Magical adventures in fantasy otherworlds may sound fun on paper, but more often than
not they’re a surprisingly risky gamble. In the best-case scenario you’ll come back home
and find only seconds have passed since you left and you won’t even get in trouble for being gone.
Sometimes time passes at a one-to-one rate and the whole time you’re gallivanting around in
the magical otherworld, time’s still passing back in the real one and you’re gonna have
some serious explaining to do if and when you get back. But the worst case scenario flips
that first one on its head - you might think you only spent a few days in the otherworld,
but hundreds of years could be passing in reality. The concept of localized time dilation
is a staple in fiction and folklore because it’s frankly deeply unnerving. As a bonus fun fact,
it’s a real thing in relativity - it’s almost totally unobservable under normal circumstances,
since we tend to stay in mostly one place relative to the earth and don’t usually
move at an appreciable fraction of the speed of light, but a clock moving relative to an observer
can be observed to tick slower than a relatively stationary one, and a clock close to a gravitating
mass will measure less time passing than a clock farther away from the same mass. Thanks to
gravitic time dilation, the core of the earth is about two and a half years younger than the crust.
This is bananas, you may remember it from Interstellar,
that's basically the only time pop culture ever used this.
Maybe those magical otherworlds simply reside… close to the event horizon… slowed and distorted
by the very nature of space-time……… or maybe it’s fiction and we don’t need to read too
far into it. Anyway, today let’s talk about a japanese folktale about the dangers of magical
otherworlds and the importance of following instructions from people who know more than you.
Our story begins with a young fisherman called Urashima who’s a very sweet guy
without a mean bone in his body. His profession of “fisherman” does make it a little difficult
for him to be completely harmless, but he’s very conscientious about the whole thing and doesn’t
do any more harm than he has to. So that’s why one day, when he fishes up a massive turtle,
he remembers hearing that turtles are supposed to live for a thousand years,
and he feels bad about cutting that short just for a tasty dinner, so he throws the turtle back and
settles in for a nice little fishing-boat nap. This is when a beautiful woman rises out of
the water, steps into the boat and tells Urashima that she was that turtle and is also the daughter
of the sea god and she’s here because he just proved himself in a secret test of
character and is qualified to be her husband. Urashima likes the sound of that, and he and
the princess sail out to the Dragon Palace to be married, where they settle in to live together in
riches and luxury for a thousand blissful years. And if only the story ended there. But while
Urashima is a big fan of this magical palace and dragon princess wife situation, after about three
years of divine marital bliss he starts feeling a little bit homesick and he wants to sail back to
his humble village to check in on his family and friends, you know? The Dragon Princess doesn’t
think this is a very good idea, but she won’t stop him, so she just warns him to be very careful,
because she has a feeling something very bad might happen if he does anything reckless. She gives him
a small box and warns him not to open it under any circumstances or he won’t be able to come back.
So Urashima tucks the box away, grabs his boat and sails back home - but it’s not quite what he
was expecting to see. The mountains and rivers are all the same, but the buildings are gone,
including his house. He flags down a couple beachgoers and asks them what happened to the
Urashima house, and they tell him that’s a weird thing to ask, since it’s an old folktale around
these parts - four hundred years ago some kid named Urashima drowned on a fishing trip and never
came home. His family are, of course, long dead, and even the village he lived in has fallen into
ruin. Urashima realizes the dragon palace might just be one of those magical fairy realms he’s
heard about, where time passes a lot slower on the inside than the outside. He thought it was only
three years, but it’s been centuries out here. Well, that’s a bummer, but what are you gonna do,
right? With no surviving friends or family and no reason to stick around,
Urashima prepares to head back - only to realize… he doesn’t remember the way. Surprise surprise,
the ocean doesn’t have too many identifiable landmarks. Urashima freaks out and panics for
a bit before remembering the box and thinking maybe there’ll be something inside he can use.
Surprise surprise - there isn’t. When he cracks the box the only thing inside is a vaguely ominous
cloud of vapor and the recollection that that was the one thing he was supposed to not do.
Whoops! Whatever magic was in the box dissipates and Urashima gets hit with four hundred years of
backlogged time all at once, rapidly aging all the way up into a corpse. Total bummer.
Moral of the story? Well, aside from the standard “don’t disobey magical orders
from fairy tale ladies”, maybe, you know, make sure you and your fiancee are fully on the same
page before moving in together. You know, you might handle your chores differently,
or have different standards of organization… that’s just the kind of stuff you should really
talk out first. And also your fiancee’s house might be a relativistic anomaly that completely
cuts you off from your friends and loved ones forever, which is just generally a red flag.
[Maybe This Time]