Customer Reviews

Faster Than Light: Superluminal Loopholes in Physics

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4 star:		(6)
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1 star:		(1)

 

 

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.

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.

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.

Is time travel possible?

Buried at the heart of this question is perhaps another, more interesting question being: Do we even have the physiological ability to accurately perceive how time passes?

Like the first question, this book provides some interesting food for thought on the second question as well. As has been pointed out by other reviewers, this book from 1988 certainly should not be read alone and to the nominated other suggested works of Brian Greene's Elegant Universe and Fabric of the Cosmos I would also add Lee Smolin's The Trouble with Physics (which questions the efficacy of string theory itself) and also David Darling's Teleportation the impossible leap which is a more recent treatment of the developments relating to using quantum entanglement as potential means for interstellar/instantanious communications.

But back to basics: Do we accurately perceive time?

It's been an incident of scientific progress that great errors occur when natural human insights are imported into scientific theory without the benefit of testing. Two cases in point are the Ptolemaic model of the universe wherein the simple observer assumption that the earth is at the center of the universe and that everything revolves around it is taken as scientific fact and also the Aristetalian dichotemy between body and soul, itself another simple observer assumption that the soul exists independently of the body.

Conversely it's also been an incident of scientific progress that when one is willing to come forward and seriously challenge convention, there is a potential for great scientific advance. Again, citing the Ptolemaic model, the Copernican revolution was seriously revolutionary because it challenged the observer assumption that we alone in the universe were motionless while the rest of creation alone moved. And again, citing the Aristetelian model, the soul/body dichotemy has come under attack based on recent developments in evolutionary psychology which have shown the close correspondence between changes in brain physiology and alterations in human behavior. (If there is a soul then why does the loss some brain cells so radically effect human behavior. See Phantoms in the Brain by V.S. Ramashandran.)

It is in these regards that the question of the human perception of time has had a particular salience and power. And until 1957, no less than Richard Feynman was betting that our perceptions of time were way off. To understand why Feynman made and lost his bet we need to review some basic physics.

There are four fundamental physical forces which govern the universe. Acting at macroscopic scales we have gravitation and electromagnetism. Significantly by 1957 testing had shown that each force was time symetrical. In other words, the processes by which it operated worked the same in forward and reverse. At the microscopic level, the strong nuclear force was also found to be time symetrical.

So when Tsung Dao Lee and Chen Ning Yang decided to test the weak nuclear force, Feynman bet that they would also find this force to be time symetrical according to Steven Pollock, physics professor from University of Colorado at Boulder.

And he lost because the Lee/Yang experiment showed that the weak force was indeed after all not time symetrical which meant that nature indeed after all did have an arrow of time.

Now that having been said, as pointed in this book, there are good reasons to believe that our perception of the speed of the passage of time does vary from the actual physical phenomenon. Likewise, as pointed out by Kurt Vonnegut Jr. in Sirens of Titan and also Slaughterhouse Five there is also a question about why we see time so linearly.

His time traveling Tralfamadoreans saw humans as extended millepeds with baby's feet on one end and geriatric feet on the other and since we exist in all those time frames the question remains as to why we do not similarly experience reality. Like Capernicus questioning the movements of the earth or modern psychology divining the engines of consciousness the question is not a frivolous one but rather, among others provides fodder for scientific discovery.

And now back to the initial question: Is time travel possible?

In this regard, it bears noting that Herbert cleverly titled his book Faster than Light because modern physics does indeed support the movement of faster than light activity at the quantum level. However, like a modern insurance contract, the devil is in the details. This is because mere faster than light travel at the quantum level does not guarantee a basis for human exploitation for time travel purposes.

So at the end of the day, Herbert's book ends up saying what Stephen Hawking says in A brief history of time and what Kip Thorne says in Black Holes and Time Warps...you can't get there from here.

However, like those books this one keys into that very human, very scientific inquiry and asks why not?

Faster Than the Speed of Light: The Story of a Scientific SpeculationNick Herbert hadn't heard of Joao Magueijo when he wrote his book and did his research.
But Magueijo didn't have that excuse for not mentioning Nick Herbert?
I give the toss to Nick Herbert as being more open to innovative ideas.
In both cases they could have been more forgiving of our ignorance and given equations...
But it is our way off the Earth to the heavens that is involved here, and Nick Herbert
put material that had to be of use in this research in his book.
The other fellow just didn't. Compare and contrast the two for yourself.

the author explores the popular concept of time travel from an optimistic however skeptical view of a quantum physicist. with the bizarre predictions of quantum theory and relativity, anything can happen (and will acording to feynman). read this book and enjoy a topic interesting from any perspective.

This is on of the best popularizations I've ever read. Almost every conceivable way to exceed light speed has been debunked here. The author does however leave open tantalizing options that still have some credibility. Read it in three sittings...

A great book that gives insight to new visual data from Hubble and other satillites. My personal view is the gravity is a negative constant. Which helps the author's theories about worm-holes. Proof and testing of his theories are still 1000 years away.

A great book that gives insight to new visual data from Hubble and other satillites. My personal view is that gravity is a negative constant. Which helps the author's theories about worm-holes. Proof and testing of his theories are still 1000 years away.