Just as I thought I was done with the issue of what takes place at turn around point of the twin heading back to Earth, I am finding myself at square 1 again as they say.
So I mumbled to myself and that I should find out what the man Einstein himself said in regard to it. I figured it is the right thing to do. I looked very close only to find out he didn't have much to say about it. It appears that he pointed that SR wasn't complete.
All the experiments with respect to SR has been done in at rest frame unless I have that wrong.
The letter of SR's non-preferred reference frame relativity says neither frame can tell who is at rest or who is moving. There seem to be no other frame mentioned here, such as an existing rest frame must be there to determine the actual trajectories of the two frames.
Furthermore the basic Twin paradox has multiple frames. A twin on a planet with respect to another destination object as at rest frame. The other twin moves between the two.
GPS satellites have the center of the Earth as the preferred rest frame, ( Earth centered inertial frame) which is the idea of Lorentz/Poincare, preferred reference frame relativity.
What I like to know if there has ever been an experiment in SR that shows what happens at the turn around point, or an experiment that did not have at rest frame? How can it even be possible?
If that is one too many questions please ignore the last one.