Wang / Sagnac Devices
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From: Androcles on 26 Oct 2009 10:44 "Jonah Thomas" <jethomas5(a)gmail.com> wrote in message news:20091026103549.14e63977.jethomas5(a)gmail.com... > HW@..(Henry Wilson DSc). wrote: >> Jonah Thomas <jethomas5(a)gmail.com> wrote: >> >"Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> >> > "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> >> >> > Sam <shayiam(a)yahoo.com> wrote: >> >> >> >> Jonah Thomas <jethom...(a)gmail.com> wrote: >> >> >> > >> >> >> >> > If a ballistic theory predicts that the speed of light >> >> >> >> > depends on the speed of its source, then in every early >> >> >> >> > Sagnac experiment the light went the same speed in two >> >> >> >> > different directions, according to an inertial observer. >> >> >> >> >> >> >> >> Right, relative to the instantaneous rest frame of the >> >emission> >> >point.> So, relative to the Galilean rest frame of the >> >hub, the> >light> >is going> faster in the direction of rotation than >> >in the> >opposite> >direction. >> >> >> > >> >> >> > No, the light goes the same speed >> >> >> >> >> >> No, relative to the Galilean rest frame of the hub, the light is >> >> >going> faster in the direction of rotation than in the opposite >> >> >direction. >> > >> >How come? >> >> The light moves at c wrt the source, which is moving at v wrt the >> nonrotating frame. >> So the rays move at c+v and c-v wrt the nonR frame. > > If the light moves at c wrt the source when it leaves the source, then > an inertial observer just might see it move at c+v if it is traveling > the direction of the sorce, and c-v if it is traveling backward, and if > it travels at any other angle theta the speed might be c + v*cos(theta). Nope, (c+v).cos(theta).
From: Jonah Thomas on 26 Oct 2009 10:58 tominlaguna(a)yahoo.com wrote: > Jonah Thomas <jethomas5(a)gmail.com> wrote: > >I want to take this opportunity to review my understanding of > >emission theory. > > > >The fundamental tenet of emission theory is that light in vacuum > >travels at speed c relative to its source. The reason this is > >important is that it could possibly provide a simpler and more > >intuitive approach to derive relativity. > > > >Light sources often appear to produce concentric waves. > >http://i847.photobucket.com/albums/ab31/jehomas/concentric.gif > > > >But when they move they are thought to compress those waves. > >http://i847.photobucket.com/albums/ab31/jehomas/eccentric.gif > > > >If you could tell whether the waves were compressed then you could > >get a handle on absolute motion. But instead special relativity (SR) > >says that time and space are distorted so that everybody sees what > >they ought to see. > > Jonah, I am going to have to modify comments I made last week about > the shape of the waves from a moving Ballistic source. While talking > with a friend of mine who runs the Walther Ritz web site, > ( http://www.datasync.com/~rsf1/ ), > he reminded me that the concentric wave model is only applicable for > the void of space. For the moving sources that we experience in our > atmosphere on Earth, there is an extinction process by which photons > are captured and re-emitted by molecules of air. I am not certain of > the extinction distance at standard conditions in our atmosphere but > it is likely to be on the order of a few millimetres. So a photon > emitted from a source moving at v with respect to the ground would be > c+v momentarily until it is captured; it would then be re-emitted > almost instantly at c relative to the molecule. So you have the air > behaving like an ether to moderate the speed of light to a value of c, > similar to what would occur if there was an ether. Therefore, the > wave shape for earth-bound moving sources would be eccentric, just as > they are for the ether and SRT theories. > Thus formulations and calculations for the Doppler radar devices we > use in our atmosphere such as for weather monitoring, police radar > guns, target acquisition, guidance, etc. would remain applicable even > though they were constructed using the ether model. I can imagine that. So you don't get any indication how fast the aether moves, but if light is traveling in air it slows down or speeds up to fit the velocity of the individual air molecules. That should quickly result in incoherence, unless some subtle effect takes place. Perhaps for some subtle reason the light which has been absorbed and re-emitted by a molecule that is traveling backwrd, will then be more like to be absorbed and re-emitted by a molecule that travels forward. I would expect fiber optic cables to maintain coherence better than air, because they are solids with constrained motion. But maybe they wind up with correlated motions that drive up the incoherence. So OK, this looks like another cop-out for emission theory. You get a special effect but in air the effect goes away. > >But if the light moved at c+v and c-v etc, then everybody would see > >it moving the same way without requiring time dilation and length > >contraction. You might still get some time dilation etc, but some of > >the weirdness might vanish. This is why it is an issue on > >sci.physics.relativity. If it was only a question of precisely how > >light works, then it would be more a question for > >sci.physics.electromag. But since it could affect relativity, some of > >the people who are biased against SR want emission theory to be true, > >while the people who are biased in favor of SR categorically deny any > >possibility that any form of emission theory could possibly be true. > > > >The problem I run into is that it appears nobody understands emission > >theory well enough to give a convincing argument what it should do. > >People often use ideas that work well when lightspeed is a constant, > >which do not apply when lightspeed varies. > > > >For example, Androcles says that (mostly?) you cannot measure > >wavelength. You can only measure frequency. Well, of course you can > >measure wavelength with an interferometer. Intererence patterns > >depend only on wavelength, not on frequency or speed. That is, they > >depend only on wavelength when the speed is constant. When you have > >light that comes into the interferometer at different speeds, then > >frequency and speed do matter and you cannot predict interference > >patterns knowing only wavelength and the phase shift at the entrance. > > > >For emission theory to have a good effect on relativity, it's > >necessary that the wavelength be the same independent of the > >lightspeed, so that the light will look like > >http://i847.photobucket.com/albums/ab31/jehomas/concentric.gif > >instead of > >http://i847.photobucket.com/albums/ab31/jehomas/eccentric.gif > > > >If the wavelength is constant, then frequency must vary with speed. > >So OK, your lightbeam has been split into two parts that travel at > >different speeds. (Exactly why emission-theory light should travel at > >different speeds in a Sagnac or Wang apparatus is one of the things > >we don't have clear. Some people say it might not, for one reason or > >another.) The two arrive at the detector at the same time, with > >different speeds and different frequencies but the same wavelength. > >You can predict the location of the first interference minimum for > >the c-v wave. You can predict the location for the c+v wave. It will > >be the same place because with a constant lightspeed that location > >depends only on wavelength, regardless what the constant lightspeed > >is. The two waves will be slightly out of phase even though they were > >in phase when they entered the interferometer, because they travel at > >different speeds and they reach the screen at different times. > >(Assuming they keep their speed difference after they bounce off a > >mirror and then travel in the same direction.) Where will the waves > >interfere with each other? They have the same wavelength so we can > >calculate where their first interference minimum will be. But wait, > >they have different speeds so we will have to adjust that for the > >speed difference. And now we have found our first interference > >minimum, and -- they have different frequencies too! If they do > >destructive interference for awhile they will then do constructive > >interference. This is not an interference minimum after all. > > > >It looks to me like to get interference, the waves must have the same > >frequency, not the same wavelength. At least they need the same > >frequency when they reach the screen. But -- what speed does emission > >theory predict for refracted light? It goes through a slit and > >changes direction, does it change anything else? Wavelength? > >Frequency? Speed? > > > >I can construct a lot of different emission theories and at most one > >of them can be correct. It looks like some of them won't get Sagnac > >interference or Wang interference at all, ever. People who think when > >you've disproved one emission theory you've disproved them all, don't > >follow the details. But why should they? They already know that all > >emission theories are wrong because they know SR is right and SR says > >lightspeed is constant in all directions with respect to the source > >and also with respect to every possible target. If that's true then > >obviously it can't be true that lightspeed is constant with respect > >to the source. > > > >To construct an emission theory you must specify what light does on > >reflection, what it does on refraction, and how interference works > >for light that travels at different speeds. (Assuming your theory > >says you can get light that is coherent enough to interfere, and make > >it travel at different speeds into the interferometer.) > > > >As near as I can tell, Androcles just throws away the whole dilemma. > >He says that light is particles and only particles, so we don't have > >to worry about all this wavelength stuff. It makes a kind of sense. > >How do you get interference without lightwaves? Well you get > >interference with electrons and buckyballs, we can let the guys who > >think out buckyball interference explain it and then we'll use their > >explanation for light too. Particles and only particles, interference > >works as shown by experiment and we can make up stories later to > >"explain" how that works in terms of something else. (I don't claim > >to understand much of Androcles's idea yet. I won't call it a theory, > >he says he doesn't have any theory. I don't even understand > >interference as well as I did (or thought I did) before I started > >looking at it in detail. It seems like the more I learn the less I > >know.) > > > >But you were talking about emission theory that had the light going > >the same speed in both directions. Superficially people would say > >that if the light from a moving source goes the same speed in all > >directions then it isn't an emission theory you are using. But the > >original Sagnac experiment had light from a stationary source, so > >that wouldn't have two speeds unless it got two speeds from bouncing > >off a moving mirror. A later Sagnac experiment had the light source > >revolving on the turntable, and the light went through a beamsplitter > >to travel in two opposite directions. It would not travel at c+v and > >c-v unless it changed velocity coming out of the beamsplitter. > >FOG-type Sagnac and Wang experiments may use a sort of laser built > >into the system that sends the same light in both directions. A naive > >view would say that the previous experiments should have all the > >light start out at the same speed and maybe keep the same speed, but > >this one should have the light start at c+v and c-v. It should then > >get a fundamentally different result from the others.... But it does > >not. So it is necessary to use an emission theory that is not that > >naive. > > > >Meanwhile, it looks to me like Wang has a result that various SR > >enthusiasts said was impossible because it would violate SR. At this > >point I believe he has the result. I also believe Tom Roberts's claim > >that it does not violate SR. What I think has happened is that these > >various SR enthusiasts misunderstood SR and did not actually know > >what would violate SR and what would not. I look forward to seeing > >what else they have misunderstood about SR. > > > >> >>>>> 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 > >> >> > >> >> Agree. > >> > > >> >So do I agree, so what's the problem? > >> >The start and end points are by the number 12, they both rotate > >> >together, they remain together when the device rotates. > >> >Isn't that what you both want? > >> > > >> > > >> >>>> 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.> > >> >> Disagree. That only applies to the re-emission theory. > >> > > >> >There is no phase shift in that diagram. > >> >If you want phase shift you need this one, where the light jumps > >> >frames. > >> > http://www.androcles01.pwp.blueyonder.co.uk/Sagnac/SagnacRing.JPG > >> > http://commons.wikimedia.org/wiki/File:Sagnac-Interferometer.png > >> > > >> >See, it has a long straight Schmidt camera that pokes out the > >side,> >only it's not a Schmidt because its a refracting telescope > >and not a> >Newtonian. > >> > > >> > http://www.androcles01.pwp.blueyonder.co.uk/Sagnac/MechModel.gif > >> > > >> >The dork Einstein did get this bit right: > >> > "the same laws of electrodynamics and optics will be valid for > >all> > frames > >> >of reference for which the equations of mechanics hold good" > >> >That's about all, though. > >> >
From: Jonah Thomas on 26 Oct 2009 11:06 "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: > "Jonah Thomas" <jethomas5(a)gmail.com> wrote > > HW@..(Henry Wilson DSc). wrote: > >> Jonah Thomas <jethomas5(a)gmail.com> wrote: > >> >"Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: > >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote > >> >> > "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: > >> >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote > >> >> >> > Sam <shayiam(a)yahoo.com> wrote: > >> >> >> >> Jonah Thomas <jethom...(a)gmail.com> wrote: > >> >> >> > > >> >> >> >> > If a ballistic theory predicts that the speed of light > >> >> >> >> > depends on the speed of its source, then in every early > >> >> >> >> > Sagnac experiment the light went the same speed in two > >> >> >> >> > different directions, according to an inertial observer. > >> >> >> >> > >> >> >> >> Right, relative to the instantaneous rest frame of the > >> >emission> >> >point.> So, relative to the Galilean rest frame of > >the> >hub, the> >light> >is going> faster in the direction of > >rotation than> >in the> >opposite> >direction. > >> >> >> > > >> >> >> > No, the light goes the same speed > >> >> >> > >> >> >> No, relative to the Galilean rest frame of the hub, the light > >is> >> >going> faster in the direction of rotation than in the > >opposite> >> >direction. > >> > > >> >How come? > >> > >> The light moves at c wrt the source, which is moving at v wrt the > >> nonrotating frame. > >> So the rays move at c+v and c-v wrt the nonR frame. > > > > If the light moves at c wrt the source when it leaves the source, > > then an inertial observer just might see it move at c+v if it is > > traveling the direction of the sorce, and c-v if it is traveling > > backward, and if it travels at any other angle theta the speed might > > be c + v*cos(theta). > > Nope, (c+v).cos(theta). What happens when the light is emitted perpendicular to the direction of the source's motion?
From: Androcles on 26 Oct 2009 12:24 "Jonah Thomas" <jethomas5(a)gmail.com> wrote in message news:20091026110630.33002af4.jethomas5(a)gmail.com... > "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> > HW@..(Henry Wilson DSc). wrote: >> >> Jonah Thomas <jethomas5(a)gmail.com> wrote: >> >> >"Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> >> >> > "Androcles" <Headmaster(a)Hogwarts.physics_p> wrote: >> >> >> >> "Jonah Thomas" <jethomas5(a)gmail.com> wrote >> >> >> >> > Sam <shayiam(a)yahoo.com> wrote: >> >> >> >> >> Jonah Thomas <jethom...(a)gmail.com> wrote: >> >> >> >> > >> >> >> >> >> > If a ballistic theory predicts that the speed of light >> >> >> >> >> > depends on the speed of its source, then in every early >> >> >> >> >> > Sagnac experiment the light went the same speed in two >> >> >> >> >> > different directions, according to an inertial observer. >> >> >> >> >> >> >> >> >> >> Right, relative to the instantaneous rest frame of the >> >> >emission> >> >point.> So, relative to the Galilean rest frame of >> >the> >hub, the> >light> >is going> faster in the direction of >> >rotation than> >in the> >opposite> >direction. >> >> >> >> > >> >> >> >> > No, the light goes the same speed >> >> >> >> >> >> >> >> No, relative to the Galilean rest frame of the hub, the light >> >is> >> >going> faster in the direction of rotation than in the >> >opposite> >> >direction. >> >> > >> >> >How come? >> >> >> >> The light moves at c wrt the source, which is moving at v wrt the >> >> nonrotating frame. >> >> So the rays move at c+v and c-v wrt the nonR frame. >> > >> > If the light moves at c wrt the source when it leaves the source, >> > then an inertial observer just might see it move at c+v if it is >> > traveling the direction of the sorce, and c-v if it is traveling >> > backward, and if it travels at any other angle theta the speed might >> > be c + v*cos(theta). >> >> Nope, (c+v).cos(theta). > > What happens when the light is emitted perpendicular to the direction of > the source's motion? No light gets transmitted in the direction of the source's motion, of course. theta=90, cos(90) = 0, 0 means none. That's what happens even if v = 0. Car headlights don't usually shine down side roads.
From: Androcles on 26 Oct 2009 14:46
"Jonah Thomas" <jethomas5(a)gmail.com> wrote in message news:20091026105837.64be2e08.jethomas5(a)gmail.com... > tominlaguna(a)yahoo.com wrote: >> Jonah Thomas <jethomas5(a)gmail.com> wrote: > >> >I want to take this opportunity to review my understanding of >> >emission theory. >> > >> >The fundamental tenet of emission theory is that light in vacuum >> >travels at speed c relative to its source. The reason this is >> >important is that it could possibly provide a simpler and more >> >intuitive approach to derive relativity. >> > >> >Light sources often appear to produce concentric waves. >> >http://i847.photobucket.com/albums/ab31/jehomas/concentric.gif >> > >> >But when they move they are thought to compress those waves. >> >http://i847.photobucket.com/albums/ab31/jehomas/eccentric.gif >> > >> >If you could tell whether the waves were compressed then you could >> >get a handle on absolute motion. But instead special relativity (SR) >> >says that time and space are distorted so that everybody sees what >> >they ought to see. >> >> Jonah, I am going to have to modify comments I made last week about >> the shape of the waves from a moving Ballistic source. While talking >> with a friend of mine who runs the Walther Ritz web site, >> ( http://www.datasync.com/~rsf1/ ), >> he reminded me that the concentric wave model is only applicable for >> the void of space. For the moving sources that we experience in our >> atmosphere on Earth, there is an extinction process by which photons >> are captured and re-emitted by molecules of air. I am not certain of >> the extinction distance at standard conditions in our atmosphere but >> it is likely to be on the order of a few millimetres. So a photon >> emitted from a source moving at v with respect to the ground would be >> c+v momentarily until it is captured; it would then be re-emitted >> almost instantly at c relative to the molecule. So you have the air >> behaving like an ether to moderate the speed of light to a value of c, >> similar to what would occur if there was an ether. Therefore, the >> wave shape for earth-bound moving sources would be eccentric, just as >> they are for the ether and SRT theories. >> Thus formulations and calculations for the Doppler radar devices we >> use in our atmosphere such as for weather monitoring, police radar >> guns, target acquisition, guidance, etc. would remain applicable even >> though they were constructed using the ether model. > > I can imagine that. So you don't get any indication how fast the aether > moves, but if light is traveling in air it slows down or speeds up to > fit the velocity of the individual air molecules. That should quickly > result in incoherence, unless some subtle effect takes place. Perhaps > for some subtle reason the light which has been absorbed and re-emitted > by a molecule that is traveling backwrd, will then be more like to be > absorbed and re-emitted by a molecule that travels forward. > > I would expect fiber optic cables to maintain coherence better than air, > because they are solids with constrained motion. But maybe they wind up > with correlated motions that drive up the incoherence. > > So OK, this looks like another cop-out for emission theory. You get a > special effect but in air the effect goes away. > You guys still don't understand relative motion. http://www.androcles01.pwp.blueyonder.co.uk/Wave/bounce.gif |