Name: How to defend Earth from asteroids
Uploaded: 2011-11-21T15:57:42Z
Duration: 13 min 59 s
Description: 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 shows us all the ways asteroids can kill us (yipes), and what we must do to avoid them.

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 shows us all the ways asteroids can kill us (yipes), and what we must do to avoid them.

How to defend Earth from asteroids

Asteroids have wiped out 75 percent of species before, but humanity now holds the tools to prevent another catastrophic impact. Even a mile-wide rock can unleash an explosion rivaling a 20-megaton bomb, while smaller ones can still shatter cities. Advances in telescopes and space technology let scientists find and even nudge threatening asteroids. Unlike the dinosaurs, humans can spot these dangers and push them aside.