Like wars erupting over FTL rather than sharing it, because the country or a corporation who would be the first to have such technology stands to have the potential to colonize distant planets.
Like wars erupting over FTL rather than sharing it, because the country or a corporation who would be the first to have such technology stands to have the potential to colonize distant planets.
That is not how speed works in relativity. Even moving with 10 times the speed of light, you still take “forward time” to move to your end point.
What will be happening though is that your point of reference will seem to travel backwards related to your starting point IF you travel away from your starting point.
So you move with FTL from A to B, then you will see A’s past light, which you overtook while traveling to B, arriving at B, thereby seeing your past “as happening now”, but only at point B. But the time will still be ticking forward. And while you travelled to B, you raced against the light coming from B, meaning you travelled faster into the future of B.
If you then travel back with same speed from B to A, you will still be in the future from when you started in the first place. But you will see yourself standing at B. And again, while travelling from B to A, you raced against the light coming from A, meaning you saw that future happening at FTL speed.
There’s no such thing as speeds faster than light—the worldlines of objects with such trajectories are called “spacelike” instead of “timelike” for a reason. “Forward” and “backward” time is only defined for events within your light-cone, and trajectories “faster than light” are outside it. Whether events outside your light-cone are in your future or your past are dependent on your current reference frame, which you can change at will by accelerating—so spacelike trajectories have no intrinsic direction with respect to time.
The thing about “moving with FTL from A to B” is that if B is far away, the event at B simultaneous with your departure from A will be highly dependent on A’s reference frame—a shift in A’s velocity will correspond to a shift in B’s timeline equal to (vx/c2)/√(1-v2/c2) (where v is the change in A’s velocity and x is the distance to B). And things are changing velocities with respect to each other all the time (e.g., for objects on earth due to the planet’s revolution and rotation around the sun), so the point in B’s timeline at which you’d arrive would be constantly swinging backward and forward in time.
And the same is true for the return trip: a minor change in B’s reference frame can put your arrival back in A’s timeline at a point before your original departure.