I guess I was aiming for more of a "hard SF", "playing with the net up" feel, a la Gregory Benford. (Or for that matter, Firefly, if you disregard artificial gravity and questionable celestial mechanics.) I wanted to explore the idea of people _in space_, not people on boats or aircraft that somehow travel through space as most science fiction seems to do.
The clearest indication of "you're not in Star Trek/Star Wars/Doctor Who anymore" is ships without a single "down" direction. After that, I wanted to ditch the whole "one city on the entire planet" cliche in a lot of media science fiction. (Planets are big. We're on one.) Making space travel actually hard in some way, and in particular making travel from one star system to another a major life choice, would emphasize that space is *different*.
As far as Einsteinian Relativity goes ... it hasn't been conclusively proven, given the scale on which it operates, but it hasn't been definitively overturned, either. There have been inconclusive experiments on faster-than-light effects, but many involve quantum entanglements and hence too random for macroscopic objects. So, if you're going to avoid rubber science, you have to uphold Einsteinian Relativity or (as with the wormhole idea) come up with some fairly esoteric loophole.
Wormhole travel isn't too bad, but it still assumes a ship that can get out to the wormhole, which might be far from a habitable planet. (Possibly by design; see Cowboy Bebop, where a prototype hyperspace gate in geostationary orbit exploded, rendering Earth nearly uninhabitable.) Unless you want to go with human-scale Stargates, which is just a "magic portal" dressed up with rubber science, and *not* the feel I'm going for at all.
Originally Posted by Farcaster
One idea I've been toying with is wormholes that do *not* violate Relativity. From a traveller's perspective, he only spent an hour or so in the wormhole ... but when he emerges, as far as the universe is concerned he's travelled his N light-years in N years and a bit. You can go to another planet, spend a month, and come back ... to find you've been gone a century.
Actually, another one I like is Ursula K. LeGuin's idea that matter can't travel faster than light -- intact, anyway -- but information can. "Think Like a Dinosaur", by an author whose name has slipped my mind, posits an information-based "teleport" from one star to another, with the slight complication that a passenger ends up both here and there ... and the one here has to be rendered into atoms in order to "balance the equation".
"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question."
- Charles Babbage (1791 - 1871)