Speed of Light: A universal Constant?
in [Relativity]
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From: Bilge on 19 Apr 2005 19:02 Jim Greenfield: >Here's the rub! SR uses TWO postulates; that distance AND time >BOTH alter inversely due to the same velocity (particle). Take up knitting. The pace of geometry and trigonometry over the past couple of millenia have outstripped your mental resources. Given a pen and some graph paper, the average high school student can plot the simple coordinate transformation, t' = t cosh(A) - x sinh(A) x' = x cosh(A) - t sinh(A) and figure out how to rewrite that as, t' = cosh(A)[ t - x tanh(A)] x' = cosh(A)[ x - t tanh(A)] and figure out how to add two such transforms. You should contact your local adult education center and sign up for remedial courses so you can at least figure out enough geometry to perform simple repairs around the house. After that, you can move on to something more advanced, like the theory and operation of a mitre saw.
From: G on 19 Apr 2005 22:35 Henri First about the crossing the street problem. I admit I have made a mistake. I assumed that if the source added its velocity to the photons it emits, then the source would appear closer.This is not true: we measure distance by size, not time it takes for light to reach us. Will leave this unattended. It is instructive to look at how radar works: apprently by checking doppler shifts http://electronics.howstuffworks.com/radar2.htm http://www.escortstore.com/policrdr.htm This is interesting because whenever we replace sources with mirrors, we get a doppler shift but, I assume NO CHANGE IN THE SPEED OF LIGHT. The MMX http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html therefore seems to be void because the apparatus will never measure any changes in c in any direction because the speed of light relative to the source (or reflector) is always c You will be very interested to know the reaction to the same type of post in http://groups-beta.google.com/group/sci.physics.relativity/msg/6bb006e9c79e80ab and the answer I received. This is a group, if accessible to you, you can see the message I happened to think Einstien's reasoning was faulty...I hapenned to think a textbook was wrong... I don't know whether there is ether or not, I just assume it irrelevant to my discussions, based on 2 postulates 1. The velocity of light is independant of the source as for sound, mechanical waves. This can be experimentally verified 2. Given (1) there is no reason to assume that the measurement of light is independant of the observer as we have seen, the reasoning for assuming this is faulty. "For another, if a correction is made for light travel time, simultaneity becomes absolute. " I agree, why can't everyone see this? You said you are a physicist, if you do not mind, can you give any additional details? G
From: Henri Wilson on 20 Apr 2005 02:48 On 19 Apr 2005 19:35:41 -0700, "G" <gehan(a)dialog.lk> wrote: >Henri > > First about the crossing the street problem. I admit I have made a >mistake. >I assumed that if the source added its velocity to the photons it >emits, >then the source would appear closer.This is not true: we measure >distance > by size, not time it takes for light to reach us. >Will leave this unattended. > >It is instructive to look at how radar works: apprently by checking >doppler shifts > >http://electronics.howstuffworks.com/radar2.htm > >http://www.escortstore.com/policrdr.htm > >This is interesting because whenever we replace sources with mirrors, >we get a doppler shift >but, I assume NO CHANGE IN THE SPEED OF LIGHT. The MMX > >http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html > >therefore seems to be void because the apparatus will never measure > any changes in c in any direction because the speed of light relative >to > the source (or reflector) is always c > >You will be very interested to know the reaction to the same type of >post in > >http://groups-beta.google.com/group/sci.physics.relativity/msg/6bb006e9c79e80ab > >and the answer I received. This is a group, if accessible to you, you >can see the message You are in it now. >I happened to think Einstien's reasoning was faulty...I hapenned to >think >a textbook was wrong... don't take any notice of smithy. He is a DHR (die hard relativist) I gather you are new to this relativity group. You should read the messages here for a while before you contribute. It is a pretty complicated subject and you will only make a fool of yourself if you don't understand the main issues. > > >I don't know whether there is ether or not, I just assume it >irrelevant to >my discussions, based on 2 postulates > >1. The velocity of light is independant of the source as for sound, >mechanical waves. This can be experimentally verified > >2. Given (1) there is no reason to assume that the measurement of light >is independant of the observer >as we have seen, the reasoning for assuming this is faulty. > >"For another, if a correction is made for light travel time, >simultaneity >becomes absolute. " > >I agree, why can't everyone see this? They don't want to. Relativity has become a religion to many. Einstein is their god. The fact that he merely concocted a disguised version of aether theory doesn't matter to them. > > >You said you are a physicist, if you do not mind, can you give any >additional details? Nobody cares who or what anyone is here. This is the real world, boy (or girl). It's what you say not who you are that counts. > > > >G 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: kenseto on 20 Apr 2005 08:51 "Henri Wilson" <H@..> wrote in message news:i0e861purbg1rjo7e5lrmucnkphaf1gvj7(a)4ax.com... > On Mon, 18 Apr 2005 12:49:23 GMT, "kenseto" <kenseto(a)erinet.com> wrote: > > > > >"Henri Wilson" <H@..> wrote in message > >news:ufs561tv60fjfc0mgintr78kn6omfr591d(a)4ax.com... > >> On Sat, 16 Apr 2005 12:54:52 GMT, "kenseto" <kenseto(a)erinet.com> wrote: > >> > > >> >> >BaT explains the double-slit experiment. > >> >> > >> >> Photon fields extend to infinity. > >> >> Photons have 'size, cross-section and volume'. > >> > > >> >So according to BaT what is the "size, cross-section and volume" of a > >> >photon? Also why is that enables the photons to interfere with each > >other? > >> > >> Infinite in all directions. ..but the fields of a photon die off very > >rapidly > >> in all directions too. > > > >So a photon is not a light bullet as the BaT asserts?? It is a wave front > >that die off raipdly? How does it know how much to die off? I ask this > >question because a photon seems to have an infinite life time. > > All fields die off according to at least an inverse square law. > The fact that the effects of a field 'die off' doesn't mean the field itself > becomes weaker with time. > If a photon encounters no 'material', its fields should live forever. So BaT is not ballistic but rather it is a field (wave) theory? > > However, since the fields of each photon ARE FINITE everywhere, it stands to > reason that some loss will always occur as light travels. This should be > distance dependent and is no doubt a major cause of the galactic redshift. > > So BIG BANG, BIG BULL!!!! So baT is big bull also!!!! > > > > > > >> I hereby invent a new term, 'half radius'....defined as the distance at > >which a > >> photon's influence is reduced to half. > > > >This seems to describe a photon as a wave front. But BaT says that a photon > >is a light bullet so how does a photon exerts influence at a distance? > > see my small demo: www.users.bigpond.com/hewn/e-field.exe ROTFLOL....'half radius' indeed. > > >> > >> It appears that the higher the energy, the smaller the half-radius of a > >photon. > >> That is why gammas behave like particles and infrared like a wave. > > > >You are making this up. > > Photons are now regarded (by the more enlightened) as consisting of rapidly > spinning +/- charge pairs, which self-propagate through space at 'c' relative > to their sources. You made this up. Do you have any reference for that?? > As you know, if you want to spin wheels really rapidly, you have to make their > diameters small, else they fly apart. > So naturally, half-radius=K/E^2 Some more make up stuff. > > >> > >> > >> Get it? > > > >ROTFLOL....no I don't get it. > > You don;t get the MMX either. Except what I said is supported by experiments. Ken Seto
From: Paul B. Andersen on 20 Apr 2005 10:45
Henri Wilson wrote: > On Tue, 19 Apr 2005 10:46:00 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>On Mon, 18 Apr 2005 16:16:22 +0200, "Paul B. Andersen" >>><paul.b.andersen(a)deletethishia.no> wrote: >>> >>> >>> >>>>Henri Wilson wrote: >>>> >>>> >>>>>On Thu, 14 Apr 2005 00:30:42 +0100, "George Dishman" <george(a)briar.demon.co.uk> >>>>>wrote: >>>>> >>>>> >>>>> >>>>>>"Henri Wilson" <H@..> wrote in message >>>>>>news:s03r51d3gmd6qick1ffuuiebr31gljr9lk(a)4ax.com... >>>>>> >>>>>> >>>>>>>What I have realised is that the standard SR explanation doesn't work!! >>>>>>> >>>>>>>FOR A CONSTANT RATE OF ROTATION, THERE WOULD BE NO FRINGE MOVEMENT. >>>>>>> >>>>>>>The pattern would remain fixed. And that is not what happens, surely. >>>>>>>Your version of Sagnac would be sensitive to angular acceleration only. >>>>>> >>>>>>Why? The animation shows that there is a >>>>>>clear time difference produced in the SR >>>>>>version. What you say is inconflict with >>>>>>what it shows yet you just make that bald >>>>>>statement without giving any reason. >>>>> >>>>> >>>>>Think about it George. >>>>>For constant rotation (incuding zero), there is a constant relationship between >>>>>the two path lengths. The fringes should remain static. >>>>>That is not what happens. >>>> >>>>Of course that's what happens, and of course that's >>>>what SR say should happen. >>>> >>>>The term "fringe shift" refers to the shift of the fringes >>>>when the interferometer is rotating compared to when it is not. >>>> >>>>What did YOU think "fringe shift" meant? >>>>That the fringes are moving? >>>>They are not in a Sagnac interferometer rotating >>>>at a constant rate. >>>> >>>>Ring lasers are quite different, though. >>>>That's why ring lasers rather than Sagnac rings >>>>are used in inertial navigational systems. >>>> >>>>Sagnac rings and ring lasers both falsifies the ballistic theory. >>>>Obviously. >>>> >>>>Paul >>> >>> >>>You are not being at all helpful for the purpose of this discussion. >> >>You are claiming that the fringes in a Sagnac interferometer >>are moving when the interferometer is rotating at a constant rate. >>That is wrong. >> >>So you don't know what is happening in the Sagnac experiment. >> >>I think it would be very helpful for the purpose of this >>discussion to know what is actually happening in the real world. >> >>But maybe you prefer your fantasy world were what >>actually happens surely isn't what happens? > > > Paul, please read the whole thread. > I pointed out that according to both SR and the BaT, fringes would not move > during constant rotation. > > I merely queried whether that was the case or or not. Henri, you wrote: "The pattern would remain fixed. And that is not what happens, surely." That's not a query, it is an assertion. A wrong one. > It apparently is and so a > continuous integration must be carried out (wrt time) in order to establish > total rotation angle moved. OK. So you have realized that your assertion was wrong. Enough about that. And of course you are right when you say that you have to integrate the angular velocity to get the angle. > I pointed out that there are inherent inaccuracies in such a method...but the > use of a long fibre obviously helps. Of course there are inherent inaccuracies, but the integration isn't the problem, this is done very precisely with DSPs these days. The precision with which the angular velocity is measured is what determines the precision. And that's why ring laser gyros rather that fibre optic gyros are used in inertial navigational systems, they are by their very nature much more precise. Compare this fibre optic gyro (reference given by Dishman): http://www.kvh.com/pdf/DSP3000_5.04.pdf to this ring laser gyro: http://content.honeywell.com/dses/assets/datasheets/ds13_gg1320_an.pdf fibre optic ring laser Bias: +/-20deg/h ? very small by nature Bias stability: 1deg/h 0.0035deg/h Angular random walk: 0.667deg/sqr(h) 0.0035deg/sqr(h) The angular velocity of the Earth is ca. 15deg/h. This means that for the fibre optic laser, the rotation of the Earth is smaller than the precision of the gyro, even when the gyro is parallel to the equatorial plane. The ring laser gyro is several order of magnitudes more precise. (I suspect this is reflected in the prices!) The reason for this big difference is easy to understand. In the fibre optic gyro, the phase difference is static when the angular velocity is constant. This means that the phase difference must be compared to the phase difference when the gyro is not rotating. This must be remembered, it can not be measured while the gyro is rotating. And it will probably drift! The ring laser gyro is very different. If the phase difference is static, the gyro is not rotating. When the gyro is rotating, the phase difference is changing at a rate proportional to the angular velocity. If the phase difference is changing with 360deg/s, (equivalent to a fringe speed of one inter fringe length per second - only there are hardly any fringes in these instruments) then the angular velocity is (360deg/2N)/s, where N is the number of wavelengths around the ring. With a ring length of - say 25cm - and a wavelength of 0.5um we get that a rotation of 0.000360deg/s or 1.3deg/h will give a phase difference change of 360deg/s. Easily measurable, and the beauty of it is that this only depend on geometric parameters and not on any calibration done at some earlier time. I know that the inertial navigational systems in commercial and military aeroplanes all use ring lasers. (The maintenance manuals for the MD-80 family and Boeing 737 happens to occupy a couple of metres of my shelf.) Paul |