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#343
Feb313, 11:24 PM

PF Gold
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#344
Feb413, 12:19 AM

HW Helper
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#345
Feb413, 06:30 AM

Mentor
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#346
Feb413, 06:42 AM

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Let me be clear. I am not insisting "that we can only analyze the situation using a single accelerated frame of reference". I am insisting that you have to use some frame of reference and that you have to follow the mathematical requirements in order to have a valid one. YOU are the one who brings in the noninertial frame using the MCIRF simultaneity convention, and I am simply pointing out that in part of the spacetime it fails to meet the mathematical requirements. 


#347
Feb413, 08:58 AM

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#348
Feb413, 10:20 AM

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I never proposed a single postulate of constant finite signal propagation... That is Einstein's second postulate. I said in post #7 that I was proposing only a portion of Einstein's second postulate, the part that says that the propagation of light is independent of the source but I was not identifying that speed as Einstein did and which is necessary to establish SR. This is probably a confusing issue. I would recommend that you look up the wikipedia article on the OneWay Speed of Light and look down to the section called "Experiments that can be done on the oneway speed of light". There you will see that it is possible to determine experimentally that light from two different sources with relative velocity propagate at the same speed but we cannot measure what that speed is. This is also assumed to be true both in a classical context (pre SR) where ether is affirmed and in a relativistic context (SR) where ether is denied. Bondi did not specifically state that he was adopting this assumption but it is obvious that he is. And thanks for your continued affirmations of my efforts to explain SR. 


#349
Feb413, 10:53 AM

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#350
Feb413, 11:35 AM

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See Ch 2, especially p. 3338 http://arxiv.org/abs/grqc/9712019 


#351
Feb413, 12:46 PM

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#352
Feb413, 01:19 PM

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You can't argue that we don't know how Brian's watch is working. We have to assume that all watches are working identically in order for them to be observing symmetrical Doppler shifts and you already agreed in post #316 that they will see the same Doppler shift: 


#353
Feb413, 10:30 PM

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And you are arguing exactly from the same position. You are using some Dopplerlike phenomena even so you have not demonstrated how it is consistent with PoR. And that is the very thing that SR does, like it or not. 


#354
Feb413, 10:58 PM

PF Gold
P: 1,376

In classical context PoR might have been slightly different PoR than the one you mean. In particular it was not applied to wave phenomena. You see, the words stay the same but their meaning changes. And as a result your argument fails. 


#355
Feb513, 12:41 AM

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The classical Doppler formulation is no exception. It had a simplified formula, which is still used today, just like F=ma is still used today, but we realize it is only a very good approximation and useful because the more complicated formula won't make any difference in our computation, as long as the speeds are small compared to the speed of light. However, there is a more complicated formulation that works at all speeds which you can read about here. But I don't want to get sidetracked on this issue as it has no relevance to Bondi's argument concerning the inverse relationship of the Doppler shifts for coming and going at the same speed. Tell me something zonde, do you understand the argument, whether or not you agree with it? 


#356
Feb513, 01:54 AM

Physics
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#357
Feb513, 08:15 AM

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#358
Feb513, 09:03 AM

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What you are calling galilean PoR just means his formulation of the transformation was incorrect, or more precisely, it only applied at low speeds which means it excluded light. The issue that zonde is concerned about is whether the Principle of Relativity plus the principle that light from two sources with relative motion propagates at the same speed is enough to prove that the traveling twin will come back younger. Can I get some help on that score instead of this side track? 


#359
Feb513, 09:39 AM

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#360
Feb513, 10:01 AM

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Someone, please tell me. Why doesn't an analysis using an IRF satisfy? 


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