While researching my previous post, I happened upon a delightful speculative essay by Kim Stanley Robinson on traveling to another solar system: “Our Generation Ships Will Sink.” It’s from 2015 and thus may seem old hat for a lot of serious sci-fi readers (or for those who’ve read Robinson’s novel Aurora), but for me it was a lot of fun to stop and wonder: can it really be done?
No, it can’t—as Robinson explains with alacrity and precision. Here’s a brief sketch.
First, the nearest stars (read: suns where a habitable or a terra-formable planet might exist) are very far away, and since we are nowhere close to achieving FTL speed, it would take many years—Robinson estimates 120-200 years—for a spaceship to reach the closest one. So you’d have to build an ark-like ship, a “generation starship,” in which only the children or grandchildren of the parents would reach the destination.
Cool. A generation starship. That can be done, right?
No. Or rather maybe, but it is so overwhelmingly improbable that it may as well be a pipe dream, and Robinson spends the rest of his essay articulating why. Highlights:
Physical problems: Enormous amount of fuel needed to speed up and slow down. No possibility of re-supply along the way. Little possibility of repair. Exposure of passengers to high levels of radiation. Possibility of catastrophic collision with space matter.
And these are supposedly the easy problems to solve.
Biological problems: Oddly enough, one of the biggest problems would be a lack of … bacterial infusions. Yes, bacterial infusions.
Most of the creatures inside us have to be functioning well for the system as a whole to be healthy. This is a difficult balancing act, and does not work perfectly even on Earth; but divorced from Earth’s bacterial load, and thus never able to get infusions of new bacteria, the chances of suffering various immune problems similar to those observed in over-sterile Terran environments will rise markedly.
Because we need a broad array of bacterial companions, one would want to bring along as much of Earth as you could fit into a starship. But even the largest starship would be about one-trillionth the size of Earth, and this necessary miniaturization would almost certainly lead to unknown effects in our bodies.
Ecological problems: The generation ship would essentially need to function as its own recycling ecological island. Easier said than done.
In short, a perfectly recycling ecological system is impossible; Earth is not one, and an isolated system a trillion times smaller than Earth would exacerbate the effects of the losses, build-ups, metabolic rifts, balance swings, clogging, and other actions and reactions. All that could be accomplished by starfarers in such an ark would be to deal with these problems as well as possible, minimizing them so that they might hang on long enough for the starship to reach its destination.
Sociological and psychological problems: Given the myriad ways things could go wrong on the ship, life would need to be strictly regimented, meaning little to no freedom or autonomy. You’d essentially have to live in a totalitarian state: “It might very well feel like exile; it might feel like being born and living one’s entire life in prison.” Insanity and chronic fear would be very real issues—issues that could endanger the passengers and thus increase the need for yet more totalitarian control.
But, says Robinson, what if we managed to solve these problems and to arrive at the new “earth”? In many ways the real challenges would just begin, depending on the planet and how conducive it is to terran life. If it is not conducive, then your only option is to terraform—which could take decades, centuries, or even longer. Welcome again to life in small, enclosed spaces.
Robinson considers some interesting alternatives like cryogenics and its limitations. Another option is to send embryos to hatch and grow up on such a planet. I chuckled at what he had to say about the latter:
But this solution ignores the issue of the microbiomes existing inside us; these too would have to be brought along, and even with suites of intestinal bacteria perfectly preserved, calibrated, and introduced into the newborns, there then remains the problem of educating and socializing the new youngsters. Often, if the problem is mentioned at all, the idea seems to be that robots and films and libraries could do the job. Good luck with that!
He explores other possible solutions as well, all of which are fascinating, and none of which are reassuring. In conclusion: we’re stuck with earth. But is that so bad? He writes:
Here everyone has to answer for themselves. I’m saying it’s not bad at all; it just is, and it can be regarded as a good thing. And good or bad, it just is. That’s reality. We are not gods, and anyone who thinks of science as a magic wand, or even as a verb, is making a mistake, a category error sometimes called scientism. Drill down a little harder on these issues, look at the evidence; use the scientific method properly. Limits to what we can do will quickly appear around you.
Now go read the whole thing. It’s marvelous. For me it was a sort of reminder to appreciate, enjoy, and care for good ol’ planet earth.