![]() If two creatures met, exploring the length of Lineland, one would be unable So long as the diameter of the extra dimension was very tiny, it would be invisible. Suppose there were beings inhabiting a garden-hose universe. But move in closer and a second, curled-up dimension appears: the circumference From a distance it looks like a geometric line, a one-dimensional object. To get a feel for what curled-up dimensions might be like, Greene asks us to envision a common garden hose. Heisenberg's uncertainty principle, which allows ''virtual particles'' to pop in and out of empty space, or Einstein's bending of space and time. But the idea, as Greene makes clear, is not a whole lot weirder than many of the other well-accepted ideas of physics, like With the extra six - unfathomable directions beyond length, width and depth - curled up too tiny to see. For it to work, the strings must be vibrating in a space-time of 10 dimensions, For those skeptical of the airier abstractions of physics, the theory is easy to ridicule. So far the only possible map physicists have come up with is superstring theory. May appear to behave differently in different realms, but there must be a sensible way to navigate between them. Many people's reaction to this might be ''so what?'' Why can't we just accept that when we go from the tiny to the enormous, the rules change? But the central tenet of physics is that we live in a symmetrical universe. Of before and after) lose their meaning.'' General relativity no longer applies. But when we focus on tinier and tinier distances, the seamless weave of time and space breaks up into what the physicist John Wheeler, always adept at coining catchy terminology,Ĭalls ''quantum foam.'' The four dimensions of space and time become so hopelessly scrambled that, as Greene puts it, ''the conventional notions of left and right, back and forth, up and down (and even When one is delineating happenings on the cosmic scale. As many experiments have shown, this idea works fine Gravity can be thought of as bends in this space-time fabric, channeling the way planets and stars can move. In general relativity, theseĪre treated as smooth dimensions, the warp and woof of the universe. ![]() String theory, on paper anyway, promises to do the trick.Īs they now stand, quantum mechanics, which describes the tiny world of atoms and subatomic particles, and general relativity, which describes the whirling stars and galaxies, conflict in how they deal with space and time. The game is finding a single theory that embraces the two great and maddeningly incompatible triumphs of 20th-century physics: quantum mechanics and the general theory of relativity. The argument that string theory is the only game in town is a very strong and powerful one.'' ''We nonstring theorists have not made any progress whatsoever in the last decade,'' he admitted to Greene, a professor of physics and mathematics at Columbia University. As Brian Greene shows in ''The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory,''Įven Glashow has come around. Music of the cosmos was as sensible, Glashow proposed, as arguing over how many angels can dance on the head of a pin.īut now some of the prejudice against the theory has been overcome by a series of conceptual breakthroughs. Speculating about how these hypothetical wisps of mind stuff might give rise to the To conjure up the energy needed to detect the vanishingly tiny strings without a particle accelerator the size of the galaxy, or even of the universe. There was no way, Glashow and others complained, Just 10 years ago, physicists like Sheldon Glashow, who won a Nobel Prize in 1979, were comparing the theory to medieval theology. In the universe as the manifestation of tiny, vibrating strings. Ne of the great intellectual surprises in the last half of the decade has been the comeback of superstring theory, the grandly ambitious attempt to explain everything Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. Will superstring theory explain the meaning of it all?
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