Most Helpful Customer Reviews
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11 of 11 people found the following review helpful:
4.0 out of 5 stars
Brisk but honest treatment by qualified physicist., June 5, 1999
By A Customer
I read this book in a few days and found it most enjoyable. It never drags. Although I have a Ph.D. in Physics, and specialized in Relativity, Herbert's book filled in many gaps in my education, and reminded me of stuff that I had forgotten. A scientifically literate lay person should be able to get the correct flavor of most ideas. A physicist, craving a more concrete and pictorial understanding then is provided here, as with any popularization, will have to work to fill in the gaps to the best of his (or her) ability. Line diagrams, so far as they go, are well done but a few more in most chapters could help the reader greatly. In particular, I recommend several more in chap. 5 on advanced waves, and in chap. 7 on tachyons and antiparticles. The common idea that lay readers are too unskilled to profit from diagrams -- and, as with math formulas, may even be scared away -- is probably unfair to many, especially the ones who would pick up a popularization on an advanced topic in Physics.Dr. Herbert's book keeps a fine level and apart from the slight shortage of diagrams, appears to have escaped any marked "dumbing down" at the hands of editors, but I add a cautionary remark. Removing visual aids apparently makes a book "easier to read," hence more marketable--an editor may reason that the reader won't have to concentrate as much. But there's a point--quickly reached in Physics --where the truncated product becomes too superficial to reward a careful and intelligent reader. So, unless handled with great care, this commercial approach throws out the baby with the bathwater, crippling the very "product" it was supposed to serve.
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21 of 26 people found the following review helpful:
1.0 out of 5 stars
A very confusing book, February 21, 2004
The author has clearly misunderstood many basic facts about the theory of special relativity. In fact, it seems that he has combined nearly all popular misunderstandings associated with the speed of light.One of the most general consequences of Einstein's special relativity from 1905 is that no physical signal (or a piece of matter) can ever move faster than light. The speed of light plays a very important role according to this famous theory. Although a lot of new insights have been accumulated since 1905, the previous sentence remained valid. Einstein discovered general relativity in 1916, and this theory of gravity allows spacetime to become warped - in fact, this theory was found exactly because Einstein knew that Newton's theory of gravity allowed the signals to be sent superluminally, and therefore it contradicted special relativity. Newton's theory could not be quite correct. Moreover, many physicists have studied various solutions of general relativity that admit the closed time-like curves, i.e. time travels. Although most scientists believe that these solutions are unphysical because of various reasons (such as instability), it is legitimate to study such solutions, and many popular books have been written about these solutions. Herbert's approach is more primitive. In most of his book, he wants to derive the existence of faster-than-light motion (and time travels, which are then an inevitable consequence) from special relativity itself. One of the main points of special relativity is that exactly this is impossible. There exists a concept of tachyons (from Greek "tachos" which means "speed"), fictitious particles that always move faster than light. Quantum field theory shows that the existence of such particles would also make the Universe unstable because such tachyons could be created in pairs (their energy can be both negative as well as positive). Many of my fellow string theorists revisited the question of tachyons (initially, we would simply eliminate every version of string theory that predicts a tachyon), but all of them agree that the existence of tachyons in the real world would spell doom for the whole Universe. The real goal of the recent calculations involving tachyons in string theory is really to find out the final state of the collapsing Universe (or a membrane floating in the Universe). Herbert is also confused by the Einstein-Podolsky-Rosen effect in quantum mechanics. He thinks that the entanglement - the correlations between distant objects in the Universe - can be used to send information. No, that's not possible. In his example involving calcium vapors, he does not appreciate that the information comes from the vapor source, not the crystal, and therefore the crystal can't send any usable information. The EPR effect allows correlations between distant objects, but because the outcome of the experiments are random (quantum mechanics only predicts probabilities), there is no way for us to affect the outcome of a faraway experiment i.e. no way to send an e-mail faster than light, for example. I could continue: he incorrectly interprets the large phase speed of some vibrations in the upper atmosphere, violation of the CP (and T) symmetries by the kaons, and so on. If you want to get the wrong answer to all conceivable questions related to the speed of light, buy this book. If you prefer to learn how the Nature really works, I recommend you a different book. For example "The Fabric of the Cosmos" by Brian Greene explains nearly everything about space and time, including a very entertaining (yet correct) treatment of the Einstein-Podolsky-Rosen effect.
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28 of 36 people found the following review helpful:
4.0 out of 5 stars
A must-read, with one flaw, September 16, 1999
The author gets high marks for realizing that an acceleration of 1g for 1 year will yield light speed and for analyzing every possible means to break the light speed barrier for both space travel and communications. The book gets four stars instead of five, though, due to a faulty analysis on the communications front. The author makes the intuitive leap that since the Einstein - Podolsky - Rosen experiment reveals the production of two like-polarized photons from the exitation of one calcium vapor atom which can then be detected by calcite crystals at different locations, faster than light communication is possible between the two calcite crystal locations by modulating the crystals themselves. In doing so, he fails to grasp that the signal emanates from the calcium vapor source, not the crystal, and that usuable information can only be fed into the system or changed at the source. The remainder of the book is excellent.The reader should also be aware that this book was originally written in 1988, and this paperback edition has not been updated to include the ramifications of string theory or M-theory. This book should therefore be followed with "The Elegant Universe" by Brian Greene.
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