I'm really geeking out about something right now.
For a while I've had an idea for a sci-fi concept which I call a "vacuum propeller". The concept is that a ship can be propelled by exploiting the quantum fluctuations in empty space. Ever since Stephen Hawking wrote about the phenomenon I thought it was pretty cool, and that this would be a cool application for it if it could be exploited. The cool part is that since you're propelling yourself through a medium, you don't have to carry reaction mass, and your spaceship can be many, many times smaller. Look at how much larger a rocket is than a jet, and you get the idea.
Well, it looks like somebody else had the same idea (as they should... it's obvious), and took it way farther by actually working out how it would work. It's explained here in Technology Review.
BTW, I love just thinking about such stuff. For instance, with this technology I wonder, since quantum fluctuations are particle/antiparticle pairs, could you exploit it for both propulsion (particle) and fuel (antiparticle)? Would it leave a wake?
I LOVE old space operas (of the "Doc" Smith genre) and this has every hallmark of it. The very best science fiction, IMHO, takes ONE possibility and explores the ramifications of it. It keeps everything believable by grounding everything in real science except the one speculative bit. (That's what keeps Star Trek firmly in the fantasy genre for me... they can solve any problem whatsoever by making up a bit of jargon, and they do.) For me, real science fiction can "cheat" on known physics... but only once.
Here's one I'd like to see explored. What if a real force field were possible? The sci-fi staple applications are shields and jail doors (which are silly, IMHO... why burn the power when you could have just put a door in the hole?). What more unusual applications could result? Could you use it as a balloon by forcing air molecules away from your ship? Could this allow you to realize the old sci-fi achievement of apparently levitating your ship well away from the surface prior to kicking in the reaction engines (giving an advantage similar to the advantage that White Knight gives SpaceShipOne)? Could it take the place of your usual reaction engine by accelerating the propellant away from the ship? Would it give you "levitating" cars like Luke Skywalker's landspeeder? No antigravity here... just various applications of the one forcefield technology.
One that I'm absolutely sick of seeing is "magic gravity". The only way of achieving artificial gravity is to substitute mass with acceleration. It doesn't matter what kind of acceleration. So if you constantly speed the ship up you have apparent gravity. Spin the ship (or part of it) and you again have artificial gravity. But "gravitons" and "gravity deck plating" etc don't explain anything. In fact, it becomes a major problem if you consider that in most sci-fi tales the artificial gravity works even when all ship's power dies. And why don't people walk on the ceiling? They should be able to if the deck above you also has "gravity plating". Gravity isn't directional. So lay off the magic gravity. Also, I wish they'd lay off the complicated carousels when designing spaceships with plausible artificial gravity. It's safer, simpler, and more reliable to do away with all the mechanical hocus pocus and simply spin the whole ship. You don't want to have to try to replace or repair a monstrous carousel gimbal while you're a gazillion miles from home.