More impactfulness found

It's possible that major asteroidal and cometary impacts are far more frequent--perhaps by two orders of magnitude--than supposed. According to a story in the International Herald Tribune, some large sediment formations called chevrons contain a lot of deep ocean microfossils and elements associated with impact events. They are hypothesized to be the result of 'megatsunamis' that would have dwarfed the recent one that hit the coast of Sumatra so hard.

If the evidence mounts in favor of this hypothesis, planetary defense might still sit on the back burner, but the pot would bubble a little more. The Tribune story claims that all "earth-grazing" asteroids are catalogued and monitored, and the likely frequency of impacts are estimated from that data. But maybe they haven't been adequately covered.

I happed to run into Piet Hut while I was in Berkeley earlier this year. He said that the B612 Foundation takes up maybe only 5% of his time. I don't suppose it's anybody's first priority right now.