Wormholes and time travel paradoxes
Jul. 24th, 2018 10:44 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
jackI posted a short version of this, but I feel a longer version may get more comprehensive answers. I'm sure I remember a conversation that came to a conclusion once long ago, but not the details.
Suppose you have a stationary wormhole allowing FTL travel. If you can move one end of the wormhole to the other, you get plenty of time travel paradoxes, because the two ends will no longer be synchronised in time -- the one that's travelled will have experienced a shorter journey time, so when they're next to each other, someone entering the other one will exit from that one earlier, opening the question of "can they prevent themselves entering the wormhole".
But suppose you *don't* move the ends of the wormhole. I *think* that FTL + general relativity[1] must mean there's a time travel paradox somewhere for someone. Maybe someone travelling very fast relative to your wormholes? But for whom?
[1] I believe Stellaris DOES have time travel hidden somewhere but in general doesn't try to stay faithful to general relativity :)
Suppose you have a stationary wormhole allowing FTL travel. If you can move one end of the wormhole to the other, you get plenty of time travel paradoxes, because the two ends will no longer be synchronised in time -- the one that's travelled will have experienced a shorter journey time, so when they're next to each other, someone entering the other one will exit from that one earlier, opening the question of "can they prevent themselves entering the wormhole".
But suppose you *don't* move the ends of the wormhole. I *think* that FTL + general relativity[1] must mean there's a time travel paradox somewhere for someone. Maybe someone travelling very fast relative to your wormholes? But for whom?
[1] I believe Stellaris DOES have time travel hidden somewhere but in general doesn't try to stay faithful to general relativity :)