THE Book of the Week - The Lightness of Being: Big Questions, Real Answers

Graham Farmelo admires a sassy new overview of theories of fundamental particles

July 23, 2009

After its embarrassing false start last September, the Large Hadron Collider (LHC) is about to be rebooted. Soon it will be shedding light on nature's most fundamental laws by the crude but effective means of smashing together ultra-high energy protons and examining the debris. As Frank Wilczek says, this gigantic state-of-the-art machine is "our civilisation's answer to the pyramids", because it is "a product of co-operation, not command" and "born of curiosity, not superstition".

These days, most commentators try to capture public interest in the LHC by describing it as a kind of "Big Bang machine". This is because it can reproduce - fleetingly but at will - the conditions in the early Universe, less than a billionth of a second after the beginning of time. This is very much a modern viewpoint: 30 years ago, people would have been hooked by a description of the machine as the world's most powerful microscope. Its users are particle physicists, descendants of the Greek philosophers who began the intellectual quest to find the ultimate constituents of matter.

Wilczek's bracing new book is written mainly from the particle physicist's perspective. Writing for curious non-specialists, but keeping a close eye on experts, he focuses on modern theories of the most basic particles and the fundamental forces between them. The core theory of these particles and interactions is known as the Standard Model, which Wilczek rightly describes as "a grotesquely modest name for one of humankind's greatest achievements". The model summarises almost everything we know about the fundamental laws of physics (apart from gravity) in a set of equations that would fit on the front of a child's T-shirt, with room to spare. These equations provide, Wilczek points out, a complete foundation for biology, chemistry and stellar astrophysics. He confidently expects that the model will stand the test of time, conceding only that it may require alteration in a few billion years. However, the model is not entirely satisfactory to theoreticians, and it is one of the main tasks of the LHC to shed light on its deficiencies and on the best way of extending it so that it can be used at extremely high energies, for example, during the early stages of the Big Bang.

We could scarcely wish for a more knowledgeable guide to subatomic physics than Wilczek, a leading theoretical physicist for almost four decades. He is most famous for the pioneering role he played in illuminating the strong force between quarks (constituents of protons and other subnuclear particles), and was joint winner of the 2004 Nobel Prize for Physics. Wilczek is well known for the breadth of his interests and the liveliness of his imagination, qualities he brings to his book, giving us fresh perspectives on material that hundreds of other authors have already covered, although rarely with his insight and brio.

He begins by considering why things have mass - why quite a bit of the stuff in the Universe is not as insubstantial as light. From most popular accounts of particle physics, you would think that this origin would be entirely explained by the hitherto elusive Higgs particle, but Wilczek demonstrates why such a view is simplistic (that is, wrong). Most of the mass of a proton, for example, is generated by its quarks and the gluon particles that mediate their strong interactions. This explanation holds good even if the quarks had no mass - so the lion's share of the proton's mass is generated from no mass at all: "Mass without mass." Wilczek's account is full of such remarks - pithy and surprising.

In the book's second and shortest section, he discusses one of the central challenges of modern physics - understanding why gravity, the most familiar force of all, is so feeble compared with the forces that hold sway in atoms, governing how they are bound together and decay. Wilczek argues that the correct way to understand gravity's weakness is to pose the question in terms of the masses of the particles that comprise most matter, such as the proton. So we should ask: Why are protons so light? Again, we are treated to a virtuoso explanation (although to reveal it here would be a plot-spoiler).

Finally, Wilczek questions whether Keats' view of aesthetics always holds good: in theoretical physics, is beauty really truth? Although the LHC will test the Standard Model, many theoreticians believe that the new experiments will confirm a beautiful generalisation of the model, featuring a property known as supersymmetry. Many experts believe that nature could scarcely be as perverse as to pass on the opportunity to ensure that its fabric obeys this gorgeous symmetry (Einstein said something similar about his theory of gravity). Wilczek believes that the discovery of supersymmetry "will inaugurate a new golden age in fundamental physics". If nature's fabric does have this symmetry, then dozens of particles will exist (they were briefly present during the Big Bang). If the LHC has enough energy to produce them, experimenters are about to make a slew of new discoveries, many of which could well hit the headlines.

Throughout The Lightness of Being, Wilczek's energy is unflagging. Even the appendices and glossaries make rewarding reading, replete with jokes, perceptive observations and wise recommendations for further reading. The book is an object lesson in how an original thinker can take familiar material and impress on it an originality of interpretation that makes it come alive, even for experts who have been studying it for years.

It would be hard to read this book and fail to appreciate the sheer number of unsolved problems in understanding the masses of the fundamental particles and the huge proportion of the Universe that is not accounted for. Wilczek appears agnostic about the potential of string theory to solve such problems, while acknowledging the brilliance of the physicists working on it.

It is a shame, however, that the book lacks the literary polish appropriate to its intellectual quality. For much of the time, the editor seems to have gone Awol, leaving us with repetitions and quite a few technical terms that appear with little or no introduction (it seems, for example, that readers are assumed to be au fait with superconductivity). More importantly, a strong editor would have kept the focus not on keeping the experts happy but on enlightening the readers who simply want clear and entertaining explication. I wager that an extra month's editorial graft would have made the book much more appealing to a wide audience and thus have increased its readership many-fold.

But there is no doubt that Wilczek writes with a compelling sassiness. Among the pharaohs of modern theoretical physics, he is the best qualified to take up the mantle of Richard Feynman as its most inspirational communicator. The Feynman Lectures on Physics, based on his undergraduate course at the California Institute of Technology, appeared almost 50 years ago; but the work, although hugely influential, now looks dated. Perhaps Wilczek's colleagues at the Massachusetts Institute of Technology may persuade him to take up a similar challenge and give us The Wilczek Lectures on Physics. That could be a great monument to his flair, insight and infectious curiosity.


Frank Wilczek, Herman Feshbach professor of physics at the Massachusetts Institute of Technology, is perhaps best known for winning a Nobel prize in 2004.

Wilczek and his wife, Betsy Devine, eloped in 1973, and since then have celebrated "powers-of-ten-iversaries" in seconds, with the 100- billion milestone being passed in 2005.

On her blog, Devine says there's nothing wrong with this practice: "If we were truly geeky, we'd be celebrating powers-of-two-or-eight-or-16-iversaries."

Wilczek says that throughout his life he has had a "mostly friendly" relationship with music. He plays the accordion, the drums and the piano, and recently wowed the World Science Festival's Street Fair with a song he wrote about an oxygen molecule's love for a human being.

He is also working on a murder-mystery novel about four scientists who make a discovery that should earn them a Nobel prize. The twist? "According to the rules, at most three people can share ...," he says.

The Lightness of Being: Big Questions, Real Answers

By Frank Wilczek
Allen Lane
ISBN 9781846142451
Published 4 June 2009

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