Scientists believe that we would not be here it were not for three great cataclysms in the early history of Earth and of the universe. This is the first book to explore the deep connection between the events that shaped life on Earth: the "Big Bang" that spawned an entire universe; the explosion of a supernova, which seeded the solar system with heavy elements; and the crash of a comet or asteroid that caused the extinction of the dinosaurs and cleared the way for the evolution of mammals.