Edward Witten on a New Kind of Geometry
In this video, Edward Witten, Breakthrough Prize in Fundamental Physics Laureate (2012) and Charles Simonyi Professor in the School of Natural Sciences, discusses string theory and the need in physics to reconcile quantum theory, used for small things like atoms and subatomic particles, and Einstein's theory of gravity, used for large things like stars, galaxies, and the universe.
Watch the video from Breakthrough.