33 of 34 people found the following review helpful:
4.0 out of 5 stars
Straightforward description of many topics about time., October 13, 2000
This review is from: About Time: Einstein's Unfinished Revolution (Paperback)
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.
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21 of 21 people found the following review helpful:
5.0 out of 5 stars
This is a brilliant treatment of a very difficult subject., June 27, 1999
This review is from: About Time: Einstein's Unfinished Revolution (Paperback)
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.
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23 of 24 people found the following review helpful:
2.0 out of 5 stars
Ok, But Not the Best, December 29, 2005
This review is from: About Time: Einstein's Unfinished Revolution (Paperback)
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.
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