| > At best I think we're at least 100 years off for any long-term self-sustained space colony We think alike - but IMHO that's going to happen only if we begin now. That's why we shouldn't hold off. > If we can't solve exponentially simpler earth-based problems, then I think we have no business in expanding, and would be unlikely to succeed regardless. It's not like there's a single "we" that can keep attention at one thing at a time only. There are a lot of great engineers excited about space stuff, who don't care about ecology/whatever else at all. It makes sense to use their skills and enthusiasm while other engineers excited about that work on solving our Earth-bound problems. Another point is - whatever helps us survive on Mars and the Moon will help us greatly to reduce harm done to Earth. > Even if Mars or another planet were to survive the destruction of Earth, a stand-alone colony or space station would be doomed. > We can work on both, but one's a much more imminent danger. For sure, but there are also dangers other than climate change - war, asteroid impact, pandemics, rogue AI takeover... It's not that either Earth gets destroyed and the Martian colony will die anyways or nothing has happened and we don't need the backup. Perhaps there will be another pandemic and the people on Earth will die off but the Martians survive. Perhaps asteroid impact will make Earth uninhabitable for 10-50 years but no more. Etc |