Pentcho Valev
2013-12-28 20:48:53 UTC
A clock on the ground is at rest but a train is moving to and fro so that the clock on the ground effectively commutes between the front and the back of the train. The speed of the train is constant except for the turn-arounds when clocks on the train suffer sharp acceleration. Will the clock on the ground run slower or faster than clocks on the moving train?
It should be noted that a clock at the front of the moving train coincides with the travelling twin's clock in the usual twin paradox scenario. Accordingly, relativity predicts that the clock at rest on the ground runs FASTER than the clock at the front of the train.
On the other hand, the same relativity predicts that, all along, except possibly for the turn-arounds (?), observers on the moving train measure the clock at rest on the ground to run SLOWER than clocks on the train.
So if the turn-arounds can be ignored, that is, if calculations are entirely based on the inertial phases of the movement, we have REDUCTIO AD ABSURDUM. The clock at rest on the ground runs faster, as judged from the ground, and slower, as judged from the train, than clocks on the train. The underlying postulate, the principle of constancy of the speed of light, is false and should be rejected.
Can the turn-arounds be ignored? Some Einsteinians, fellows of the Royal Society, say yes:
http://www.damtp.cam.ac.uk/research/gr/members/gibbons/gwgPartI_SpecialRelativity2010.pdf
Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."
Other Einsteinians may disagree but then they will have to explain, IN TERMS OF TURN-AROUND ACCELERATION, why Jill, by travelling twice as far, increases twice the amount of time gained.
Pentcho Valev
It should be noted that a clock at the front of the moving train coincides with the travelling twin's clock in the usual twin paradox scenario. Accordingly, relativity predicts that the clock at rest on the ground runs FASTER than the clock at the front of the train.
On the other hand, the same relativity predicts that, all along, except possibly for the turn-arounds (?), observers on the moving train measure the clock at rest on the ground to run SLOWER than clocks on the train.
So if the turn-arounds can be ignored, that is, if calculations are entirely based on the inertial phases of the movement, we have REDUCTIO AD ABSURDUM. The clock at rest on the ground runs faster, as judged from the ground, and slower, as judged from the train, than clocks on the train. The underlying postulate, the principle of constancy of the speed of light, is false and should be rejected.
Can the turn-arounds be ignored? Some Einsteinians, fellows of the Royal Society, say yes:
http://www.damtp.cam.ac.uk/research/gr/members/gibbons/gwgPartI_SpecialRelativity2010.pdf
Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."
Other Einsteinians may disagree but then they will have to explain, IN TERMS OF TURN-AROUND ACCELERATION, why Jill, by travelling twice as far, increases twice the amount of time gained.
Pentcho Valev