Asteroids bombard our atmosphere all the time. Some are harmless, burning up in a flash of light. But others explode with a great sonic boom, smashing windows and throwing people to the ground. Worst of all, some asteroids strike our planet, blasting out massive craters and destroying everything nearby on impact. Follow the award-winning author Elizabeth Rusch into the field with scientists as they search for dangerous asteroids in space, study asteroids that have smashed into the ground, and make plans to prevent an asteroid strike if one ever threatens our planet.