The Chelyabinsk Meteor: Can We Survive a Bigger Impact?

What would happen if an asteroid collided with the Earth? On February 15 2013, a rocky projectile entered the Earth's atmosphere traveling at more than 11 miles per second. It was about 65 feet in diameter, or half the diameter of the impact of 1908, which flattened a thousand square miles of Siberian forest. Its terminal explosion, at an altitude of 14 mi, released energy of about half a megaton, equivalent to a couple dozen Hiroshima-sized atom bombs. About two minutes later, the shock wave reached the ground in Chelyabinsk, Russia, breaking windows and injuring about 1500 people from flying glass. Since the impactor approached the Earth from very near the direction of the Sun, it could not have been seen by any ground-based optical telescope of any size. It therefore struck without warning. Has this event served as a kind of cosmic wake-up call for planetary defense? NASA recently announced a 'grand challenge" to find all asteroids that could threaten human populations, and to figure out how to deal with them. David Morrison will discuss the Chelyabinsk impact and evaluate ways we might meet the grand challenge to protect our population from space impacts.

Speaker: Dr. David Morrison, SETI