Customer Reviews

The Future of Spacetime

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I'm usually wary of books that are collections of essays, especially essays by several different people. Like many such books, The Future of Spacetime is something of a hodgepodge. Still, when I saw that the authors included Stephen Hawking, Kip Thorne, Timothy Ferris, Alan Lightman and Igor Novikov, it seemed to be worth taking a look. That decision was very well rewarded.

The five essays in The Future of Spacetime were first presented as talks for a celebration of the 60th birthday of Kip Thorne, a leading theoretical physicist. Three of them, plus a brief introduction by physicist Richard Price, deal with relativity, and especially with the possibility and implications of "closed timelike curves" in spacetime--time travel for short. In addition, Tim Ferris writes insightfully about why it is so important for scientists and science writers to do a better job of informing people about scientific theories and discoveries, but even more importantly clueing them in about how science works. He points out that it may take 1,000 years for a concept to penetrate to the core of society. Since modern science is at best 500 years old, there's lots left to be accomplished. Alan Lightman, who is both a physicist and a novelist, beautifully describes the creative process that lies at the heart of both science and creative writing. Scientists and novelists, he argues, are simply seeking different kinds of truths.

The three physics essays are gems. Each sheds at least some light on the nature of spacetime, on the possibility (or impossibility, or improbability) of time machines and time travel, and on intimately related issues such as causality and free will. Novikov, for example, concludes that the future can influence the past, but not in such a way as to erase or change an event that has already happened. Hawking argues that time travel is happening all the time at the quantum level, but that nature would protect against an attempt to use a time machine to send a macroscopic object, such as a human being, back in time. I was particularly impressed by Kip Thorne's essay, in which he makes a series of predictions concerning what physicists and cosmologists will discover in the next thirty years. He explains the importance of the gravity-wave detectors that are now starting to come on line. They promise to let us read the gravitational signals of such primordal events as the collision of black holes and even the big bang itself. It is as fascinating to get to piggyback on how these great minds think as it is to read their conclusions.

In short, The Future of Spacetime is a bit of a salad, but an extremely delicious and satisfying one.

Robert E. Adler, author of Science Firsts: From the Creation of Science to the Science of Creation (Wiley & Sons, 2002).

It is easy to recommend this book. The five authors of the articles in the book are all prominent in the field os cosmology and its interpretation. The editor, Richard Price, presents a good introduction of the subject of spacetime. It is not for the novice, but it is good. The sections by Hawking and Novikov are part of symposium in honor Kip Thorn's sixtieth burthday. Ferris and Lightman are excellent popularizers of difficult physics. The best part of this book is it shows that physics is fun. All of the authors obviously know each other and enjoy each other's company. This book is almost like sitting around a dinner table and overhearing the authors needle each other but still explain the basis of the universe as we understand it.

This is the best book I have read on this subject in years.

We have 4 scientific essays here, about space, gravity and possibilities of traveling in time, many drawings, figures and pictures and only two math equations.
However, this writings are, in my opinion, for "advanced" laymen, who collect, cherish and have fully digested at least a "Brief History of Time" or other popular science books dealing with cosmology, quantum and relativity.

Introduction (essay number one) by Richard Price presents known facts about relativity, but author uses innovative way to teach us about different types of transformation between reference frames. With elegance he introduces concept of spacetime diagrams and worldliness. Good beginning.

Then comes Igor Novikov: his essay straightforward and easy to read. Supported by well designed drawings it explains how the wormhole can work and why it is rather impossible to kill your grandfather by traveling to the past.
If you have his book "River of Time", you will know what I am talking about.

Third essay by Stephen Hawking is rather hardly digestible highbrow dissertation, with plenty of inward shortcuts. Drawings and figures are not clear and without indications to which part of the text they belong. This part of the book is least meritorious, but... help can be found later.

The most impressive essay by Kip Thorne creates the hub of the book. Kip Thorne has proposed Laser Interferometer Gravitational Wave Observatory in 1984 and is a cofounder of this project. He also believes in potential of a String Theory.
Thorne's current writing is an excellent addition to his famous book "Black Holes and Time Warps" published 8 years ago. He predicts now many interesting discoveries related to LIGO/LISA gravity waves project. If successful, this project will greatly contribute to new theory connecting general relativity with quantum fields and will help to solve mysteries of neutron stars and singularities. History of Thorne's bets with Hawking is funny and adds flavor to this chapter.

End of the book contains Glossary (whole 17 pages of it) and I read it with a big pleasure since this helped me to understand Hawking's text.

Last two essays about skills of popular writing in science were also interesting but of a less importance to me...

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This slim volume consists of six essays, based on talks presented at the Kipfest [note 1] on the occasion of Kip Thorne's sixtieth birthday. Thorne, the Feynman Professor of Physics at Caltech <http://astro.caltech.edu/people/faculty.html> is best known to the general public for his 1988 wormhole "time machine" proposal, and indeed much of the book is taken up exploring the question, "is time travel possible?"

Physicist Richard Price leads off with a concise refresher-essay, "Welcome to Spacetime." Danish physicist Igor Novikov explores classic time-travel paradoxes, with some cool diagrams and novel results: in essence, "closed timelike curves" [note 2] are theoretically possible, but paradoxes aren't allowed -- with a time-machine, you could visit your grandfather, but you couldn't kill him. The universe wouldn't permit it -- which in essence is Hawking's Chronology Protection conjecture. Hawking speculates that the unfortunate time-traveler would be incinerated by (literally) a bolt from the blue. Well, what he actually says is, "one would expect the energy-momentum tensor to be infinite on the Cauchy horizon" [note 3], which (sigh) is a pretty typical Hawking attempt at "popular" science.

Fortunately, Thorne himself is a master popularizer, and he ends up explaining Hawking's ideas as well as his own. His essay amounts to an update chapter for his wonderful 1994 book, Black Holes & Time Warps: Einstein's Outrageous Legacy, which I enthusiastically recommend: <http://www.sfsite.com/10b/bh67.htm>. Thorne reluctantly concludes that things really don't look very good for wormholes, especially for time travel -- though he does leave a tiny ray of hope for some super-advanced future civilization to make wormholes for space travel [note 4]. Thorne notes that our grasp of basic physics is so crude that we can really only understand maybe 5% of the stuff that fills our universe -- the "normal" baryonic matter that makes up people, planets and stars. Thorne guesses that 35% of the universes's mass is in some unknown form of "cold dark matter", and the remaining 60% is some even more mysterious form of "dark energy" -- so there's certainly plenty of room left for discovery!

The book concludes with a nice explanation of why good popular-science books are needed, by noted pop-science writer Timothy Ferris, and with Alan Lightman's essay on "The Physicist as Novelist". Lightman, a former student of Thorne's, went on to write Einstein's Dreams and other well-regarded novels.

The Future of Spacetime is written for a general audience -- aside from Hawking's essay, everything should be understandable to any science-literate reader. I particularly recommend it to readers who've liked Thorne's earlier pop-science works.
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Note 1). a clever play on festschrift, the traditional name for such a tribute volume.

Note 2). As Hawking cheerfully points out, "closed timelike curve" is just physics-speak for time travel, because you can't admit you're studying that sci-fi stuff in a grant proposal...

Note 3). Arthur C. Clarke notes that "the most convincing argument against time travel is the remarkable scarcity of time travellers..."

Note 4). As you may know, a faster-than-light spaceship could also be used as a time-machine, another reason why most physicists think FTL travel is very unlikely. I'd love to see a theoretical treatment of FTL travel that wouldn't violate Hawking's "Chronology Protection Clause"... Note also that there's no theoretical barrier to wormhole spaceships travelling a bit *slower* than light.

Peter D. Tillman
Consulting Geologist, Tucson & Santa Fe (USA)
Review first published at SF Site:
http://www.sfsite.com/11a/fs139.htm

A series of essays on the concept of Time in current Theoretical Physics. The papers were presented in 2000 following a tradition within the community of Physics. These topics honor Kip Thorne on the occasion of his 60th birthday. Thorne has investigated the possibility of actual time travel in current concept of Spacetime.

Igor Novikov provides arguments for the possibility of travel to the past, but concludes that it is impossible to change the past, which has already happened, including any effects of a future person traveling back into time. Stephen Hawking argues that travel in time, in the science fiction concept, is impossible, likely violating the laws of physics as we understand them now.

Contributors discuss the latest knowledge on black holes and singularities. This volume was enjoyable as a view of Physics enjoying itself, taking its possibilities seriously, while enjoying the adventure along the way. Insights from Quantum Physics contribute to our possibilities in the macro world.

Timothy Ferris explores the factors involved in the popularization of science. He provides some shocking statistics about the general ignorance of the American public about science and our knowledge of the universe. Alan Lightman takes us into the world of writing to compare the insights and themes of science fiction and physics.

This a book derived from 5 physicists who gave a discourse to honor Kip Thorne on his 60th birthday. If you're interested in the musings of some of the greatest minds in science, this is an excellent book. Absent is the mathematics that gives substance to the thoughts, which makes this subject very approachable to the lay audience.

The topics are far ranging in the field of physics and the discussions are beyond the edge of what is currently provable. This is the area of where knowledge meets intuition, where great theories and insight are born.

If time travel, the universe as four dimensions, and related subjects are not for you, then this isn't the book for you. If your interested in the thoughts that will propel further investigation in the quest for knowledge and understanding, this is an excellent book.

I had the chance to attend a Kip Thorne lecture at UCI in 2008 and enjoyed his contribution to this book, as another chance to try to understand his "warping versus curving" of space and black hole structure theorizing. The Future Of Spacetime is not exactly a *substitute* for the "live" experience, but I surmise it works for initiated *and* the inquisitive, mathematically-lacking individual.

I still can't fathom how backwards time-travel is possible as human beings are in an evolutionary process and once a cll is used up...well, how does on retreive it?
So I'll revisit those passages on occasion.

The Introduction mentions that Einstein's breakthrough was based, however, on basic Math, so this work, with clearly detailed graphs and drawings, is a nic "breakthrough" for new and old students alike.

Time travel appears pretty impractical based on this book. Maybe it's mathematically possible to fold time and punch wormholes in it in theory, but I don't think NASA or Greyhound is going to be offering trips back and forth through our lives. However, it's always intriguing to read what really smart people come up with, because they make a lot of it seem so obvious, even though I could never come up with it on my own.

It is incredible how they trust blindly in EVERY aspect of General Relativity. Space-time warpages and singularities happens ONLY in mathematics! There is no way out. It is funny how Scientific American gives credibility to such a kind of science-fiction. It is time to stop lying to the public!

Hawking and Thorne, grasp it: Time-travel is physically IMPOSSIBLE.