Even though NASA and other space agencies have most of the nearby asteroids mapped—key word there being most—the possibility of one heading straight for us is something worth preparing for. After all, even with all of our advanced space imaging, the occasional rock still ends up surprising us. And asteroid surprises are not good surprises. So, yes, let's consider nuking the damn thing.
There are other options—at least on paper. We could push it out of the way with a spacecraft, attach a rocket to the thing and let it blow itself in another direction, or, um, using a giant rope. Most of these "plans" sound farfetched at best, so it's no surprise the "Ah whatever, just nuke it" option is getting scientific focus. It's still untested (phew!), but it's, sadly, the most feasible at this point. After all, we do have a lot of nukes down here. But do we know what would happen if we slammed one into a barreling space grenade?
Luckily, the bright radioactive minds at Los Alamos National Laboratory are looking for a definitive answer to that. Right now, they're using a 32,000-processor rig to simulate a nuclear attack against an incoming asteroid. Above, a one megaton "nuclear energy source" (warhead) hits the Itokawa asteroid—half a kilometer wide. And good news! The blast and subsequent shockwave would be enough to "mitigate" the rock's threat to our tiny planet. Which means it wouldn't kill us all, right? Why don't we bump it up to two megatons, gents.