So
Space.com had an interesting article on research being done towards meteor detection systems, and how to mitigate that threat for Earth. As one can expect, nuclear bombs are a proposed (and perhaps plausible) solution. The notion is that, depending on the size of the asteroid, a nuclear explosion could either fragment the asteroid into harmless (or far less harmful) bits, or it could knock it off course. It would be delivered via a
Hypervelocity Asteroid Intercept Vehicle (HAIV), which could theoretically punch a hold in the asteroid, then deliver the nuke, which could have greater destructive force due to the insertion (I guess
Operation Plowshare was good for something, right?)
Asteroid detection is another concern, however, especially in the light of
last year's meteoric explosion over Chelyabinsk, Russia, which nobody saw coming. Similarly,
the Tunguska Event in 1908 (also in Russia) is also (I think) thought to have been a meteorite.
in 2015, the ATLAS (
Asteroid Terrestrial-Impact Last Alert System)
is expected to be online, with warnings ranging from a day to three weeks. In a strange mirror, the sizes of asteroid impacts, like nuclear ones, are also measured in megatons (the above linked site calls a "city killer" 5 megatons, and a "county killer" 100 megatons (like the
Tsar Bomba).
