[JMvS]

Originally Posted by DragoZERO

Also keep in mind that we didn't know the true effect a large object would have on the Earth 30 years ago. I think an asteroid would be more cataclysmic than a colony though because its one big piece.

And as for Char's Counterattack,

Spoiler for Char's Counterattack:

Axis has nuclear propulsion and such which would cause the nuclear winter.. maybe, I'm stretching here, I know.

It's all a matter of size an speed.

BTW a nuclear winter doesn't require anything nuclear: it is caused when a large amount of particles and/or sulfur are propelled in the atmosphere, obscuring the sunlight as long as they remain in the atmosphere (which can last quite long).

Nuclear holocaust was the prime hypothesis, and the one that gave it it's name: but it in fact it would require A LOT of nuclear explosions, and ground explosions, because airborne explosions don't generate a lot of dust.

More natural causes, involved in the many mass extinctions that occured during the history of life, include asteroid impact (remember this one that fell in the Yucatan at the end of the Cretaceous?), and large volcanic eruptions (actually a much more potent extinction factor).

Spoiler for CCA:

Due to the large size of Axis, Char was most likely intending to create a nuclear winter, his claimed objective being to render the Earth inhabitable to force humanity to move to space.

Also, massive colony drop causing a nuclear winter is the premise of After War Gundam X.