[cookiecaper]

This is kind of "putting all your eggs in one basket", though. If we're going to be terraforming and altering global or continental environs, we might as well do so on the Moon or Mars so that we have some insurance in case of nuclear war/meteor/other apocalyptic death scenarios.

[bld]

If you go through all the trouble to adapt to living in space for travel between the planets, why bother landing? Colonize the asteroids and short period comets, which are full of resources and much easier to access. No landing vehicles and ascent rockets are required. The gravity is so low that a spacecraft optimized for interplanetary travel can dock with them, or loiter nearby and transfer people & goods with space tugs.

Of course, it's a matter of preference. Many would still prefer to live on a planet. A dispersed civilization that includes the small bodies would be even more resilient to any one collision. More eyes out among the asteroids would also increase the chances of spotting potential collisions.

[dennisgorelik]

1) It's much cheaper protect yourself from nuclear war and meteors while staying on the Earth (e.g. digging down) than move to the Moon. Moving to Mars/Venus is even worse than Moon.

2) If you want to "insure" our civilization from disappearance -- focus on developing smart machines that can travel anywhere and carry our civilization accomplishments to other places. Sending people to other planets/asteroids is extremely inefficient in comparison with other options.