Michio Kaku & Brian Green Explain String Theory in a Nutshell: Elegant Explanations of an Elegant Theory

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.

Relat­ed Con­tent:

Free Online Physics Cours­es, a sub­set of our col­lec­tion, 1,700 Free Online Cours­es from Top Uni­ver­si­ties.

Michio Kaku Explains the Physics Behind Absolute­ly Every­thing

What Is Déjà Vu? Michio Kaku Won­ders If It’s Trig­gered by Par­al­lel Uni­vers­es

The Feyn­man Lec­tures on Physics, The Most Pop­u­lar Physics Book Ever Writ­ten, Now Com­plete­ly Online

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness