Michael Turner of the University of Chicago talks about the Big Bang and the Inflationary Universe. A deep subject given a light hearted treatment. You might want to get up to speed on the physics idea of "time horizon" in relation to the speed of light before digging in. Or keep repeating the section from about 7 1/4 minutes in on the first video until it makes sense. His "view graphs" owe a lot to Batman Comics. The videos require "Real Player".