2. Even if limited interstellar space was possible I'm not sure that a civilization is going to put the resources into blasting a very few people into the great unknown for perhaps multiple generations.
I don't really see why it has to be people. Von neuman machines are all that we need. Well, Von Neuman machines that are also capable of producing something.
3. Long term exposure to space radiation looks like it might be a difficult problem to solve.
I don't see why. The solution isn't to build a spaceship that's perfectly shielded from radiation: it's to build either robots or humans that can live with it. There are microbes that can sustain massive radiation without any problems, I don't see why building computers, robots, or people that could do the same is undoable. As long as technology continues to advance, it's inevitable that we'll learn how. (because there is a way: obviously if it were impossible we would never do so, but as I said: microbes already do it. All you need is good error checking, and during our evolution there was never any reason for it to be that good. In fact, if it were better than it is, it would have been selected against.)
4. My guess is that at least some of amb's pessimism is well placed and the goldilocks type planets are uncommon and there just may not be one near enough to us to get to in even a few generations.
Yeah, I agree to that generally as well. However, I don't see why we need one. With advanced enough technology we might even
prefer a few asteroids and comets to a "goldilocks planet".
Still as I wrote this I was kind of amazed by all the things I don't know about the future and the unpredictable ways things might go. Maybe people end up with greatly lengthened lives and traveling through space for a few hundred years seems like an ok thing to do,
I don't really see how that's
avoidable. I mean, there's no necessary barrier to how long we can live: it's just a matter of solving the problems. Of course, that may take us a very long time, but eventually we'll learn how our bodies work, learn to change them and fix them as need be.
Maybe mass launchers turn out to be pretty easy to do and getting big chunks of stuff into space isn't that big a deal. Maybe the giant space based planet hunting telescopes get built and people learn enough about a target planet some place that finding a planet with conditions adequate for human life becomes possible.
Those would both be very cool.
Or maybe we just kill ourselves before any of this stuff becomes possible in some massive nuclear exchange.
Very possible.
