Taking A Shot At Einstein
Seeking a grander theory, rebel physicists break a cosmic speed limit
Even if João Magueijo had not advocated castrating an editor at a prestigious science journal, and even if he hadn't suggested that rival physicists, ostensibly brilliant like Magueijo, were just posers--in short, even if Magueijo were a less colorful rebel, his ideas would have attracted attention. After all, he is taking on Einstein, and ever since we placed Einstein on a pedestal, we have been titillated by the idea of knocking him off. Magazine editors know that putting the antic-haired genius on the cover, perhaps over the words Faster Than the Speed of Light --the somewhat misleading title of Magueijo's recent book--all but guarantees sales.
And yet Magueijo, a physicist at Imperial College, London, is for real, and he is not alone. As we near the end of our first century in a relative universe, challenges to Einstein's theory are in the air. They are respectful challenges; even Magueijo isn't proposing to throw relativity out the window, any more than Einstein junked Newton. "We get E-mail and letters all the time from amateurs who think they have found a mistake in Einstein's theory," says Lee Smolin, a physicist at the Perimeter Institute in Waterloo, Ontario. "That's not what is going on here." If relativity is wrong, it is wrong by such tiny amounts or in such particular circumstances that you have to go to great lengths to find the error.
But there is optimism these days that, by studying light from the distant universe, researchers may soon be able to measure such smaller-than-nano deviations. They may need to find them, if they are ever to create a unified theory of all the forces of nature. To fulfill that dream, which obsessed Einstein after he turned 40 or so, physicists may have to tinker with the theory he invented when he, too, was a young revolutionary, disguised as a patent clerk. They may have to bend his best-known principle: the one that says the speed of light is an absolute, always and everywhere the same, and faster than anything else.
C is special. That principle was born in 1905, when Einstein wedded space and time into something called spacetime. Until then, in Newtonian physics, space and time were separate, independent of each other and of the things in them. Time flowed at the same rate for everyone, and space was a fixed stage on which the universe played out its history. Nineteenth-century physicists filled that stage with a mysterious, invisible "aether," a medium that transmitted light waves the way air transmits sound waves. The aether was assumed to be at absolute rest, a fixed "reference frame" for all motions.
No one could ever detect the aether, though; in the 1880s, Albert Michelson and Edward Morley tried ingeniously and failed. And after Einstein proposed his theory of special relativity two decades later, physicists realized they should give up on absolute space and time. Einstein postulated, first, that the laws of physics don't prefer one reference frame over another, as long as each is moving at a constant velocity. Second, he said that c, the speed of light, will appear exactly the same to every observer, in every frame of reference.
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