Star Trek Warp Speed Mystery Solved By Fans

In the original Star Trek show, the warp speed scale was all over the place, with the Enterprise capable of achieving upwards of warp 14 on its own and warp 15 with some help. In The Next Generation and beyond, though, warp 10 is the maximum theoretical speed, and the fastest Starfleet ships can go is warp 9.9 as they approach that limit. There has never been an in-universe reason for why this change was made, but one fan theory claims this happened as a result of Starfleet’s experiments with the transwarp drive of the Excelsior. 

To understand this Star Trek theory, we have to go back to the Federation’s first attempt to escape the limits of the old warp speed scale: transwarp drive. In The Search For Spock, we hear that the Excelsior is getting a prototype transwarp drive, one that (through means that are never fully explained) would be faster than ships like the USS Enterprise. Scotty sabotages the Excelsior, though, ensuring that it is unable to pursue the Enterprise after Kirk hijacks his old vessel.

We see the Excelsior again in Star Trek VI: The Undiscovered Country and its maximum velocity on the warp speed scale is never named. However, a cut line of dialogue from the movie implies that its maximum speed is warp 9. According to the fan theory, this may be part of how and why Starfleet revised the scale in between live-action shows.

No official Star Trek movie or show has ever officially commented on either the warp speed scale change or what happened with Starfleet’s transwarp drive experiments. Regarding the latter, the closest thing we got to an explanation was a line in the first edition of the Star Trek Chronology saying Starfleet considered the experiment a failure and fitted the Excelsior with a standard drive. According to this fan theory, the combination of previous Excelsior research and a cut line from The Undiscovered Country may finally explain the warp scale change. 

In Star Trek VI: The Undiscovered Country, it’s not entirely clear what warp speed scale is being used because characters don’t name the speeds at which they are traveling. However, we know that the Excelsior is traveling at its maximum possible speed thanks to the great scene where Sulu responds, “Fly her apart, then!” to a crewman who points out that going any faster might destroy the ship. In a cut line of dialogue from the original script, it is revealed that Sulu was traveling at warp 9 to make it to Khitometer in time to save the day.

Such a line would implicitly confirm that the Excelsior’s maximum speed is 9, which is a far cry from Kirk’s Enterprise being able to travel up to warp 15 in The Original Series. Furthermore, the maximum Warp is very similar to what we see in The Next Generation, where a few decades of improvements have helped the ship go up to 9.9. Given these data points, it seems like the Excelsior was using the later warp scale even if no other ships were at the time.

This Star Trek fan theory holds that Starfleet’s experiments with the Excelsior’s transwarp drive are what led to the warp speed scale permanently changing. It would make sense that the Excelsior was still testing out new engines and using the new scale in The Undiscovered Country, a movie that takes place in 2293. According to franchise science advisor André Bormanis, the scale was changed fleetwide in 2312, which might mean Starfleet finally accepted the experimental changes pioneered by Sulu’s ship.

Right now, this is merely a Star Trek fan theory and not established canon, though we wouldn’t be surprised if Lower Decks makes some jokes about the warp-speed scale in its final season. Until then, it’s up to the fans to figure out this mystery and all the other weird things about this venerable space franchise. And this fan theory is as good as any when it comes to explaining the in-universe motivation for the franchise’s most mysterious change.