Viewing a single comment thread. View all comments

shimadon t1_j8f4fnn wrote

Reply to comment by Aseyhe in In the twin paradox, what happens if the travelling twin never U-turn to get back to earth? (explanation in the post) by PoufPoal

That's a very good answer. Everyone talks about acceleration all the time, but it's really the length of space time path. For example: you can have a situation in which one twin is in a space ship orbiting earth, and the other twin is in a space ship which is hovering above the surface, canceling gravity with a constant force upwards by its thrusters. In this case, the twin who is moving in orbit will be younger, but he is in constant free fall! It's the twin who hovering which will be older, but he was the one who was subjective constantly to an external force! So it's not acceleration, it's space time length...

7

klawehtgod t1_j8la1mg wrote

Is it the overall length, or just how much of the movement is through the time dimension? Moving “faster” or “straighter” is just putting more of your movement through the time dimension and less through the space dimensions, right?

1