A couple years ago, when I reviewed Neil deGrasse Tyson’s Space Chronicles, Angela mentioned that Tyson had been picked to host a sequel to Carl Sagan’s famous “Cosmos” miniseries. That sequel, “Cosmos: A Spacetime Odyssey” is now being aired to great acclaim (and some controversy, among creationists)–the 8th of 13 episodes will air on Sunday.
So now seems like a perfect time to dip into some great science writing. Jeffrey Bennett’s What is Relativity? is certainly one of the best nonfiction books I’ve read this year: a fast-paced, highly readable account of one of the most important scientific discoveries of all time.
The basic principle on which Relativity stands is simple, if incredibly counter intuitive: the speed of light is always constant. This means that even for someone traveling at very close to the speed of light, light will still travel away from them as quickly as if they were stationary. Add in a couple of thought experiments and an explanation of black holes, and you can sum up the theory fairly quickly–as deGrasse did in the March 30 episode of “Cosmos.” But as Bennett shows, even his 200 page book barely scratches the surface of the deeply complex implications of the theory.
Fortunately, we have Bennett to explain these implications, and he does so with great vigor. I remember being utterly amazed when I first learned as a teenager about the famous “twin paradox”–two twins, one traveling near the speed of light, the other remaining on earth, upon being reunited will be vastly different ages (it’s still amazing to me). Indeed, this is exactly the kind of mind-blowing thought that makes science fun and interesting for many children and teens.
Want to get a preview of Bennett’s easy explanations without reading the whole book? Take a look at this wonderful Q and A from his website.
BENNETT, Jeffrey. What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter. 224p. illus. index. Columbia Univ. Mar. 2014. Tr $25.99. ISBN 9780231167260; lib. ed. ISBN 9780231537032.
Starting and ending with a guided tour of a black hole, Bennett’s prose lives up to the subtitle of his book, offering readers not only an intuitive, but a highly entertaining and accessible account of Einstein’s theories of relativity. Relativity itself rests on two rather simple principles–that the laws of physics apply to everything equally, and that light is observed traveling at the same speed by everyone. Since the first one had been fully accepted since the time of Isaac Newton, Bennett explains, if we can understand how and why the speed of light always remains constant, we can understand all the seeming paradoxes of relativity, such as the famous dilation of time—the fact that time moves more slowly as objects approach the speed of light. The “intuitive” part of Bennett’s account is his copious use of thought experiments, an appropriate enough approach, since that is how Einstein developed the theories in the first place. And the accessibility of the book stems from Bennett’s aversion to using math—E=mc2 and v=d/t are the only equations that crop up—and Bennett is careful to explain all the elements of these equations each time he uses them. This eminently readable book could easily have been marketed to teens as it addresses a topic about which many of them want to know more, without using math or terminology out of their reach.—Mark Flowers, John F. Kennedy Library, Vallejo, CA