- #51

JesseM

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I'd say the person writing the quote is working from within G's rest frame, which is certainly the most natural frame to use when analyzing this sort of the problem, although this should have been stated more clearly.Jesse - what do you think of this:

An observer A, travelling into space in a rocketship, accelerates during a period T1 until he attains a speed v relative to the frame G of the fixed stars. He then falls freely towards some distant celestial object, where he reverses his motion during a period T2, and returns freely to earth with the same speed as before. Finally he decelerates during a period T3 and lands. If for example v = square root of 3 times c over 2, A's clocks will have gone at half-rate compared with those of G during his free motion.

They aren't "the" lines of simultaneity, they are just what you get if you stitch together the lines of simultaneity from two different inertial frames, as I said in my last post. But this doesn't uniquely define the "perspective" of the accelerating twin--in basic SR you're only allowed to use purely inertial frames, and once you bring in non-inertial coordinate systems you're free to use any smooth coordinate sytem you want, you could draw the lines of simultaneity as wavy lines and it'd be just as valid.yogi said:Jesse from your post 46: "He doesn't see that, what he sees is explained on the doppler shift explanation of the twin paradox page."

Yes he does if you draw the lines of simultaneity

Can you link to some please?yogi said:Actually, I don't think it is available for free on line, but there are several almost complete excerpts.

I don't understand what you mean by "taking into account the distance between the two clocks". Does this notion of primary vs. constructive come from Einstein's paper? Are you claiming that Einstein says there is some objective truth about which of two distant clocks is ticking faster? If so I really don't believe that, I'd need to see some quotes where you think he suggests this.yogi said:A primary theory would be SR or the 2nd law oif thermodynamics, a constructive theory would be created by adding up all kinetic energies of the individual motions of the molecules to reach the same conclusion, or in the case of relativity, to account for the time dilations during each acceleration taking into account the distance between the two clocks

Again, the wikipedia quote is just saying what happens if you stitch together his inertial rest frame before the acceleration and his inertial rest frame afterwards. But there isn't really any justification in SR or GR for saying this uniquely defines the "perspective" of an accelerating observer.yogi said:Jesse - more on my comment in post 48 from Wikipedia see last line: