why do we call the "twin paradox" a paradox in einstein's theory of relativity when we know exactly that the phenomena it describes is possible theoretically
von Laue's argument as you describe it is totally spurious, because no one argues that the difference in ages somehow only occurs during the period when the other twin is accelerating--the argument about acceleration is just that it allows us to know which twin traveled in a straight line through spacetime between the two events and which twin traveled in a broken line (as seen in any inertial reference frame). This is just like the "right triangle paradox" where you have two twins who walk between two points in space A and B, and one travels in a straight line while the other travels straight away from A, then makes a 90-degree turn, then travels straight until he arrives at B; the twin who made the turn will have walked a longer distance than the twin who didn't, but the extra distance didn't all accumulate during the moments he was turning!yogi said:Most authorities, including Born and Langevin quickly dismissed the paradox by asserting that kinematical symmetry is broken because the traveling twin changes from one inertial system to another during turn around i.e., the traveling twin feels the acceleration and deceleration that is required to change velocity and direction. This proscription was quickly challenged by von Laue who argued that the dynamical aspects of turn-around would be insignificant compared to the ageing effect of an extended voyage.
Yes, so do I, just like I attribute the longer path length in the "triangle paradox" to the fact that the twin made a 90-degree turn. But that doesn't mean that all the extra path length happened only during the moments he was executing that turn.yogi said:Jesse - my old critic. I think you will find there are many who attribute twin ageing differences to the acceleration in one way or another.
What Born is saying is that if you want to try to consider things from the non-inertial "frame" of the twin who accelerates, you must bring in GR (and even if you do this, I don't think Born is saying that all the age difference happens during the moments of acceleration, although I'm not very well-versed in GR so I can't be sure). My explanation was just about how the two paths look if you stick to analyzing both twin's motions from the point of view of an inertial frame (which doesn't necessarily have to be the frame of the stay-at-home twin), as you must if you want to deal with the problem using only SR. So, I see no conflict between my explanation and the quotes by Born you posted.yogi said:I think Born is way off base on this - I merely quoted it to show that there are many ways of explaining the twin caper -
and please don't write me a book about it.