Separate thread. Wikipedia often does not do a great job on this type of topic for some reason. Example:
The standard textbook approach treats the twin paradox as a straightforward application of special relativity. Here the Earth and the ship are not in a symmetrical relationship: the ship has a turnaround in which it undergoes non-inertial motion, while the Earth has no such turnaround. Since there is no symmetry, it is not paradoxical if one twin is younger than the other. Nevertheless it is still useful to show that special relativity is self-consistent, and how the calculation is done from the standpoint of the traveling twin.
The argument completely neglect the initial acceleration of the ship and only considers the U-turn acceleration. The symmetry is broken with initial acceleration.
It doesn’t really start until after the initial acceleration.
Imagine that the ship just passed the Earth, rather than taking off from it. Everything would work out the same, but turning around is clearly the only break in symmetry.
No the symmetry breaking event would just be further back in time. Also you could not call it the twin paradox, because you would not be able to explain how one of the twins got into the moving reference frame with out accelerating.
It doesn’t matter how they accelerated before the experiment began, so long as their clocks are synchronized. If they’re in the same place, they can synchronize their clocks.
Separate thread. Wikipedia often does not do a great job on this type of topic for some reason. Example:
The argument completely neglect the initial acceleration of the ship and only considers the U-turn acceleration. The symmetry is broken with initial acceleration.
It doesn’t really start until after the initial acceleration.
Imagine that the ship just passed the Earth, rather than taking off from it. Everything would work out the same, but turning around is clearly the only break in symmetry.
No the symmetry breaking event would just be further back in time. Also you could not call it the twin paradox, because you would not be able to explain how one of the twins got into the moving reference frame with out accelerating.
It doesn’t matter how they accelerated before the experiment began, so long as their clocks are synchronized. If they’re in the same place, they can synchronize their clocks.