#59 Tarnsman
With all due respect, you show a lack of vision. People don’t need to live on a planet. There could be huge artificial structures made from asteroids that would spin and provide, from centrifugal force, the “gravity” needed.

And how much gravity is needed to maintain bone structure? I don’t know. But if you have to live on a planet or moon, and if the moon or Mars, for example, has sufficient gravity to do so, there are things that could be done that don’t involve terraforming. You want a fair sized living area, protected from radiation? Set off a clean nuke deep under the ground. You get a glass lined dome. Provide light, and provide the right mix to fill them, and you can have a working ecology. Not big enough? Set off several or many bombs close to one another and build tunnels between the domes.

And in regards to the technical difficulties of getting off “this rock” its more a matter of will than anything else. Look at Project Orion. Its 1960′s technology, but it could throw a payload the size of an aircraft carrier into orbit. Its not a problem of technology, its a problem of politics.