Elon Musk, the billionaire founder and CEO of the private spaceflight company SpaceX, wants to help establish a Mars colony of up to 80,000 people by ferrying explorers to the Red Planet for perhaps $500,000 a trip.
(...) we've put all our eggs in one basket. If we were on many worlds and were to mess up down here, there's a way for the human species to continue. I don't for a moment propose that the Earth is a disposable planet, and we have to put enormous efforts into making sure we don't muss up down here. But there is a chance.
I've thought the same thing. A big, deep, independent, hermetically sealed, geothermally powered complex under say Iceland or New Zealand gets you most of the x-risk mitigation that a martian colony does.
In most cases of "conventional" xrisks (< 10km diameter impactors, (current tech) wars, famine, super volcanoes, (nearly all) climate change scenarios, global computer failure, most pandemics (sub 100% lethality), most supernova scenarios) you don't even need the shelter.
It is sufficient to have the tech necessary to be self sufficient in a small (say 1000 people) group independently from ecosystem services (i.e. food, water, maybe air - not an issue in most scenarios, organic raw materials, fossil fuels). This is the minimum requirement for ... (read more)