Via Radiotimes.com:

Don’t be surprised if Carrie Fisher’s Princess Leia looks a little older than her brother Luke when the Star Wars twins return to cinema screens later this year: scientists at the University of Leicester say that by now she actually has about two years on him.

And it’s all thanks to Einstein’s Theory of Relativity (no pun intended).
For those of you who aren’t familiar with the old E = mc 2 jargon, Einstein’s theory says that if you move fast enough through space, the observations that you make about space and time differ somewhat from the observations of other people, who are moving at different speeds.
That means, for example, that the time on a ship which is moving very quickly appears to pass slower than on Earth. And they call this little phenomenon time dilation.

The students from the university’s Department of Physics and Astronomy decided to carry out a study to figure out how time dilation might have affected Luke and Leia, based on their journeys to Cloud City in Empire Strikes Back.

Leia starts her journey in the neighbouring system of Anoat and arrives at Cloud City in around 6.72 hours, while Luke’s journey from Dagobah, in a star system much further away, takes around one week.

The Millennium Falcon also packs larger and probably more powerful engines than Luke’s X-Wing fighter, so the students presumed that it would travel at a much faster speed, giving Leia’s journey a time dilation of 62.6 days.

Meanwhile Luke’s journey results in a time dilation of 700.8 days, making him roughly 683.2 days younger than his sister by the time they both arrive at their destination.

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