The Committee to Nuke Elysium

We humans are land-dwellers on Earth in the later high-oxygen period; conditions on earth even one billion years ago would have been rapidly fatal for an unprotected human, and even today, survival on 90% of our planet’s surface area is contingent on the availability of cultural artefacts like boats (80% is water) or clothing (for protection in hostile climates). So the real question isn’t, “can intelligent life colonize other star systems?” so much as “can intelligent life propagate itself, and its supporting biosphere and technosphere to run in alien environments? Which is a very different question. Call it the Ark Problem; if your name is Noah and you’re going on a one-way trip to another world, how big an Ark do you need (and how many specimens per speciality, be they biological or technological)?