I don’t actually look at it as ‘time travel.’ After all, we are all traveling forward in time, at the same rate.
What the ‘time travel’ hypothesis seems to be saying is that the person (object) ‘traveling’ is actually slowing down his rate of forward travel (in time). The rest of the universe goes on into the future, and when the ‘traveler’ comes to rest, he is in our common future without having experienced the intervening years.
‘Travelers’ stay relatively young, others age, and there is no ‘going back’ in time for the traveler.
> After all, we are all traveling forward in time, at the same rate. <
That was Newton’s view of time. It makes all the sense in the world. But Einstein showed that Newton’s view was wrong. The rate of time is affected by relative speed. So if two objects are moving relative to each other, those objects will not be moving forward in time at the same rate.
We don’t notice this because the rate difference is very small at everyday speeds. It only becomes noticeable when the speeds are great - near the speed of light - or if you have very sensitive atomic clocks.
Let’s say you and I both have such a clock. The times agree to the nanosecond. You jump on a plane, go to Europe, then return. When you land our clocks will not agree. Your clock will have run slower simply because of the relative motion between us.
The difference is how much you “time-travelled” into my future. It will be way, way less than a second because your plane went nowhere near the speed of light.
This experiment was actually done with the Concorde. The clocks differed by the amount Einstein’s equation said they would.
I appreciate your post, Jack.