A Little Knowledge/Dangerous Things
I was at a performance of William Missouri Burroughs' play Mad Gravity last night. It turns out the play involves a bit of audience participation, so at one point a character asks the audience if anyone knows the difference between an asteroid and a comet. My date pointed to me, so I offered that asteroids were rocky denizens of the inner Solar System while comets were icy wanderers of its distant outskirts. It seems that the plot involved a close approach and possible impact by a comet. I didn't get around to mentioning it, but overall comets are a heck of a lot more menacing than asteroids. Orbiting mostly in our near neighborhood, asteroids are pretty familiar, and the big ones on nearby trajectories are pretty well cataloged. If a really big one (major extinction class event) has our number, modern astronomy should see it coming for a few hundred years before impact, probably giving us enough time to persuade even the dumbest Republican climate denialist that we ough...