*Starred Review* Doubtful in 1919 that even three scientists fully understood Einstein’s theory of relativity, the astrophysicist Arthur Eddington would marvel at this book. For in its relatively few pages, Bennett explains relativity to ordinary readers. Applying two simple principles—the uniformity of natural law and the invariance of the speed of light—readers conduct thought experiments that fuse time and space into a single concept. Armed with this concept, readers see why time slows down for space-travelers streaking across the cosmos, their spaceship growing more massive but shorter. Similarly, as they plunge into a black hole, doomed but enlightened readers can at least congratulate themselves on comprehending how extreme gravitation creates inescapably lethal tidal forces. Still, a perplexing mystery remains. Why does the singularity at the center of a black hole look irreconcilably different when viewed through quantum physics than it does when viewed through relativity? Undaunted, Bennett views this conundrum as the stimulus for scientific progress that will resolve it. Indeed, in the very fact that one man could formulate a theory as powerful as relativity, Bennett sees reason to hope that the entire human species can ultimately conquer stubborn nonscientific problems—social, political, even metaphysical. An impressively accessible distillation of epoch-making science. --Bryce Christensen
What Is Relativity? is a well-written and uniquely readable book that beautifully serves as an introduction to special and general relativity. Jeffrey Bennett carefully avoids bombastic statements and 'spectacularization' of the subject, sticking with well-established facts and presenting them in a clear and compelling manner.
(Alberto Nicolis, Columbia University)
Since it first appeared more than a decade ago, I have used Cosmic Perspectives by Jeffrey Bennett and his colleagues in no small part because of the excellence of its chapters on relativity. It is wonderful to now have a stand-alone volume in which his lucid, explanatory text and figures are coupled with a thoughtful commentary on why relativity is important in constructing our scientific and personal views of space and time.
(David J. Helfand, President, American Astronomical Society, and President and Vice Chancellor, Quest University Canada)
I have read lots of introductions to relativity, but none is as clear and compelling as this one. For anyone who is keen to grasp the fundamentally simple yet non-intuitive ideas of both special and general relativity, Jeffrey Bennett's book is the way to go. Impressively understandable and interesting.
(Seth Shostak, Senior Astronomer, SETI Institute)
...Bennett's fun book shows readers what relativity means, and what it reveals about our universe.
For in its relatively few pages, Bennett explains relativity to ordinary readers... An impressively accessible distillation of epoch-making science.
(Booklist (starred review)
A sober, comprehensible account of what every intelligent layman should know about space and time.
... [P]erhaps the best homage that anyone can pay to [Einstein] for such a groundbreaking contribution to physics in particular and science in general.