Customer Reviews

The Nature of Space and Time

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The current understanding of the physical structure of the universe is bipolar. There is Einstein's theory of relativity, which explains the macroscopic behavior of the universe to many places to the right of the decimal point. At the other end of the size spectrum, there is the quantum theory of fields, which explains the observed behavior of fundamental particles to many places to the right of the decimal point. Although one should always be very reluctant to state such a position, the resolution of this bipolar state into a unified one may be the last, great discovery of physics.
The purpose of this book is to present a debate between Stephen Hawking and Roger Penrose concerning the possibility of the issue being resolved, and in what manner. It is a series of six short lectures, three from each man and ends with a brief debate between them. These lectures are not for the general audience, as each lecturer assumes a fundamental understanding of general relativity and quantum theory. Nevertheless, there is a great deal of explanation, including diagrams, in the lectures. Therefore, it is possible to understand the material if you have a basic understanding of the two main topics. Without that, don't bother opening the book.
Of course, the issue is not resolved, as that must wait for a later date. It is interesting that Hawking tends to emphasize the points of difference, while Penrose goes to some length to describe how similar their positions are. Penrose continues with the position of Albert Einstein, in that he argues that quantum mechanics is not a final theory, but only the "gross" appearance of much subtler events. Hawking believes otherwise, arguing that the probabilistic features of quantum mechanics is the way nature does things, and there is no underlying mechanism yet to be discovered that will remove them.
The arguments are strong, yet unconvincing. Not due to their lack of power, but because they are made by two equally strong and forceful personalities. When two such powers collide, there is rarely resolution. Nevertheless, the debate sheds a great deal of light on the current state of thinking in physics, and points out some ways in which it may be resolved.

In spite of the errors mentioned in another review the discussion was fairly interesting but not as great a "debate" as I anticipated. I'd spend my money on Penrose's "The Emporer's New Mind" before this one. For those interested in Black Holes, Kip Thorne's "Black Holes and Time Warps ..." is exceptionally well written and rewarding for the reader. For the technically [mathematically] apt who wants an fascinating treatice on spacetime, try John Wheeler and Ignazio Ciufolini's book on Geometrodynamics (Princeton Univ. Press).

I found this to be a fascinating overview of some of the major issues in cosmology from both Hawking and Penroses point of view. What is amazing is the actual level of agreement between the two. Perhaps only the real physicists appreciate the nuances of their differences of opinion.

I would recommend this book for anyone who's gone to the trouble of picking up a basic understanding of relativity ( special and/or general ).

The math is not terrbily daunting in most places and you get a real overview for the big picture of the state of relativity and quantum gravity.

I really enjoyed this book. It goes beyond the popular accounts of Hawking's and Penrose's ideas, without going into all the technical detail. You get to find out (sort of) why Hawking attributes entropy to black holes, and his explanation of why we don't see the galaxies in quantum superposition. And Penrose's ideas about twistors and quantizing them, and people's caveats about twistor theory.
It would help to be familiar with:
- Feynman integral over paths
- what is the action, and how it becomes a phase in quantum mechanics
- Euler characteristic
- special relativity, what spacelike, timelike and null mean
- Basic topology and analysis. Like what does "compact" imply.
- thermodynamic partition function
- contour integral in complex analysis
- what is a manifold
- how you find the expectation of an operator in quantum mechanics
- decoherence in quantum mechanics
- what is a conformal map
That sort of thing.

I love cosmology, physics and math but this book goes outside my comfort zone...so many equations and concepts that are beyond my complete understanding. There were times where I had to re-read sections 2-3 times and I'm still not sure that I completely grasp what they were saying. Now let's be honest we are talking about 2 geniuses here so I really didn't stand a chance.

The concept of the book with both men taking different sides to the cosmos questions as they relate to General Relativity, Quantum Field Theory, gravity and much more was a blast...the learning curve is HUGE though so be sure you brush up on you algebra and calculus prior to reading this book.

I also love the questions and answers at the end!!

If you liked "The Road to reality" and have an understanding of the Mathmatics of Quantum Physics and Relativity then you will enjoy this book. Otherwise don't bother.

To really appreciate this book requires an understanding of physics. Not the superficial stuff where you still believe that Newton was right, but Quantum Mechanics, Topology, and General Relativity.

The subject and the contents of this book is very interesting. However, you have to know quite a lot mathematics .....
Far above my level!

Lots of sui generis formulas, much more philosophy than science, and above all, old (1994).
Get a nice science book from either author and you will be a lot better off, and learn much more.
Formulas include expression as (over here) + (over there) . Not useful at all.

This was an early attempt to capitalize on Hawking's commercial success with the Brief History. Roger Penrose, Hawking's PhD advisor, has also written some really fascinating books for lay readers on philosophical implications of physics such as on the nature of intelligence. However, combining the two in a debate, the form of this book, cancels out the reader-friendly accessibility of their solo works as their egos take charge and they try to outperform each other. It makes sense after the fact that if they're debating, they must be discussing matters on which they disagree, and since physics is so well settled and understood on all but the most esoteric and advanced questions, the subject matter of their disagreements must lie in that advanced realm. Of course, "advanced" is a vastly relative term to apply to physics, since many ordinary readers would balk at any physics material. But I have a degree in physics, albeit only a BS - and after the initial material I have to struggle to follow anything they're saying! They should stamp this book's cover with a caveat emptor; this is no "Brief History of Time" or "Elegant Universe." They even mention at the outset that they assume the reader has a basic understanding of physics, but these guys' idea of a basic understanding is a Ph.D. specializing in general relativity. Having said all that, the book still makes for heady reading from what I could pick up here and there, so it's a thrill if you're up to it.