Did you know the cosmic microwave background (CMB) radiation is the oldest light in the universe? It is literally the remnant heat left over from the Big Bang! This fossil relic has survived largely intact and it provides us with a unique probe of what conditions were like in the early universe, long before any stars or galaxies had formed. NASA has now flown two satellites devoted to studying the CMB: “COBE” and “WMAP”. Professor Gary Hinshaw will describe what we have learned from these missions including evidence for the Big Bang itself, new measurements of the age, shape, and content of the universe, and new evidence that all structure in the universe emerged from microscopic quantum fluctuations in the primordial soup.