But a near-miss is still a miss. In fact, the largest impact in all of human history — both recorded and archaeologically discovered after-the-fact — is Barringer (meteor) crater in Arizona, which itself only rated an “8” on the Torino scale: the same rating as the 1908 Tunguska event. These events occur every few hundred years at most, and we can often go thousands or perhaps even ten thousand years between them. The Chelyabinsk event’s damage came mostly from broken glass; no meteors of the past century have had enough energy to rate above a “0” on the Torino scale.
Moreover, the Solar System itself is more cleared of potential impactors than at any time in history. They still occur, of course, but with lower frequency than ever before. Getting hit by a giant, fast-moving massive space rock is still a real threat, but there are only two common classes of impact. The most common type of impacts — from asteroids — are the most easily trackable. If we do a dedicated ongoing sky survey of the asteroid belt and all near-Earth asteroids, we could give ourselves decades or even centuries of lead time when it comes to these potentially hazardous objects.