In my previous post, I discussed the power and creativity that can stem from omitting faster than light travel from science fiction universes. Space opera as a genre is in many ways defined by its spaceships as much as it is by the occupants of those spaceships. That first big choice about how, exactly, the ships will function can set the tone for an entire work.
Deciding to limit the ship below the speed of light may seem like just that—a limitation. It is easy to view this choice as a stuffily unnecessary constraint, and that FTL (Faster Than Light) travel, in opposition, can be seen as a far more freeing option. However, in actuality the application of limitations is about imposing rules and structure on a universe, and the application of FTL travel should be approached with the same attitude.
The bedrock of good science fiction is consistency. It is perfectly possible to write good, clever sci-fi that is not scientifically accurate. The trick is to maintain the spirit of scientific rigour; deviations from actual reality are fine, but once committed to paper, they create a new fictional reality that should be maintained. If an author is writes about magical “handwavium teleporters”, they have to keep in mind that they’re going to be scrambling to invent new ways for them to break every time they need to inject a dose of drama (looking at you, Star Trek).
There are three main FTL travel systems in fiction: warp drives, hyperspace, and wormholes. Warp drives exist in “real” 3D space and fool the light limit by riding in a bubble of distorted space-time (as described by Mexican physicist Miguel Alcubierre). Hyperspace transitions the ship to some alternate dimension where the light limit no longer applies. Finally, wormholes fold space to bring distant points close together.
The scientific differences between these technologies are, for the most part, inconsequential to story. However, each one carries a number of subtly different implications that can have an effect on narrative and tone.
Warp drives are probably the most realistic option on the list. NASA is legitimately, for real working on building a warp drive right now, although they’re obviously nowhere near a workable solution. Warp drives are also the only option on the list that keeps the ship entirely in normal space, albeit within a distorted bubble of said space. This means that a ship at warp speed could, in fact, crash into something, so characters are probably going to be fairly careful when it comes to matters of navigation.
In fact, collisions at such impossibly high speeds are going to take on an even greater risk than normal. While it’s easy enough to say that your ship has technology that protects it from being pancaked by an ultra high-speed speck of dust, what about everybody else? Researchers at the University of Sydney have determined that a warp drive will naturally accrete tiny interstellar particles as it travels, and that when it slams on the brakes, those particles will continue on ahead as huge bursts of deadly radiation. The power of these blasts scales according to the length of the trip and theoretically has no upper limit: as a result, the end of a long warp drive journey could culminate with you vaporizing the planet you had intended to visit.
Warp drive is also the only option on the list that does not immediately justify some manner of FTL communications: a radio wave can’t carry a warp drive with it, so instead of long distance phone calls characters might have to rely on messages hand delivered by spaceship.
Hyperspace posits the existence of a convenient travel dimension, and leaves normal space behind for the duration of a trip. This usually means that a ship in hyperspace can pass right through solid objects, although there is a proud tradition that says hyperdrives are only usable in “flat” space, away from gravity wells like stars and planets. The properties of the hyperspace dimension are left to the writer.
Why does hyperspace have to be just a glowy blue tube all the time? Maybe it’s a universe in its own right, inhabited by weird geography and inscrutable, tachyonic life. Maybe the higher dimensions implied by most hyperdrives are literally usable, so in addition to x, y, and z, a ship at hyperspace can fly and dodge missiles along w as well. What about the other implications of an FTL reality? In Ian M. Banks’ excellent Culture series, superintelligent A.I.s called “Minds” store most of their brains in hyperpace to literally think faster than light speed.
In contrast to warp and hyperspace, wormholes are generally portrayed as instantaneous. This can be done via the classic glowing doorway approach, a la Farscape, or by the more kinetic “jump drives” found in Battlestar Galactica. In either case ground rules need to be laid out in order to the characters from schizophrenically blinking around like Nightcrawler on cocaine. This is usually done with a simple recharge or course calculation time limit; although there are more interesting and unique rules like Stargate’s decision to make wormholes one-way, and to only stay open for 38 minutes.
Wormholes can also come part and parcel with some fun scientific details. For example, according to the original Einstein-Rosen model, a wormhole through space can also, almost by definition, be a wormhole through time. And holding a wormhole open might only be possible using something called negative mass, which is basically matter that weighs in reverse (Futurama’s -5 lb. bag of hover potatoes).
– Contributed by Matteo DiGiovanni