NOVA: The Elegant Universe: The String's The Thing

In the last few years, excitement has grown among scientists as they've pursued a revolutionary new approach to unifying nature's forces. To the uninitiated, string theory is totally mind-boggling. But physicist Brian Greene has a rare gift for conveying physics in vivid everyday images, a gift that has turned his book, "The Elegant Universe," into a mighty best-seller.

Greene brings his talent and vitality to television in this highly innovative production that makes the surreal world of string theory spring to life on the screen.

This three-part series originally aired November 9 - 23, 2011 on KPBS TV. "Einstein's Dream" rebroadcast on Wednesday, July 11, 2012 at 10 p.m., and "The String's The Thing" will rebroadcast on Wednesday, July 18 at 10 p.m. The rebroadcast of the final episode, "Welcome To The 11th Dimension" is not currently scheduled.

In the second hour of “The Elegant Universe,” delve into the nuts, bolts, and outright nuttiness of string theory. Part two, "String's The Thing," opens with a whimsical scene in a movie theater in which the history of the universe runs backwards to the Big Bang, the moment at which general relativity and quantum mechanics both came into play, and therefore the point at which our conventional model of reality breaks down.

Then it's string theory to the rescue as Greene describes the steps that led from a forgotten 200-year-old mathematical formula to the first glimmerings of strings—quivering strands of energy whose different vibrations give rise to quarks, electrons, photons, and all other elementary particles.

Strings are truly tiny, being smaller than an atom by the same factor that a tree is smaller than the solar system. But, as Greene explains, they are able to combine the laws of the large and the laws of the small into a proposal for a single, harmonious theory of everything.

But even with its many theoretical successes, as of the 1990s physicists realized that strings suffered from a pernicious flaw—an embarrassment of riches: There were five different versions of the theory, each totally out of sync with the others. We have one universe, so shouldn't there be one theory of everything?

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