Celestial Target Practice

In less than a week, three asteroids have zipped past Earth well within the orbit of the Moon, and a fourth is scheduled to fly past just outside lunar orbit April 4. Today, the asteroid 2012 EG5, 150 feet across, which was only discovered March 23, flew past at little more than half the distance to the Moon.

NASA assures us that none of those bodies pose a threat to Earth, but the sheer number of close shaves it continues to document should give policymakers around the world pause. The major question is whether a planetary defense program will be put into place before a disaster occurs, or after.