19 of 20 people found the following review helpful
An outstanding work and a challenging read,
This review is from: The Fabric of the Cosmos: Space, Time and the Texture of Reality (Allen Lane Science) (Hardcover)
In some respects this book is an extension (and a substantial one) of physicist Brian Greene's well-received The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory (1999) in which he attempted the very difficult task of explaining relativity, quantum mechanics, and string theory to the educated layperson while keeping the mathematics in footnotes. Here he covers some of the same ground as he patiently and painstakingly illuminates some of the most important ideas in physics and cosmology, employing new ways to explain the nearly unexplainable.
His watchword is "reality" and his overarching idea is that reality is not as we intuitively think it is. (p. 5) This is one of the startling revelations from relativity and the quantum world: namely that our perceptions and concepts built up through evolutionary experience are NOT adequate to understand the world of the very small or the very large. The dual nature of the particle/wave is the most obvious example, and one that Greene examines at length. We have no way of intuitively appreciating the fact that elementary particles are not just particles but waves as well--actually probability waves. But there is also our notion of something and "nothing" that is being tested by modern physics. What appears to be empty space is in fact far from empty. Moreover, space itself has unsuspected qualities, as Greene demonstrates in his discussion of the postulated Higgs fields.
Particularly exciting was the way Greene makes inflation credible ("the universe could easily have expanded by a factor of 10 to the 30th, 10 to the 50th or 10 to the 100th or more" within a time frame "as short as ten to the minus 35th seconds" p. 284) by positing that before the Higgs field made its phase transition, all quanta had zero mass. It doesn't take much energy to move something with zero mass. (Or maybe something with zero mass can't be moved at all.) At any rate, very shortly after the big bang, space and presumably time, expanded enormously (faster than the speed of light, actually--but, as Greene, assures us, the speed limit on light does not apply to expanding space).
In short what Greene does in this book is take the reader to the edge of what can be understood. What he writes is exciting and awe-inspiring, and he writes so very well, and he works so hard at trying to reach every reader. However you'll forgive me if I get some of this wrong. And of course I am compelled to point out (as Greene does himself) that the Higgs field and therefore inflation, not to mention string theory and M-theory, etc., remain as yet in the category of the not proven.
Obvious is Greene's faith in the "beauty" of mathematics to point the way to physical truth. He recalls the work of Glashow, Weinberg and Salam in predicting the existence of W and Z particles because of the "strong faith these physicists had in the power of theory and the beauty of symmetry that gave them the confidence to go forward." (p. 266) Whether the beauty that physicists see in the equations for string theory, etc., will lead them to a deeper understanding of the cosmos remains to be seen. Most readers are familiar with what one ugly fact can do to a beautiful theory.
One of the most enjoyable parts of the book is Greene's delineation of time and time's "arrow." I have always been fascinated with time and have spent many hours trying to figure out what it is. Reading between the lines, it would appear that Greene believes that events create time. Or more precisely, that asymmetry creates time. He writes "If the universe had perfect temporal symmetry--if it were completely unchanging--it would be hard to define what time even means." (p. 228) Of course this is somewhat circular, but I think I can add that if the universe were completely empty, it would also "be hard to define" what time means.
On the question of "Does time have a direction?" Greene writes that "the laws of physics...show a complete symmetry between past and future." (pp. 144-145) Yet, in everyday life, time is always aimed toward the future. An egg splatters. It doesn't unsplatter. Why is that? Greene brings entropy into the picture, noting that entropy has increased since the big bang. He explains that the unsplattered egg has a very low degree of entropy (that is, it is highly ordered, thanks to DNA, energy from the sun, etc.). Eggs splatter more easily than they could ever hope to unsplatter because there are an uncounted number of ways that the egg can have high entropy (ways it can be splattered about) but only one (or very few) ways it can be pristine. In a footnote on page 511 Greene articulates something that I have been waiting to hear from a prominent physicist. Suppose the universe began to contract, seemingly reversing time's arrow. Would eggs unsplatter? Greene's answer: "Physical processes (eggs breaking, people aging, and so on) would still happen in the usual direction..."
What impressed me the most about this book is just how well produced it is. Greene improves on his previous opus in two important ways. His explanations are more detailed and more accessible to the average reader; and his information and understanding are more up to date. Furthermore, the book is beautifully presented with many drawings, a glossary, selected readings for further study, and a fine index. There are 493 pages of text and 43 pages of notes. It is handsomely presented and beautifully edited and proofread. This is a book clearly worth the money and then some.