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From: PD on 3 Jul 2010 10:10 On Jul 3, 1:04 am, colp <c...(a)solder.ath.cx> wrote: > On Jul 3, 2:57 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Jul 1, 6:25 pm, colp <c...(a)solder.ath.cx> wrote: > > > > On Jul 2, 2:26 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jul 1, 12:53 am, colp <c...(a)solder.ath.cx> wrote: > > > > > > On Jul 1, 11:37 am, Koobee Wublee <koobee.wub...(a)gmail.com> wrote: > > > > > > > On Jun 30, 4:20 pm, artful wrote: > > > > > > > > On Jul 1, 8:47 am, colp wrote: > > > > > > > > The statement that "moving clocks run slow" isn't an > > > > > > > > oversimplification, it is directly inferred from Einstein's > > > > > > > > "Electrodynamics of Moving Bodies". > > > > > > > > It IS an over simplification. There is more to SR than just clocks > > > > > > > running slow. > > > > > > > Nonsense and mysticism. <shrug> > > > > > > A postulate is just an assumption with better table manners. > > > > > Yes, indeed. By DEFINITION, a postulate is something that is ASSUMED. > > > > > In science, the test of a postulate is based on experimental check of > > > > the *consequences* of postulates. A direct test of the postulate is > > > > not required. > > > > One such test is the test for paradoxes arising from one or more > > > postulates. For example, the following two postulates lead to a > > > paradox, meaning that not all the postulates are correct: > > > > 1. Statement 2 is true. > > > 2. Statement 1 is false. > > > > The paradox that arises from the postulates of Einstein's > > > "Electrodynamics of Moving Bodies" can be described as follows: > > > > "Examples of this sort, together with the unsuccessful attempts to > > > discover > > > any motion of the earth relatively to the light medium, suggest that > > > the > > > phenomena of electrodynamics as well as of mechanics possess no > > > properties > > > corresponding to the idea of absolute rest. They suggest rather that, > > > as has > > > already been shown to the first order of small quantities, the same > > > laws of > > > electrodynamics and optics will be valid for all frames of reference > > > for which the > > > equations of mechanics hold good.1 We will raise this conjecture (the > > > purport > > > of which will hereafter be called the Principle of Relativity) to > > > the status > > > of a postulate, and also introduce another postulate, which is only > > > apparently > > > irreconcilable with the former, namely, that light is always > > > propagated in empty > > > space with a definite velocity c which is independent of the state of > > > motion of the > > > emitting body." > > > > Einstien, Electrodynamics of Moving Bodies (Introduction) > > > > This text describes Einstein's postulate that there is no preferred > > > inertial frame of reference. > > > > "If at the points A and B of K there are stationary clocks which, > > > viewed in the stationary system, are synchronous; and if the clock at > > > A is moved with the velocity v along the line AB to B, then on its > > > arrival at B the two clocks no longer synchronize, but the clock moved > > > from A to B lags behind the other which has remained at B ..." > > > > Einstien, Electrodynamics of Moving Bodies (Section 4) > > > > The text describes the time dilation of a clock that moves from point > > > A to point B. If there is no preferred frame of reference then it is > > > just as true to say that > > > the clock is viewed as part of a stationary system and the points A > > > and B are in a moving system which moves at velocity -v. The > > > conclusion that time for both systems can be dilated with respect to > > > the other system is paradoxical. > > > No, it's not paradoxical at all. > > It is paradoxical because time for both systems cannot be dilated with > respect to each other. This is your assumption about what can and cannot be. > > > > > In the moving frame, the clocks at A and B were never synchronous. > > There aren't multiple clocks in the moving system in Einstein's > example. There are at least two clocks. There is one at point A and there is one at point B. One of them moves from A to B, and the other remains at B. In the reference frame K where A and B are at rest, then the clocks are synchronized initially. In the reference frame K' where A and B are moving, the clocks are NOT synchronized initially. When the clock at A ends up next to clock B and we discover that the reading on A is behind the reading on B, the account in the K frame is that the clocks were initially synchronized but that A ran slower than B. The account in the K' frame is that the clocks are NOT initially synchronized, and so even though B ran slower than A, it is STILL true that the reading on A is behind the reading on B when they are next to each other. As I said, colp, it would help if you would learn what special relativity ACTUALLY SAYS, rather than what your superficial COR says, then you will see that there are no contradictions in SR. PD
From: Daryl McCullough on 3 Jul 2010 10:10 harald says... > >On Jul 3, 1:02=A0pm, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: >> harald says... >> >> >If you google search, you will find me explaining that Einstein >> >claimed to have solved GRT's clock paradox. ;-) >> >> The use of GR to explain the results of the twin paradox is a little >perverse, > >Sorry but no, you missed the point (how is that possible after all >these years?). The original clock or twin paradox is NOT the SRT >exercise of textbooks at all, despite the fact that most confused >commentators parrot that error. Instead, it is a challenge to GRT's >postulate that an accelerated reference system may be considered to be >"in rest". I'm not sure what paradox you are referring to, then. GR doesn't really *have* a notion of "rest". For a particular coordinate system, you can use the term "at rest" to mean that the time derivative of the spacial coordinates are all zero, but that doesn't have any particular physical meaning, except in the cases where the metric is time-independent. >> because GR is a generalization of SR. In the case of empty space far >> from any large gravitating bodies, GR reduces to SR, so any GR solution >> to the twin paradox would have to have already been a solution in SR. > >Irrelevant. It's not irrelevant to *MY* point. It is my point. And this is my thread, so my point counts. -- Daryl McCullough Ithaca, NY
From: PD on 3 Jul 2010 10:14 On Jul 3, 1:06 am, colp <c...(a)solder.ath.cx> wrote: > On Jul 3, 3:03 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Jul 1, 7:56 pm, colp <c...(a)solder.ath.cx> wrote: > > > > On Jul 2, 2:21 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jun 30, 5:47 pm, colp <c...(a)solder.ath.cx> wrote: > > > > > > <quote> > > > > > > > > At best, all you've done is show the > > > > > > > fallacies or assumptions inherent in COLP's Oversimplified Relativity. > > > > > > What specific fallacies or assumptions? Quotes, please. > > > > > > Sure. You've used the statement from COLP's Oversimplified Relativity > > > > > that moving clocks run slow (which you've said is true even for blue- > > > > > shifted clocks), and you've used the statement that COLP's > > > > > Oversimplified Relativity makes no provision whatsoever for a > > > > > compression of time for a clock turning around. This immediately leads > > > > > to several paradoxes, and this is ample reason to chuck Colp's > > > > > Oversimplified Relativity. > > > > > </quote> > > > > > > The statement that "moving clocks run slow" isn't an > > > > > oversimplification, it is directly inferred from Einstein's > > > > > "Electrodynamics of Moving Bodies". > > > > > It IS an oversimplification. If you've inferred this from his 1905 > > > > paper, then you've oversimplified. > > > > No, inferring something from a paper does not constitute an > > > oversimplification. > > > It does if it's an oversimplification of what's presented in the > > paper! > > It isn't. Claiming that it is without showing why is of no value. You aren't owed an education on a newsgroup, despite your taunts to the contrary. I pointed you to a URL with plenty of reading about the twin puzzle, and the only effort required of you is a mouseclick and some reading and paying attention. If you are not willing to do that, and if you are demanding that people educate you on the difference between special relativity and Colp's Oversimplified Relativity, here and at your whim, you will find that people are not sympathetic to your laziness. I can recommend some excellent reading materials that have been prepared with CONSIDERABLY more care, thought, and consistency than what you will ever find on a newsgroup even on a good day. If you'd like to pursue those, I'd be happy to point you in the direction of quality. PD
From: Esa Riihonen on 3 Jul 2010 11:04 Follow ups to: sci.physics.relativity Koobee Wublee kirjoitti: > On Jul 2, 5:23 am, Esa Riihonen wrote: >> Androcles kirjoitti: > >> > Go ahead, the most of the cranks, quit babbling and start using >> > mathematics. >> >> Why should I? I was not doing physics here - and natural language seems >> to be much superior for this kind of meta discussion. >> >> And regarding the specific problems Colp is having with the "symmetric >> twin paradox", the mathematical walk through has already been given by >> someone (McCullogh, PD - don't remember) in a much clearer form than I >> believe I can do myself. As far as I have seen Colp didn't respond to >> that at all. > > So, you don't know what math is involved with the problem. You don't > know what the issues are with relative simultaneity. You don't know > anything about the Lorentz transform. You are easily bedazzled by the > mathemagic shows where all these mathemagic shows contradict each other. > That is a fine trait of Einstein Dingleberrism. <shrug> The math involved is the math of SR - specifically regarding the twin "paradoxes" (symmetric or not) it is more or less just Lorentz Transforming the coordinates of the events between different inertial frames. But perhaps I really don't know anything about this stuff - however I hope you won't reveal this to my current employer or former teachers that let me pass the exams. But perhaps you could now show how the solution of the symmetric twin paradox provided earlier was flawed? Esa(R) -- Space is what is needed to keep everything from being in one place. Time is what is needed to keep everything from happening at once. And for everything else, there's duct tape.
From: harald on 3 Jul 2010 11:22
On Jul 3, 4:10 pm, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > harald says... > > > > >On Jul 3, 1:02=A0pm, stevendaryl3...(a)yahoo.com (Daryl McCullough) > >> wrote: harald says... > > >> >If you google search, you will find me explaining that Einstein > >> >claimed to have solved GRT's clock paradox. ;-) > > >> The use of GR to explain the results of the twin paradox is a little > >perverse, > > >Sorry but no, you missed the point (how is that possible after all > >these years?). The original clock or twin paradox is NOT the SRT > >exercise of textbooks at all, despite the fact that most confused > >commentators parrot that error. Instead, it is a challenge to GRT's > >postulate that an accelerated reference system may be considered to be > >"in rest". > > I'm not sure what paradox you are referring to, then. I did some digging to understand the main cause of confusion. What I found, is the clock paradox started out as the one that Einstein was confronted with, as criticism of his GRT. At least, concerning SRT, before the development of GRT, I found no trace of such a paradox in the old literature. Did you? > GR doesn't really *have* a notion of "rest". Einstein's GRT holds that reference systems in any form of motion may be used as physical reference system, relative to which objects are "in rest" - that's the basis of the "clock" or "twin" paradox, and how it started. > For a particular coordinate system, > you can use the term "at rest" to mean that the time derivative of the spacial > coordinates are all zero, but that doesn't have any particular physical > meaning, except in the cases where the metric is time-independent. > > >> because GR is a generalization of SR. In the case of empty space far > >> from any large gravitating bodies, GR reduces to SR, so any GR solution > >> to the twin paradox would have to have already been a solution in SR. > > >Irrelevant. > > It's not irrelevant to *MY* point. It is my point. And this is my > thread, so my point counts. Irrelevant for Einstein's clock paradox, which KW brought up in your thread. ;-) Harald |