It is quite common to find (pseudo?) scientific statements to the effect that blowing up asteroids which are heading our way is a very bad idea, and that the movie Armageddon got this point totally wrong. I would like to explore this a little bit more. I have particularly seen statements that breaking it up makes it significantly worse.
Shouldn't breaking up the asteroid into 2 drastically increase its surface area or cross-section when its going through the atmosphere? Wouldn't this then both increase the chance of burning up in the atmosphere itself, causing an air-burst (not too sure about this one) or at the very least slow down at a slightly higher rate? Wouldn't all of these reduce the damage done?
At the extreme, if the asteroid is broken down to the size of sand or nearly so, wouldn't the damage to earth be minimal?
Additionally I would figure this has a bit more finality to it rather than diverting the asteroid by rockets or gravity. This may not matter much.
This method would be lot more effective than the diversion methods if the asteroid were discovered too late as well wouldn't it?
I am thinking more carpet bomb than a single giant bomb such as in the movie.