2 ms·

So This may not be an FTL drive, but the way I always sort of pictured it is that the FTL moves you forward in time to the relative observer (so if you move dis

So This may not be an FTL drive, but the way I always sort of pictured it is that the FTL moves you forward in time to the relative observer (so if you move distance x you move (c/x)^-1 forward in time). So if you send an FTL courier (assuming travel time of 2) from point A with times tA=102 tB=51 it would arrive at point B at times tA=52 tB=104 (A time 53 units in the future from tA), if it got sent back it would arrive at point A at tA=106 tB=53 (A time 53 units in the future from point B). The distance traveled would be c*53 distance (53 units of time for light to travel) in 2 units of time. This also works for the mars/earth scenario (say they are 14 minutes apart). Traveling to the place that the light you see in 14 minutes will be coming from instantly would only ever be traveling forward in time. Forward time travel doesn't break causality(?) This is always sort of how I envisioned wormholes work (and is indeed how they work on shows like star gate). You go in one end and come out the other, unless you can communicate through the wormhole it would take light (distance times c) years to tell people on the other end you succeeded. But perhaps I'm missing something...

lmm 14y ago
So as far as B's concerned, when he sends the FTL courier to A that courier will goes slower than a light-speed message? He could send a message at tB=53,tA=26.5 and it would reach A well before tA=106. This only works if you assume the FTL drive is fixed to some sort of absolute reference frame (which happens to be the same as A's frame). At which point you've given up on relativity, and I'll bet it's possible to come up with some cute paradoxes
- SolarNet 14y ago
  I realize how this violates relativity, but I don't understand your counter example (if it was one?) because I wasn't talking about absolute time frames, I'm talking about going forward in time when going FTL. And at no point in my example could B reply before A sends a courier.
  - lmm 14y ago
    It's not a counterexample as such, but it seems obviously absurd (and violating relativity) that B's FTL message to A arbitrarily goes a lot slower than A's FTL message to B, given that the situation is completely symmetrical (you can even have them both send their messages at tA=100,tB=100, which is simultaneous from the point of view of an observer C who stayed behind on the asteroid where the two spaceships initially met up). The point I was trying to make was that your example description makes sense if the FTL drive is somehow fixed to A's reference frame, i.e. A's reference frame is some kind of absolute reference frame and therefore the situation is not symmetrical between A and B. But that introduces its own problems.

lmm 14y ago

So as far as B's concerned, when he sends the FTL courier to A that courier will goes slower than a light-speed message? He could send a message at tB=53,tA=26.5 and it would reach A well before tA=106. This only works if you assume the FTL drive is fixed to some sort of absolute reference frame (which happens to be the same as A's frame). At which point you've given up on relativity, and I'll bet it's possible to come up with some cute paradoxes

SolarNet 14y ago
I realize how this violates relativity, but I don't understand your counter example (if it was one?) because I wasn't talking about absolute time frames, I'm talking about going forward in time when going FTL. And at no point in my example could B reply before A sends a courier.
- lmm 14y ago
  It's not a counterexample as such, but it seems obviously absurd (and violating relativity) that B's FTL message to A arbitrarily goes a lot slower than A's FTL message to B, given that the situation is completely symmetrical (you can even have them both send their messages at tA=100,tB=100, which is simultaneous from the point of view of an observer C who stayed behind on the asteroid where the two spaceships initially met up). The point I was trying to make was that your example description makes sense if the FTL drive is somehow fixed to A's reference frame, i.e. A's reference frame is some kind of absolute reference frame and therefore the situation is not symmetrical between A and B. But that introduces its own problems.