Compelling evidence for in vacuo light speed anisotrophy
in [Relativity]
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From: Dono on 12 Apr 2008 10:07 On Apr 12, 6:47 am, Surfer <n...(a)spam.please.net> wrote: > On Sat, 12 Apr 2008 00:31:45 -0700 (PDT), Dono <sa...(a)comcast.net> > wrote: > > > > >> "The repeated detection of the anisotropy of the speed of light .... > > >... all the experiments > >designed to detect it came up null withing the error bars. > > It depends on how the experiments are analysed. > Opinions differ, as you know. Yes, the crackpot opinions differe from mainstream, I agree :-)
From: Tom Roberts on 12 Apr 2008 11:44 Surfer wrote: > [...] > [1] Anderson J.D., Campbell J.K., Ekelund J.E., Ellis J. and Jordan > J.F., > Anomalous Orbital-Energy Changes Observed during Spaceraft Flybys of > Earth, Phys. Rev. Lett.,100, 091102, 2008. I have not had time to study the references (including the above). Given his history of stupid mistakes and outrageous claims, I have little interest in Cahill's analysis. But the data themselves are interesting -- a second type of spacecraft anomaly is intriguing.... Somewhere among the references someone said something like "the speed in the earth-centered frame is unchanged", which is wrong. That is true ONLY in a local ECI frame in which all other gravitational fields are negligible, and here both of those conditions are probably not good approximations to the accuracy required. It is tantalizing that the anomaly is about one part per million, which "just happens" to be the magnitude of the curvature of spacetime near earth. So I have to wonder if this is related to an inaccurate approximation in the coordinates used in the analysis. IOW: the speed of light in the coordinates used might not be isotropically c to sufficient accuracy over the distances involved. This is NOT a simple thing to check.... Tom Roberts
From: Surfer on 12 Apr 2008 12:08 On Sat, 12 Apr 2008 07:07:56 -0700 (PDT), Dono <sa_ge(a)comcast.net> wrote: >On Apr 12, 6:47 am, Surfer <n...(a)spam.please.net> wrote: >> On Sat, 12 Apr 2008 00:31:45 -0700 (PDT), Dono <sa...(a)comcast.net> >> wrote: >> >> >> >> >> "The repeated detection of the anisotropy of the speed of light .... >> >> >... all the experiments >> >designed to detect it came up null withing the error bars. >> >> It depends on how the experiments are analysed. >> Opinions differ, as you know. > > > >Yes, the crackpot opinions differe from mainstream, I agree :-) > Concerning the flybys, here is a mainstream opinion. http://www.planetary.org/news/2008/0228_Researchers_Investigate_New_Cosmic.html <Start extract> Anderson, Campbell, and Jordan, along with JPLers John E. Ekelund and Jordan Ellis, spent 18 months closely analyzing the data from all Earth flyby's. By the time they were done they had come up with a formula that accurately predicted the size of the anomaly based on the spacecraft's flight path. The extent to which the velocity of a spacecraft deviates from its expected value during a flyby, they found, depends of the difference in latitude (or "declination") between the spacecraft's incoming and outgoing trajectories. The greater the difference in latitude, the greater the anomalous velocity shift after the flyby. The spacecraft NEAR, for example, approached Earth from a near-equatorial latitude, but left close to a polar latitude. According to the formula, this large difference between the two should result in a substantial flyby anomaly, and this was indeed the case. The NEAR flyby became most clear-cut case-study for the mysterious effect. MESSENGER, in contrast, approached and departed along nearly the same latitude, which according to the formula should result in a miniscule effect. And indeed, no flyby effect was detected in the MESSENGER data. But as Anderson points out, coming up with a mathematical formula that can predict an effect is very different from having a physical explanation for it. Could it be some as yet undiscovered physical force, or something known as "dark energy" at work? Such revolutions in physics, Anderson mused, don't happen very often, but in the absence of a better explanation such radical hypotheses cannot be ruled out. "The formula doesn't suggest anything to us" he readily admitted, but perhaps some physicists will be able to come up with an explanation. <End extract> Cahill has provided an explanation that works very well. I know you don't like it, but do you know of any alternatives?
From: Tom Roberts on 12 Apr 2008 12:21 Surfer wrote: > [...] > Now if the speed of light varies with direction, then time dilation > will also vary with direction, and if these effects cancel the > variable speed of light would be completely hidden. Do you come up with theories by throwing darts at a dartboard? > In contrast, when radar doppler shift is used to measure the speed of > space craft, the radar signal is simply reflected from the spacecraft, > so is immune to spacecraft time dilation effects. Not in GR. In GR (speaking rather loosely, but good enough here) the "time dilation" of a clock is related to both its speed and the value of the metric at its location, compared to the same quantities at the location of the observer's clock. The metric also affects the path of light rays, and the speed of light measured over a path along which the metric varies need not be c. That, in turn, can affect the observed Doppler shift. In this case, the metric clearly varies over the relevant signal path(s). I do not yet know if the experimenters took that into account, or whether they simply used a local ECI frame. Nor do I yet know if this is significant at the level of the measurements. > That difference could explain why anisotropy in the speed of light is > so clearly observed in the spacecraft case. This is not "clearly observed" at all -- they observed an anomaly in the Doppler shift of signals, not any speed. It is important to keep track of the actual observation, because different models can give different values for other quantities. It's remarkable how often people unfamiliar with the actual operation of science make the same mistakes. For instance, this is the same basic mistake Van Flandern makes. Tom Roberts
From: Dono on 12 Apr 2008 12:23
On Apr 12, 9:08 am, Surfer <n...(a)spam.please.net> wrote: > > Cahill has provided an explanation that works very well. > I know you don't like it, but do you know of any alternatives? No , Cahill provided paragraph 2, the one that is rife with rookie mistakes. Like him, you are trying to give some respectability to the paper by attempting to associate it with a respectable reference. "Rag" Cahill does this all the time, he comes up with a short paragraph (mistake-ladden) and tries to associate it with mainstream references. In the past, I have pointed out his mistakes, I don't do it anymore because I don't want him to correct them, I like him stooopid as he is :-) I will tell you one last time: you (and Rag) do not understand relativistic Doppler effect. Paragraph 2 is nothing but a risible attempt to reconstruct the effect by using ballistic theory. Maybe "dr" Ralphie Babbage ghost-wrote it for "Rag-the dirtbag". :-) |