I doubt it. The bible, or any other holy book/ prophet/ cultural group can't predict what future events will be.
A comet collision would be a convinient end for most of these groups, because it shows an awesome and unstoppable power from above that can destroy the world in a second.
The tribualtion, following from the rapture, is, according to www.raptureready.com, when the antichrist will come to power and rule over the world. I am not religious and I actually find pretty much all of this stuff as complete bs, but from what it seems nothing will be falling from the skys according to the fundamentalists.
Also, such a collosion would not only affect the 3rd World. The 1st World would be just as affected. We would just survive slightly longer.
As for the end of the world? In about 4bn years, when the sun expands and consumes the Earth.
