Speed of Light: A universal Constant?
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From: Henri Wilson on 7 Apr 2005 18:24 On 7 Apr 2005 13:59:01 -0700, "PD" <pdraper(a)yahoo.com> wrote: > >kenseto wrote: >> "PD" <pdraper(a)yahoo.com> wrote in message >> news:1112887032.405849.87520(a)l41g2000cwc.googlegroups.com... >> > >> > >> > Medium, schmedium. There is nothing in the explanation of >diffraction >> > and interference that is based on the presence of the medium, nor >on >> > the velocity of the wave transmission. >> >> You wer the one who uses water wave to explain the interference of >light. So >> are you backing off that assertion? > >Not at all. But the presence of the medium is not essential to the >interference in that case, either. The fact that there IS a medium with >a water wave is irrelevant. Your argument is akin to saying that >gravity acting on an apple falling from a tree cannot be linked to >gravity acting on the moon, because the apple is surrounded by air and >the moon is not. The air is irrelevant to the force of gravity acting >on the apple. Another prime example of SRian logic at work!!!! :) > >Here's a visual "derivation" of interference: >http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/youngexpt4.htm >Click Play, and then after a bit click Pause. Then click Show Path >Difference. The only thing that determines whether there is >constructive or destructive interference is the ratio of the path >difference to the wavelength. Note that there is NO mention of medium >in this derivation, nor is there any need of any velocity appearing in >that ratio -- only path difference and wavelength. What gives rise to the property we call 'wavelength' in a single photon, PD? You cannot seem to discriminate between generated radio waves and individual photons. > 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: George Dishman on 7 Apr 2005 19:20 "Henri Wilson" <H@..> wrote in message news:gvbb519mnbu1f2gkf04fe92nhkuhson1ui(a)4ax.com... > On 7 Apr 2005 05:43:16 -0700, "Dishman" <george(a)briar.demon.co.uk> wrote: > >>Henri Wilson wrote: >>> On Wed, 6 Apr 2005 23:36:36 +0100, "George Dishman" >><george(a)briar.demon.co.uk> >>> wrote: >>> >>> > >>> >"Henri Wilson" <H@..> wrote in message >>> >news:65g851dn7asmetb67jjv5cnue56cbsjlai(a)4ax.com... >>> >>> >>> >>>It should demonstrate that a change of angle >>> >>>as illustrated in the case of the elliptical >>> >>>motion has no effect on the brightness as long >>> >>>as the path length of both beams remains the >>> >>>same while path length does have an effect even >>> >>>if the angle remains constant. >>> >> >>> >> In the elliptical case, the intensity of the beam will remain >>constant >>> >> only in >>> >> a plane perpendicular to the beam direction. >>> > >>> >Note I am describing the intensity only at a >>> >single point. In other situations that may >>> >extend to other points by symmetry but not >>> >in this case. >>> >>> Yes, the intensity on a 'line' will be constant... >> >>I am only discussing intensity at a point, not >>along a line. How the intensity varies spatially >>also depends on other factors (like the shape of >>th source). That is just for clarification, it >>doesn't impact your next point: > > OK >> >>> ...but the fact that one beam is >>> coming in at a different angle as you move the mirror around the >>ellipse will >>> surely affect the way the two beams interfere. >> >>No. The general formula for a wave propagating >>along the x axis is >> >> f(x, t) = A * sin(w*(t - x/c) + p) >> >> A is the amplitude >> w is the angular frequency >> c is the speed >> p is the phase >> t is time >> x is the distance from the source >> >>At any given point x is a constant so we >>can define p' = w*x/c+p as a local phase >>which is again fixed and simplify as: >> >> f(t) = A * sin(w*t + p') >> >>When you take two such waveforms and combine >>them, the sum of two sine waves is also a >>sine wave but with an amplitude that depends >>only on the product of the values of A and >>difference between the values of p', the >>phase difference. Any detector averages the >>power over many cycles so the relative >>intensity depends solely on the phase >>difference as the amplitude is a common >>factor. > But if two beams cross at right angles, there will be no fringes because > of the > cosine law. If two beams cross in free space, the field at any point is the instantaneous sum. Superposition applies. If there is a screen at any angle that allows both beams to fall on the same side then you do get fringes. >>> It isn't just a matter of >>> intensity. >> >>It is just a matter of relative phase. > > yes OK, but the contrast will diminish as angle increases. I don't think so, the contrast will be reduced if the beams aren't of equal intensity and as the path length difference becomes comparable to the coherence length of the source (hence the use of lasers) but angle doesn't matter. I will admit I have a small doubt that if the angle of the beams to the screen differs , the same beam power spread over a larger area would reduce the intensity but this is just what I said above, contrast is reduced if the amplitudes are not equal because you don't get complete cancellation where the phase difference is exactly 180 degrees. >>Both experimental and theoretically, at >>any given point the angle of incidence has >>absolutely no effect, only the relative >>phase matters. As I have acknowledged >>several times, when you consider the >>spatial behaviour, then you need to know >>how x varies over the screen since it >>affects p' hence the angle would matter. > > Yes OK. I was really considering the connection between angular > difference and path length. Yes, I agree with that, it's why I have tried to focus dealing with one point rather than an extended area. >>http://www.java.com/en/download/ > > OK. It now works. Thanks for that. Maybe some of my own Java > programs will run now. Excellent :-) Even if we never agree the Sagnac experiment details, something positive has been achieved. > I will study your model in more detail. Thanks. It only shows the beams and you have to imagine that the mirrors are at the locations where reflections occur. The principle is simple, each leg is identical to the others because the table rotates equal amounts in equal times. You should find all the reflections obey the rules. >>> I'll run one up on Vbasic too. >> >>Cool, then we can compare ideas :-) > > I will use the nonrotating frame. That's the same as mine. Moving the slider is equivalent to changing the speed of the table though is isn't animated to show the table motion. > I will also try to incorporate the c+v factor at the source and each > mirror. Think carefully about that. c+v from the source hitting a mirror moving at v means a relative incident speed of c, hence a reflected speed of c relative to the mirror or c+v in the lab frame again. > It will be based on the 45 deg component for the four mirror system. Again, same as mine. > This program may take some time. Understood. My next one deals with the speed aspect whereas the first one only shows the paths so you can see the sense in which the beams rotate. George
From: Henri Wilson on 7 Apr 2005 21:09 On Thu, 07 Apr 2005 17:00:03 GMT, The Ghost In The Machine <ewill(a)sirius.athghost7038suus.net> wrote: >In sci.physics, H@..(Henri Wilson) ><H@> > wrote >>>> >>>> It is completely unproven. >>> >>>And c' = c+v has been disproven, experimentally. >> >> Don't be silly Ghost. You know that is not true. > >Ah, Ok. In that case I'm sure you'll have no trouble >substantiating it with such things as PSR B1916+16. What is that? >> This is just another way of expressing the postulate. >> It doesn't prove it. It is an extension of the old aether idea. > >In a way, it is. There's even a postulate that the >Earth is twisting it. (Gravity Probe B is checking >this hypothesis.) Of course it has different properties >than the aether the MMX disproved (the old aether didn't >postulate spacetime distortions). That's probably because 'spacetime' is not a physical entity and, unlike SR, aether theory was at least a physical theory. >> >> That is not the same as saying light leaves the star >> with an infinite number of speeds. > >Light leaves with one speed: c. >Light enters the user's eyeball with one speed: c. >Light can be intercepted but is always measured with one speed: c. > >The catch is that the user's eyeball might be moving, and >the interceptor moving as well. But one still measures lightspeed c. Ghost you are preaching something you have been taught and accepted without question. You are indoctrinated. There is absolutely no proof to back up your claim. Why do you stick to it? > >> >>> >>>I'm not sure this is proof of much, of course, beyond >>>the fact that the math is internally self-consistent. >>>However, it does show that it is possible to define a >>>Universe with a metric (namely, the Minkowski) which >>>gives OWLS=c everywhere under the Lorentz transformation. >> >> It is a maths technique to make the postulate true. >> It is not a proven physical reality. > >There is no way to prove physical reality anyway. All we >can do is take measurements. ...and one day very soon, somebody will find that OWLS from a moving source is not c. > >[rest snipped] 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 7 Apr 2005 22:13 On Fri, 8 Apr 2005 00:20:38 +0100, "George Dishman" <george(a)briar.demon.co.uk> wrote: > >"Henri Wilson" <H@..> wrote in message >news:gvbb519mnbu1f2gkf04fe92nhkuhson1ui(a)4ax.com... >> On 7 Apr 2005 05:43:16 -0700, "Dishman" <george(a)briar.demon.co.uk> wrote: >> >>> >>>No. The general formula for a wave propagating >>>along the x axis is >>> >>> f(x, t) = A * sin(w*(t - x/c) + p) >>> >>> A is the amplitude >>> w is the angular frequency >>> c is the speed >>> p is the phase >>> t is time >>> x is the distance from the source >>> >>>At any given point x is a constant so we >>>can define p' = w*x/c+p as a local phase >>>which is again fixed and simplify as: >>> >>> f(t) = A * sin(w*t + p') >>> >>>When you take two such waveforms and combine >>>them, the sum of two sine waves is also a >>>sine wave but with an amplitude that depends >>>only on the product of the values of A and >>>difference between the values of p', the >>>phase difference. Any detector averages the >>>power over many cycles so the relative >>>intensity depends solely on the phase >>>difference as the amplitude is a common >>>factor. >> But if two beams cross at right angles, there will be no fringes because >> of the >> cosine law. > >If two beams cross in free space, the field >at any point is the instantaneous sum. >Superposition applies. If there is a screen >at any angle that allows both beams to fall >on the same side then you do get fringes. yes I suppose you could always tilt a screen so both beams had a component on it, even if they were at right angles.....but since we don't really know what 'photon fields' look like, I will reserve judgement on that. > >>>> It isn't just a matter of >>>> intensity. >>> >>>It is just a matter of relative phase. >> >> yes OK, but the contrast will diminish as angle increases. > >I don't think so, the contrast will be reduced >if the beams aren't of equal intensity and as >the path length difference becomes comparable >to the coherence length of the source (hence >the use of lasers) but angle doesn't matter. >I will admit I have a small doubt that if >the angle of the beams to the screen differs , >the same beam power spread over a larger area >would reduce the intensity but this is just >what I said above, contrast is reduced if the >amplitudes are not equal because you don't get >complete cancellation where the phase difference >is exactly 180 degrees. That part is true. yes. > >>>Both experimental and theoretically, at >>>any given point the angle of incidence has >>>absolutely no effect, only the relative >>>phase matters. As I have acknowledged >>>several times, when you consider the >>>spatial behaviour, then you need to know >>>how x varies over the screen since it >>>affects p' hence the angle would matter. >> >> Yes OK. I was really considering the connection between angular >> difference and path length. > >Yes, I agree with that, it's why I have tried >to focus dealing with one point rather than an >extended area. > >>>http://www.java.com/en/download/ >> >> OK. It now works. Thanks for that. Maybe some of my own Java >> programs will run now. > >Excellent :-) Even if we never agree the Sagnac >experiment details, something positive has been >achieved. I'll have a look at my Java programs again. Maybe my code will run now. > >> I will study your model in more detail. > >Thanks. It only shows the beams and you have to >imagine that the mirrors are at the locations >where reflections occur. The principle is simple, >each leg is identical to the others because the >table rotates equal amounts in equal times. You >should find all the reflections obey the rules. > >>>> I'll run one up on Vbasic too. >>> >>>Cool, then we can compare ideas :-) >> >> I will use the nonrotating frame. > >That's the same as mine. Moving the slider is >equivalent to changing the speed of the table >though is isn't animated to show the table >motion. > >> I will also try to incorporate the c+v factor at the source and each >> mirror. > >Think carefully about that. c+v from the source >hitting a mirror moving at v means a relative >incident speed of c, hence a reflected speed of >c relative to the mirror or c+v in the lab frame >again. Not so George. You forget the mirrors rotate slightly as the light is traveling between them. So each mirror is moving at slightly off 90 deg wrt to the previous one...... that complicates the issue somewhat. > >> It will be based on the 45 deg component for the four mirror system. > >Again, same as mine. > >> This program may take some time. > >Understood. My next one deals with the speed >aspect whereas the first one only shows the >paths so you can see the sense in which the >beams rotate. good luck. > >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: Henri Wilson on 7 Apr 2005 22:15
On Thu, 07 Apr 2005 17:00:04 GMT, The Ghost In The Machine <ewill(a)sirius.athghost7038suus.net> wrote: >In sci.physics, Sam Wormley ><swormley1(a)mchsi.com> > wrote >on Thu, 07 Apr 2005 12:41:29 GMT ><ZT95e.11438$g65.373(a)attbi_s52>: >> Jim Greenfield wrote: >> >>> >>> Absolutely I agree that speed=frequency x wavelength; what I >>> absolutely disagree, is that the "speed" is always the same. >>> >> >> Empirical fact of life, Jim. >> > >Confirmable, as well. The SR and the BaT predict different results >for such things as spectroscopic binaries, even if one can't >measure the speed directly. You are very confused now Ghost. Getting desperate I would say. 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. |