Asteroid collisions are not unknown to our planet. The atmosphere protects Earth from most of these heavenly bodies, but the largest ones can make it through. So far, although large asteroids have permanently altered Earth's terrain and the organisms living on it, no asteroid has yet been destructive enough to completely eradicate the planet. Is this a future possibility? What are scientists' plans in case of such an emergency? This volume examines these questions and more. The age-appropriate main text, supported by engaging fact boxes and enlightening graphic organizers, provides young readers with scientific facts and avoids scare tactics.