Preferred Frame Theory indistinguishable from SR
in [Relativity]
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From: Tom Roberts on 6 Jul 2010 21:10 Edward Green wrote: > Actually, as postulates of SR go, I prefer to use the > following: The laws of physics are Lorentz invariant. Done. That's not really a postulate of relativity, but the conclusion. As I have said before, all one needs is the PoR; from that and the "hidden postulates" one can derive three theories, only one of which survives experimental tests, and is known as SR. > I would > now like to understand why the laws of physics have this structure. Yes. In particular, why spacetime is 4 dimensional, etc. Be careful when interpreting such "why" questions. Some aspects of "why" are appropriate in science, some are not. I intend only those that are. > I > think Lorentz took a step in that direction. Nope. How is his rather arcane approach "a step in that direction"??? Here's what he did: * guess that there is an ether at rest in some inertial frame, in which Maxwell's equations hold * guess that the Galilean velocity transform applies * guess the form of a new "change of variables" * lo and behold with all the above one finds that Maxwell's equations look the same in terms of the ether-frame coordinates and the changed variables of a moving frame IOW: simply postulating an unobservable ether is not "a step in that direction" at all. Assuming an uncaused cause is not any sort of "understanding". Tom Roberts
From: Tom Roberts on 6 Jul 2010 21:18 Paul Stowe wrote: > While observationally > equivalent from LR verse SR perspective of 'relativity', an actual > change of the electric potential profile of charges with speed will > result in a EMF, which will create a 'force' in opposition to any > departure from any current equilibrium condition. THAT! is a > significant difference. By any reasonable definition is certainly not > 'nothing'... A reasonable meaning of "significant difference" between the predictions of two theories is that it be measurable. With that meaning, what you describe is not a significant difference. Tom Roberts
From: Tom Roberts on 6 Jul 2010 21:36 Paul Stowe wrote: > On Jul 5, 9:34 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> Edward Green wrote: >>> Is the assumption of a hidden rest frame somehow inconsistent with >> So, for instance, LET violates the above requirement, as does the theory derived >> from the preferred-frame postulates Daryl gave. This is so even though both of >> those theories are experimentally indistinguishable from SR, and both of them >> have an unobservable preferred frame. > > So, how does that cause a violation of local Lorentz invariance??? By having a unique frame distinguished by reference in the equations. Local Lorentz invariance applies to the equations of the theory. > If > it does, shouldn't that BE a means of distinguishing a difference? It would be, except that for LET the ether frame is completely unobservable. One cannot measure an unobservable quantity, such as one's velocity wrt the ether frame of LET. Tom Roberts
From: Paul Stowe on 6 Jul 2010 21:38 On Jul 6, 6:18 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > PaulStowewrote: > > While observationally > > equivalent from LR verse SR perspective of 'relativity', an actual > > change of the electric potential profile of charges with speed will > > result in a EMF, which will create a 'force' in opposition to any > > departure from any current equilibrium condition. THAT! is a > > significant difference. By any reasonable definition is certainly not > > 'nothing'... > > A reasonable meaning of "significant difference" between the predictions of two > theories is that it be measurable. With that meaning, what you describe is not a > significant difference. > > Tom Roberts What is not measurable about a resistance to changes in speed of material systems? Paul Stowe
From: Paul Stowe on 6 Jul 2010 21:42
On Jul 6, 6:36 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > PaulStowewrote: > > On Jul 5, 9:34 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > >> Edward Green wrote: > >>> Is the assumption of a hidden rest frame somehow inconsistent with > >> So, for instance, LET violates the above requirement, as does the theory derived > >> from the preferred-frame postulates Daryl gave. This is so even though both of > >> those theories are experimentally indistinguishable from SR, and both of them > >> have an unobservable preferred frame. > > > So, how does that cause a violation of local Lorentz invariance??? > > By having a unique frame distinguished by reference in the equations. Local > Lorentz invariance applies to the equations of the theory. > > > If > > it does, shouldn't that BE a means of distinguishing a difference? > > It would be, except that for LET the ether frame is completely unobservable. One > cannot measure an unobservable quantity, such as one's velocity wrt the ether > frame of LET. > > Tom Roberts Thus, logically, LR has the very same 'local Lorentz invariance'. Note it's NOT! called local Einstein invariance... The rest frame does not violate this and is quite observable... Paul Stowe |