In science fiction, faster-than-light travel is a narrative convention that allows you to move standard human beings over interstellar distances cheapIn science fiction, faster-than-light travel is a narrative convention that allows you to move standard human beings over interstellar distances cheaply. But if you want to do science fiction rigorously -- with the net up, as Gregory Benford calls it -- you have to go without FTL (it's not an engineering problem; it breaks known physics). They're mutually exclusive. The problem is, you can't have an interstellar civilization without FTL, can you?
My father and I have been debating this back and forth for years. On the face of it it's intrinsically impossible: if you can't have FTL, the distances and costs involved in travel make trade and communication prohibitive. To accelerate goods and people to relativistic velocities would be insanely expensive, and it would still take decades to get there. Hardly anything would be worth the shipping costs: it would be easier and cheaper to synthesize what you need rather than import it. Transmutation is less expensive than interstellar trade. (No doubt this is why sf focuses on rare goods, from melange to unobtanium.)
Absent that trade, there's no rationale for having an interstellar civilization. Even if you were able or willing to colonize other planets (though again, the cost of sending a colony ship is of a magnitude that many in science fiction fail to grasp), the colonies would be on their own. With no reason to trade, how would the investment in a colony ship be recouped? And what purpose would there be for an interstellar government -- Empire, Federation, whatever -- if there was no trade for it to regulate?
One exception, dealt with in some depth at a panel at the Chicago Worldcon in 2012, is trade in information: planets could beam intellectual property at one another. Inventions and works of art. An interstellar government's role would be to regulate copyright and patent law. (Enforcement would be trickier: at said panel, Charles Stross suggested the use of a Nicoll-Dyson laser.) But there would be no travel, and no spaceships; everything from trade to diplomacy to war would be conducted remotely. (So much for space opera.)
Thing is, FTL isn't a solution to the problem of interstellar civilization; it's a solution to the limitations of human biology. Both interstellar travel and a galactic civilization become a lot easier to contemplate if you take our limited lifespan, and the need to keep us alive (fed, watered, breathing and sheltered from cosmic rays) for the duration of the voyage, off the table in some fashion. Time dilation takes care of the lifespan of the voyagers (at least if they're travelling at relativistic velocities), but it means that origin, destination and traveller get out of sync.
Fortunately, human immortality is an easier problem to solve than Einsteinian physics. Sf writers have had some luck moving that lever instead. Take, for example, Scott Westerfeld's Succession series -- The Risen Empire and The Killing of Worlds -- which posits a galactic empire where the ruling elite possesses a life-after-death form of immortality: those who are not immortal must deal with relativistic sublight travel. And Charles Stross's Neptune's Brood not only features posthuman protagonists, it builds an entire economic system on the limitations of interstellar travel: Stross's solution for the problem of interstellar trade is banking.
With Lockstep, Karl Schroeder has come up with something quite different. And also quite extraordinary. He's managed to square the circle of space opera and known physics, and arrived at a scenario that is both startingly original but makes use of what is known and what is possible.
Lockstep's 17-year-old protagonist, Toby McGonigal, emerges from a cryogenic sleep 14,000 years long to discover that a civilization has sprung up among the rogue planets between the Sun and Alpha Centauri. Resources are scarce on these planets, so the human inhabitants survive by use of the locksteps: for every month they spend awake, they all spend thirty years in cold sleep, which allows those resources to replenish themselves. But more importantly, space travel is done during cold sleep: ships use the thirty year gap to move from one world to the other; the passengers awaken as though it was an overnight trip. When they return, a month later, the same amount of time has elapsed back home: by spending only 1/360th of the time awake, Schroeder's civilization has shrunk the virtual distances between the worlds.
is a classic space opera universe, with private starships, explorers and despots and rogues, and more accessible worlds than can be explored in one lifetime. There are locksteppers, realtimers preying on them while they sleep, and countermeasures against those, and on and on. In short, it's the kind of setting for a space adventure that we've always dreamt of, and yet, it might all be possible.
Whereas a space opera universe that requires FTL isn't.
Schroeder wraps his cutting-edge setting around what is from all appearances a fairly traditional adventure story, replete with a missing heir and family drama, that would not be out of place in, dare I say it, a Heinlein juvenile. Toby discovers not only that it was his family who created, and controls, the lockstep, but that a cult in his name had arisen in the millenia since his disappearance. I recoil to some extent from stories about young people who discover they're the Most Important Person in the Universe -- oh look, another Chosen One -- but Karl does a reasonable job with it. Lockstep is fast-paced and clever, and makes full use of the implications of the universe he's built.
I mentioned Heinlein juveniles, and Lockstep is being referred to as a young-adult novel (what with its teenage protagonist), but Paul Di Filippo, in his review of Lockstep for Locus Online, argues that it's reductionist to call it that. Rather, he says, it's an example of what others have called "entry-level sf": more accessible to readers who haven't spent the last few decades absorbing sf's advanced reading protocols. In that I think it succeeds admirably. It's certainly an easier read than, say, Neptune's Brood, but the clarity and accessibility of its prose should not mask the importance or significance of what is clearly a major work of science fiction.
Full disclosure: I received an ARC of this book via Goodreads First Reads. The author and I are also socially acquainted.