Crazy Speed Demon : An idiosyncratic Cambridge scientist says the fastest thing in the universe was once even faster.(Joao Magueijo on light)

When Joao Magueijo signed up for a graduate fellowship at Cambridge University in England in 1990, he thought he would be joining the rich tradition of Isaac Newton and his intellectual heirs, the ideal place for a young scientist to plumb the mysteries of the cosmos. What he found instead was a weird social life. The English students and professors were eccentric, bratty, prone to striking absurd aristocratic poses even when giving directions to the local pub. It didn't help that Magueijo was a foreigner. He had been born and educated in Portugal--about as far from England, culturally, as you can get and still be in Europe. Until he was 7 a fascist governed the country, and even by the late 1980s people still half expected punishment for expressing their views. "My first year at Cambridge was very depressing," he says. "I was in one of the biggest, snobbiest colleges. Everybody was trying to show off. It was a very bad environment."

Magueijo eventually fled the claustrophobic campus. He won a prestigious Royal Society Fellowship and moved to Imperial College in London, eventually earning tenure. He's published numerous papers in scientific journals on the cosmic microwave radiation left over from the big bang--a perfectly respectable scientific topic. But what really gets Magueijo going is a pet theory he dreamed up one day while he was hanging out with some of those very same upper-class English twits he knew at--of all places--Cambridge.

Magueijo, a youthful 35-year-old with an antiauthoritarian streak, turns out to have had more in common with Cambridge eccentrics than he first thought. His theory questions the whole premise that the speed of light, the fastest thing in the universe, has always and everywhere been the same. That the speed of light is immutably constant is the bedrock assumption of present-day physics--it was, after all, Albert Einstein's starting point when he brainstormed his way out of the Swiss Patent Office. Magueijo is proposing that light in the early universe, shortly after the big bang, was for a time faster--a lot faster--than it is now. The notion may very well prove to be wrong--at the moment, the smart money in science gives it pretty long odds. But if it turns out to be right, it will rock the world of physics. And the social environment at Cambridge--warped as it may be by vestiges of the English class system; marginalized, perhaps, by the American scientific juggernaut--will have played a pivotal role.

After that first difficult year, Magueijo began to realize that the hierarchy of English university life, in which college fellows dine on tables physically raised above the students', came along with a tolerance for individual differences. "The overall feeling is of a benign madhouse," he writes in "Faster Than the Speed of ...