Thread: twin paradox
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Al68
Al68 is offline
#242
Oct10-08, 08:54 PM
P: 801
Quote Quote by JesseM View Post
Only if you choose to use the inertial frame where the Earth is at rest, and the traveler is instantaneously at rest at the midpoint of the acceleration. But this was exactly my point, that your method only works if you use the coordinates of a single inertial frame, which you seemed to be disagreeing with when you said "It works in every frame. All frames would agree on the result." If you still maintain it works in every frame, tell me how it works in the inertial frame where the traveler is at rest during the outbound journey before accelerating (which is not the same as a non-inertial frame where the traveler is at rest at every moment, including during the acceleration).
It works the same in that frame as in the standard resolutions. The ship's twin realizes that if the earth sends a signal at t=4.5, and if his ship broke so he could never accelerate, when he receives this signal and subtracts the time it had to take for the signal to reach him at c, he would conclude that the signal was sent at t'= 7.5 yrs in his frame. And he would realize that if he had decelerated to come to rest with earth, then earth's clock would read 12.5 yrs simultaneously with the ship's clock reading 7.5 yrs.

Al