The three big bangs : comet crashes, exploding stars, and the creation of the universe.

Scientists believe that we would not be here if 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 catastrophic events that shaped life on Earth: the "Big Bang" that spawned an entire universe; the catastrophic explosion of a supernova, which seeded the solar system with heavy elements; and the crash of a gigantic comet or asteroid that caused the extinction of the dinosaurs and cleared the way for the evolution of the mammals. In July 1994, the theoretical basis of this third big bang was lent dramatic support by the collision of the comet Shoemaker-Levy with the planet Jupiter. If such a comet had collided with Earth, civilization as we know it might have been destroyed.