“SORRY, BUT IT'S TRUE. It has to be said: the stars exist beyond human time, beyond human reach. We live in this little pearl of warmth surrounding our star; outside it lies a vastness beyond comprehension. The solar system is our one and only home.” 2312’s quiet insistence on the radical inaccessibility of the stars — their infinite retreat from the horizon of human agency — manifests as an iron law not only in this novel but across the fiction of Kim Stanley Robinson. We might hurl interstellar starships out into the void in search of other Earthlike planets, as characters in fact do in both 2312 and in Robinson’s earlier “Mars Trilogy” — but the many-thousand-year timetable of these voyages means this can only be a branching of the human story and not its final, ecstatic culmination. The stars are out there, and we are here; they are not for us, they are not a part of our history, they won’t be the thing that saves us.

If the stars are truly forever out of reach — as contemporary physics says they almost certainly are, to the heartbreak of space-opera fans everywhere — then humanity is permanently enclosed within a solar system that is, in the cosmic scheme of things, actually a pretty tight space. And the solar system, alas, is also fairly inhospitable; aside from Earth, there’s no place we can live without performing a tremendous amount of very expensive work to make it habitable, and enduring an equally tremendous amount of constant risk to keep it that way. On Earth we have sun, air, copious water, nutrient-rich soil; extraplanetary colonies must replace each of these natural bounties with intricate human-designed reserve systems, whose temporary failure would mean universal death. In contrast to the expansionist fantasy that typically drives science fiction — humanity consuming more and more of the universe’s resources, as it operates at grander and grander scales — Robinson’s vision of the settlement of outer space is significantly more precarious and austere. “We’re all vulnerable in space,” one of 2312’s protagonists tells another. “There isn’t a single off-Earth settlement that couldn’t be destroyed, except for Mars.” Getting off Earth isn’t any kind of permanent solution to resource scarcity or ecological crisis, no matter how our Star Trek fantasies would have it; if you think it’s tough living within the natural constraints of a huge, rich, fertile planet like Earth, just think about the superhuman effort that would be required to try and live anywhere else. Outer space, the poet said, ain’t the kind of place to raise your kids.

The general ban on interstellar travel in Robinson’s fiction, the insistence on the solar system as an ultimate species limit, is more than just an arbitrary narrative choice among others; it is part and parcel of the intertwined strains of environmentalism and anti-capitalism that characterize nearly every one of Robinson’s novels. Environmentalism: if the solar system is our only home, and most of it is totally barren, and life nearly everywhere would be agonizingly difficult, then the Earth’s ecosystem becomes that much more precious, the vital core of everything we have. And anti-capitalism: if the limits of the solar system are our ultimate barrier — if Earth is the one and only really good place we’ll ever know — then an economic system predica...