Aren't most of those explanations for faster than light travel and the actual speed of impulse derived from fan speculation, though?
As I said, the very concept of any kind of space warp propulsion in science fiction is derived from the equations of General Relativity. Those equations, formulated by Einstein a century ago, are the very things that first defined the idea of spacetime having a geometry that could be changed like distorting a fabric. Any time you talk about warp drives, wormholes, space folds, or anything of the sort in any science fiction universe, you are talking about general relativistic concepts. People tend to think that FTL drive means ignoring or violating relativity, but they're thinking of Special Relativity, which is limited to the case of unaccelerated motion. The broader General Theory incorporates acceleration due to thrust or gravity, and that leads to the equations showing that the topology of spacetime is mutable -- i.e. that space can be warped by mass or energy. So in fact, most forms of FTL propulsion in fiction come from relativistic theory in the first place, rather than violating it. (The only exceptions being things like quantum-jump drives.)
The discussion of impulse velocities comes from the
TNG Technical Manual by Sternbach and Okuda; it states that normal impulse maneuvers are limited to 25% of lightspeed to avoid time dilation, while also stating clearly that much higher velocities are attainable in emergencies. However, the
Encyclopedia confused the issue by calling that "full impulse," leading many fans to the mistaken conclusion that impulse engines are incapable of going faster. (Which is ridiculous; there's no friction in space, so as long as your engines continue firing, you just keep accelerating. Even a feeble ion drive could get arbitrarily close to the speed of light if it had enough fuel to remain in continuous operation long enough.)
Do general relativity equations actually predict there exists 'Subspace'?
They're related ideas, in that GR posits a four-dimensional spacetime, and that idea can be extended to include further dimensions; in mathematical terms, a subspace is a subset of fewer than
n dimensions in an
n-dimensional space.
Of course, the term "subspace" did not originate with
Star Trek; it's been around in science fiction
since the 1930s at least. In the SF sense, it probably emerged as a variant of the concept of hyperspace, which has been used in fiction since the 1920s at least. That, in turn, owes a lot to Kaluza-Klein theory, which was developed as a 5-dimensional extension (4 space dimensions, 1 time dimension) of General Relativity, and was a forerunner of other higher-dimensional theories such as string theory.
Science fiction is called that for a reason. It doesn't pull its ideas out of a vacuum, but generally bases them on ideas coming from scientific theory, even if it often elaborates on them in fanciful ways.
No. Not at all. Your statement is backwards. Warp drive was not derived from the equations of general relativity. Warp drive was a device of fantasy invented out of pure imagination for a television show in the mid-1960s by television science fiction authors who applied technobabble to create verisimilitude and make it sound like it fit in with general relativity.
Hardly.
Star Trek did not coin the concept of warp drive any more than it coined the concept of subspace. The first use of "warp" in science fiction to refer to an FTL drive (that I know of, anyway) was in John W. Campbell's "Islands of Space" in 1930.
Star Trek did not innovate -- it took well-established concepts from prose and pulp science fiction and popularized them for a mass audience.
And again, the very word "warp" means to distort, to change the shape or topology of a thing -- and the idea of space as something whose topology could be altered comes directly from General Relativity's equations.
Anyway, on the subject of properties specific to fictional universes, I can't help thinking of properties that are common to most fictional worlds but don't apply in reality -- like the tendency of cars to blow up at the slightest provocation or the way thunder and lightning are always simultaneous. And I've noticed another one in two different shows I've watched in the past two days: Nobody in TV and movies seems to have the ability to distinguish where a sound is coming from. They can be easily fooled into thinking that a sound from a nearby speaker is actually coming from outside, or into thinking they've gotten a text on their phone when the ping actually came from another phone in the other direction in the next room.
