Speed of Light: A universal Constant?
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From: George Dishman on 28 Mar 2005 05:52 "Henri Wilson" <H@..> wrote in message news:hlie41lsobbs9jnn3l8ai3g08pi2e0se0o(a)4ax.com... > On Sat, 26 Mar 2005 00:10:05 -0000, "George Dishman" > <george(a)briar.demon.co.uk> > wrote: > >> >>"Henri Wilson" <H@..> wrote in message > >> >>>>As we have discussed before, ballistic theory is >>>>disproved by the Sagnac Experiment. >>> >>> Bull. The reason for the fringe shift has nothing to do with light >>> speed. >>> It is due to the fact that the mirrors rotate slightly during the time >>> light >>> travels between them. The two opposite beams are deflected in opposite >>> directions. >> >>We went over that last time. You got the >>geometry wrong, the beams are deflected >>such that they maintain the angle between >>them at the interferometer. > > No they don't. > Just draw a simple diagram. Here's the one I drew a year ago: http://www.briar.demon.co.uk/Henri/lab.gif I have added a small indicator showing where the rotation maintains the 90 degree angle at the detector in the four-mirror case. Note also any change of angle would alter the gap between the fringes and not produce a lateral shift. > The angular deflection of the beam at each miror is double the angular > change > of the mirror during the travel time. Correct for each beam, but it is in the same direction for the two beams so cancels. > For three mirrors, the total angular difference is 16 x rotation during > total > light travel time. > > Like I said, whether c or c+v is used is of little consequence. On the contrary, since the detector is sensitive to the time difference and not the angle between the beams, speed is the critical factor. > Don't use the rotating frame. There is too much room for > misinterpretation. True, we need to be careful, but here is the same drawing as above in the rotating frame. http://www.briar.demon.co.uk/Henri/paths.gif It produces the same conclusion. <snip> >>... show your >>calculations if you think you can explain >>how the first order output arises. > > Let the light travel time around the four mirror system be 10 ns. > > An apparatus rotation of (2pi/3600) radians/hour (0.1 deg/hr) should > result in > a deflection difference between the two beams of 12 x 3 (m) x 10/3600/10^8 > metres/sec. > > That is 10^-9 m/sec. > > or 0.001 um. > > ~ 500 x wavelength? > > How wide is a fringe? You seem to be calculating the lateral shift of the beam but that is parallel to the wavefront so has no effect on the fringe pattern or the brightness at the centre. The relative brightness at any point is a measure of the phase difference between the beams so you need to find the difference in propagation time as a fraction of the period (1/frequency of course). Referring to this: http://www.briar.demon.co.uk/Henri/lab.gif It should be obvious that the red path for the co-rotating beam is longer than the green path for the counter-rotating beam. If the speed is c in the lab frame, that length difference produces exactly the output observed while if it is c+v for the red beam and c-v for the green beam, the speed difference exactly cancels the path length difference so the propagation time for the two beams is identical meaning no output for the Ritzian model. Let me turn that around - if you measure the difference in propagation time and you know the speed of the table, you can calculate the speed of the beams. That answer is c in the lab frame regardless of the speed of the table even though the source, the detector and the mirrors (or the fibre in the case of an iFOG) are all moving. The experiment measures the speed of light from a moving source and the observed result is c, not c+v. George
From: bz on 28 Mar 2005 05:59 H@..(Henri Wilson) wrote in news:4hgf4152vbnmi93d0aqd2adk72u1qevbab(a)4ax.com: > On Mon, 28 Mar 2005 02:54:28 +0000 (UTC), bz > <bz+sp(a)ch100-5.chem.lsu.edu> wrote: > >>H@..(Henri Wilson) wrote in >>news:i9ke41pi6c62gfr6mkb14efoeher4odrg4(a)4ax.com: >> >>> On Sat, 26 Mar 2005 01:36:41 +0000 (UTC), bz >>> <bz+sp(a)ch100-5.chem.lsu.edu> wrote: >>> > >>>>because photons always travel at the speed of light, which is >>>>constant. >>> >>> There is no such animal as 'speed of light' or 'speed of anything' for >>> that matter. Speed must be specified relative to something else. >> >>Light travels at c relative to any observer. > > Who said? The data. http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#one-wa y%20tests [quote] as of this writing there are no reproducible and generally-accepted experiments that are inconsistent with SR, within its domain of applicability. [unquote] The author has reviewed many experiments. > >> >>>>>>Why, when we measure the speed of those photons, do the photons seem >>>>>>to move at the same speed? >>>>> >>>>> Silly boy. Nobody has measured the OW speed of light under any >>>>> circumstance. >>>> >>>>Define 'one way speed of light'. >> >>You still haven't defined the 'one way speed of light'. > > listen bz, read up on this before you make an even bigger fool of > yourself. I am not the one that said: >>>>> Silly boy. Nobody has measured the OW speed of light under any >>>>> circumstance. How do YOU define 'one way speed of light'? It must be different from the way others do because MANY experiments have measured something called 'one way speed of light' but it must be different from your definition. I wanted yours. > >> >>>>I fire a laser pulse at two detectors, 1 at 1 meter and 1 at 10 meters >>>>from the laser. I have a timer located mid way between the two >>>>detectors. >>>> >>>>When the pulse hits the first detector, it starts the timer >>>>When the pulse hits the second detector, it stops the timer. >>>> >>>>Taking into account all the propagation delays, I calculate the time >>>>that it took the light pulse to travel between detector 1 and detector >>>>2. >>>> >>>>Why is this not the 'one way speed of light'??? >>> >>> Ask any of your SRian colleagues. >> >>I ask you because you made the claim that the doppler effect was due to >>changes in speed of light rather than changes in wavelength. > > It can be. 'Frequency' of an EM signal is the number of wavecrests > passing per second. Naturally, that is dependent on observer speed > relative to the source. > Frequency is not velocity. I can measure the frequency AND the velocity. When I do, I find the frequency has shifted, but not the velocity. > > ..but please recall that I have raised the question about how a > diffraction grating can measure doppler shifted light. Do you understand how a diffraction grating works on non doppler shifted light? It works the same on doppler shifted light. > >> >>> >>> Clue: How do you synchronize the separated clocks? >> >>In my experiment there is no need for separated clocks. > > You have two separated clocks but haven't realized it. show me. > >> >>>>>>How distant must the source be? Why must it be distant? I can't see >>>>>>any reason that photons from a distance source should be different >>>>>>from those from a nearby source. >>>>> >>>>> The effect will only work in a pure vacuum....far purer than >>>>> anything we can produce here. >>>> >>>>Oh, that makes it nice. I can claim a special effect that can only be >>>>measured when the moon is full and in the constellation 'southern >>>>cross'. You can't disprove my claim because the moon is never in the >>>>constellation when it is full. [it is, in fact, never in the southern >>>>cross.] >>> >>> unrelated drivel. >> >>The claim that the effect will only work in a pure vacuum is similar. It >>means the effect will never be observed. > > I say there is a critical density of matter, below which all kinds of > strange things happen. Does that critical density occur anywhere? If not, then strange things are never observed. > >> >>>>>>In my mind, 5 feet is distant compared to the wavelength of light. >>>>>>Will you allow me to call 5 feet 'distant'? >>>>> >>>>> ULF wavelengths are longer. >>>>> They are EM. >>>> >>>>ULF? Do you mean UHF? ULF would be ultra low frequency, and we would >>>>be talking about wavelengths in the thousands of km. >>> >>> Well, ain't that longer that 5 feet? >> >>Yes, but what did it have to do with my question as to what you >>considered to be 'distant'. > > 5 feet is NOT distant compared with say, the wavelength of 100 hz EM. Lets get back to light again, is 5 feet 'distant' with respect to 500 nm EM radiation? [visible light, in case you are wondering]. > >> >>>>What does that have to do with light? We were talking about light, >>>>weren't we? Why did you suddenly jump to talking about 196.7 MHz >>>>(lamda=5 ft). Lets get back to light. 5 feet is about 3 million >>>>wavelengths for 500 nm light. That seems 'distant' to me. >>> >>> Sorry, you aren't making much sense. It was YOU who raised the 5 feet >>> issue, not I. >> >>I was trying to extablish what you consider 'at a distance'. because you >>said the 'light changes speed rather than wavelength' can only be >>observed at a distance. I asked if 5 feet was far enough when talking >>about light. >> >>If you say NO, I will ask why not. If you say YES, then we can go into >>the lab and test your theory. >> >>So how far is 'distant'? > > Sorry, I don't have the slightest idea what you are talking about. If 5 feet is 'distant' where 500 nm light is concerned (and I think it should be because it is millions of wavelenghts) then we can test your statements in the lab with a 5 ft optical bench and some other equipment. -- 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: kenseto on 28 Mar 2005 08:15 "Tom Roberts" <tjroberts(a)lucent.com> wrote in message news:_KL1e.15294$DW.3498(a)newssvr17.news.prodigy.com... > Sam Wormley wrote: > > There has NEVER been a prediction of SR or GTR that was contradicted > > by an observation. NEVER! > > I would not say that so unconditionally -- there are numerous > observations that at least appear to contradict SR or GR. And there are > some phenomena that call into question the validity of GR. For instance: > dark matter > dark energy > the anomalous acceleration of the Pioneer and other spacecraft > As far as I am concerned, the scientific jury is still out on these (and > probably will be for some time...). > > But I can say that there have been no reliable and reproducible > experiments or observations that contradict SR within its domain of > applicability. That's because mainstream physicists refuse to do experiments that could potentially contradict SR. For example: 1. Test for OWLS with two same frame spatially separated and synchronized clocks. 2. Do the experiment decribed in the following link (page 3): http://www.journaloftheoretics.com/Links/Papers/Seto.pdf 3. The LT is: t'=gamma(t-vx/c^2) The inverse transform is: t=gamma(t'+vx'/c^2) Where is the SR reciprocity in these equations?? Ken Seto > > > Tom Roberts tjroberts(a)lucent.com
From: Jerry on 28 Mar 2005 08:37 kenseto wrote: > "Tom Roberts" <tjroberts(a)lucent.com> wrote in message > news:_KL1e.15294$DW.3498(a)newssvr17.news.prodigy.com... > > ... I can say that there have been no reliable and reproducible > > experiments or observations that contradict SR within its > > domain of applicability. > > That's because mainstream physicists refuse to do experiments > that could potentially contradict SR. For example: > 1. Test for OWLS with two same frame spatially separated and > synchronized clocks. One-way light speed from moving sources has been measured many times. The results are quite unambiguous. The speed is always c. Alvaeger, Farley, Kjellman and Wallin, Physics Letters 12, 260 (1964) Babcock and Bergmann, Journal Opt. Soc. Amer. Vol. 54, p. 147 (1964) Beckmann and Mandies, Radio. Sci. 69D (1965), p623. Brecher, Phys. Rev. Lett. 39 1051-1054, 1236(E) (1977) Filipas and Fox, Phys. Rev. 135, 1071 B (1964) Sadeh, Phys. Rev. Lett. 10 no. 7 (1963) Google search shows that the above references have been provided to you, or on threads known to be read by you, multiple times. You have never bothered to look them up, and have always discounted their unambigous message without having read them. Jerry's big brother
From: kenseto on 28 Mar 2005 08:49
"PD" <pdraper(a)yahoo.com> wrote in message news:1111961159.929557.184000(a)f14g2000cwb.googlegroups.com... > > kenseto wrote: > > "PD" <pdraper(a)yahoo.com> wrote in message > > news:1111770058.196421.21200(a)l41g2000cwc.googlegroups.com... > > > > > > kenseto wrote: > > > > "bz" <bz+sp(a)ch100-5.chem.lsu.edu> wrote in message > > > > news:Xns96217F0FC3412WQAHBGMXSZHVspammote(a)130.39.198.139... > > > > > "kenseto" <kenseto(a)erinet.com> wrote in > > > > > news:24Z%d.14316$cC6.10056(a)fe2.columbus.rr.com: > > > > > > > > > > > What you said is hogwash. If we define that the wave length > of a > > > > > > specific light source remains constant in all frames then the > > > observed > > > > > > Doppler shift is due to the varying speed of light from these > > > different > > > > > > sources. > > > > > > > > > > > > > > > > Are you going to say that doppler shift of sound is ALSO due to > > > varying > > > > > the speed of sound? A car drops a fire cracker on the ground > and > > > sets off > > > > > a fire cracker on the hood of the car at the same time. The > 'bang' > > > from > > > > > the fire cracker on the ground and the one on the hood of the > car > > > reach me > > > > > at the same time. The bang from the one on the hood of the car > is > > > dopplar > > > > > shifted, the one on the ground is not. They both travel through > the > > > same > > > > > air. Why should one travel at a different speed than the other? > > > > > > > > I assume that you mean that the fire cracker is at rest wrt the > > > ground when > > > > it goes off. In that case there is no Doppler shift. The fire > cracker > > > on the > > > > car would be Doppler shifted. The sound generated by that fire > > > cracker would > > > > be closer to the detector with the passage of incremental time > and > > > this is > > > > the cause of the doppler shift. There is no valid way to measure > the > > > speed > > > > of sound from a moving fire cracker because there is no valid way > to > > > measure > > > > the distance between the fire cracker and the detector at rest > when > > > the fire > > > > cracker generate the first sound wave. > > > > > > Oh, good Lord. I can't believe you said such a thing. Never mind > light. > > > First pick up a book and learn what causes the Doppler effect in > sound. > > > Jiminy. Whoowhee. > > > > Hey idiot....what do you think that causes Doppler shift?? Hint: > Changing > > distance with time between the source and the detector. Therefore the > > observed Doppler shift can be interpreted as that the speed of sound > (or > > light) arriving from a moving source is different than that if the > source > > and the detector are at rest wrt each other. This conclusion is based > on the > > assumption that the wave length remain constant whether the sound (or > light) > > wave is generated by a stationary source or a moving source wrt the > > detector. > > > > Ken Seto > > No, what causes Doppler shift is that successive wavefronts are closer > together because the source is moving in the same direction as the > wavefronts. However, the wavefronts are still traveling at the same > speed as they would for a stationary source. The speed is the same, but > the wavelength (the distance between wavefronts) is smaller, and > therefore the frequency is higher. No, successive wave crests remains the same distance apart in the ether. The absolute motion of the detector moving toward the wave crests or away from the wave crests is what causes the Doppler shift. All observers measure the same speed of light because the speed of light is a constant math ratio as follows: Light path length of rod (299,792,458m)/the absolute time content for a clock second co-moving with the rod. Ken Seto |