We won't go to the stars until we're actually IN space. Not visiting, but there permanently. When people are born, live and die without ever being dirtside on Earth; when they live in habitats made from lunar and asteroidal materials, we're there. When we've colonized this system we will be prepared to reach out to another.
Now imagine these people, who've lived all their lives in wonderful space habitats, worked in ships and on other planets and such. I don't think they'll be looking for another Earth. Why would they? They'll think their space habitat is far more comfortable.
As far as interstellar travel is concerned, I'm certain we will solve longevity well before we travel to the stars. FTL won't be the big obstacle it seems now. When your lifespan is several centuries, spending 30-50 years of it traveling across the stars is as reasonable as our ancestors crossing Europe, the Atlantic or Pacific oceans, or the American Continent to colonize a new land.
Since their colony ship is a fine habitat, they won't be looking for an Earth-like planet; they'll be looking for a Sun-like star. Of which there are many. Humans can spread out at a sub-light speed across our arm of the Galaxy. But most trips will be one-way. Each colony must be self-sustaining. The best find would be an asteroid belt in the habitable zone. Cheap resources!
>They'll think their space habitat is far more comfortable.
I really, really, really doubt that. People who spend most of their time living on oil rigs now, or people who lived large parts of their lives on ships, did not end up losing the desire for dry land.
I don't see them as comparable. A space habitat several kilometers in size with plenty of interior enjoyable space, and managed, perfect weather is nothing like an oil rig. And its better than a cruise ship, and there are people who would love to live permanently on those, although not as crew. Since they aren't down this deep gravity well, they are already more than halfway to anywhere in the neighborhood. For them, visiting The Moon or Venus is vastly more practical. An afternoon spent in Zero G games is always available. Insect pests such as roaches and mosquitoes aren't a problem. Which is why traveling from Earth to the habitat will be subject to such a strict quarantine.
Given the cost of every square foot of living space in a space habitat I imagine the conditions would be closer to that of a nuclear submarine than a oil rig.
The cost of living space in space is high now only because we have to propel it into space from our big gravity well. As soon as we start mining on for example the moon we will definitely see an exponential drop.
Just because you can bootstrap a computer to run arbitrary programs doesn't mean you're significantly closer to general AI.
Similarly, it's easy to argue that there will be incremental improvements in space technology, but it's very hard to argue that they will snowball into large-scale luxury platforms that can sustain human life indefinitely.
The earth has a wide variety of resources important to comfortable human life. The moon has rocks and sand and sunshine. Moon mining is but one of the prerequisites to living cheaply in space.
Yes. We'll probably move into space only after we are good into autonomously turning water, organics and some rocks into comfortable habitat. Not earlier.
That is probably not too far away. We are getting very good into semi-autonomous transformations, and at turning anything into the materials we want.
If this were true, one would expect life on earth to differ dramatically from what one observes today. A lack of necessary materials keeps billions of people in poverty.
Also because we're propelling it into space using disintegrating totem poles. Lofting it using something like a momentum exchange tether, launch loop, or space fountain would also make habitats of that scale much cheaper. Better materials science could also significantly reduce the necessary lift mass; inflatable shelters, for example, scale really well as they get bigger.
Having a planet's atmosphere to burn up flying space debris or at least being inside of a cave in an asteroid (as long as it is really a cave) can provide a lot of protection. A high-speed space rock could easily tear through the one foot of protective wall in your space station, and all of the pretty plants and oxygen in your biosphere will be dead from having been almost instantly frozen, even if you patch it up.
If we want colonization, we not only need orbiting stations/stations at Lagrangian points, we must be colonizing big rocks. Once you perfect your shields, it's another story, but we are nowhere near the energy requirements or technology of a ship or viable station that is safe for humanity to live in long-term. Even if I live to be 1000 years old, I'd never want to take my chances in a station or ship that isn't at least in orbit, protected by a large planet on one side, for any great length of time. And our orbit is filled with space junk- not very safe.
Now, if it were a Firefly-class ship, that'd be different. I'd live in that in a heartbeat. Or the original Enterprise or the Tantive IV.
> and all of the pretty plants and oxygen in your biosphere will be dead from having been almost instantly frozen
This is a myth. If you remove the air from a spacecraft you don't instantly freeze, nor almost instantly freeze. Without air there is no means to conduct the heat away from your body, so you'll stay warm until you radiate your heat away.
The effects of sudden decompression are more an issue than freezing. The moisture in your mouth and eyes will start to boil off, the dissolved gasses in your body fluids will start to come out of solution. But if you can fix the decompression issue quickly enough most things will survive.
This is similar to the view of those in Iain M. Banks's "Culture" novels. They view living on a planet as hopelessly primitive and inefficient. Most of its mass is dead, useful only for the gravity it generates. Terraforming is artificial and arguably immoral. And you're subject to all sorts of astronomical and geological catastrophes... why wouldn't you live on one of the many lovely Orbitals?
Now imagine these people, who've lived all their lives in wonderful space habitats, worked in ships and on other planets and such. I don't think they'll be looking for another Earth. Why would they? They'll think their space habitat is far more comfortable.
As far as interstellar travel is concerned, I'm certain we will solve longevity well before we travel to the stars. FTL won't be the big obstacle it seems now. When your lifespan is several centuries, spending 30-50 years of it traveling across the stars is as reasonable as our ancestors crossing Europe, the Atlantic or Pacific oceans, or the American Continent to colonize a new land.
Since their colony ship is a fine habitat, they won't be looking for an Earth-like planet; they'll be looking for a Sun-like star. Of which there are many. Humans can spread out at a sub-light speed across our arm of the Galaxy. But most trips will be one-way. Each colony must be self-sustaining. The best find would be an asteroid belt in the habitable zone. Cheap resources!