Frontiers of Physics

Tragedy struck Ron Mallett when he was ten years old. His beloved father died and he wanted to bring him back. So he dreamed of building a time machine. Ron Mallett grew up to become a theoretical physicist. Now he studies quantum mechanics and he's still trying to figure out how to go back in time. In this hour of To the Best of Our Knowledge we'll talk about the physics of time travel and the debate over why the universe is so finely-tuned for life.