A few years ago, String Theory seemed the prime candidate for the “long-sought Theory of Everything,” the holy grail of physics that will reveal, writes Jim Holt in The New Yorker, “how the universe began and how it will end… in a few elegant equations, perhaps concise enough to be emblazoned on a T-shirt.” Popular physicist and science communicator Brian Greene has touted the theory everywhere—in his book The Elegant Universe and PBS series of the same name; in interview after interview, a World Science Festival forum and TED talk…. Given such evangelism, you’d think he’d have his elevator pitch for string theory down pat. And you’d be right. In an io9 Q&A, he defined it in just 14 words: “It’s an attempt to unify all matter and all forces into one mathematical tapestry.”
All of this might make string theory sound simple to understand, even for a lay person like myself. But is it? Well, you will find no shortage of primers online in addition to Greene’s exhaustive explanations. There’s even a “String Theory for Dummies.” If you’d prefer to avoid being insulted by the title of that instructional series, you can also watch the video above of another excellent popular physics communicator, Michio Kaku, explaining string theory, with helpful visual aids, in four minutes flat. He quickly lays out such essential components as the multiverse, the big bang, wormholes, and the cheerful inevitability of the death of the universe. The short talk is excerpted from Kaku’s Floating University presentation “The Universe in a Nutshell,” which you can watch in full here.
For all of Kaku’s references to Einstein and the equations of string theory, however, he doesn’t quite explain to us what those equations are or how and why physicists arrived at them, perhaps because they’re written in a mathematical language that might as well come from an alien dimension as far as non-specialists are concerned. But we can still learn much more about the theory as lay people. Above, watch Greene’s short TED talk on string theory from 2005 for more straight talk on the concepts involved. And as for whether the possibly unfalsifiable theory is still, ten years later, a candidate for the grandly unifying “Theory of Everything,” see his article from this past January in the Smithsonian magazine.