A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Jerry on 7 Mar 2010 08:19 On Mar 6, 2:56 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > On Mar 6, 5:21 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > > There are no hidden assumptions concerning clock synchronization > > in their experiment. They did make assumptions, however, about > > their "test theory" that turn out to have been unwarranted. > > Gagnon et al. believed that their setup was capable of > > distinguishing between between LET and SR. In other words, they > > believed their experiment capable of detecting a LORENTZIAN > > aether wind. This turns out to have been wrong. > > That is why in my response to PD I asked if assumptions were made > about contraction of the equipment. I had noticed that after pointing > out the distinction between SR and LET he didn't use LET but GGT > instead. GGT was their "test theory". Tom Roberts explains better than I can what test theories are all about: "A test theory of SR is a generalization of the Lorentz transforms of SR using additional parameters. One can then analyze experiments using the test theory (rather than SR itself) and fit the parameters of the test theory to the experimental results. If the fitted parameter values differ significantly from the values corresponding to SR, then the experiment is inconsistent with SR. But more normally, such fits can show how well a given experiment confirms or disagrees with SR, and what the experimental accuracy is for doing so. This gives a general and tractable method of analysis which can be common to multiple experiments." http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html ----------------------------------------------------------------- One cannot just throw in additional parameters willy-nilly into a theory and get a test theory out of it. Test theories need to satisfy many of the same tests for physical reasonableness as "real" theories. One important physical reasonableness criterion is that a set of transformations must form a group. If you apply the Lorentz transform twice in a row, the result should also be a Lorentz tranform. If you use the Lorentz transforms to map events from a first frame onto a second frame, it should be possible to do an inverse mapping from the second frame back onto the first, and so forth. http://en.wikipedia.org/wiki/Group_(mathematics) It is trivial to demonstrate that the Galilean transforms form a group. It is a somewhat tedious, but when you finally succeed, rather satisfying exercise to demonstrate that the Lorentz transforms form a group. The GGT transforms do not form a group. ----------------------------------------------------------------- On these newsgroups, one frequently sees the assertion that LET is experimentally indistinguishable from SR. Remind me some time to explain why I consider that to be a false statement, although a few technological breakthroughs might be necessary before definitive tests can be made... Jerry
From: bert on 7 Mar 2010 08:34 On Mar 7, 8:19 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > On Mar 6, 2:56 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > On Mar 6, 5:21 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > > > There are no hidden assumptions concerning clock synchronization > > > in their experiment. They did make assumptions, however, about > > > their "test theory" that turn out to have been unwarranted. > > > Gagnon et al. believed that their setup was capable of > > > distinguishing between between LET and SR. In other words, they > > > believed their experiment capable of detecting a LORENTZIAN > > > aether wind. This turns out to have been wrong. > > > That is why in my response to PD I asked if assumptions were made > > about contraction of the equipment. I had noticed that after pointing > > out the distinction between SR and LET he didn't use LET but GGT > > instead. > > GGT was their "test theory". Tom Roberts explains better than I > can what test theories are all about: > > "A test theory of SR is a generalization of the Lorentz > transforms of SR using additional parameters. One can then > analyze experiments using the test theory (rather than SR > itself) and fit the parameters of the test theory to the > experimental results. If the fitted parameter values differ > significantly from the values corresponding to SR, then the > experiment is inconsistent with SR. But more normally, such > fits can show how well a given experiment confirms or disagrees > with SR, and what the experimental accuracy is for doing so. > This gives a general and tractable method of analysis which > can be common to multiple experiments." > http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html > > ----------------------------------------------------------------- > > One cannot just throw in additional parameters willy-nilly into > a theory and get a test theory out of it. Test theories need to > satisfy many of the same tests for physical reasonableness as > "real" theories. > > One important physical reasonableness criterion is that a set of > transformations must form a group. If you apply the Lorentz > transform twice in a row, the result should also be a Lorentz > tranform. If you use the Lorentz transforms to map events from a > first frame onto a second frame, it should be possible to do an > inverse mapping from the second frame back onto the first, and > so forth.http://en.wikipedia.org/wiki/Group_(mathematics) > > It is trivial to demonstrate that the Galilean transforms form a > group. It is a somewhat tedious, but when you finally succeed, > rather satisfying exercise to demonstrate that the Lorentz > transforms form a group. > > The GGT transforms do not form a group. > > ----------------------------------------------------------------- > > On these newsgroups, one frequently sees the assertion that LET > is experimentally indistinguishable from SR. Remind me some time > to explain why I consider that to be a false statement, although > a few technological breakthroughs might be necessary before > definitive tests can be made... > > Jerry Light going from gamma to radio photons lose energy but their speed is the same. It would not be a photon if it went slower than c TreBert
From: Bruce Richmond on 7 Mar 2010 12:58 On Mar 7, 8:19 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > On Mar 6, 2:56 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > On Mar 6, 5:21 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > > > There are no hidden assumptions concerning clock synchronization > > > in their experiment. They did make assumptions, however, about > > > their "test theory" that turn out to have been unwarranted. > > > Gagnon et al. believed that their setup was capable of > > > distinguishing between between LET and SR. In other words, they > > > believed their experiment capable of detecting a LORENTZIAN > > > aether wind. This turns out to have been wrong. > > > That is why in my response to PD I asked if assumptions were made > > about contraction of the equipment. I had noticed that after pointing > > out the distinction between SR and LET he didn't use LET but GGT > > instead. > > GGT was their "test theory". Tom Roberts explains better than I > can what test theories are all about: > > "A test theory of SR is a generalization of the Lorentz > transforms of SR using additional parameters. One can then > analyze experiments using the test theory (rather than SR > itself) and fit the parameters of the test theory to the > experimental results. If the fitted parameter values differ > significantly from the values corresponding to SR, then the > experiment is inconsistent with SR. But more normally, such > fits can show how well a given experiment confirms or disagrees > with SR, and what the experimental accuracy is for doing so. > This gives a general and tractable method of analysis which > can be common to multiple experiments." > http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html > > ----------------------------------------------------------------- > > One cannot just throw in additional parameters willy-nilly into > a theory and get a test theory out of it. Test theories need to > satisfy many of the same tests for physical reasonableness as > "real" theories. > > One important physical reasonableness criterion is that a set of > transformations must form a group. If you apply the Lorentz > transform twice in a row, the result should also be a Lorentz > tranform. If you use the Lorentz transforms to map events from a > first frame onto a second frame, it should be possible to do an > inverse mapping from the second frame back onto the first, and > so forth.http://en.wikipedia.org/wiki/Group_(mathematics) > > It is trivial to demonstrate that the Galilean transforms form a > group. It is a somewhat tedious, but when you finally succeed, > rather satisfying exercise to demonstrate that the Lorentz > transforms form a group. > > The GGT transforms do not form a group. > > ----------------------------------------------------------------- > > On these newsgroups, one frequently sees the assertion that LET > is experimentally indistinguishable from SR. Remind me some time > to explain why I consider that to be a false statement, although > a few technological breakthroughs might be necessary before > definitive tests can be made... > > Jerry Thanks once again for the thorough answer. But my point was that the author had implied that his experiment could distinguish between SR and LET, so why not use LET as the test theory. To disprove a theory that was known to be wrong to "confirm" SR hardly seems fair. Isn't that what is called a strawman? The fact that he couldn't disprove LET shows that somewhere in the analysis of the experiment an assumption was made, since LET definitely uses c+v. Bruce
From: BURT on 7 Mar 2010 14:08 On Mar 6, 11:08 pm, "Inertial" <relativ...(a)rest.com> wrote: > "Y.Porat" <y.y.po...(a)gmail.com> wrote in message > > news:fe409bc5-8cb7-40c9-85dc-a5a000ea7e83(a)z4g2000yqa.googlegroups.com... > > > > > > > On Mar 5, 1:51 pm, "Inertial" <relativ...(a)rest.com> wrote: > >> "Y.Porat" <y.y.po...(a)gmail.com> wrote in message > > >>news:868926cb-233d-417e-86c8-cd8987c43419(a)q16g2000yqq.googlegroups.com.... > > >> > On Mar 4, 7:44 pm, PD <thedraperfam...(a)gmail.com> wrote: > >> >> On Mar 4, 11:09 am, Ste <ste_ro...(a)hotmail.com> wrote: > > >> >> > On 4 Mar, 16:48, mpalenik <markpale...(a)gmail.com> wrote: > > >> >> > > On Mar 4, 10:19 am, Ste <ste_ro...(a)hotmail.com> wrote: > > >> >> > > > On 4 Mar, 12:19, "Inertial" <relativ...(a)rest.com> wrote: > > >> >> > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> >> > > > > > Not really, because if the total acceleration is small, then > >> >> > > > > > so > >> >> > > > > > is the > >> >> > > > > > speed. > > >> >> > > > > That is a nonsense argument. Acceleration can be small and > >> >> > > > > speeds very > >> >> > > > > large. > > >> >> > > > When I went to school, you could not have a large change of > >> >> > > > speed > >> >> > > > with > >> >> > > > only a small amount of total acceleration. > > >> >> > > The problem is your use of the term "total acceleration". If by > >> >> > > total > >> >> > > acceleration, you mean integral(a dt), then yes, you are correct. > >> >> > > However, there is already a word for integral(a dt) -- it's called > >> >> > > "the change in velocity". The term "total acceleration" isn't > >> >> > > actually defined. Acceleration is defined, velocity is defined, > >> >> > > deltav is defined. But "total acceleration is not". > > >> >> > Essentially, I'm defining "total acceleration" as something akin to > >> >> > total force, so that even though the force may be small, if it > >> >> > continues for a long time then the total force will be the same as > >> >> > if > >> >> > a large force was applied for a short period of time. In this way, > >> >> > if > >> >> > the application of force is what is causing either part or the whole > >> >> > of the time dilation effect, then it is the final speed that counts, > >> >> > not how quickly the object reached that speed. > > >> >> Indeed. This should tell you that it is not the details of the > >> >> acceleration that matter. > >> >> The overly simplistic statement would be, "Yes, you see that is why > >> >> SR's effects are based on speed, not on acceleration." > > >> >> In fact, there is a speed time dilation effect on GPS satellites, > >> >> which are going around in a circular path at constant speed, relative > >> >> to earth clocks, and accounting for this is crucial to their proper > >> >> operation. This is the same speed dilation effect, though different > >> >> size, as seen in muons in a circulating ring. (Since, by the way, the > >> >> GPS satellites are certainly not inside a magnetic ring but still > >> >> experience time dilation properly calculated by SR, this is another > >> >> good way to be sure that the magnetic ring is not what's responsible > >> >> for the time dilation of the muons.) > > >> >> Regarding something I alluded to earlier, though, what really matters > >> >> is how straight the path through spacetime is. We're used to thinking > >> >> that the shortest path through space is the straight one (and that's > >> >> right), but the straightest path through spacetime yields the LONGEST > >> >> duration. Any change in motion (such as an acceleration) introduces a > >> >> kink in this path (something that can be illustrated visually very > >> >> easily) and so lowers the duration. Why this is, has to do with the > >> >> structure of spacetime and we could discuss that. But this is perhaps > >> >> the most intuitive way (once these concepts are explained) to > >> >> understand why the traveling twin returns younger. > > >> >> > > Also, you could just be dealing with a system where the velocity > >> >> > > started out high and you never measured any acceleration. > > >> >> > Indeed. > > >> > ---------------------- > >> > (:-) > >> > to mix **biologic process** with > >> > inorganic physics > >> > is ridiculous!!! > > >> He didn't .. there was no biologic process mentioned in the above. > > >> > (i said it in a big understatement ...(:-) > >> > Y.Porat > >> > ----------------------- > > > here is a quote from PD > > quote > > > 'and so lowers the duration. Why this is, has to do with the > > structure of spacetime and we could discuss that. But this is perhaps > > the most intuitive way (once these concepts are explained) to > > understand why the traveling twin returns younger. > > end of quote > > ------------- > > so the tarveling twin returns younger ???!!! > > Yes. Gees, don't you know this already? > > > 2 > > if you dont rmind > > EM radiation HAS MASS! > > Nope > > > therefore it i influenced by gravity > > By space curvature .. yes > > > SIMILAR BUT NOT EXACTLY AS ANY OTHER MASS!! > > no curvature and no shmervature of space > > Except nature behaves as though there is. Nature knows better than you > > > but that is again not for born parrots > > BYE > > I wish- Hide quoted text - > > - Show quoted text - The constant flow of the speed of light is in the space frame. Light flows at C in all directions. Matter can get behind it in the space frame. Mitch Raemsch
From: Jerry on 7 Mar 2010 15:13
On Mar 7, 11:58 am, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > Thanks once again for the thorough answer. But my point was that the > author had implied that his experiment could distinguish between SR > and LET, so why not use LET as the test theory. An experiment to test a theory need a framework of assumptions that are broader in scope than those of of the original theory. One cannot test a theory in terms of itself. The idea behind a test theory is to parameterize a theory's basic assumptions so that a -quantitative- comparison can be made between the theory's predictions and the results of experimental test. The form of the test theory constrains the questions that one asks in a particular experimental analysis. http://en.wikipedia.org/wiki/Test_theories_of_special_relativity Take, for instance, Newton's law of gravity. What exponent in r is consistent with the observed distribution of stellar velocities in the nearby galaxies? An appropriate test theory might be F = GmM/r^(2+delta), and after lots and lots of curve fitting against Doppler measurements, the best-fit value of delta might be found to be -1.32e-8 +/- 2.19e-9 (totally made-up numbers). Such an observation would show that something is seriously lacking in our understanding of stellar dynamics in galaxies. It would not necessarily mean that the inverse-square law actually needs to be modified, but the use of a test theory provides A COMMON LANGUAGE FOR DISCUSSION among people researching a problem. Viewed in terms of my over-simplified test theory, it -would- appear as if the force of gravity falls off more slowly than inverse-squared. An alternative test theory might choose to model galaxies as surrounded by a dilute halo of invisible matter, in which case the question is, how much of this invisible stuff would be needed to account for the observed Doppler measurements? Different test theories use different parameterizations, and the different parameterizations imply different questions. This is just the nature of the beast. Test theories are generally not meant to be taken seriously as real explanations of nature, but as I said, offer a framework for common understanding Going back to Gagnon et al., the questions that they tried to address with GGT were (1) how to parameterize the Lorentz transforms so that any measured anisotropies might be accounted for in terms of the parameterized theory (2) to distinguish between the predictions of SR and LET. Standard test theories of special relativity do not distinguish between the predictions of SR and LET, so Gagnon et al. rolled their own. > To disprove a theory > that was known to be wrong to "confirm" SR hardly seems fair. Isn't > that what is called a strawman? Gagnon et al. didn't know that their test theory was inconsistent. So it wasn't an -intentional- strawman. > The fact that he couldn't disprove > LET shows that somewhere in the analysis of the experiment an > assumption was made, since LET definitely uses c+v. Jerry |