In clear, nontechnical language, string theorist Brian Greene explains how our understanding of the universe has evolved from Einstein’s notions of gravity and space-time to superstring theory, where minuscule strands of energy vibrating in 11 dimensions create every particle and force in the universe. (This mind-bending theory may soon be put to the test at the Large Hadron Collider in Geneva.) (Recorded February 2005 in Monterey, California. Duration: 19:06.)