Science Forums 2

[lawcat]

I am not concerned with machine construction for time travel. Whatever it is , it appears that it has to be some sort of tunnel which bypasses the physical spacetime.

The biggest problem with any theory is that matter does not move in time, or in space, but in spacetime. Matter needs space. Thus, matter must move in spacetime, not merely time.
When matter moves in spacetime, matter must move at relativistic speeds. Some particles may be able to cheat the spacetime constraints through tunneling, but such particles will merely be moving faster in spacetime, so they will get to the target in relatively less time. So, we say, relatively to us the particles are in the future of our spacetime. But the problem is one of contraint of spacetime, and speed of travel, not of travel in time merely.

IMO, the only thing that can truly move only in time is thought.