Join James Peebles, one of the world's foremost cosmologists, as he explores the universe. Like fossils, thermal radiation carries information about the past, in this case the nature of the early universe. This information has confirmed ideas about the expanding universe, and it has presented us with new challenges. In particular, dark matter and dark energy. Series: "UC Berkeley Graduate Council Lectures" [2/2007] [Science] [Show ID: 12005]