Noisy bars, cosmic quests

Albert Einstein stands out among scientists of the 20th century. His mane of white hair, bushy moustache and sad brown eyes are synonymous with genius and are instantly recognisable. More important, his ideas revolutionised science. It is little wonder that the life and work of the legendary scientist continue to inspire new books.

The press release that accompanies E=mc2 claims that the book will make even the blondest and least mathematical publicist knowledgeable about Einstein's most famous equation. This blonde science journalist remained unimpressed by both the quip and the book.

David Bodanis was inspired to write his book after reading an interview with Cameron Diaz in which she said she really wanted to know what E=mc2 meant. Rather than try to write another account of the theory of special relativity or a biography of Einstein, Bodanis concentrates on describing what the symbols E , m and c mean and their roles in the equation.

It is an excellent idea, but the approach fails because Bodanis abandons scientific accuracy in pursuit of maximum popular appeal. Comments such as "the amount of energy God had set for our universe would no longer remain fixed. There could be more" -are typical of the empty and sensationalist statements Bodanis uses. Physicists are likely to hop up and down with anger at the elementary mistakes and at the impression given in the second half of the book that Einstein was to blame for the nuclear arms race. Bodanis might argue that E=mc2 is aimed at the layperson and that the science populariser needs lively anecdotes and metaphors. That is true, but it is possible to explain science in simple language without dumbing down the arguments to the point where they become almost worthless.

Bodanis should take a leaf out of Marcia Bartusiak's book to experience science writing at its best. Einstein's Unfinished Symphony is an excellent account of the struggle to detect gravitational waves: tiny ripples in the fabric of space-time that are predicted by Einstein's general theory of relativity.

In the first few chapters, Bartusiak explains what led Einstein to recognise that waves of gravitational radiation would be produced by moving celestial masses in much the same way that radio waves are generated when electrical charges travel up and down an antenna. Although astronomers have good indirect evidence for gravitational waves, the consensus is that none has been detected directly so far. And for a good reason. Were the gravitational shock waves produced by a star exploding in our own galaxy to hit this page, the dimensions of the paper would be stretched and squeezed by an amount 10,000 times smaller than the size of an atomic nucleus.

Yet physicists are convinced that gravitational waves are out there waiting to be discovered and have been building ever more sensitive detectors to find them. These range from large aluminium bars weighing several tonnes that will ring like a bell in response to a passing gravitational wave, to laser interferometers several kilometres long.

In such an enterprise, the stakes are high -the discovery of a gravitational wave would surely merit a Nobel prize. So it is not surprising that the field is dogged with controversy, which began in the late 1960s when Joseph Weber claimed to have detected gravitational waves. Bartusiak discusses the events, charting Weber's battle with his critics. Most experimentalists agree that Weber's investigation was picking up noise. It would be easy to dismiss the man whose insistence that his critics were wrong almost damaged the field irreparably, but Bartusiak gives a sympathetic account of Weber and his work. Her interviews with the leading lights in the gravitational-wave community reveal that it takes huge amounts of ingenuity, optimism and sheer pigheadedness to stay in the field.

In the hallway opposite theorist Kip Thorne's office at the California Institute of Technology is a row of ten framed letters. Each records a bet that he has made with a prominent astronomer or physicist. Recently, he conceded a case of wine to a colleague when his prediction that gravitational waves would be detected by January 1 2000 fell through. Yet Thorne is eager to place another bet with any takers. Readers less inclined to take such risks should read Einstein's Unfinished Symphony rather than E=mc2.

Valerie Jamieson is features editor, Physics World , and a former particle physicist.