Re: space colonization and the future of mankind
If we go on long enough, without a total social collapse (from what ever cause) I believe we'll do it. Probably all wrong, but do it anyway.
The moon? Quite likely, although I doubt whether it will ever be terraformed. Not because it is technically impossible – no, it couldn't hold an atmosphere long term, in planetary terms, but a couple of hundred thousand years? And that's longer than humanity has been around. The trouble is that crashing a couple of comets against it to provide the volatiles will annoy the underground residents who settled in a couple of generations earlier, and when you have the technology to soft land them there's nowhere left on the surface uninhabited enough to risk it. So I see colonising there as basically underground; and we don't yet know much about how well humans function in very low gravity. If foetal development requires a near Earth gravitational field (quite possible – even likely) then it's going to take genetic modification for true colonisation of a lot of the real estate in the solar system, or lots of centrifuges.
But if the beanstalk boys have their way, and the space elevator is built fast, the first colony might be in geostationary orbit. Yes, I mean colony, not half a dozen engineers hanging around in a tin can.
If you want to be able to haul battleship-mass lumps into orbit, your counterweight needs to be the size of Hawaii. Now, this is small in planetary terms, but easily big enough to be worth homesteading. Obviously, you don't lift this into orbit from Earth; you go looking for a convenient sized piece of junk in space you can manoeuvre into place (and what a gorgeous target for terrorists; your very own extinction event, just requiring a 2% error of calculation). Since an orbital tower is built from the roof down (actually from the central floors up and down) you start, as with all planned cities, with a population of construction workers and support professions, and some of them won't want to go back home. Instant slum, instant colony. Again, the gravity problem, but free fall construction workers would be the ones with the solutions.
And most of the places in the solar system open to human occupation are going to be small, or much to big. Mars and Venus are the only reasonable sized bodies, with a couple of gas giant moons within useable. So the gravity problem will be solved, one way or another. For convenient transport of whatever is produced in space, we can not afford to go too deep into any gravity well apart from Earth's (unless some radical drive development changes the equations). Mars, while the easiest to terraform, is not convenient for delivery of anything but information; and can a scientific research station merit the title of "colony", with the relative independence this implies, even if tours of duty are long enough that offspring are born and raised outside the Earth's direct influence?