The idea of the Federation having a spherical zone of exploration goes back to Franz Joseph, but really for the sake of this discussion of distances and speeds (and not really positions) the concept of the sphere is just a convenient way to generally understand the length and scope of the Enterprise’s travels.
The idea of space lanes could explain different speeds Cosmic Strings might allow a variable speed of light https://en.m.wikipedia.org/wiki/Variable_speed_of_light Why not a variable speed of warp?
Ironically, the old Star Trek Star Charts book suggested the same thing back in '02 with "subspace shortcuts." It proposed that NX-01 Enterprise used one (thanks to a Vulcan star chart) to make the journey from Earth to Qo'noS in just four days, implying that it would have taken much longer without it. The Enterprise-A may also have used a subspace shortcut to get towards the center of the Galaxy so quickly. On the other hand, not knowing where any subspace shortcuts were in the Delta Quadrant may have doomed the Voyager to a long trip home.
^And this is why the SS Valiant can reach the galaxy “edge” on what might have been the first real FTL interstellar flight- it stumbled on (or searched for and discovered) one of these subspace currents (or chi routes, or warp highways) right out of the solar system (possibly related to whatever sent Voyager 6 on its way almost a century earlier).
I’m all for space anomalies of all sorts. Magnetic storms, wormholes, what they used to call a black hole. On multiple occasions, there are advanced species which somehow teleport the Enterprise 1,000 ly. But I just don’t think it’s part of the background assumption of normal travel, which seems to be point A to point B, with no consideration for a detour to point C to catch a slipstream. To me the answer to “Why not a variable speed of warp?” is simply because it’s not very helpful. It obscures rather than clarifies your actual speed. It takes something fathomable and makes it unfathomable. And it’s just not intended in the script.
Yeah, the only thing that one could infer from the show is that warp speeds do seem slower when closer to a star (presumably because of some interaction of the drive with a gravity well). Other than those examples most canonical times/distances are measured in thousands of times the speed of light. It seems easier to just believe the warp drives are much faster than any behind the scenes stuff would indicate than trying to make up other variables/conditions that are never mentioned on the show.
I don’t see it as any different than having a sailing ship featured in a story be becalmed by a lack of wind and forced to wait - “The Rime of the Ancient Mariner” - or the opposite, a “strong, unstaggering breeze” that propels the Pequod forward in chapter 124 of “Moby Dick”. And then there is the surreal 40 mph wind-powered sledge to Omaha in Jules Verne’s “Around the World in 80 Days”. That wind is what let’s Phileas Fogg make his train to NYC. Anomalies of warp speed add romance to what would otherwise be a Trek trapped in certainty.
*drunkpost* I’m all for all of that. My only point is that 40 mph means 40 mph no matter how it’s achieved. If nobody is arguing against that, we’re 100% good.
It would make warp factors dependent on local stellar and subspace conditions, and in a fully charted region of space, a starship navigator may even know where the fastest "currents" are and take those in account when plotting a course.
Yeah 40mph = 40mph but Warp factors are more like Mach numbers and the actual speed varies by the local speed of sound. I think there are lots of space terrain that speeds up or slows down impulse and warp engines. But... for board game purposes that would be laborious to implement so using an average or fixed speed would be just as good.
I recall the TNG novel Reunion has a subplot where the Enterprise hits a sort of warp stream, propelling the ship at high warp with no ability to seemingly control it. Eventually Geordi learns that the angle of the ship's shields can be used to slow the ship, like the surface of a rock hitting the water of a fast stream. The shape of the rock and its angle of entry partly determines how its course of travel is dictated within the stream.
It seems that the only two in-episode factors that affect the speed of ships are magnetic potentials (WNMHGB and The Galileo Seven) and diving/traveling close to a sun (Tomorrow Is Yesterday, Operation: Annihilate! and The Paradise Syndrome) with the second cases maybe just a reverse spin on the first factor, i.e. magnetic potentials. The first factor propelled ships much faster than the normal speed of the ship (SS Valiant and Shuttlecraft Galileo). The second factor slowed a ship at high warp as it traveled near a sun. In these slower cases, a ship at warp may have been slowed by running head-on into a sun's magnetic field and its ionized, electromagnetically charged solar wind. Otherwise, warp factors are a constant speed but much, much faster than we think.YMMV .
Yeah, magnetic potentials are definitely a factor but I suspect there probably are other things too which is why they also do "weather scans" ("Court Martial") in addition to gravimetric and space density readings ("Squire of Gothos", "WNMHGB", "By Any Other Name"). I like that it's rather vague so it can be flexible. I do think "Balance of Terror" had the best visualization of variable speed warp travel since you can watch and measure the Enterprise's movement on the map and see that she is not traveling at a constant speed across it (and she is not increasing speed either - her speed varies.) YMMV
40 mph against a 35mph headwind is 40mph, but effectively 5mph. And that’s just dealing in two dimensions and two factors. Movement is rarely that simple. What if it is a current AND a crosswind? With a barnacle-encrusted hull of poor design? One propellor missing? What if there is sleet falling and ice clinging to the ship? A novice helmsman? The engines will say the ship is doing enough work to go 40mph but the ship is going backwards. So no, 40mph is not always 40mph. And it’s kind of goofy that warp 3 is always warp 3. I have no idea what warp speed might really be like if ever there be such a thing, but if it correlates in any way with movement on Earth, it won’t be a simple 1:1 relationship. There will be other things to consider. And my point is, those other things should not necessarily be seen as as having been poorly written. They should be understood by people making and watching as part of the background that affords some license for storytellers.
For raw data, there's an extensive listing and discussion of warp speed examples, including from TOS, here: http://www.starfleetjedi.net/forum/viewtopic.php?t=6329