Yes, yes, yes Okinbo.

I do not dispute your quotes. As you correctly observed, it is your misunderstanding of those quotes that is at issue. For Einstein, in Special Relativity, a "vacuum" has no gravitational field. Recall that Einstein was the person that first predicted that light would interact with a gravitational field; he famously predicted that during a total eclipse of the sun, light would be deflected as a result of this interaction. In Special Relativity, "Vacuum" means "nothing for light to interact with". Consequently, it means no Gravitational field.

You asked "Was it not Earth-based experiments that gave birth to it?" No. Never. It was purely conceived as a "thought" experiment. It (the constant speed of light) is POSTULATED, not Experimentally Observed nor Theoretically Predicted. Of course, it was Maxwell's Theory and the Michelson-Morley experiment then lead Einstein to these Postulates. Recall that, at the time of the latter, it was supposed that light propagated by INTERACTING with the Aether. But that experiment demonstrated that there was no Aether. So this lead to the question: How does light behave, in the absence of any interaction with anything? Special Relativity is Einstein's answer to that question.

Special Relativity, like Newton's theory of gravity, can obviously be used on earth. But only as an approximation. In most circumstances, they are very good approximations, but if you what maximum accuracy, as in GPS location systems, then General Relativity is required.

Rob McEachern

Roger Barlow, Professor of Particle Physics: "The Doppler effect - changes in frequencies when sources or observers are in motion - is familiar to anyone who has stood at the roadside and watched (and listened) to the cars go by. It applies to all types of wave, not just sound. (...) Moving Observer. Now suppose the source is fixed but the observer is moving towards the source, with speed v. In time t, ct/lambda waves pass a fixed point. A moving point adds another vt/lambda. So f'=(c+v)/lambda."

Paul Fendley: "Now let's see what this does to the frequency of the light. We know that even without special relativity, observers moving at different velocities measure different frequencies. (This is the reason the pitch of an ambulance changes as it passes you it doesn't change if you're on the ambulance). This is called the Doppler shift, and for small relative velocity v it is easy to show that the frequency shifts from f to f(1+v/c) (it goes up heading toward you, down away from you). There are relativistic corrections, but these are negligible here."

That is, if the frequency measured by the stationary observer is f=c/L (L is the wavelength), the frequency measured by an observer moving towards the light source with speed v is:

f' = f(1+v/c) = (c+v)/L = c'/L

where c'=c+v is the speed of the light waves relative to the moving observer. Special relativity is violated.

Pentcho Valev

    Rob, Akinbo,

    You're both right but trivially incomplete. Rob you ignore all from Romer to binaries in dismissing an empirical basis for postulating CSL, but no matter. You also distracted from the key point by apparently dismissing not just 'generalising' SR in gravity.

    Akinbo you allowed Robs overstatement to distract you, Rob's central analysis is correct and just another way of describing discrete field dynamics. What the DF Model does is complete the ontology with the quantum mechanisms implementing the postulates and the LT, ergo 'curved space time'.

    SR, GR and QM are like 3 complex 3D dynamic jigsaw puzzle pieces with dried mud on them. When they fit together, as the DFM and in line with Rob's description, SR 'becomes' GR, and both are implemented by logical quantum mechanisms (QM).

    Speed is only a relative concept. c is then relative locally to ALL matter, which moves relative to other matter. The secrets were then only the mechanism for c to change (which also explains GR as plasma 'vortices' have G-potential) and for the non-linear asymptotic Limit represented by the Lorentz Factor. Those were the final pieces that made it all fit and work, exposing the great and simple beauty of nature. (I posted the LT link to Florin).

    Rob. Shockingly Maxwell's equations need some massaging to rid them of anomalous virtual electrons, 'partial time derivatives' and Fraunhofer refraction, and to recover Snell's law or refraction. Are you up for discussing it and manipulating a few symbols? Do you recall my references to the (orig 1950's) 'two-fluid' plasma dynamics, surface plasmoids etc?

    Best wishes

    Peter

    Very nice, Rob. If only the relativity deniers would appreciate it.

    Rob,

    Did Einstein really define "the phase velocity of light, in a vacuum, to be a constant"? In his 1905 SR paper he used Poincaré synchronization and two-way speed of light.

    I came across of the phase/group velocity matter when Nimtz claimed having measured transmission of light with a speed in excess of c.

    Today I found "The Great Einstein/de Broglie Velocity Equation derivation and notes by Douglass A. White" and an argumentation that questioned the correctness of Michelson's null result as measuring phase.

    My own argument is perhaps the only one that is consistent with Michelson 1881/83 and Michelson/Pale 1925.

    Eckard

    Here the fatal equation c'=c+v is explicitly used in the derivation of the Doppler frequency shift:

    Professor Sidney Redner: "The Doppler effect is the shift in frequency of a wave that occurs when the wave source, or the detector of the wave, is moving. Applications of the Doppler effect range from medical tests using ultrasound to radar detectors and astronomy (with electromagnetic waves). (...) We will focus on sound waves in describing the Doppler effect, but it works for other waves too. (...) Let's say you, the observer, now move toward the source with velocity vO. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: v'=v+vO. The frequency of the waves you detect is higher, and is given by: f'=v'/(lambda)=(v+vO)/(lambda)."

    For light waves v is replaced by c:

    f' = c'/(lambda) = (c+vO)/(lambda)

    where c'=c+vO is the speed of light relative to the observer. Clearly special relativity is violated.

    Pentcho Valev

    Eckard:

    You asked: "Did Einstein really define "the phase velocity of light, in a vacuum, to be a constant?"

    Yes. Here is a quote from (in translation) the 2nd paragraph of Einstein's 1905 "On the electrodynamics of moving bodies":

    "We will raise this conjecture (the purport of which will hereafter be called the "Principle of Relativity") to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body."

    Note that in "empty space", the phase velocity and group velocity are equal, so, in this special case, it is not important to distinguish between the two.

    See the wikipedia entry for "Dispersion (optics)", for more info regarding phase/group velocity

    Rob McEachern

    Peter,

    I prefer not to rewrite history. For me, the issue is not what I ignore or dismiss, more than 100 years after Einstein wrote his 1905 paper on SR. I don't believe gravity was even mentioned in that paper. As for the experimental observations, I'm sure Einstein would not have made his postulate, if they showed the speed of light to be obviously variable. But in the paper, in the first paragraph he cites problems with Maxwell's equations, and in the second paragraph, he cites "unsuccessful attempts to discover any motion of the earth relatively to the "light medium"" as his primary considerations.

    "Shockingly Maxwell's equations need some massaging to rid them of anomalous..."

    Einstein also noted anomalies... Einstein's 1st sentence in the 1905 paper: "It is known that Maxwell's electrodynamics-as usually understood at the present time-when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena."

    "Are you up for discussing it and manipulating a few symbols?" Perhaps. But to what end?

    "Do you recall my references to the (orig 1950's) 'two-fluid' plasma dynamics, surface plasmoids etc?" No.

    Rob McEachern

    Rob,

    I misspelled Gale 1925.

    You wrote to Florin: "The problem is that you, like the vast majority of people, have confused "group velocity" for "phase velocity". Einstein simply DEFINED the phase velocity of light, in a vacuum, to be a constant. He said nothing about group velocity being constant."

    When did Einstein speak of phase velocity?

    The velocity he referred to in 1905 has now been called front velocity.

    The mistake of Nimtz is a frequent one. He measured a phase velocity in excess of c and then he questioned the meaning of c as the maximal possible speed for transmission of signals.

    Shouldn't you reconsider your argumentation?

    Eckard

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    • Post #330

    Rob,

    Nice to learn that in the absence of matter, phase velocity will equal group velocity.

    You say, "Special Relativity, like Newton's theory of gravity, can obviously be used on earth. But only as an approximation. In most circumstances, they are very good approximations, but if you what maximum accuracy, as in GPS location systems, then General Relativity is required".

    Since you know G, M and r for Earth, I want maximum accuracy, give it to me please!

    Special relativity is being used to define the constancy and the value of that constant, would you then agree given your statement that the use of words like "exactly" in such definitions is wrong but rather "approximately" and "good approximation" should be preferred? Take note that all experiments that claim that Special relativity has passed ALL tests are conducted on earth vacuum and gravitational field and they don't lay claim to any "approximate validity" in their results. Finally, since you say I may be misunderstanding what I quoted Einstein to have said, what is your own understanding of: "the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity and to which we have already frequently referred, CANNOT claim any unlimited validity... ONLY SO LONG as we are able to disregard the influences of gravitational fields (OF THE EARTH) on the phenomena {e.g. of light}" (Capitals are mine).

    From the quote and your understanding, I take you to mean that the law of the constancy of light in vacuo is invalid under (very strong) gravitational influence? And valid only where there is no gravitational field?

    Akinbo

    Eckard,

    Front velocity refers to the leading-edge of a signal. There is no leading edge on an infinitely long sinusoid.

    Einstein's 1905 paper is dealing with a mathematically idealized case, not messy reality. In reality, there is no such thing as "empty space", and no such thing as a single frequency (hence infinitely long, since any finite "truncated" signal has a spectrum). Nevertheless, it is just such an idealized case that Einstein was writing about. Give the guy a break. He turned out an amazing amount of good work that year. Why complain that he didn't deal with EVERY problem then?

    You asked "Shouldn't you reconsider your argumentation?" It is not my argument. It is Einstein's. If you believe in an afterlife, then, when you arrive there, you my query Einstein about his choice, just as Odysseus queried Achilles about his, in Homer's tale.

    Rob McEachern

    "There is no leading edge on an infinitely long sinusoid."

    Rob, I know what a strain it is to try and bring anti-relativists to an understanding of continuous functions.

    Good luck.

    Akinbo,

    You stated that "Since you know G, M and r for Earth, I want maximum accuracy, give it to me please!"

    Unfortunately, I do not know the number of free electrons encountered by any signal along its path. Since the travel-time of the signal depends upon this number, neither I nor anyone else can be absolutely accurate. I know, from personal experience, that that number can change dramatically in time-scales less than 0.001 seconds, for signals traveling through the Earth's ionosphere. This is a major source of error, in attempting to geo-locate signals via their measured travel-times, especially at low frequencies.

    You stated that "Special relativity is being used to define the constancy and the value of that constant"

    Special relativity only defined the former, not the latter.

    You stated "I take you to mean that the law of the constancy of light in vacuo is invalid under (very strong) gravitational influence? And valid only where there is no gravitational field?"

    "Invalid" is too strong a word. As you increase the content of (formerly) "empty space", by adding gravitational fields, free electrons, or anything else that light may interact with, then the speed of light traversing that space will increasingly deviate from its speed in "vacuum".

    Rob McEachern

    "You (Akinbo) stated that Special relativity is being used to define the constancy and the value of that constant'

    "Special relativity only defined the former, not the latter."

    Exactly right. It seems the hardest thing to convince an anti-relativist that the constant of proportionality between energy and mass is exactly 1. They think the empirical value of the speed of light has meaning. It does not.

    Eckard,

    You suggested your 'idea' is consistent with the 1925 Michelson Gale Pearson finding. MGP concluded that there is a light carrying medium, reporting; 'fringe shifts due to ether flow with respect to the Earth's rotation' in an Earth centred (orbiting) aether at rest (i.e. the ionospheric frame). This was also consistent with Millers independent findings of increasing ('birefringent') effect with altitude. Such subtleties are normally missed or ignored as they appear difficult to reconcile with SR.

    What is however certain is that your thesis is not consistent with this finding any more than it is with the simplistic 'standard' interpretation or SR. The finding is however entirely consistent with Rob's. It seems then it may not be Rob who needs to reconsider his 'argumentation'.

    Are you familiar with J.D Jackson and varying 'extinction distances' with density?

    Akinbo;

    Considering extinction may also be helpful to you to better understand my descriptions and Robs point on approximation due to plasma density.

    Best wishes

    Peter

    Rob,

    "Perhaps. But to what end?" Explaining the 'asymmetry' to advance understanding.

    A whole tranche of anomalies and paradoxes may be resolved by more precisely matching the mathematical description to the underlying physical 'mechanism' of Maxwell's near / far field transition (which includes deriving the 'LT' non-linearity). The SR postulates re-emerge with a more complete specification and explanation.

    A bit like the currency conversion; The maths may be perfectly precise but give little clue as to the physical mechanisms required to actually implement a transfer from pounds to dollars. The physical reality will also always be an approximation of the mathematics to ~0.5 cents.

    I stated some of the anomalies which would be lifted. Non-linear optics is beset with them, but most are unfamiliar as they're 'swept under the carpet'. The violation of Snell's Law at 'kinetic reverse' refraction is just one, recovered by the mechanism. I can provide a full mechanistic description of processes, some of which you already understand, but manipulating the representative symbols isn't my game. Contact me on peter.jackson53(at)ymail.com to have a closer look. I'm also joint author on a paper on superluminal quasar jet acceleration and collimation mechanisms you may be interested in (presently in review).

    Two-fluid plasmas are very interesting mechanisms, relating to increased photo-ionization rates with intensity, so 'Higgs process' pair production rate linked with relative motion, also closely related to the phase/group matter.

    Best wishes

    Peter

    Rob, Tom,

    "There is no leading edge on an infinitely long sinusoid." Well, for this reason I consider R and cosine transformation more appropriate than the use of R and Fourier transformation in combination with Heaviside's trick. The leading edge is the now, the point zero of elapsed time.

    Ripping apart Einstein in this respect seems to me more important than revealing in what your argumentation (and also Peter's still untenable idea of nested local velocities) were inconsistent.

    Eckard

    Okay Rob, let me digest your reply.

    Since you prefer not to rewrite history... I said "Was it not Earth-based experiments that gave birth to SR?", And you reply, "No. Never". The experiment took place in 1887, and SR was born in 1905.

    But you redeem yourself when you say, "Of course, it was Maxwell's Theory and the Michelson-Morley experiment then lead Einstein to these Postulates".

    Happy weekend.

    Happy weekend to you too Tom. I know you are a Die Hard supporter of Einstein but you deny him on many occasions. And as for "they think the empirical value of the speed of light has meaning. It does not". Don't say this in Einsteiniana. You may be excommunicated. BIPM define a metre and a second with that same value which you say has no meaning.

    Akinbo

    The only way to save special relativity:

    If a light source emits pulses the distance between which is d (e.g. d=300000 km), an observer moving with speed v towards / away from the source measures the frequency of the pulses to be f'=(c±v)/d. Accordingly, the speed of the pulses relative to the observer is c'=c±v, in violation of special relativity.

    There is an assumption allowing the speed of the pulses relative to the observer to remain unchanged (c'=c) while the measured frequency is still f'=(c±v)/d. However this assumption is extremely silly and clever Einsteinians would never advance it explicitly. Here it is:

    The extremely silly assumption without which special relativity is doomed: When the observer starts moving towards / away from the light source with speed v, the distance between the pulses somehow shifts from d to d'=cd/(c±v), Divine Einstein, yes we all believe in relativity, relativity, relativity.

    Pentcho Valev