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The cosmic questions. A physicist's search for answers, told in laymen's terms

A Brief History of Time: From the Big Bang to Black Holes, by Stephen W. Hawking. Illustrations by Ron Miller. New York: Bantam Books. Glossary and index. 240 pp. $18.95. (Canada $24.95). ``Where have we come from? What are we? Where are we going?'' These fundamental questions, which inspired Gauguin's famous picture, also give Stephen Hawking his theme. Gauguin expressed them in the imagery of painting. Dr. Hawking explores them through the concepts of physical science.

The great problem of being - its source, nature, and destiny or (to put it in physical terms) the origin, evolution, and fate of our universe - that's what this book is about. Time, which figures so prominently in the title, comes into it only because time and our universe are inseparable. Our universe evolves through time. Time has no meaning apart from our universe, nor do the laws of physics that Hawking uses to think incisively about his baffling subject.

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Gauguin posed his questions with a sense of despair at getting any answer. Hawking writes with the physicist's faith that scientific exploration can at least put the enigma into new and unexpected perspective. People, he says, ``yearn to know why we are here and where we came from ... [this] is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in.''

His book recounts how far we have come toward that goal - further than one might have expected three decades ago when Einstein's lifelong quest for a unifying theory of nature ended in failure. But physicists are still only exploring the foothills at the base of the mountain from whose summit they hope to find the unifying perspective they seek.

Even Hawking - who optimistically predicts we'll find the elusive unity within a generation - admits he doesn't really know how steep the ascent will be.

This is one of the best books for laymen on this subject that has appeared in recent years. Hawking is one of the greatest theoretical cosmologists of our time. He is greater, by consensus among his colleagues, than other expert authors who have written good popular books on the subject recently. And he is greater, by far, than the ``experts'' who have ``explained'' quantum physics and cosmology in terms that support a religious agenda.

There are no dancing Zen masters or hidden faces of deity here. When Hawking mentions God, he, like Einstein, tends to use the term metaphorically. He discusses cosmic science imaginatively, even at times poetically. He leads readers to share his delight in its mysteries, but without descent into mysticism.

Einstein made little progress toward a single underlying physical theory because knowledge he needed simply did not exist in his day. Physicists work with the concept of four basic forces - gravity, electromagnetism, the weak force of radioactivity, and the strong force holding an atomic nucleus together.

This is a convenient classification for theorists, which, as Hawking notes, ``may not correspond to anything deeper.'' A unified theory seeks to explain these four forces as aspects of a single underlying force.

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By the mid-1970s, physicists had a theory linking the weak and electromagnetic forces that experiments support. They now have theories uniting the electro-weak and strong forces - the so-called Grand Unified Theories - for which there is as yet no experimental evidence. And theorists are playing with super-theories that would achieve the ultimate unity that Einstein sought. They don't know which, if any, of these schemes may be correct. But they at least believe they now know what such a theory should probably contain.

Yet, even though the more advanced theories may still be speculative, cosmic scientists can use them to gain new insight into the ultimate nature of our universe. For example, Hawking, who is a leader in such thought, explains how the new physics allows one to speculate meaningfully about the possibility that our universe appeared virtually from nothing.

This would not violate the law that energy can't be created from nothing, since the new universe would appear with equal amounts of positive and negative energy whose total would be zero. Hawking explains this and other arcane physical concepts well, allowing laymen interested enough to make the effort to think along with him.

And there is an effort involved. This is Hawking's first book for general readers. It has one possibly serious flaw - if indeed it can be called a flaw. It is neither technical nor academically obscure. But it is written in a scientist's mode of thought.

This can be an impediment to understanding for laymen unfamiliar with the way scientists habitually use seemingly common terms in uncommon ways - terms such as time, force, work, energy, principle. When these are used technically in connection with specific phenomena or specific theories, the use of such terms can be clear. But when a scientist moves from such specifics to general comments or conclusions about cosmic origins and reality, laymen can become confused.

This might happen, for example, when Hawking uses real and imaginary time - a quite definite mathematical concept - to track our universe's history. But readers who make the not-too-demanding effort to think along with Hawking should soon catch on.

While Hawking, the optimistic physicist, can show how physics has put the fundamental cosmic questions into a new perspective, its practitioners may be no closer to definitive answers than are Gauguin's Tahitians.

Hawking notes that while ``we already know the laws that govern the behavior of matter under all but the most extreme conditions [such as the birth of the universe] ... we have, as yet, had little success in predicting human behavior from mathematical equations!''

Thus, Hawking explains, ``A complete, consistent, unified theory [of the basic forces] is only a first step: our goal is a complete understanding of the events around us, and of our own existence.'' If Hawking's optimism is justified, we may indeed unify the forces within a generation. But no one knows when - if ever - physical science will give us such understanding.

Robert C. Cowen is the Monitor's natural science editor.

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