Elon Musk has described the colonization of Mars as a planetary “insurance policy.” If we’re going to trash Earth, we’ll need somewhere else to go. The New Yorker’s archive editor, Joshua Rothman, is a lifelong science-fiction fan who has often fantasized about going to the red planet. He speaks with Elizabeth Kolbert, a New Yorker staff writer who is against the galactic-colonization plan, and Jacob Haqq-Misra, a scientist who writes about what the political landscape of an inhabited Mars might look like.