We can survive killer asteroids — but it won’t be easy
April 4, 2012
More than a thousand known asteroids are classed as “potentially hazardous,” based on size and trajectory, says astronomer Neil deGrasse Tyson in Wired Science.
Currently, it looks doable to develop an early-warning and defense system that could protect the human species from impactors larger than a kilometer wide. … Smaller ones, which reflect much less light and are therefore much harder to detect at great distances, carry enough energy to incinerate entire nations, but they don’t put the human species at risk of extinction.
One killer asteroid we’ve been monitoring is Apophis, which could hit Earth in 2036, likely slamming into the Pacific Ocean. The tsunami it creates will devastate all the coastlines of the Pacific Rim.
The gravitational tractor is a favorite solution. This involves parking a probe in space near the killer asteroid. As their mutual gravity draws the probe to the asteroid, an array of retro rockets fires, instead causing the asteroid to draw toward the probe and off its collision course with Earth.