It is really neat to see how "planetary impact" has really become a good science in the last 20 yrs or so. I remember the stuff we were taught in 5th grade about stuff that in these few years has turned out to be dead ass wrong (DAW). A good example of DAW teaching was that all biological life depended on the sun. That turned out not to be true at all, after the discovery of biologics near volcanic vents at the bottom of the oceans.
Are Asteroids History's Greatest Killers?