If on some planet asteroid falls, the first of its mass must "burn" in the atmosphere, and should remain a fiery smoke trail, and secondly, after the fall of the meteorite, one has a thick "shell" in the atmosphere from the wreckage two (or more) bodies, which will not miss sunlight and heat, that is supposed to occur so-called "nuclear" winter. I see these things in the US2 yet, but when the game comes out, I wish they were there.