Last month, Christopher Nolan tackled the subject of relativity with Interstellar, giving audiences without scientific minds a flabbergastingly odd look at the different ways in which time works in deep space. And watching that, you may have thought to yourself, “Say, what about all the other movies that deal with deep space that never mention physics at all?” Well, a team of scientists have put the world of Star Wars to task and have concluded the traveling done therein would mean that twin siblings Leia and Luke Skywalker should actually be completely different ages in the films.
A paper in the Journal of Interdisciplinary Science Topics went into detail here, using The Empire Strikes Back as its example, particularly the trip to Cloud City made by both Luke and Leia from different locations. Luke travelled from the distant planet Dagobah, while Leia headed out of Anoat, which is much closer to their final destination. Since trying to paraphrase this would turn my brain into Hutt-jelly, here’s how some of the math goes:
Luke’s journey was ~7 days travel in his own reference frame, which was estimated to be 25 times longer than Leia’s, making her journey 0.28 days (6.72 hours) in her own reference frame. Additionally, as Leia travels in the Millennium Falcon, a much larger ship with more powerful engines than Luke’s X-Wing Starfighter, it was assumed that it reaches a higher velocity of 0.99999c compared to the 0.99995c achieved by the X-Wing.
They also take into account that Cloud City is above the gas giant Bespin, which adds its own twist to the scenario, as the planet’s massive size causes a distinct gravitational time dilation. (Pretend I’m showing you all this with some amazing graphics on a 3D display.) After everything is said and done, the study’s writers calculate that it would take millions of years to correct the twins’ age difference back to what it was at their birth.
An attempt was made to use gravitational time dilation as a tool to restore the difference between the ages of the twins. The results above indicate that this type of time dilation has a much less significant effect than velocity time dilation. Due to the length of time required to correct for the velocity time dilation, the gravitational dilation would be unfeasible to correct the age difference of the twins as they would need to be 9.77 million years old in proper time. Even at very large distances away from the gas giant, time does not pass considerably faster as the gravitational pull of the planet becomes negligible.
That’s insane. Now, I don’t recall any scenes in the Star Wars franchise where Luke and Leia distinctly state how old they were and used some kind of carbon dating on themselves to prove that they’re the exact same age. But we can assume that none of the siblings’ conversations revolved around their changing age gaps because George Lucas was more invested in cool space explosions over equation-based math. And considering Mark Hamill is younger than Carrie Fisher anyway, it probably doesn’t matter.