Earth has been struck by asteroids many times. It will happen again. The question is how soon, and whether the asteroid will be large enough to cause significant damage. A Kansas man is helping to track asteroids with the potential to become a threat, and he does it from his own backyard — with a telescope he made himself. Machinist by day, amateur astronomer by night, Gary Hug is making a name for himself as one of the most prolific asteroid-trackers in the world.