Impact! The Threat of Comets and Asteroids

65 million years ago a large asteroid or comet collided with the earth and caused a worldwide catastrophe. The collision caused a blast twenty million times more powerful than the largest hydrogen bomb, punching a hole ten miles deep in the earth. Thousands of species of plants and animals were obliterated, including the dinosaurs, some of which may have become extinct in a matter of hours. In Impact, Gerrit L. Verschuur offers an eye opening look at such catatrophic collisions with our planet. Perhaps more important, he paints an unsettling portrait of the possibility of new collisions with earth, exploring potential threats to our planet and describing what scientists are doing right now to prepare for this awful possibility.