In The Last Jedi, the plot hinges on the idea that it is impossible to track ships through a hyperspace jump without cutting-edge First Order technology. I am going to make my case that it was always possible to track ships through hyperspace, and that this plot point is an example of bad continuity.
Now at first glance, it seems that I am just wrong. After all, the Millennium Falcon always escapes Imperial pursuers by going to lightspeed. However, we need to examine the circumstances, here. Plainly, hyperspace jumps are not instantaneous, just very, very fast. Also, ships do not seem to be able to interact with each other physically (e.g. to fight battles) while in hyperspace. Our first encounter with hyperspace is with the Falcon jumping away from Tatooine. Let’s look at that scene:
We have seen the Falcon jump to hyperspace. Then much later, at least long enough for Luke to start lightsaber training and R2-D2 to get involved in a board game with Chewbacca, Han comes in and says, “Well, you can forget your troubles with those Imperial slugs. I told you I’d outrun ’em!”
At the total lack of reaction he then says, “Don’t everybody thank me at once.”
Now, why this announcement, if the jump to lightspeed in itself meant they were untrackable? The clear implication is that the Empire was (or may have been) following them, and Han has spent the intervening time making sure of their escape. Of course Han was rather confident of his ability to do this: he’s flying the ship that “made the Kessel Run in 12 parsecs” after all (whatever that means) and believes himself to be one of the best star pilots in the galaxy.
Later, upon emergence in the Alderaan system, they encounter a TIE fighter. The exchange that follows is revealing:
LUKE: “It followed us!”
BEN: “No, it’s a short range fighter.”
The implication is that a longer-range craft could potentially have followed them. Ben isn’t just speculating about how it got there, because he doesn’t start that until his next line: “A fighter that small couldn’t have gotten this far into space on its own…”
Additionally, how is it possible that the Empire is chasing down Princess Leia’s ship at all at the beginning of the movie if there is no way to track ships through hyperspace? Rogue One clearly establishes that this has happened. Remember, Obi-Wan Kenobi, last of the Jedi Knights, is hiding out on Tatooine. There is nothing else of importance there and the Empire does not know he is there.
Now, in Empire we seem to see some of the strongest evidence that hyperspace tracking is impossible, because the Falcon’s final getaway is by jumping to lightspeed, and the whole plot of the film hinges on the Falcon’s broken hyperdrive. However, it seems reasonable that by this time the Empire has simply learned that the Falcon is uniquely able to elude pursuit by jumping to hyperspace because of its speed. If the Falcon can complete a jump and start a new one before Imperial forces arrive, then of course it cannot be tracked.
Now, when Han Solo pulls his disappearing act by charging the Star Destroyer, Darth Vader orders the Falcon’s trajectory extrapolated from “its last known trajectory,” after killing the Star Destroyer’s captain for incompetence. Clearly, Vader expected better. Perhaps that he could have tracked them through hyperspace? After all, how would Vader have known the hyperdrive was malfunctioning? That Han Solo pulled off a gutsy and complex maneuver that foiled the Empire’s ability to track them does not imply that no such tracking ability exists.
Finally, in Return of the Jedi, we have our strongest piece of evidence that tracking a ship through hyperspace is possible. It can be seen in this video at about 2:26-2:30.
There is a screen showing the Death Star II, and a cloud of rapidly approaching dots, just as Leia says, “Han, the fleet will be here any second.” Occam’s Razor suggests, “Hey look, the Imperials are tracking the Rebel fleet in hyperspace as it approaches.”
Now, none of this makes The Last Jedi a crappy movie. As stated earlier, I quite liked it. But it’s not in line with earlier continuity, and to my mind, that’s just a bit of lazy writing. I invite all arguments, but they’re going to have to explain away all of these incidents, not just one of them.
From Somewhere In Orbit