Viewing a single comment thread. View all comments

wedgebert t1_j8i9ukt wrote

Reply to comment by shimadon 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

It's only a paradox due to misunderstanding what is happening.

It's not the motion or velocity that causes the time dilation, it's the acceleration. The twin on the ship experiences acceleration (which is absolute, not relative) while the Earth-bound twin does not.

Once you take this into account, the paradox is easily solved.

2

shimadon t1_j8iufiu wrote

Acceleration is still not the big picture. Only within the framework of special relativity it is true that an acceleration will always result in a shorter length of space time path. When you're talking about acceleration, you are restricted to special relativity only. But the twin paradox can be formulated in general relativity framework as well. In general relativity, you can have situations in which the accelerating twin is older, because in general relativity, even accelerating objects can have longer spacetime lengths...

1

Any-Broccoli-3911 t1_j8mpxqk wrote

Only if the accelerating twin passes through regions of lower space-time curvature (lower gravitational field).

And unless he gets in a region of negative curvature (doesn't exist in our universe as far as we know) his speed must not be too fast.

1