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. Phil Plait currently blogs for Bad Astronomy, a Discover Magazine Blog, he worked for six years on the Hubble Space Telescope, and directed public outreach for the Fermi Gamma-ray Space Telescope. He is a past president of the James Randi Educational Foundation, and was the host of Phil Plait's Bad Universe, a documentary series on the Discovery Channel.