It'll be one of the biggest astronomical events since Shoemaker-Levy went to play in Jupiter:
The biggest fragment of that hit Jupiter with a force estimated at six million megatons.
It'll be a very interesting event if it does hit because we have so many probes around and on Mars that we can get some good data from it. Poor Curiosity might get a bit sand-blasted if its still going, but it'll capture footage that'll make Michael Bay sit back and go 'Dayum'.
Then, of course, the Martians will HAVE to invade Earth to get extra resources.
