Comment by PaulHoule
19 days ago
With D-D fusion it might be possible to "live off the land" between the stars which probably have numerous interstellar objects of various sizes between them with a much larger cumulative mass than planets orbiting stars -- and it may be possible to completely disassemble those kind of bodies which are much richer overall in carbon, hydrogen, oxygen and nitrogen than terrestrial planets.
A species with that kind of capability would be able to visit another solar system in 10,000 or so years but might care less to mess around with dry little solar system bodies like the Earth. The case against "grabby" aliens is that Ceres and Pluto are still here, not that we can't find evidence of them on Earth.
I like to imagine that if that kind of interstellar traveler were to visit Earth it might take them a few decades to perfect a "reverse space-shuttle" because they'd gone 10,000 years without doing anything like that... And they can't just 3-d print one out of 10,000 year old plans because they've improved their 3-d printers to print the stuff they've been printing all that time better.
A true spaceborne civilization, assuming anti-gravity isn't in there bag of tricks, probably wouldn't bother with the gravity well planets.
I feel like for this reason we should be focused on colonizing asteroids rather than the moon or mars. We can do various tricks to get artificial gravity via centrifugal force. For example if the asteroid is solid enough, we can consider putting it into a spin. If it's not solid enough, we can consider laying a track around the circumference and/or boring a tunnel around the circumference and essentially having the habitat(s) constantly rotating around the asteroid.
Exactly. Those kind of people could support much larger populations than the Earth with a lifestyle they find comfortable in interstellar space and would look at living on Earth at best the way we look at living on Mars.