Thomas James notes something that I didn’t get around to noting yesterday–how limited in his thinking Stephen Hawking is:

If you’re going to have to terraform even barren worlds with Earth-like parameters, how is that so much different from developing Mars-like planets as well? Why be so picky?

In fact, there just happens to be a Mars-like planet nearby, which wouldn’t require anti-matter rockets or tens of thousands of years to reach…

And for that matter, there are plenty of asteroids and moons in the universe, not to mention the infinite possible variations on O’Neillian space settlements. Settling Earth-like planets isn’t the only way to preserve the species.