The Fabric of the Cosmos
Brian Randolph Greene is an American theoretical physicist and string theorist. He has been a professor at Columbia University since 1996 and chairman of the World Science Festival since co-founding it in 2008.
Greene's area of research is string theory, a candidate for a theory of quantum gravity. String theory attempts to explain the different particle species of the standard model of particle physics as different aspects of a single type of one-dimensional, vibrating string. One peculiarity of string theory is that it postulates the existence of extra dimensions of space: instead of the usual four dimensions, there must be ten spatial dimensions and one dimension of time to allow for a consistently defined string theory. The theory has several explanations to offer for why we do not perceive these extra dimensions, one being that they are "curled up" (compactified, to use the technical term) and are hence too small to be readily noticeable.
This video is based on his own work in his book of the same name. It serves as a general introduction to the central thesis of accepted theory and we will detail other theories on other pages.