If an asteroid the size of Earth itself hit Earth, that would probably destroy the planet, and definitely destroy all life on it. That would basically be the Planet X scenario. However, there is evidence all over the world of the craters left behind by asteroids that hit Earth before there was life on it. One theory is that the Gulf of Mexico was created by the asteroid that theoretically wiped out the dinosaurs.
Yeah thats what would happen, but I still question could live exist on the remnants left of the planet, could any remnants left hold gravity to support the atmosphere, I guess it depends on how severe the damage would be.
Agent Mulder says the aliens are coming to colonize Earth December 21 2012. The Truth Is Out There.
It seems everyone of any importance made statements about whats going to happen on that date.
I heard people say thats when we evolve into the next density.
I heard people say Aliens will land.
I heard people say war will end all life.
I heard people say Polar Shift will occur.
I heard people say they looked into project looking glass and saw basically nothing.
I heard people say Planet X will come
I heard people say the planets align.
it goes on and on.
other words no one knows but maybe 1, its basically choose above which one it is, one of them may happen.