and forces from which the universe is made. Two beams of subatomic particles will be forced to collide at very high speed inside the circular accelerator, creating conditions similar to those just after the big bang.
One of the LHC’s key assignments is finding the Higgs particle. The Higgs, thought to be responsible for giving other fundamental particles their mass, is the last piece in the jigsaw of the “standard model,” the theoretical framework used to understand all known particles and forces. The Higgs is thought to have too much mass to be made in existing accelerators—the bigger this (still unknown) mass, the more energetic particle collisions have to be to spawn a Higgs. The mightiest accelerator until the LHC, the Tevatron at Fermilab in Illinois, lacks the necessary oomph.
The LHC’s failure happened when an electrical short circuit caused a leak of the liquid helium coolant, which in turn ripped from its moorings one of the immense magnets used to accelerate particles through the 27km tunnels, blasting a hole in the ring and contaminating it with debris. The clean-up and installation of new safeguards have been going on ever since.
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Stephen Eales
One of my favourite astronomy memories dates from the mid-1990s. I had gone out to the Mauna Kea Observatory in Hawaii to measure the brightness of some high-redshift radio galaxies—a worthy but routine piece of science—and discovered that they were fainter than expected. This may not sound terribly interesting, but it was exciting for me and the other 100 or so scientists around the world who care about these objects. My memory, however, is of what happened after the observing run. During the night, we received an email that the space shuttle was due to pass over Hawaii. Just before dawn we went out of the telescope dome to watch. I had been expecting the shuttle to look something like a plane, but instead a bright point of light shot upwards at a crazy angle, crossing the sky in a couple of seconds, an upside-down meteor hurled towards the gods.
With time, this memory has come to stand for a big shift in my discipline. The space shuttle involved hundreds of collaborators and budgets of millions. As for my project, apart from the telescope operator, I was observing by myself, and the only other person involved was my friend Steve Rawlings, who was at home in Oxford. How things have changed in ten years. The global astronomy community has now just finished applying for observing time on the Herschel Space Observatory, a €1bn project due to be launched by the European Space Agency in early 2009. Last autumn, after finally submitting my own proposal, I counted the number of collaborators on it. There were 101. In ten years, astronomy has gone from a multitude of small-scale projects to Big Science schemes like Herschel.
One reason for this is the development of cameras and other instruments capable of observing large chunks of the sky in a single shot. It now makes sense to get together a large team who will carry out a large survey that can then be used for multiple projects. My own Herschel programme is a good example. Herschel will operate in the submillimetre waveband—the region of the electromagnetic spectrum between the infrared and radio wavebands—in which the universe is still largely unexplored, and so there is a good chance that our survey will discover something unexpected. But the data will also be used for many different projects, ranging from the study of protostars to galaxy evolution. Another reason for the change to this kind of big international project from the old-style small-scale projects is the revolution that has occurred in our understanding of the universe in the past ten years.
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Philip Ball
What to do with our nuclear waste
Now that the climate change bill has cleared its first hurdle in the Commons, it seems likely the government will have to reduce carbon emissions by at least 60 per cent by 2050. But while you might think this strengthens the case for a new generation of nuclear power stations, they will not necessarily be required. There is nothing in the bill to stop the government discharging its obligation by buying carbon credits from other countries, while not lessening emissions one jot.
Even if this loophole is closed, some people argue that massive investment in alternative energy technologies, particularly carbon capture and storage (CCS), can bring about the reductions instead. CCS, in which carbon dioxide is removed—or “scrubbed”—from power station emissions before it reaches the atmosphere, and is then stored underground, looks increasingly like a technology whose time has come. Veteran climate scientist Wally Broecker of Columbia University has been promoting the carbon scrubber developed by his engineer colleague Klaus Lackner, while the former British chief scientific adviser David King is also a fan of CCS. (As is Nicholas Stern—see our interview in this issue.)
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Gwyneth Lewis
I am probably the only person to look round a particle accelerator in two-inch peep-toe sandals.
It was my first visit to Cern (the European Organisation for Nuclear Research), and I had come to Geneva to see the world’s largest particle collider as it prepares to go live. The Large Hadron Collider (LHC) is a circular tunnel built 100 metres under the suburbs of Geneva, overlooked by the Jura mountains, a limestone wave about to break on the valley below. Soon, this 27km-long tunnel will be used to fire two beams of protons at each other, reaching 99.999999 per cent the speed of light. The beams will create up to 600m collisions per second and create showers of new particles, some of which have not existed since the big bang. Detectors will record their tracks as they smash off each other. It is hoped that, among other things, this will prove the existence of the Higgs boson, an entirely theoretical entity.
The Higgs particle matters hugely to physicists because it might explain why bodies have mass and open a window on the earliest moments of the universe. It became a kind of holy grail for experimental physics after it was christened the “God particle” by Leon Lederman in 1994. It is believed that a Higgs-like mechanism could have played an important role in the early universe, contributing to the structure of the world we see today.
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Philip Ball
The great boson race
Most scientific instruments are doors to the unknown; that’s been clear ever since Robert Hooke made exquisite drawings of what he saw through his microscope. They are invented not to answer specific questions—what does a flea look like up close?—but for open-ended study of a wide range of problems. This is as true of the mercury thermometer as it is of the Hubble Space Telescope.
But the Large Hadron Collider (LHC), under construction at the European centre for high-energy physics (Cern) in Geneva, is different. Particle physicists point out that because it will smash subatomic particles into one another with greater energy than ever before, it will open a window on a whole new swathe of reality. But the only use of the LHC that anyone ever hears about is the search for the Higgs boson.
The Higgs boson is pretty much the last missing piece of the so-called standard model of fundamental physics: the suite of particles and their interactions that explains all known events in the subatomic world. The Higgs boson is the particle associated with the Higgs field, which pervades all space and, by imposing a “drag” on other particles, gives them their mass. (In the standard model, all the fields that create forces have associated particles: electromagnetic fields have photons, the strong nuclear force has gluons.)
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John Horgan
Not Even Wrong by Peter Woit
Jonathan Cape, £18.99
“String theory is still promising,” I once heard the physicist and Nobel laureate Frank Wilczek quip, “and promising, and promising.” String theory is a so-called unified theory, which attempts to wrap quantum mechanics and relativity into one tidy mathematical explanation of all nature’s forces, and it has been promising for more than 20 years now without delivering.
Depending on which variant you prefer, string theory holds that reality is woven out of infinitesimal strings, or loops, or membranes vibrating in a hyperspace of ten, or 11, or whatever dimensions. Advocates—I will call them “pluckers”—claim that string theory represents a “theory of everything” that will answer the most profound of all questions: how did the universe come to be? And why did it take this particular form rather than some other form that would not have permitted our existence?
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Fred Pearce
They call themselves “fusion gypsies”—scientists who have travelled the world, moving from one nuclear reactor to the next, living the dream that some day, somewhere, they can re-create the reactions that take place in the heart of the stars to generate huge amounts of cheap, clean electricity for the world.
Their goal is nuclear power, but not as we know it. This is fusion and not fission. Fission involves mining, processing and irradiating vast amounts of uranium, and leaving behind an even larger legacy of radioactive waste with half-lives stretching into the next ice age. Whereas, say the fusion gypsies, a small vanload of fuel supplied to a fusion power station could supply the electricity needs of a city of 1m people for a year, and leave behind only paltry amounts of radioactive waste that will decay to nothing within a century.
Fission reactors split atoms to make power; fusion reactors force the elemental particles of the universe together till they fuse, releasing energy in the process. Fusion powers the sun, the gypsies say, and one day it could power the world’s electricity grids too.
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Michael Prowse
Education and innovation are at the heart of Labour’s plans for modernising Britain. The government has an ambitious ten-year programme for boosting the nation’s R&D performance, thereby creating a “knowledge economy.” Yet this cannot succeed in the absence of suitably qualified people. A lack of the right sort of human capital is a far bigger constraint on innovation than a lack of cash or laboratories. Microsoft and Google were set up in garages by students with few assets other than their highly numerate brains.
Yet while endlessly stressing the importance of scientific research, ministers have failed to implement the education policies needed to realise their goals. The contrast between rhetoric and reality was illustrated again in November’s stark analysis of the decline of physics in Britain’s state schools by Alan Smithers and Pamela Robinson of the University of Buckingham.
Most recent debate on education has focused on structural and administrative issues. Like its Tory predecessors, the Blair government argues that schools will perform better if they have more autonomy and if parents have more choice. Yet if schools cannot find maths, physics and chemistry teachers, and if students keep on opting for easier subjects, British education will remain sub-standard, regardless of the level of competition or choice.
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Lisa Randall
In a couple of years, we might be forced to radically revise our ideas about the underlying nature of matter and our conception of the universe. In 2007, the large hadron collider (LHC) will begin operating at Cern, near Geneva, boosting particles to energy levels that have never before been produced on Earth. Physicists will then combine results from the LHC experiments with insights from their theoretical investigations to explore phenomena whose effects are only detectable at small distances and high energies.
The theory known as the Standard Model of particle physics describes all known matter and the forces through which it interacts. Experiments have thoroughly tested the Standard Model, and its basic ingredients are almost certainly correct. But the Standard Model cannot be the final word: it leaves open important questions about the origin of elementary particle masses and puzzles such as the relative weakness of gravity. The LHC will help to resolve these mysteries, and scientists all over the globe are busily preparing experiments they hope will provide answers to these questions. Perhaps the most exciting proposal for extending and completing the Standard Model involves additional hidden dimensions of space beyond the three dimensions with which we are all familiar: up-down, left-right, and forward-backward. As a theoretical physicist working on extra dimensions, I look to LHC experiments to guide my future investigations.
The premise underlying particle physics is that elementary particles constitute the building blocks of matter. Peel away the layers, and inside you will always ultimately find elementary particles. Because of Einstein’s E=mc2 equation, which states that energy (E) is equal to mass (m) multiplied by the square of the speed of light (c), we need high energies to create particles with big masses. The LHC will produce enormous amounts of energy that can then be converted into particles we would never find in any other way. But matter is not a Russian doll, with the same elements repeated on smaller scales. At smaller distances, it is not only new elements of matter that should reveal themselves but new physical laws too.
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Michio Kaku
The universe is out of control, in a runaway acceleration. Eventually all intelligent life will face the final doom—the big freeze. An advanced civilisation must embark on the ultimate journey: fleeing to a parallel universe.
In Norse mythology, Ragnarok—the fate of the gods—begins when the earth is caught in the vice-like grip of a bone-chilling freeze. The heavens themselves freeze over, as the gods perish in great battles with evil serpents and murderous wolves. Eternal darkness settles over the bleak, frozen land as the sun and moon are both devoured. Odin, the father of all gods, finally falls to his death, and time itself comes to a halt.
Does this ancient tale foretell our future? Ever since the work of Edwin Hubble in the 1920s, scientists have known that the universe is expanding, but most have believed that the expansion was slowing as the universe aged. In 1998, astronomers at the Lawrence Berkeley National Laboratory and the Australian National University calculated the expansion rate by studying dozens of powerful supernova explosions within distant galaxies, which can light up the entire universe. They could not believe their own data. Some unknown force was pushing the galaxies apart, causing the expansion of the universe to accelerate. Brian Schmidt, one of the group leaders, said, “I was still shaking my head, but we had checked everything… I was very reluctant to tell people, because I truly thought that we were going to get massacred.”
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