Customer Reviews

About Time: Einstein's Unfinished Revolution

5 star:		(24)
4 star:		(11)
3 star:		(5)
2 star:		(2)
1 star:		(1)

 

 

This is a book about the meaning of time, what it is, when it has started, how it flows and where to. If you ever wondered about the puzzles and paradoxes of time, if you ever wanted to learn more about what Einstein's relativity implies about time itself, this is a book you will not want to miss.

Davies covers most of the questions about time; I found interesting how he explains the rather weird relationship between real time and our mental notion of it. The weirdness of bizarre possibilities should be enough to confuse anyone thinking about it for the first time; the way time relates to quantum physics, being sometimes even stranger to understand.

Black holes, the warping of space-time, theories about time travel, and the notion of "now": the division of past, present and future. From the inevitable "what existed before the Big Bang" to the Hartle Hawking theory, Wormholes, time dilation, etc, much is covered about time. Here are some of the subjects you will be able to read about:

1.Tachyons: Davies wonders if Tachyons can be ruled out. The special theory of relativity has been tested to unprecedented accuracy, yet tachyons are a problem. Allowed by the theory, they bring with them all sorts of unpalatable properties.

2.Black holes: Could there be really an end to time-a singularity- and the centre of all black holes? Can they form tunnels to other universes, or can we use them like wormholes that thread back into our universe? What happens to matter falling in them?

3.Time Travel: Just a fantasy? The investigation of exotic space-times that seem to permit travel into the past will, according to Davies, remains an active field of research, but there are no realistic time-travel scenarios known. But as with Tachyons, the absence of a no-go proof forces science to keep it on the agenda, along with the usual paradoxes, of course. :-)

4.Quantum questions: Davies spends some pages describing the wonderland of weird and perplexing temporal teasers in the quantum domain. The way relativity of time fits uneasily into the quantum picture of a world where the collapse associated with measurements occurs abruptly at specific moments. The measurements of time itself are fraught with problems, since all clocks are physical objects afflicted by quantum fuzziness.

5.The Origin of Time: You'll also be able to read about the usual topic of how time originated, with all sorts of questions concerning causality, God and eternity.

The Age of the Universe: Davies spends some time on the measurements of the expansion rate of the universe, which combined with realistic assumptions about dark matter lead to the absurd conclusion that there are objects in space older than the universe itself. What's going on anyway?

These are just some of the main issues. This title is definitely only for those who have questioned time. Davies book is a bit dry sometimes, and can probably bore the reader who is expecting more impact. Some parts like the explanation of the quantum eraser dreamed up by physicist Marlan Scully might be a bit challenging for those with no background in the subject, but in general, the whole book is very readable and clear. Little math is required, if you know how to square a negative (imaginary number), you probably know enough to keep up, almost no math is presented. And to help, we have Davies sense of humour; while it might annoy some readers, I thought it was helping the book to flow better. It all depends on who's reading. :-) The book has good recommended Bibliography, and a decent Index. Unfortunately, there is no glossary.

If I had to summarize the book in a paragraph, surprisingly, I would perhaps just write that we probably don't know much. Despite all the progress of the past decades, Time is still a mystery, and the revolution that Einstein started is still very incomplete. His word on the subject won't be the last.

Unfortunately, this book ends up raising more questions than those it answers. Not Davies fault, it's really the subject itself. :-)

Very interesting work for the layman who is curious about time.

In this book Paul Davies provides a comprehensive, brilliant discussion of the nature of time. Beginning with Einstein's revolution which abolished the classical view of absolute time and space, Davies ranges widely into the scientific and philosophical ramifications of relativity. The bottom line is that our "common sense" notions of past, present, and future and our perception of time as flowng from present into future are distortions of reality. Instead of a flowing time that moves from present to future, time is actually a block of past, present, and future that is simply "there." The common sense notion of past, present, and future must be discarded if we are to understand the nature of time.Davies' discussion of time is exhaustive. And, while the book is difficult, particularly to a non-scientist like me, Davies has a gift for explaining very complex ideas in a way that a layperson can comprehend (but with effort; this is not casual reading!). Davies' prose is elegant and clear. He provides interesting insights into the lives of major scientific figures, particularly Einstein. And, he has a likable sense of humor. This book was a JOY TO READ.

About Time discusses twentieth century developments in theoretical physics and their impact on our notion of time. Davies is a well known and prolific Australian science writer. I offer the following thoughts for potential readers.

Aimed at the general reader the book does not require a detailed knowledge of physics or mathematics. In light of the counter intuitive nature of modern theoretical physics, however, the uninitiated reader may require a little effort to get the gist of this intriguing but esoteric topic. Given the broad scope of material addressed in the text the time spent on each issue is relatively limited.

I concur with previous reviewers that the book is generally quite readable - Davies' technique of using a hypothetical skeptic as a means to highlight certain issues may strike some as awkward (that was my impression). From an overall stylistic perspective, however, Davies has improved significantly from his earlier efforts and become a solid writer.

The author does a nice job of discussing relativity and some of its implications. For instance, his handling of the twins paradox is among the best I have come across. I agree with Davies that there is solid empirical evidence to support time dilation - his transition from this to a tenseless view of time, however, seems premature - or at least insufficiently argued. Indeed, many of Davies assumptions regarding the nature of time, though interesting, will likely not be convincing to those who do not hold his narrow verificationist view of knowledge.

I found the latter part of the book that discusses highly speculative issues such as time travel to be of limited value. At this point much of the thought in this area, though wonderful to ponder, is largely unstructured and untestable - more science fiction than science. Probably the two biggest challenges facing About Time, however, is it dating (a lot has happened in the interim) and the increased competition in this genre of writing.

Overall, it is not a bad book. There are, however, better options available to readers interested in this subject matter - Greene, Singh and Ferris are authors worth looking at.

This is a masterpiece. I have read all of the relativity/time books by Hawking, Feynman, Rohrlich, etc., and this is the best by far. It is extremely easy to understand, plus Davies presents ideas that most authors leave out (such as Wheeler's single particle universe). If you have any interest in relativity or the nature of time, read this one.

I initially bought this book for a presentation I was doing in college on "time". I had already read A Brief History of Time by Stephen Hawking, but this book seemed to offer clearer explanations of the sometimes tough concepts, although I still can't figure out imaginary time. I really enjoy reading the quotes he inserts at the beginning of the chapters-they really make you think. Probably what most impressed me, though, was the style of the book: whenever there is an obvious, or not so obvious, question or criticism about a concept that Davies is explaining, he beats you to it. Most every question that you would ask when reading this book IS ASKED in the book and Answered in the book. Lastly, I understand that all of his answers may not be understood, and, well, probably much of the book is hard to comprehend. It is easier to cope with than Hawking's, though, even without the pictures. Davies sums it up best in the Preface to this book, "Nevertheless, you may well be even more confused about time after reading this book than before. That's all right; I was more confused myself after writing it." Time is confusing, but Davies makes it about as clear as possible

Paul Davies doesn't mince words. I just finished reading this book so I flipped to page 1 and started over again. It's a very enjoyable, exciting journey. I agree with the first reviewer who said it reminded him of reading a novel. The book is somewhat technical and some of it was over my head, but I read it because I knew it would be slightly beyond my grasp. I like the challenge. I liked the chapters on quantum physics the most. Oh, I'm no writer, so I'll just say it's an excellent, entertaining, incredibly thought-provoking journey to a place I wanted to go!

This was such an enjoyable and lucid book I was sorry it wasn't even longer! Although I've come across many of the concepts in other books on quantum and relativity physics and cosmology, this is the first book I've read that was specifically dedicated to time itself. I was amazed at the number of ways there are of analyzing time. Among a myriad of other topics, Davies discusses it: as an historical subject of conjecture among the early Greeks, a subjective experience of the human mind as a byproduct of consciousness, a possible artifact of the "big bang," a possible reversible process in the event of the "big crunch," a vector quantity exhibiting directionality, rate of movement and even possibly a rate of change, the multiworld hypothesis and the possiblity of different types of time in these other worlds, and so on. Although some of the book is a little dated--the information from the Hubble orbiting telescope is mentioned in future tense--on the whole almost everything that can be said of time is included in the book in a clear fashion. I'm not a math-physics type person really, but I found the Davies book quite understandable. I especially enjoyed his insertion of a "devil's advocate," so to speak, who could point out problems or ask pertinent questions of the author. It was like attending a class with a particularly gifted student in its midst. Very much worth the time!

This is by far one of the best books I have read in a long time. It explains strange ideas in time and quantum physics and such. It was also very explanatory and easy to comprehend, even to me, a 13 year old.

I am a big fan of prof. Davies' books, but I found that this one had not the same high standard as his other books. Some chapters were boring and gave the impression that they were written purely to expand the volume of this work.

But as always, he explains clearly and understandably his subject, like such important items as the opposite direction of time's arrow in thermodynamics (downhill) and in the Darwinist evolution(uphill), or the disappearance of time in quantum mechanics.

Remarkably, one of the main themes of his more compelling and recommendable book 'The 5th Miracle' is already announced here: "Many scientists are adamant that the 'concretization' of quantum reality has nothing whatever to do with the mind, others maintain that the mystery of the 'collapse' (of the wave) and the mystery of consciousness are intimately bound up with each other." (p. 278)

I prefer the books written by G. Whitrow about 'all sorts' of times.

If you've ever wondered what is time, where did it come from, does it flow, why does it seem to go in one direction, will it have an end, or is it slowing down, you'll not find your answers in Paul Davies' book "About Time." Neither are you likely to find your answers anywhere else. For me, the most profound knowledge that came from reading Davies' book is the reminder that we really don't know what time is. We live in it, experience it, but really - on a fundamental level - fail to comprehend it.

Davies has subtitled his book "Einstein's unfinished revolution," and he does an excellent job of exposing the reader to some of the unexpected (from a common-sense point of view) conclusions we draw about time from the special and general theories of relativity. He offers an interesting historical perspective on the life of Einstein, and how he developed his theories. Davies also provides some interesting background on experiments that have validated Einstein's space-time, reviewing the qualitative results from some of the more important experiments.

After this introduction to the non-universal time of relativity, Davies takes us to the ultimate time machine: black holes. He offers some interesting explanations about what an imaginary traveler to a black hole might see looking out, and how we - looking in - might view the hapless victim as she neared the event horizon.

As the book progresses, conclusions and examples become less and less concrete. Relative time is a proven fact, and most physicists consider black holes a foregone conclusion. From there, Davies takes us to the very root of some of the biggest issues in cosmology: the origin of time and the age of the universe. Davies clearly believes there are problems with the current Big-Bang theory of the universe, and proposes Einstein's cosmological constant as one possible solution.

Things get weirder still. From cosmology he moves to quantum time and the implications of tunneling and EPR experiments. There is some brief mention of Hawking's imaginary time and, of course, no book on time would be complete without a chapter on possible time travel. Davies looks at all the possibilities, and some of the discussions and speculation runs wild.

For the most part I really enjoyed this book. It is well written, and clear, but sometimes the author fails to define terms properly. He appears to use the term "timewarp factor" synonymously with "time-dilation factor" but the formula on page 58 disagrees with the top figure on page 61. Also, in his discussions about problems with the Big Bang theory, I felt the author failed to give sufficient coverage to inflationary models of the universe that might resolve some of the issues he raised.

Overall, Davies' book is worth the time to read it. It may not answer all the deepest questions about time, but it will help you appreciate how little of the subject we truly comprehend. I'd also recommend his book "The Last Three Minutes."

Duwayne Anderson