Having seen Gerard Butler save Katherine Heigl from herself in a previous movie, I think I can skip this one. Morena Baccarin is way too classy to be in a movie with him, too, although that very dynamic could be interesting.
Also, the astrophysics don't seem to make sense, and you know, I know something about that, having had summer jobs at an astrophysics library, and having played D&D with actual astrophysicists, as well as being involved in Traveller since forever.
So it seems to me that there won't be more than one set of impacts from a comet -- and that assumes that the comet is composed of something so vastly massive and so able to withstand heat, pressure, and vibration, that it won't be completely destroyed by our atmosphere.
If it's a giant block of ice, probably probably none of it actually gets to the surface. So maybe it's ice surrounding a giant block of iron. The ice would be burning off in space, making a comet. Our gravity won't have much effect on it. The ice would vaporize quickly and possibly explosively as it entered our atmosphere. The iron block might break up, depending on its structure.
Then it's all about angle of attack and what's in the flight path. Probably most of of it ends up in the ocean, potentially causing tsunami effects, and a lot of steam.
goes back to the year 2000!
