"<a href=""https://www.youtube.com/watch?v=50r-5ULcWgY&amp;t=47m26s"">47:26</a> .. What Mr. Rees is overlooking is the fact that Earth is a sitting duck. Humanity can be wiped out overnight by a meteor that we failed to detect. And even if we did", we are far from being able to deflect a meteor strike. We need to get off planet (biologically .. not just robots with downloaded brains) because if we don't, we may not survive such an event as a meteor strike. This also applies to the possible risk of a human created holocaust. We could go from DefCon 5 to the Stone Age literally overnight (if we're lucky .. otherwise we may just get wiped out altogether, and the Earth may start again with roaches or something). The point is we need to start colonies off planet. It will be hard on our bodies .. but we will EVOLVE. We have to think far ahead and realize we can't be selfish. We need to think of the future of Humanity and that means we need to get some off world colonies started. I agree that we need to ALSO send AI's into space .. to explore the universe and report back. But we cannot ignore the existential risk our species faces, being stuck on Planet Earth.