Wang / Sagnac Devices
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From: Tom Roberts on 19 Oct 2009 00:30 tominlaguna(a)yahoo.com wrote: > Sue posted a link to a Wang & et al paper which describes their fiber > optical gyro (FOG) experiments. That paper has been superseded by: > http://arxiv.org/ftp/physics/papers/0609/0609235.pdf. This latest > paper provides a more detailed account of that work. > Figure 3 of the new Wang paper shows that when a linear section of the > FOG is moved in translation, there is a fringe shift that is > proportional to the length of that section and the speed of its > motion. Most people that I have discussed this with believe that Dr. > Wang has demonstrated that his design can detect translational motion. Yes. This is all fully consistent with SR. > I disagree. They measured the acceleration of the fiber section from > zero to some constant velocity. Cannot be so. The signal is larger when a longer section of fiber is in the moving section or when the fiber makes more turns around the whole apparatus. That does not change the acceleration, but it does change the \integral v.dl of Wang et al. Their formula is only approximately correct in SR. They ignored the effect due to the differing propagation speeds in a moving fiber. For each of their apparatuses this is vastly smaller than the effect they describe. Moreover, imagine not turning on the source until the section of fiber on the conveyor is moving -- the phase shift will still be there (relative to zero velocity of the conveyor). > The Wang paper has lead me to conclude that the "Sagnac effect" is a > phenomenon peculiar to situations when the source and/or receiver are > experiencing acceleration. Hmmm. Wang et al show otherwise. In their apparatus of Fig 3 neither the source nor detector accelerate, yet there is a signal. If one took a flexible fiber and coiled it up around a rotatable disk (< 1 full rotation), and placed both source and detector on the table nearby, one essentially has a Sagnac interferometer in which neither source not detector moves or accelerates. Their formula predicts a signal when the disk is rotated, even though neither the source nor detector are accelerated. This is consistent with the prediction of SR for this physical situation (again neglecting the different propagation speeds). This is all easily explained in SR: in all cases the light propagating in the two directions takes different paths IN THE INERTIAL FRAME, and the time difference and phase shift are proportional to the difference in path lengths in that frame. > The generalized Sagnac effect does not deal > with enclosed areas and angular velocity; Right. Wang et al give a formula that depends on \integral v.dl. And they show how it includes the usual Sagnac formula as a special case. Only for a rigidly rotating apparatus does "angular velocity" make sense, and only for that case does the enclosed area actually apply; for all other cases of the generalized apparatuses they consider it is \integral v.dl that matters, not "enclosed areas and angular velocity". For their original device, that is v times the perimeter, which is how I phrased it in other posts in this newsgroup. > Saburi in 1976 demonstrated that there was a radio signal > transit time difference east-west between two earth-stationary > receiver/transmitters. Certainly. This confirms the prediction of SR. > The GPS network is corrected each day to > adjust their clocks so that the one-way transmission of signals is > accurate due to the Sagnac effect. This is not quite stated correctly. The GPS satellites are updated daily to account for their clocks' drift, variations in their orbits, and some other minor variations (e.g. those due to sun and moon). There is no possible way to "correct" for the Sagnac effect, it must be computed for each measurement, based on the actual satellites used (it depends on the geometrical relationship between GPS receiver and the satellite). > Tom Roberts erroneously states that the ballistic model cannot explain > Sagnac. I will acknowledge that the "re-emission" ballistic model is > denied by the Sagnac results. Tolman (1912) and Panofsky and Phillips > (1961) describe three ballistic models. Waldron (1977) describes two > of the three: the ballistic model of Ritz/Waldron and the re-emission > model. The re-emission model fails in explaining Sagnac and a host of > other experiments. My statement was not "erroneous". It applies to all ballistic models in which Snell's law holds IN THE REST FRAME OF THE MIRROR. Ballistic models that do not obey that are refuted by literally zillions of observations and experiments, and those that do obey it are refuted by Sagnac and all of Wang et al's observations. > In the Ritz/Waldron model, a mirror is not a new source, and therefore > light may or may not be reflected at c with respect to it. Its speed > after reflection is based on any relative motion between the source > and the mirror. If there is no relative motion, the reflected photon > will be moving at c; if there is relative motion, v, its speed will be > c +/- v� all with respect to the mirror. You have oversimplified, and in the process you omitted important caveats (e.g. you implicitly assume the light was traveling at c before hitting the mirror, and it hits the mirror perpendicularly; these are not necessarily so). But that model obeys Snell's law in the rest frame of the mirror, and is refuted. Tom Roberts
From: tominlaguna on 19 Oct 2009 02:40 On Sun, 18 Oct 2009 07:35:35 -0700 (PDT), "Dono." <sa_ge(a)comcast.net> wrote: >On Oct 18, 5:35 am, tominlag...(a)yahoo.com wrote: >> On Sat, 17 Oct 2009 07:56:20 -0700 (PDT), "Dono." <sa...(a)comcast.net> >> wrote: >> >> >> >> >On Oct 16, 11:08 pm, tominlag...(a)yahoo.com wrote: >> >> On Fri, 16 Oct 2009 09:01:34 -0700 (PDT), "Dono." <sa...(a)comcast.net> >> >> wrote: >> >> >> >On Oct 16, 8:43 am, tominlag...(a)yahoo.com wrote: >> >> >> On Fri, 16 Oct 2009 08:31:15 -0700 (PDT), "Dono." <sa...(a)comcast.net> >> >> >> wrote: >> >> >> >> >On Oct 16, 8:08 am, tominlag...(a)yahoo.com wrote: >> >> >> >> >> In the Ritz/Waldron model, a mirror is not a new source, and therefore >> >> >> >> light may or may not be reflected at c with respect to it. Its speed >> >> >> >> after reflection is based on any relative motion between the source >> >> >> >> and the mirror. If there is no relative motion, the reflected photon >> >> >> >> will be moving at c; if there is relative motion, v, its speed will be >> >> >> >> c +/- v� all with respect to the mirror. >> >> >> >> Regards, >> >> >> >> Tom Miles >> >> >> >> >If the speed is ANYTHING but c, the model fails BOTH the Sagnac and >> >> >> >the Ives experiments. >> >> >> >> I suspect you are referring to the passive type of interferometer >> >> >> devices. In that case, you are wrong: whatever the speed of the >> >> >> initial ray of light, components going in each direction after >> >> >> splitting will have the same speed, be it c or u. The outcome is the >> >> >> same. As a practical matter, since the sources in the experiments you >> >> >> cite are not in motion with respect to the device, the speed will be >> >> >> c. >> >> >> >Prove it . Show the math. >> >> >> I don't know what there is to prove. First, please let me know which >> >> Ives experiment you are discussing. >> >> >Ives-Stilwell. >> >> >> I was not aware of an Ives >> >> experiment that tested the Sagnac effect. >> >> >Who told you that? I told you that all flavors of the ballistic theory >> >are disproved by the Ives experiment AND by the Sagnac experiment. >> >Prove that this isn't so. >> >> >> The point I was trying to make was simply that whatever the speed of >> >> the incoming ray was, that speed was retained by the two components >> >> after the ray is split. >> >> >Irrelevant, you need to write the equations of the complete >> >experiment. If you ever manage to do that (I doubt it), you will find >> >out that you are wrong: Ives, Sagnac, Fizeau experiments all falsify >> >the ballistic theory. So does MMX in a medium with refraction greater >> >than 1. >> >> Sorry, we're discussing Wang and Sagnac... > > >So, discuss Sagnac. I told you that it refutes the ballistic theory, >you keep trying to dodge the subject. You will find this forum much >tougher than the sympathetic one at the crackpot forum of Walter >Babin, Tom.... I'm not dodging the issue. I wrote in my opening that Sagnac refutes the re-emission ballistic theory, not the emission theory of Ritz and Waldron. Perhaps I missed your presentation of why and how Sagnac refutes their ballistic theory. Can you restate your position?
From: tominlaguna on 19 Oct 2009 02:49 On Sun, 18 Oct 2009 07:37:53 -0700 (PDT), "Dono." <sa_ge(a)comcast.net> wrote: >On Oct 18, 7:14 am, tominlag...(a)yahoo.com wrote: >> >> The prominent thing I see on that page is the "lie" that Sagnac is >> disproof for the Ballistic theory. > >It is not a lie, Tom. It is the truth. > > >> Who is the idiot author of Mathpages, anyway? I stopped looking there >> when he stated that Dingle was feeble-minded. >> > >He is a famous math professor by the name of Kevin Brown. >And you are just another sad crackpot. But you are no longer on the >Walter Babin crackpot forum, if you don't like the treatment here, you >can always return there.... Where did you get the idea that I am no longer on the Walter Babin forum? First of all, I've never been on it; and secondly, I didn't even know he had one. I have been posting historical papers General Science for all to access.
From: tominlaguna on 19 Oct 2009 03:00 On Sun, 18 Oct 2009 16:48:33 -0400, Jonah Thomas <jethomas5(a)gmail.com> wrote: >"Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> <tominlaguna(a)yahoo.com> wrote in message >> > "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: > >> >>Sorry to disappoint you, but this analysis >> >> http://www.mathpages.com/rr/s2-07/2-07.htm >> >>is isomorphic to Einstein's lunatic "thought experiment": >> > >> > The prominent thing I see on that page is the "lie" that Sagnac is >> > disproof for the Ballistic theory. >> > Who is the idiot author of Mathpages, anyway? I stopped looking >> > there when he stated that Dingle was feeble-minded. >> >> http://www.mathpages.com/home/contents.htm >> �1994-2009 Kevin Brown All bigots are certain they are right or they >> >> wouldn't be bigots. > >Nothing is more dangerous than an idea, when it is the only >idea we have. > Alain, 1908 > >From that same source: http://www.mathpages.com/home/quotes.htm > >The mathpages guy has a tremendous breadth of knowledge and he's >definitely a valuable resource. You can't depend on everything he says >to be true, but he can provide a great big headstart on a lot of >problems if you aren't already as familiar with them as he is. You make a good point. I slammed him for his bigotry, but I see now I was being no different. I have gained knowledge there.
From: Inertial on 19 Oct 2009 04:02
<tominlaguna(a)yahoo.com> wrote in message news:e63od5t7bl229oahgcrjfud7ts7f1i113f(a)4ax.com... > On Sun, 18 Oct 2009 18:58:18 +0100, "Androcles" > <Headmaster(a)Hogwarts.physics_p> wrote: > >> >><tominlaguna(a)yahoo.com> wrote in message >>news:lt7md512qegmkrme8hh6h7icq47u302ht4(a)4ax.com... >>> On Sat, 17 Oct 2009 12:21:32 +0100, "Androcles" >>> <Headmaster(a)Hogwarts.physics_p> wrote: [snip] >>>>Both contain the same blunder, namely, there are two angles alpha >>>>and -alpha not one, as shown here, >>>> http://www.androcles01.pwp.blueyonder.co.uk/Sagnac/SagnacIdiocy.htm There are lots of angles, alpha and -alpha, made by the beams relative to the start/end point in the rotating frame .. which is what Androcles animation in that page shows. Those angles both end up as zero when the beams meet at the detector. Of course, this is not the alpha described in the article. Androcles is confused. The article describes alpha as the amount the start/end has rotated from its initial position, in the non-rotating frame. Androcles doesn't understand that, as is obvious from his irrelevant animation and nonsensical questions in red on that page. In emission theory, there is only one alpha value (ioe one angle through whic h the start/end point has rotated in the non-rotating frame) when the beams arrive back at the start/end location. Because the rays meet simultaneously, there is no phase shift. In SR, the beams do not arrive simultaneously, so there are two alpha values ... one alpha value when the first arrives, and a slightly larger alpha value when the second other arrives. >>> Sorry, I don't see your reasoning. Noone does >>> The end point has moved for both >>> beams to the 1 o'clock position. Androcles is rotating the clock. >>Both beams have started from and returned to the 12 o'clock position, When your clock rotates, yes. >>and the start position is now at the 11 o'clock position. More precisely .. where the start position WAS in the non-rotating frame is now at the 11 o'clock position in the rotating frame. >> The position >>of the start is history and not relevant to the simultaneous meeting of >>beams. Yeup .. and it is that simultaneous meeting which refutes emission theory. SR does not have a simultaneous meeting, because the light travels two different length paths at the same speed, and so they arrive at the detector at different times, giving a phase shift. So far Androcles has failed to grasp that. >> http://www.androcles01.pwp.blueyonder.co.uk/Sagnac/ring.gif And that animation shows how the light in an emission theory arrives at the detectors at the same time and in phase, hence refuting emission theory. There's no relevant meaning for those two alpha values, nor for the animation to pause where it does .. other than Androcles own confusion about what is happening. >>The end point hasn't moved at all, it is still at the 12 o'clock position. The end point in the rotating frame is ALWAYS at the 12 o'clock position in the rotating frame .. and the start point in the rotating frame is ALSO ALWAYS at the 12 o'clock position in the rotating frame. The start and end points in the rotating frame remain at the same point in the rotating frame all the time. However, the start and end points in the non-rotating frame (two different fixed point in that frame) DO move in the rotating frame. The start point in the non-rotating frame moves from the 12 o'clock to 11 o'clock position in the rotating frame, and the end point in the non-rotating frame moves from the 2 o'clock to the 12 o'clock in the rotating frame. It all depends on where you mark your start and end points .. on the rotating frame, or on the non-rotating lab frame .. and in which frame you measure their positions over time. >>What part of that reasoning do you not understand? It is clear enough >>in the gif I drew! Its clear that Androcles is confused. > Sorry, I still don't get it... The start and end points remain > together when the device rotates. Yes. In the rotating device frame. In the lab frame they both rotate together > Rays should be shown leaving the > start place and returning to the now displaced, start place. Yes .. at the same time according to emission theory .. so no phase shift. |