The New Time Travelers: A Journey to the Frontiers of Physics

  • David Toomey
W. W. Norton: 2007. 320 pp. £15.99, $25.95 9780393060133 | ISBN: 978-0-3930-6013-3
The physics of wormholes: are there shortcuts through time? Credit: M. KULYK/SCIENCE PHOTO LIBRARY

There are innumerable books on time travel, including the masterful Black Holes and Time Warps by Kip Thorne, one of the key players in a serious scientific investigation of the possibility of time travel. The subject has a chequered history, peppered with false claims and hyperbole. The title The New Time Travelers had me worried that the book belonged to 'People magazine popular science' — the genre that propagates the false notion that somehow researchers are more interesting than research. Happily, David Toomey, professor at the University of Massachusetts, Amherst, has produced an honest, intelligent and largely accessible work of impressive scholarship on a difficult subject. Most important, he provides a rare glimpse into the day-to-day practice of science, in which the right direction is never clear and false starts abound.

After some historical, scientific and philosophical scene-setting, the book focuses on the surge of attention, which began almost two decades ago, on the question of whether general relativity allows for the possible and practical realization of time travel. This heightened interest followed the 1988 paper published in Physical Review Letters by Thorne and his colleagues on the physics of wormholes, shortcuts through space and perhaps time. The paper was inspired by a question Carl Sagan posed to Thorne when writing his science-fiction novel Contact.

The discussion of time travel in a mainstream science publication attracted media attention and piqued interest in the scientific community. It also encouraged a lot of fanciful speculation by scientists about ideas on the very edges of respectability. And it motivated the writing of numerous popular books.

Since the mid-1990s, most concrete results regarding the possibility of time travel have been negative. The few outstanding issues ended up mired in quantum gravity, which remains ill-defined and elusive. As a result, interest in this issue in the physics community has subsided somewhat.

Toomey remains enamoured with the philosophical and literary possibilities of time travel, so is less critical of some dubious proposals than he might be. He nevertheless provides a largely accurate rendering of time-travel science with all its twists and turns, errors and dead ends. This is sometimes frustrating: it is tough to labour through detailed discussions of complex ideas that Toomey eventually correctly reveals to have proved fruitless. But it is also refreshing: popular books too often present research as a logical narrative that bears little relation.

Errors, as might be expected from someone writing outside his field, have crept in. Early discussions of physics, including special and general relativity, are quite clear. Later explanations of modern topics, such as inflation, are more uneven. A grating mistake is Toomey's statement that the Planck length is a million times smaller than the size of a proton. It is actually closer to a million million million times smaller. We regularly investigate regions a million times smaller than a proton with large-particle accelerators: it is the vast chasm between even these minute sizes and the Planck length that makes probing quantum gravity so difficult.

Aside from such gaffs, The New Time Travelers is sound and informed. If readers leave this book feeling unsatisfied, Toomey may have done them a service. He captures the nature of the scientific process — that one never knows where fundamental research will lead, that most of it doesn't result in ground-breaking developments, and that even negative results can prove enlightening. It is sometimes difficult for us to be honest about these facets when popularizing our work. That an 'outsider' has captured this is impressive, and useful.