I’M EXPECTING AN EARTH-SHATTERING KABOOM: Even Smaller Asteroids Are A Threat. “The real issue is that articles calling these asteroids ‘potentially dangerous’ miss the point: The asteroids that caused the Chelyabinsk or Michigan events weren’t labeled ‘potentially hazardous’ because they weren’t tracked at all. Something the size of the Chelyabinsk meteor (15-20 meters) hitting an urban center could still be devastating.” We’ll need a lot better surveillance if we’re going to keep track of those.