When Worlds Collide

Planet Earth is regularly being struck by interplanetary debris: fine dust, rocks, boulders (big enough to outshine the Sun as they streak through the atmosphere), asteroids, comets, and even small stray planets. Some of these collision events offer glorious night-time views; others can cause planetary annihilation. Infall of secondary debris (“shrapnel” from the original impact) can raise atmospheric temperatures by of degrees, globally

Speaker: Kevin Zahnle, NASA Ames

Editor's Note: This talk replaces the one by Penelope Boston originally scheduled for this date.