"Mars is clearly the best permanent-­residence location other than Earth, and we can go there in case somebody or something blows up Earth. We will have a place

"Mars is clearly the best permanent-­residence location other than Earth, and we can go there in case somebody or something blows up Earth. We will have a place that ensures the survival of the human race." This always struck me as a dicey argument. Almost any catastrophe that befell the earth, short of a comet liquefying the entire crust, would still not leave it much less habitable than Mars. If the entire ecosystem died out tomorrow and the atmosphere vanished into space, then Earth would still be more hospitable than Mars. I think investing a few billion in spotting earth-vaporising comets would be a better investment from that point of view. (for the difficulty of blowing up the earth, see yesterday's post; http://news.ycombinator.com/item?id=1446612 http://news.ycombinator.com/item?id=1446612 )