Superforce: The Search for a Grand Unified Theory of Nature
Perfect Symmetry: The Search for the Beginning of Time
O amazement of things—even the least particle!
—Walt Whitman, “Song at Sunset”
Theoretical physicists are in a state of high excitement these days, and for good reason. New discoveries in particle physics, combined with brilliant theoretical invention, suggest that they are on the verge of nothing less than explaining everything.
Well, not exactly Everything, but everything possible for physics to explain. More precisely, they believe they are close to constructing a unified field theory that will describe exactly how the universe, almost instantly after the big bang, acquired all the particles and forces that allowed it, some 15 billion years later, to grow into the universe we know. A few adventuresome theorists think they may soon be able to explain how the primeval explosion itself was caused by a random quantum fluctuation of Nothing.
One of the two books under review is by the American physicist Heinz Pagels, whose previous book The Cosmic Code is one of the best introductions to quantum mechanics I have ever read. The other volume is by the British physicist Paul Davies, author of many earlier books that are models of science writing for laymen. Both books are admirable up-to-the-minute accounts of the search for what Pagels calls the Holy Grail. Those who work in “the shadowy world of fundamental physics,” Davies writes in his first paragraph, are about to complete their long quest “for a prize of unimaginable value—nothing less than the key to the universe.”
Is it really true that physics may be nearing the end of a road, “going for broke,” as Pagels puts it? Of course, there will remain the infinite problems on what Pagels calls “the frontier of complexity”—such trifles as explaining how the basic forces and particles manage to get together and write books about themselves—but there may be nothing more to learn on a bedrock level. The situation will be something like that of plane geometry. All its theorems are implied by its axioms, but the number of theorems yet unknown is infinite. A unified field theory would in no way be the end of science or technology. There will be endless inventions to make, endless worlds out there in space to explore. It would only mean the end of the search for fundamental laws.
Unfortunately, physicists have been in previous states of euphoria about reaching the end of the road. In the late Twenties everything seemed wonderfully simple. Maxwell’s field equations had explained electromagnetism. Einstein’s field equations had explained gravity. And Einstein was hard at work on a theory to unify these two forces. All matter was made of atoms that contained just two kinds of particles: protons in the nucleus and electrons whirling around in paths described by probability waves. “Physics as we know it will be over in six months,” said Max Born, one of the great architects of quantum mechanics.
In 1932 nature began to look shaggy again. A new particle, the neutron, was found hiding in the nucleus. Paul…
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