"It is unlikely that there is a way to reduce a 2km asteroid into harmless dust. Any attempt to do so could result in far worse consequences."<br /><br />I have never understood this argument. Most would agree that at some point, an asteroid would become civilization destroying and destroy the vast majority of human life on the planet. The only issue is what size that asteroid must be, whether its 1km, 10km, 100km, whatever. But if that is true and you could break that asteroid into 4 smaller chunks, that would seem to me to be a good thing. For example, if it takes a 10 km asteroid to destroy civilization, it seems to me that breaking that into four 2-3km asteroids that would destroy four nations, rather than the entire earth, would be a good thing. Similarly, if a 2 km asteroid is nation destroying, it would seem to me that breaking that into four .5km city destroying asteroids would be a good thing, on down the line. As the gravity of an asteroid is too low to prevent the chunks from escaping from each other, it would seem that multiple nation destroying strikes, would be preferable to one civilization destroying strike. Since size and velocity create kinetic enery, it would seem to me that 4 strikes with .25 of the kinetic enery would be much better than 1 strike with all the kinetic energy (since the relative volocity of all four parts would not change), in terms of the earth's ability to absorb the strike. (And this ignores the fact, that one or more of the chunks might be pushed far enough away to miss Earth all together.) In any event, even if it didn't help, I can't imagine how breaking up a large asteroid, could ever possibly "result in far worse consequences." Am I missing something here?<br />