Meet the researchers testing the “Armageddon” approach to asteroid defense

Rather, it’s asteroids a size range down—those upwards of 460 feet (140 meters) long—that are of paramount concern. About 25,000 of those are thought to exist close to our planet, and just under half have been found. The day-to-day odds of an impact are extremely low, but even one of the smaller ones in that size range could do significant damage if it found Earth and hit a populated area—a capacity that has led astronomers to dub such midsize asteroids “city killers.” If we find a city killer that looks likely to hit Earth, we’ll need a way to stop it. That could be technology to break or “disrupt” the asteroid into fragments that will either miss the planet entirely or harmlessly ignite in the atmosphere. Or it could be something that can deflect the asteroid, pushing it onto a path that will no longer intersect with our blue marble. Because disruption could accidentally turn a big asteroid into multiple smaller, but still deadly, shards bound for Earth, it’s often considered to be ... Read full article.