Apocalypse Almost

Re-examination of some astronomical data from 1883 indicates that we dodged a bullet that year, as a billion-ton comet broke up and whizzed by Earth less than 8,000 km from the surface -- that's five times nearer than a communications satellite:

Each fragment was at least as big as the one thought to have hit Tunguska. Manterola and co end with this: "So if they had collided with Earth we would have had 3275 Tunguska events in two days, probably an extinction event."

As a species, we're still a grenade target and look to remain so for quite some time. The older I get, however, the less I care. To paraphrase Robert Heinlein, this attitude is often mistaken for "mature wisdom."