Astronomers warn that it's not a question of "if" Earth will be hit by an asteroid, but "when." If a private group of space veterans has its way, a Sun-orbiting spacecraft will find threatening objects decades before they can strike us.
A meaty review of the impact hazard facing Earth has just been released by the U.S. National Research Council. The bottom line? If Congress and NASA are serious about finding all the truly threatening asteroids in our planet's vicinity, they'd better fund the search properly.