Physics, schmisics!

Maybe you’ve questioned the feasibility of Harry Potter’s invisibility cloak. Or you’ve doubted that you’ll ever be able to transport your body through space with a command as simple as Star Trek’s “Beam me up.” It might be easy to regard these ideas from science fiction as wildly impossible, but Michio Kaku’s new book will keep you from dismissing them so quickly.

In Physics of the Impossible, theoretical physicist Kaku explains the science behind science fiction and explores the extent to which current fictions may become future realities. “Like many physicists,” Kaku says, “when I was growing up, I was mesmerized by the possibility of time travel, ray guns, force fields, parallel universes, and the like.”

As an adult, Kaku has become a pioneer in the field of string theory, and he has authored several other books that have made complex scientific ideas accessible to the general reader, including Parallel Worlds, Beyond Einstein and his best-seller Hyperspace.

In his latest book, Kaku considers the likelihood that today’s impossibilities may become possibilities within our lifetime—or maybe just a little bit later on, like centuries or millions of years in the future. Based on his projections of how long such a conversion may take, Kaku labels his impossibilities Class I, Class II or Class III.

Class I impossibilities, he explains, are those that do not violate any known laws of physics but do involve technologies beyond the current realm of possibility. These are the technologies most likely to develop in the near future and include invisibility devices, hand-held ray guns (called phasers, of course) and advanced forms of artificial intelligence.

Kaku’s Class II impossibilities lie at the outer limits of our current understanding of the physical world and may take millions of years to develop—if they are possible at all. These include time machines, hyperspace travel and travel through wormholes. Instead of ruling out these far-fetched scenarios, Kaku explains why their development may be problematic and, assuming they can be developed, what their moral implications might be for a highly advanced society.

Kaku only devotes his book’s final chapters to exploring what he identifies as Class III impossibilities because, surprisingly, says Kaku, “there are very few such impossible technologies.” He identifies perpetual-motion machines and precognition as Class III impossibilities because their development would require a fundamental shift in our understanding of physics.

The book’s strength goes beyond its author’s ability to translate the complexities of physics into terms that readers can understand. Kaku’s knowledge of science fiction and popular culture also runs deep, and he deploys it nimbly. References to sci-fi staples such as H.G. Wells’ The Invisible Man, Douglas Adams’ The Hitchhiker’s Guide to the Galaxy and the Star Trek series only add to the book’s popular appeal.

Kaku also makes sure in each chapter to orient his ideas within their historical and literary contexts. Throughout his explanations of burgeoning technologies, he tells the stories of science’s most fascinating figures, including Newton, Einstein and Hawking. Even the most sciencey prose makes for an exciting adventure.

Although Physics of the Impossible explains why invisibility cloaks might not be hanging in our closets anytime soon, it prepares readers to think past impossibility and provides a fascinating glimpse of what we might expect from science in the coming years, or decades, or centuries, or millennia, or eons.