Phil Plait: How to defend Earth from asteroids

What's six miles wide and can end civilization in an instant? An asteroid - and there are lots of them out there. With humor and great visuals, Phil Plait enthralls the TEDxBoulder audience with all the ways asteroids can kill, and what we must do to avoid them.

I love the approach Plait recommends; it's like jiu-jitsu meets astro-engineering.