QUOTE (Balta1701 @ Jun 14, 2009 -> 08:54 PM)
Like fire and brimstone raining from the sky, tsunamis that are kilometers high if it hits the ocean, all plantlife burned away in gigantic wildfires triggered by the flaming debris, 5 year nuclear winter from the airborne debris, all surface animal life dies of starvation, massive earthquakes as the crust readjusts, probably vaporize a good chunk of the oceans temporarily, etc.
You don't kill all life because there's still places life can survive. Maybe some ice caps survive and life is protected under them during the nuclear winter. Life survives in caves, or at the bottom of the ocean, places that are protected still exist.
On the other hand, you slam Mars in to Earth (this is how we formed the moon) and you literally melt the entire surface of the earth down to a depth of hundreds of kilometers and blow the atmosphere off in to space. The only protected environment there is any spores or bacteria that survive out in space and then return as debris from the blast comes back to the planet over the next few million years.
So, you're saying, there's a chance?