The Future of Spacetime

An exotic mix of ideas

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 a lot 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 closely 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, with an intense blast of radiation. 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 just now starting to come on line. They promise to let us read the gravitational signals of such primordial 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 salad, but a very tasty and satisfying one. Robert E. Adler, author of Science Firsts: From the Creation of Science to the Science of Creation (Wiley & Sons, 2002).