Speed of Light: A universal Constant?
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From: Henri Wilson on 27 Apr 2005 17:25 On Wed, 27 Apr 2005 20:26:52 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> wrote: >H@..(Henri Wilson) wrote in news:p5sv619burqs4c63c49pd7896v8tjklqnv@ >4ax.com: > >> >>> >>>There is NO NEED TO MEASURE OWLS accurately!!!!!! >> >> OK, there is only need to '''compare''' OWLS from two differently moving >> sources. > >TIME OF FLIGHT light speed. (TOFLS) > >TOFLS from the same source as the speed of the source is changed from -600 >mph to +600 mph in steps of say.... 20 mph. > >90,000 rpm ccw to 90,000 rpm cw > >each revolution gives us a new data point, a new batch of photons going >down the line from detector 1 to detector 2. We just need to see if the >time for that flight changes as we change the speed. > >cables from detector 1 and detector 2 are identical in length and do not >change during the experiment. The scope measures time from pulse 1 to pulse >2. > >You say 'do the math'. I have. There are scopes that will tell us if the >photons make the trip from detector 1 to detector 2 faster as the source is >moving toward the detectors. Let's imagine we can spin a double sided mirror at 200 rps at a 48cms radius. The peripheral speed is about 60000 cms/sec, or 0.000002c. If the experiment is carried out over 300 metres, light travel time is around 1 microsec. O------------300m--------------L---S A light source L is placed near the rotating mirrors, S. The reflected light moves at c+2v. The difference you need to resolve between c+2v and c-2v is 8E-12 secs. Not exactly an easy task!!!! The mirror positions only have to distort by 100 microns to throw the whole thing out. > > > > >> >> That is very difficult. It has never been done. > > >> >> My proposed experiment can achieve it. >> >> Please contact NASA and ask them to do it so we can finally stop all this >> arguing.,,. >> >I will be glad to lobby for your experiment. You lobby for mine. HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: Henri Wilson on 27 Apr 2005 17:53 On Wed, 27 Apr 2005 22:04:23 +0100, "George Dishman" <george(a)briar.demon.co.uk> wrote: > >"Henri Wilson" <H@..> wrote in message >news:2smt61dfvhv39do69dtek7f2lsa68u9up0(a)4ax.com... >> On Tue, 26 Apr 2005 23:31:31 +0100, "George Dishman" >> <george(a)briar.demon.co.uk> wrote: >>>"Henri Wilson" <H@..> wrote in message >>>news:4htq6158ipi6ngp1ueqrvacan9aktauok3(a)4ax.com... >>> >>>> Have a look at http://www.users.bigpond.com/hewn/sagnac.exe >>>> >>>> This simulates the standard explanation. >>> >>>It looks close and certainly it is qualitatively >>>correct. However, there seem to be some small >>>problems. I haven't had much time to play with >>>it but perhaps these are fairly easy to fix: >> >> It is now upgraded and complete. Very enlightening. > >It does the job nicely :-) > >> I have assumed that the light speed does not change at each reflection. > >That is correct in both theories, and it appears >you have kept the law of reflection as well >which is also correct if the speed doesn't >change. I have said that before but I did a quick >sketch to explain why: > > http://www.briar.demon.co.uk/Henri/Huygens.gif > >I'm sure you can sort out the relation between >the angles but hopefully this explains how the >slope of the wavefront would get changed. Except that the position of A' moves during the time light goes from A to A'. Is that not important? I assume the distance B-A' is related to some property of the mirror surface. > >Of course this would give some very odd results. >Hold a mirror at 45 degrees to look along a road >and a car driving towards you would seem to be >in the ditch since its angle of reflection would >not be the same as the stationary landscape! If it was traveling at about 0.005c maybe. > >>>At first glance it doesn't look as though the >>>returning beams hit the detector. >> >> That's because they don't....not at the high rotation rates used here, >> anyway. >> The beams both move sideways. > >The problem is that you have to change the launch >angle in the lab frame. Note the slight change of >angle in the Java version: > > http://www.briar.demon.co.uk/Henri/SagnacAngles.html > >There is a degree of dispersion and a different >part of the beam will reach the detector. In >reality, the speeds are of course much smaller >than this exaggerated view and the beam width >needed is tiny, far smaller than real sources. >Correcting that won't change your conclusion >to any great degree: > >> At high speeds, the path length difference under BaT appears to be >> slightly >> less than half that according to SR. I assume that this also applies at >> low >> speeds. > >You have mentioned V/sqrt(2) in the text boxes >which is the projection of the tangential speed >onto the chord of the light path. I think the >factor would therefore be 1-1/sqrt(2) or about >29% of the SR prediction. > >> So the sagnac effect still works under source dependency. > >Right but for the four mirror setup the delay >is wrong by about a factor of about three. > >Now consider a similar setup but with eight >mirrors, what would the 1/sqrt(2) factor be? >Can you see it will be closer to 1 because >the chord is nearer to being parallel to >the mirror hence the delay will be less than >in the four-mirror setup? > >Then consider the fibre gyro. As you said >when we started, you can think of it as >the same experiment but with a very large >number of reflections, each at grazing >incidence. The projection factor then tends >to a limit of exactly 1 and the delay tends >to zero. That is my qualitative argument, >fibre gyros shouldn't work at all with a >ballistic light model. > >You have gone beyond that and found the >quantitative result that even a four mirror >setup gives the wrong result for a ballistic >model. I'm impressed Henri. How do you know it is the wrong result? > >> Have a look at the latest version. Much improved.. >> Same address as above. >> >> When each light ray reaches a mirror, its direction changes. I do this by >> detecting the change in pixel color. You will notice how the mirrors also >> change color after a reflection. That was necessary to overcome the fact >> that >> the lines oin the screen have steps and every now and then the reflected >> beam >> was superimposed on the 'step' , which sent it off in the wrong direction. > >Much better and the difference is clear now. >Fixing the launch angle would be good but >it isn't essential. The key is that the >experiment has been run by many people and >the amount of the delay has been measured >very accurately so an error even of a factor >of two would be obvious. Well, I'm not at all convinced. There are a few other factors to consider yet. I'm not sure about the correct departure angle from the source. Also, I have to look at the reflection at each mirror more closely. I have already made up a new version of the program with a much higher resolution than 1 pixel. I took out the timer and replaced it with a 'for ...loop', using machine delay instead. The problem was that the mirrors were in place one pixel before the ray reached it but had moved before the ray left...and I thought the reflection angles might be slightly out. However the higher resolution made no noticeable difference so the current demo appears OK. I also want to magnify the end section so that I can see exactly what happens at very low rotation speeds. > >> I have doubled the spot size as the beams approach eachother. When this >> happens, they have both traveled the same distance. That distance is the >> same >> for all parameter settings. > >That works nicely, good idea. > >> If you want to transpose this into Java, it should not be all that >> difficult. >> The code is straightforward maths stuff, with lots of 'if...thens' > >I won't have a chance for some time, I have to >set up a VPN and remotely debug a database :-( > >Once I get that cleared, I might have a go but >I'll adjust the launch angles too. I'll look into it. I might even have another go at Java with this one. It is relatively short and simple.. > >best regards >George > HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: bz on 27 Apr 2005 18:19 H@..(Henri Wilson) wrote in news:4ovv61p49735hg861242gcer776bqlqng8(a)4ax.com: > > Let's imagine we can spin a double sided mirror at 200 rps at a 48cms > radius. The peripheral speed is about 60000 cms/sec, or 0.000002c. that is only 12,000 rpm. I know we can go 90,000 rpm or 1500 rps. > > If the experiment is carried out over 300 metres, light travel time is > around 1 microsec. right. > > O------------300m--------------L---S I wouldn't say that 300 m would be > > A light source L is placed near the rotating mirrors, S. The reflected > light moves at c+2v. 1) there will be no rotating mirrors. The light source, which will launch a beam of light tangential to a single point on the edge of the wheel will be an optical fiber fed from a laser at center of the rotating wheel. I want the source of the photons to really be moving. No c+2v, it will be c+v and c-v as we rotate the source in different directions. At some moment during the rotation, the beam will be aimed directly down the line that passes by detectors 1 and 2. > The difference you need to resolve between c+2v and c-2v is 8E-12 secs. There are scopes that will do much better than that. > Not exactly an easy task!!!! > The mirror positions only have to distort by 100 microns to throw the > whole thing out. There will be no rotating mirrors. I don't need to worry about throwing things out. My beam just has to hit the two detectors, one after another and they must be stable enough so that there is no correlation between variations in the speed of the source and vibrations of the detectors. The beam splitter for the first detector may need to be a screen rather than a half silvered mirror, so that no one can say that adsorption/reradiation by a stationary object has changed the speed of the photons back to c. -- bz please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+sp(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
From: George Dishman on 27 Apr 2005 19:02 "Henri Wilson" <H@..> wrote in message news:28107116lmsk694q33fpre15ufn6uk47rs(a)4ax.com... > On Wed, 27 Apr 2005 22:04:23 +0100, "George Dishman" > <george(a)briar.demon.co.uk> > wrote: >>"Henri Wilson" <H@..> wrote in message >>news:2smt61dfvhv39do69dtek7f2lsa68u9up0(a)4ax.com... >> >>... it appears >>you have kept the law of reflection as well >>which is also correct if the speed doesn't >>change. I have said that before but I did a quick >>sketch to explain why: >> >> http://www.briar.demon.co.uk/Henri/Huygens.gif >> >>I'm sure you can sort out the relation between >>the angles but hopefully this explains how the >>slope of the wavefront would get changed. > > Except that the position of A' moves during the time light goes from A to > A'. > Is that not important? The diagram is easiest to understand in the mirror frame so the motion would be a rotation of the mirror about a point midway between B and A'. Take the mid-point as the reflection of a notional ray which exactly joins the source to the detector. The effect is to make it either slightly concave or slightly convex depending on which beam we are considering but the motion is so small in the time involved the effect is negligible compared to the inherent spread of even a laser. > I assume the distance B-A' is related to some property > of the mirror surface. No, you can simply think of it as the width of the light beam but really it is just two arbitrarily close hypothetical rays within the beam. It should be clear that the angles are independent of the width, only the ratio of the speeds affects the result. >>Of course this would give some very odd results. >>Hold a mirror at 45 degrees to look along a road >>and a car driving towards you would seem to be >>in the ditch since its angle of reflection would >>not be the same as the stationary landscape! > > If it was traveling at about 0.005c maybe. For a fibre gyro detecting say 1 degree per minute of rotation with a loop of fibre a few cm in diameter, what is the tangential speed? These things are amazingly sensitive. I'm only guessing of course but if you try to do some modification of the law of reflection, I think you might find this is a real problem even for cars travelling at sub-orbital speeds ;-) ..... >>> At high speeds, the path length difference under BaT appears to be >>> slightly >>> less than half that according to SR. I assume that this also applies at >>> low >>> speeds. .... >>You have gone beyond that and found the >>quantitative result that even a four mirror >>setup gives the wrong result for a ballistic >>model. I'm impressed Henri. > > How do you know it is the wrong result? Because you said "At high speeds, the path length difference under BaT appears to be slightly less than half that according to SR.". The SR prediction was first tested in 1913 and has been checked many times since then so there is no doubt it is accurate. For example it is the basis of the design for the fibre gyro industry and they would soon scream if it didn't work. >>... The key is that the >>experiment has been run by many people and >>the amount of the delay has been measured >>very accurately so an error even of a factor >>of two would be obvious. > > Well, I'm not at all convinced. There are a few other factors to consider > yet. Yes, that's where I see your real challenge. You would need to exhaust all the possible effects before you could be convinced, but I think this experiment has a far better chance of giving you an answer than any other. The simplest ballistic model is ruled out but there are a number of ways you might try to construct a theory that fits the data. > I'm not sure about the correct departure angle from the source. > > Also, I have to look at the reflection at each mirror more closely. The launch angle is easy, it is whatever is necessary for the light to reach the detector. You only get interference if two beams fall on the same spot simultaneously (it is of course the emission time that differes slightly while we are finding the arrival time difference). The harder part is that the required launch angle depends on the angles at all the reflections. The diagram we discussed at the top then relates that back to the ratio of the speeds so hopefully that reduces the variables but the speed depends on the details of your ballistic model so that's about as far as I can go to help. > I have already made up a new version of the program with a much higher > resolution than 1 pixel. I took out the timer and replaced it with a 'for > ..loop', using machine delay instead. > The problem was that the mirrors were in place one pixel before the ray > reached > it but had moved before the ray left...and I thought the reflection angles > might be slightly out. However the higher resolution made no noticeable > difference so the current demo appears OK. OK, that's a good check of robustness. Eventually, you should do this analytically but it is essential to understand the various processes involved first and I think your simulation is invaluable for that. > I also want to magnify the end section so that I can see exactly what > happens > at very low rotation speeds. It should be linear since the sense of the delay swaps at zero speed. >>Once I get that cleared, I might have a go but >>I'll adjust the launch angles too. > > I'll look into it. > > I might even have another go at Java with this one. It is relatively short > and > simple.. I found EJS took all the pain out of doing the GUI which was the bit I found hard when hand-coding Java. George
From: G on 28 Apr 2005 00:58
Rats! |