The Lorentz transformations were introduced after 1905 as an "improvement" of the Galilean transformations, since the latter could not maintain the invariance of the Electromagnetic Phenomena between IRFs. The LT are supposed to be just coordinate transformations since they also define a group.
They implement ithe postulates of the constancy of the speed of light and relativity of motion.
The RDE was derived from the phase invariance of the EM waves under the LT and, as such, the effect should be only due to a change of "View point" on the same EM phenomenon. How the same wave is seen from a different reference frame moving at relative speed V.
It is clear also that two inertial reference frames, having relative motion, which need to import reciprocal physics have to exchange EM waves, and thus exibit RDE.
Even under the HP that these waves do not interfere with the inertiality, under the experimental accuracy, the energy momentum of the waves gets altered.
The Relativistic Doppler Effect is also an energy and momentum exchange between matter and radiation. It can be derived infact from the conservation laws of energy and momentum and the principle of relativity of motion, assuming the inelastic scattering of Quanta of light (E. FERMI).
Due to the last description when "light quanta" impinge on the receiver their frequency is raised or lowered according to the relative motion between the receiver and the emitter.
What occurs is not properly a variation of the "view point", but it is an actual alteration of the properties of the quantum during the absorption process. (The moving atom would be able to emit an higher frequency than the one emitted, once at rest with the source).
In conclusion the LT:
1) have to be considered valid only between IRFs which is the initial HP and this is already an approximation.
Article CO-ACCELERATED CLOCKS maintain their synchronization?
2) They define a group of transformations and this would suggest that they are good candidates to be coordinate transformations.
3) The viewpoint which LT should express though, is not "neutral" . It is varied by the actual exchange of energy and momentum between the wave or quanta and the bodies relevant to the IRFs. The frequency of the wave gets altered by exchanging kinetic energy with the absorber, in the RF of the emitter.
As it was measured by Lorentz and Maxwell, physically LT express the transformation of the radiation exchanged between relative moving objects at constant speed whose direct consequence is the RDE.
http://file.scirp.org/pdf/JMP_2014032810410864.pdf
Dear Christian,
From the abstract and the picture of the book, we see that the author is accusing those who don't agree with SR of being bad persons or even racists. I don't think this is related to science and physics.
I have respect for Einstein and all scientists, who are all hard workers. What we are talking about in this thread is about physical insights, physical phenomena, physical interpretation and we should not present the problem like if it were a personal attack to anyone.
Stefano, to understand relativistic Doppler, image a flashing light, like the xenon strobes on aircraft, but on a spaceship departing from the Solar System. Draw a spacetime diagram and see how and why the received frequency differs from that transmitted.
Then think of each flash as a wave crest of the carrier of a radio signal.
Then imagine that continuous wave signal broken into photons. By duality, each one must have the same frequency as the Doppler-shifted carrier.
George,
I think I understand RDE. The wave and the particle description agree. But this is not the point. The point is the actual meaning of LT it seems they do not fit a coordinate transformation.
Stefano, that's why I suggested drawing a spacetime diagram which makes the geometrical understanding explicit. You can then see how that approach corresponds to the wave model (and hence the particle model as you say).
The Lorentz transformation is a pure mathematical concept. Its relation to the Galileo transformation can best be seen when both transformations are derived from group concepts. https://en.wikipedia.org/wiki/Derivations_of_the_Lorentz_transformations#From_group_postulates
In this derivation both transforms represent special conditions of the same transform. A third condition is considered as unphysical.
This derivation already introduces concepts such as time dilation and length contraction for conditions in which the Lorentz transform hold.
Both transforms can be applied to space-progression structures that have a Euclidean signature or an Minkowski signature. However, in those cases the meaning of the variables must be adapted.
Both transforms apply to flat Euclidean parameter spaces. Deformed living spaces require a corresponding conversion.
The Euclidean signature structure is easier comprehensible.
Mainstream physics applies the Minkowski structure.
In the realm of Hilbert spaces the Euclidean signature fits without dismantling of the space-progression structure. The Minkowski signature structure must first be dismantled before operators can handle them.
The Lorentz transform uses the speed of information transfer as a limiting speed. This means that implicitly this transform uses the notion of an observer and a corresponding observed event. These are expected to be located at some distance of each other. In this situation it is possible to apply a model wide ticking clock or it is possible that both the observer and the observed event own a private clock. Proper time is measured at the location of the observed event. That time is calculated by the observer and the result is used as coordinate time by the observer. In the calculation the speed of information transfer and the distance between the two locations are used. This calculation poses problems in a deformed living space.
docs.com/hans-van-leunen
Hans,
the LT are based on
a) the speed of light in vacuo is c in every Inertial Reference frame
b) the principle of relativity of motion.
The viewpoint which LT should express though, is not "neutral" . It is varied by the actual exchange of energy and momentum between the wave or quanta and the bodies relevant to the IRFs. The frequency of the wave gets altered by exchanging kinetic energy with the absorber.
According to the 3rd point it is difficult to attribute the property of coordinate transformations to LT, since it is present an actual interference of the Viewpoint itself. Not only the Kinetics have to be considered in this case but also the dynamics.
Stefano,
The energy-mass equivalence principle is is not directly related to relativity of movement.
In order to understand this the model must involve how massive particles deform their living space and how energy is transferred. These are quite different processes that are only directly coupled at particle creation and annihilation events.
The transfer of energy by photons is not clear as long as the concept of the photon is full of contradictions. The current interpretations is that photons are EM waves. This interpretation conflicts with the fact that photons can travel billions of light years and after that trip can still be detected by small photon detectors.
Two homogeneous second order partial differential equations exist. One of them uses d'Alembert's operator and offers waves as its solutions. Both homogeneous second order partial differential equations offer other solutions that can be classified as shape keeping fronts. They occur in odd numbers of dimensions and the one-dimensional versions also keep their amplitude. These solutions do not feature a frequency. Thus in order to get a frequency the fronts must be emitted at equidistant instants. The one-dimensional shape keeping front is the only solution that can keep its integrity during a billion year travel through empty space. During such trips the EM field is an unlikely carrier. Instead our living space is a more likely carrier candidate. Each front can carry a bit of energy. The Planck-Einstein relation E=h v requires that all photons, independent of their frequency take the same emission duration. With constant light speed this also means a fixed spatial length.
If the emission is indeed a step by step procedure, then the emission of photons at particle annihilation means that a unit bit of mass is converted in a unit bit of energy. This means that the number of fronts in the photon equals the number of massive elements that define the elementary particle. These elements can be identified with locations where the elementary particle can/could be detected. The location density distribution conforms to the squared modulus of the wave function of the elementary particle.
.If the elementary particle is considered to hop along the locations that determine the location density distribution, then the hop landings may cause a vibration of the living space field. That vibration will then be a spherical shape keeping front that moves away from the landing location. When this ripple is integrated over a long enough period, then the result is the Green's function of the living space field. If this Green's function is convoluted with the location density distribution, then the result is the contribution of the elementary particle to the deformation of the living space field.
George,
the space time diagram is born out of the acceptance of the LT as coordinate transformations. I would like to go a step behind.
Stefano, I think there is a little confusion in the conversation. You said "The point is the actual meaning of LT it seems they do not fit a coordinate transformation.".
I suggested drawing a spacetime diagram because that will illustrate how they do fit, and they fit very well.
On the other hand, you seem to be looking for an alternative to the geometric understanding as a coordinate transform in which case I can't help. Looking for a new idea that nobody else has come up with yet needs that bit of inspiration beyond the perspiration ;-)
Dear Stefano,
in reply to your question: "What is the actual physical meaning of the Lorentz Transformations?" I send you the obvious answer: "There is no actual physical meaning of the Lorentz Transformations." As you know it was derived by Voigt assuming c=const for all observers, but this is an absurd postulate that does not correspond to reality. Einstein himself refuted the LT in his book of 1938.
"Spacetime" is a construction combining apples with pears. It does not lend physical meaning to the LT. As there are two different Doppler formulae for moving source and for moving observer - both obtainable from momentum and energy conservation, but also from the LT - it contradicts the relativity principle from which it was not derived by Einstein. Instead, he used c=const copied from Voigt.
Regards from
Wolfgang
See also:
The above explanation that shows how our living space field follows from the fact that it describes the swarm of locations that defines the squared modulus of the wave function unifies quantum physics with gravitation theory. It also explains why and how energy and mass relate to each other. The story has nothing to do with the relativity of motion and it does not relate to the Lorentz transform.
In discussing these items it is sensible to separate the signature of space--progression constructs from the consequences of relativity of motion in which a maximum speed of information transfer plays a role.
I take objection to Wolfgang's articulation regarding LT. We can of course engage ourselves in the way various pioneers of science did view STR from the perspectives they had when they were active as researchers. As I have stated many times LT is a consequence of the relativity postulates. The derivation is straight forward and only necessitates high school math. To answer Stefano's question its meaning, the actual interpretation is simply that the theory is correct in the sense that the postulates of relativity is a good representation of the physical situation under discussion. Any discrepancies must by default be associated with one or several violations of the defining axioms. This is a simple example of the trivial, yet for many scientists including Mr. Engelhardt, hard to understand, but fundamental principle of deductive thinking. For me as a professional scientist it is incredibly surprising that so many researchers and almost all independent researchers do not grasp the simple logical character of deductive reasoning. Maybe we should formulate a new RG question. What is wrong with deductive thinking?
@ Erkki Brändas:
"Any discrepancies must by default be associated with one or several violations of the defining axioms." Fully agreed! The defining axiom resulting in LT as formulated by Voigt is c = const. It is refuted by experiments in first order as repeatedly said.
Furthermore, Einstein has himself refuted the LT in his book of 1938 as discussed at length in a different thread.
Wolfgang,
If you violate the axiom c=const then we are not talking about STR or LT. Your interpretation of Einstein's view on synchronization do show that your interpretation is not in agreement with STR. You don't say that you agree with me – you say that you agree with me but....
WWE: The defining axiom resulting in LT as formulated by Voigt is c = const. It is refuted by experiments in first order as repeatedly said.
Voigt's transform is related to Lorentz's by a change of scale, both satisfy the requirement that the speed of light invariant1.
When symmetry is considered, that scale factor must be 1 as in the LT rather than Voigt's use of what we now know as gamma, so experiment refutes Voigt's version but not Lorentz's.
1: Nitpick - if c varied over cosmological timescales, it would not invalidate SR so "constant" is inappropriate.
Dear all,
I think you all are quite intelligent people (scientists) who can make the effort to understand your "contrasting" viewpoints.
What Erkki says: "As I have stated many times LT is a consequence of the relativity postulates".
Means that LT is a direct consquence of the constancy of the Speed of light and the principle of the relativity of motion of IRFs, we just have to do some math and these transformations come out.
"To answer Stefano's question its meaning, the actual interpretation is simply that the theory is correct in the sense that the postulates of relativity is a good representation of the physical situation under discussion."
this is not an answer about what they phisically represent, this is just to say that the LT have been verified as giving good predictions where they have been applied.
"Any discrepancies must by default be associated with one or several violations of the defining axioms."
I think so too... Though in this case I have to add that LT have been used where they were not allowed to (twin paradox for example) if we have to comply to the above HP.
"For me as a professional scientist it is incredibly surprising that so many researchers and almost all independent researchers do not grasp the simple logical character of deductive reasoning."
I add again that we have to be very rigourous in respecting the HP and see the consequences. Regardless of the fact that they have given results.
---------------------------------------
according to Wolfgang: "There is no actual physical meaning of the Lorentz Transformations. As you know it was derived by Voigt assuming c=const for all observers, but this is an absurd postulate that does not correspond to reality."
This is again not an answer, since these relations lead to the RDE so they should have a physical role.
""Spacetime" is a construction combining apples with pears. It does not lend physical meaning to the LT."
I see your point of view.....
"As there are two different Doppler formulae for moving source and for moving observer - both obtainable from momentum and energy conservation, but also from the LT - it contradicts the relativity principle from which it was not derived by Einstein"
Fermi, Schrodinger and then Redzic derived RDE from the conservation prinicple as well so your derivation for me is quite correct.
-----------------------------
A simple derivation of Doppler of Light from energy and momentum (in the non relativistic approx) of the atom and quantum, brings to formulas originally found by Christian Doppler for the binary stars and suitable also for material media.
Since in deep space the only thing you could say about two bodies is that they approach or depart, the two relations of the RDE have to converge to a unique expression. The Lorentz factor comes out imposing such convergence of the two formulas.
--------------------------------------
I don't understand a passage of your paper which is supposed to be the GIST and it is not in agreement (as also you affirm) with the current interpretation of the RDE.
"If both source and detector move with the same velocity, the
motion dependent factors in (12) and (18) cancel out so that just
the frequency is measured. The cancellation occurs also when detector and source move in opposite directions, but alpha is 90 degrees."
same velocity in the LAB frame but opposite directions???
So according to your opinion the RDE relation is found valid only if the detector (the source) is at rest in the lab frame and the source (the detector) moves with relative V.
"The null result of the experiment published in [2], where source and detector are placed at the periphery of a rotating disk, conrms this expectation."
it confirms the expectations in the case of rotating, but does it have a validity for linear motion?
Dear dr.Quattrini,
geometrically speaking, Galilei, Poincaré, and Lorentz transformations are linear transformations of the space in itself. It means that one can construct a geometric space – not necessarily the same space, which is invariant under any one of the above transformation groups.
Geometric invariance is broadly related to symmetry. It was developed from the so called classical invariant theory (https://en.wikipedia.org/wiki/Invariant_theory), which studies transformations of space in itself, that leave an algebraic form unchanged. In Minkowski’s times there was a well developed theory of quadratic invariant forms (https://en.wikipedia.org/wiki/Quadratic_form), to which Minkowski went back.
In my opinion two points are particularly delicate, when trying to answer your question:
1) As pointed out by prof. Engelhardt, initially Einstein failed to appreciate Minkowski’s representation of the world, because a four-dimensional space cannot easily be conceived, and in addition time doesn’t have any spatial meaning as such. Of course, space-time may be thought of as the union of the Cartesian representation of space and the representation of the equations of motion (in Italian: diagramma orario del moto). But, in Minkowski’s time that kind of representation was not yet used in geometry.
2) If an algebraic quadratic form is symmetric, it can be interpreted as a conservation principle. This interpretation was given by Noether for dynamical systems, and presupposes a dynamical interpretation of space. Phase space is a classical example of a dynamical space. However, the quadratic invariant form
dx2 + dy2 + dz2 +(-icdt)2 = 0
may not be called positive definite. In addition, due to Heisenberg’s uncertainty, the phase space is split up into configuration and momentum space in quantum mechanics.
In my opinion, the dynamical, as opposed to the geometric interpretation, of Lorentz transformations is complicated by those (principial?) issues.
@ Erkki Brändas wrote: "If physics violate STR, WHICH IT DOES, the failure
is due to one or several of its postulates." I fully agreed to this statement.
Erkki also wrote above: "Your interpretation of Einstein's view on synchronization do show that your interpretation is not in agreement with STR." It is not a matter of my personal interpretation, but Einstein's view on his synchronization according to § 1in his paper of 1905, as depicted by him 1938 in the lower drawing of Figur 36 (https://www.researchgate.net/publication/282325187_Einsteins_eigene_Widerlegung_seiner_Theorie, https://www.researchgate.net/publication/309312005_Einstein%27s_own_refutation_of_his_theory?ev=prf_pub). I have complemented this figure by three more clocks. Erkki agreed to complement 1, which rules out complement 2 as resulting from the LT. Complement 1 is physics, complement 2 is postulate. Upshot: It was Einstein who ruled out LT=STR.
It is a mystery to me why some relativists still hold up LT which leads to a number of contradictions with physics. One should not sacrifice physical truth on the altar of speculation (postulates).
Article Einsteins eigene Widerlegung seiner Theorie
Article Einstein's own refutation of his theory
@ G. Dishman: It is well known that Voigt's transformation differs from Lorentz's by an irrelevant gamma-factor which does not change the absurd postulate c=const.
There are certainly at least these two "issues":
a) the attempt to solve the twin paradox with the LT. The only way to solve the paradox is with non inertial motion (acceleration) of one of the two clocks, while LT are defined in inertial reference frames. Any attempt to solve the paradox within the LT is a contradiction in terms as also supported by Vladimir Fock.
b) the retarded clocks in accelerated motion, which is also at the base of the equivalence principle. This comes out as a result of the LT as rigorously found by Rindler.
@ Stefano Quattrini: "This is again not an answer, since these relations lead to the RDE so they should have a physical role."
As the predictions of LT contradict physics, LT does not have any physical meaning. It is the meaningless consequence of an absurd postulate as refuted by Einstein himself in 1938.
"same velocity in the LAB frame but opposite directions???" Sorry, I should have said "speed". There is a relative velocity of 2 omega r between 2 points rotating diametrallicy on the periphery of a disk. In this case RDE is not observed. If the source is in the center and the detector rotating on the periphery, formula (12) is confirmed. If the detector is in the center and the source rotating on the periphery, formula (18) is confirmed.
"does it have a validity for linear motion?" My derivation from conservation of momentum and energy does not have any restriction to linear motion.
WWE: It is well known that Voigt's transformation differs from Lorentz's by an irrelevant gamma-factor which does not change the absurd postulate c=const.
a) The postulate is not that c is constant.
b) The extra gamma factor is what cause Voigt's transform to fail experimental tests, the Lorentz version does not fail.
c) The only "absurd" aspect is your silly attempt to pretend the Lorentz form fails by criticising the Voigt version.
SQ: a) the attempt to solve the twin paradox with the LT. The only way to solve the paradox is with non inertial motion (acceleration) of one of the two clocks,
That is not true Stefano, you can perform the experiment use three clocks by synchronising them as they pass.
George,
I would like you to read the paper of Wolfgang about the RDE, it is quite interesting.
Dear Wolfgang W. Engelhardt,
This is regarding you paper on the paradox:
From my understanding of Einstein's 1905 paper, synchronization should be done at same positions for the two system S and S' (reset of the chronometer).
Synchronization is obtained for each position such that we choose for a given point the system S and S' which verify t=t'=0 and x=x'=0. Choosing other systems that does not verify synchronization for the considered position does not allow to use the Lorentz transformation.
Also I think it is more interesting to analyze dt'/dt rather than the parameter t'.
Best regards
Dear Wolfgang,
You can introduce as many clocks as you want and involve yourself with various concepts of synchronization and further speculate what Einstein might or might not have thought. In the end LT translates space-time coordinates between privileged systems in a consistent and physical meaningful way nothing more nothing less.
SQ: I would like you to read the paper of Wolfgang about the RDE, it is quite interesting.
It's a long way to get there but at first glance he seems to derive the usual formulae in (12) and (18). I wouldn't use the old "relativistic mass" fudge, the formulae are much more easily found using the usual geometrical approach.
I suspect that may be causing a problem in his eqn. (19) where he states "If the photons are neither emitted nor absorbed, but just elastically scattered at moving mirrors, the rest-mass of the mirrors remains unchanged". That is only true in the "centre-of-momentum" frame, in all other frames the recoil of his mirrors will alter their kinetic energy and hence their "relativistic mass" so I would be dubious of the results from that point onwards without carefully checking the frame he's using.
George,
"I wouldn't use the old "relativistic mass" fudge, the formulae are much more easily found using the usual geometrical approach"
I agree that what can be defined and measured is the relativistic momentum / energy, but eventually it comes out to be the same result.
"I suspect that may be causing a problem in his eqn. (19). If the photons are neither emitted nor absorbed, but just elastically scattered at moving mirrors, the rest-mass of the mirrors remains unchanged".
Actually in such case the inelastic scattering should be double: absorption first and then re-emission processes.. but since the processes are supposed to be reversible and one is exactly the reverse of the other (also thermodinamically), the overall contribution is 0, only the classical Doppler effect remains.
It is true in any case that the radar doppler of the moving mirror is the composition of a direct Doppler and reverse Doppler, it is also true though, that this fact emerges also from the LT.
.That is only true in the "centre-of-momentum" frame, in all other frames the recoil of his mirrors will alter their kinetic energy and hence their "relativistic mass" so I would be dubious of the results from that point onwards without carefully checking the frame he's using."
The only way I see to model the absorber, as maintaining the inertiality through the scattering process with the photon, is as a huge mass concentrated in the scattering point. The center of momentum matches with the center of scattering.
What I don't understand is the formula 34...and for this I should ask Wolfgang...
Wolfgang,
sorry but I miss something in your paper. Explain me please the (34) of your apeiron paper "Relativistic Doppler Effect and the Principle of Relativity and its consequences"
@ G. Dishman
“The postulate is not that c is constant.”
Your German is apparently not good enough for reading and understanding Voigt’s paper. From his equations, however, you can see that his homogeneous wave equation (1) is transformed with the coordinate transformation (2) into another (unnumbered) homogeneous wave equation of the same form (“da ja sein muss”) just before (3). It has the same propagation velocity omega as (1). This requires making time a function of space (10).
As Voigt was dealing with the homogeneous wave equation his result may be multiplied with any arbitrary factor without changing the propagation velocity. Poincaré chose the gamma-factor in order to secure form invariance for the inverse “Voigt”-transformation. He baptized the result after Lorentz (see: https://www.researchgate.net/publication/258818001_On_the_Origin_of_the_Lorentz_Transformation?ev=prf_pub).
“The extra gamma factor is what cause Voigt's transform to fail experimental tests, the Lorentz version does not fail.”
The Lorentz version fails already in Einstein’s demonstration of time dilation of 1938 as I have shown. There is no point testing it and, indeed, it has never been tested in an experiment.
May I remind you that I am not “silly”. This kind of language may be used among relativists in an act of projection, but not in scientific discussions among serious physicists.
Article On the Origin of the Lorentz Transformation
@ Dear Halim Boutayeb,
please read § 1 of Einstein's paper. Synchronization is performed in order to establish a common time for all positions in an inertial system. It connects all clocks in a system to a reference clock reading an arbitrary time. Einstein has chosen t (x=0) = 0 and t' (x'=0) = 0 in his Figur 36. Having made this choice all clocks in K' will show t'=0 when the first one does it (see my first complement). I agree with you that the LT is at variance with t'(x') = 0 at x=0 and must be abondened (2. complement). Consequently we have dt'/dt=1, as time is not a function of space and the same in all inertial systems.
Best regards from
Wolfgang
Dear Erkki,
as you know I was only involved with Einstein's synchronization procedure and his illustration in Figur 36 of 1938. I have introduced only two more clocks in the upper system in order to symmetrize Einstein's example. These clocks read - in contrast to the prediction of the LT - t' (x') = 0 at t=0 in the lower system. You agreed already to this consequence of Einstein synchronization.
I am surprized about this statement: "In the end LT translates space-time coordinates between privileged systems in a consistent and physical meaningful way nothing more nothing less." as you wrote already: "If physics violate STR, WHICH IT DOES, the failure is due to one or several of its postulates." In other words: If the postulate LT violates physics, it is not physically meaningful. Complement 2 in Figur 36 is certainly not physically meaningful, when complement 1 is correct as you confirm.
Best regards from
Wolfgang
Caro Stefano
If we accept that physical space is homogeneous and isotropic, and that physical time is uniform (including arrow of time), then the physical space-time has pseudoeuclidean geometry (Minkowski). You may read about this in Logunov's book (and papers).
Under this conditions the Lorentz Transformations are mathematical consequences (isometries).
So, the Lorentz Transformations validity implies that physical space-time has the alluded properties, and viceverse.
Regards
Yes Wolfgang,
Physics violates STR and LT since it does not include gravity. However, your illustration concern synchronization procedures which does not pertain to gravity, hence LT is physically correct in this particular situation. What is it you do not understand?
erkki
Dear Wolfgang,
I have read your paper "On the Origin of the Lorentz Transformation" several times. I have no any objection. Lorentz transformations seem to add complexity, they have too much limitations (use of privileged systems) and they present non-physical results as you pointed out, whereas the equations 5, 7, 10 and 11 are more straightforward and agree with physics. I also like very much your description of the history because history seems to be an important part of the problem.
I am just wondering how should we write complete Maxwell's equations for moving bodies. Also, I am wondering if abandoning Lorentz transformations will change the relativistic form of the kinetic energy (I use to like the fact that the classical kinetic energy is a first order approximation of the relativistic one).
Best regards
GD: “The postulate is not that c is constant.”
WWE: Your German is apparently not good enough for reading and understanding Voigt’s paper.
My German is almost non-existent, but I was talking about Einstein's paper which is the basis of SR, not Voigt's work.
Perhaps you would be so kind as to give me your translation of this passage and in particular the word "bestimmten":
- "daß sich das Licht im leeren Raume stets mit einer bestimmten, vom Bewegungszustande des emittierenden Körpers unabhängigen Geschwindigkeit V fortpflanze."
The translation I've seen is this from the linked source:
- "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."
Google translate gives:
- "That the light in the empty space always propagates with a certain velocity V independent of the state of motion of the emissive body."
Google suggests "constant" would have been "konstanten", so what is the difference between that and "bestimmten"?
http://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf
SQ: Actually in such case the inelastic scattering should be double: absorption first and then re-emission processes.. but since the processes are supposed to be reversible and one is exactly the reverse of the other (also thermodinamically), the overall contribution is 0, only the classical Doppler effect remains.
The time dilation part cancels leaving the classic form but both absorption and re-emission push the mirror in the same direction resulting in a smal increment to the speed of the mirror relative to the source/detector. To be accurate, you have to include that in the Doppler equation, the speed used is neither that before nor after the reflection but close to the average.
SQ: The only way I see to model the absorber, as maintaining the inertiality through the scattering process with the photon, is as a huge mass concentrated in the scattering point.
The reflected light has lower frequency, hence energy, than the incident (if the mirror is moving away from the source/detector) and that lost energy is transferred to the mirror which means it's relativistic mass must increase. A lighter mirror would be accelerated more so the energy loss would be higher but the limit as the mass tends to infinity remains a finite energy exchange.
SQ: The center of momentum matches with the center of scattering.
I should perhaps have been clearer, I meant the 'center of momentum frame' which only defines a velocity, not a location. In that frame, the momenta of the photon and mirror are of equal magnitude and opposite direction both before and after reflection, the reflection merely reverses the direction of both.
Dear Erkki,
"LT is physically correct in this particular situation." (Figur 36 in Einstein's book of 1938).
You have apparently changed your mind and opt now for my second complement. LT yields "in this particular situation" t' = - x' v/c^2 when t(x) = 0 in K. This contradicts Einstein's synchronization procedure of § 1 which results in t'(x') = 0, since t'(x'=0) = 0 as assumed by Einstein.
Can you please explain what caused you to believe now that the clocks in K' cannot be synchronized? Previously you insisted that after synchronization all clocks in K' read t'=0 when the one at the origin does it.
Best regards,
Wolfgang
I have another argument for Wolfgang.
I don’t know if this has been used before. Please correct me if I am wrong.
If we consider a rigid rod along the x axis and we suppose that the extremities are at positions 0 and x1 at time t=0.
If we suppose that this rod moves with the speed v, and we call x’ and x’’ the positions of the two extremities (we call this hypothesis, hypothesis A).
Then we have x’=vt and x’’=x1+vt. These two points move with the speed dx’/dt=v and dx’’/dt=v which agree with the hypothesis A.
Now if we use Lorentz transformations we cannot resolve the problem for the extremity that is not at the origin at time t=0. Even worse, dx’/dt is not equal to v which is the hypothesis A. Indeed, in sytem S, any position x is not changing with time, then dx/dt=0, any position x’ and x’’ should satisfy dx’/dt=v and dx’’/dt=v but this is not the case. This show clearly that the coordinates and times parameters obtained from Lorentz transformations have no physical meaning. They just make Maxwell’s equation invariant in problem with a moving body.
When we want to model a problem we need to use physical positions and physical time, we do not need to use these additional parameters given by Lorentz transformations.
Best regards
George,
"The time dilation part cancels leaving the classic form but both absorption and re-emission push the mirror in the same direction resulting in a smal increment to the speed of the mirror relative to the source/detector.""To be accurate, you have to include that in the Doppler equation, the speed used is neither that before nor after the reflection but close to the average."
Remember that we are in the inertiality ipothesys, there is no room for any change of speed in this case (LT are for IRFs). Only if I assume a finite mass of the absorber I will be able to detect its variation of the speed.
"The reflected light has lower frequency, hence energy, than the incident (if the mirror is moving away from the source/detector) and that lost energy is transferred to the mirror which means it's relativistic mass must increase."
the energy is transferred to the mirror and got back. The net energy transfer is greater that 0, but in principle you cannot increase an infinite mass of anything... I know this is a paradox and the paradoxical situation is overcome assuming a finite mass. But as long as I stay in the LT I have to assume an infinite mass, otherwise in presence of radiation recoil I would lose the inertial motion.
I should perhaps have been clearer, I meant the 'center of momentum frame' which only defines a velocity, not a location. In that frame, the momenta of the photon and mirror are of equal magnitude and opposite direction both before and after reflection, the reflection merely reverses the direction of both.
Yes There is no frame where this can occur..
Christian,
I reply with the fact that some very important experiments on macrobodies have not been performed yet and the last word can be given only after them:
a) retardation/desynch of twin atomic clocks which underwent the same proper acceleration
b) variation of frequency of radiation in accelerated motion (pound and rebka without gravitation), doppler effect in accelerated motion.
Since the prediction of SR in the first case is totally absurd, either SR is wrong or the reality counterintuitive. But while QM is understandable SR would not be in this case.
The only possible constructive approach is through results of experiments, there is no other way.
Math is fundamental to allow to formalize laws the way these can be tested in reality. It is also very good to see if something brings to absurd conclusions.
It has been reasonably good in predicting new behaviours, but sometimes it has been given for true something which has not been carefully tested and this is not Physics is prone acceptance of a theory. ANd what makes me mad is that SR is not even considered a theory anymore, is considered a truth, a framework.
The only possible framework I see are the conservation laws, till somebody will show that they can be broken in very particular cases...but always with a ultrarigorous experiment....
SQ: Remember that we are in the inertiality ipothesys, there is no room for any change of speed in this case (LT are for IRFs). Only if I assume a finite mass of the absorber I will be able to detect its variation of the speed.
You are confusing different requirements. The simplest version of SR applies if the frame is inertial, not the objects. Einstein's paper was entitled "On the Electrodynamics of Moving Bodies" because it dealt with accelerating bodies.
GD: "The reflected light has lower frequency, hence energy, than the incident (if the mirror is moving away from the source/detector) and that lost energy is transferred to the mirror which means it's relativistic mass must increase."
SQ: the energy is transferred to the mirror and got back. The net energy transfer is greater that 0,
Right, not all is returned.
SQ: but in principle you cannot increase an infinite mass of anything...
Nor does infinity prevent addition. This is a good example of why I deprecate the use of relativistic mass, it leads to confusion and errors.
The bottom line is that in any inertial frame in which the mirror is moving prior to the reflection, energy is transferred from the light to the mirror and if the amount lost is dE, the relativistic mass increases by dE/c2. For an arbitrarily large mass, you can make the change of speed of the mirror arbitrarily low but you cannot eliminate the energy change.
SQ: I know this is a paradox and the paradoxical situation is overcome assuming a finite mass. But as long as I stay in the LT I have to assume an infinite mass, otherwise in presence of radiation recoil I would lose the inertial motion.
The motion doesn't need to be inertial, only the coordinate frame in which it is measured.
GD: In that frame, the momenta of the photon and mirror are of equal magnitude and opposite direction both before and after reflection, the reflection merely reverses the direction of both.
SQ: Yes There is no frame where this can occur..
What do you mean? Of course there is.
Dear Hugo Alberto : “So, the Lorentz Transformations validity implies that physical space-time has the alluded properties, and viceverse.”
Space-time without matter does not make any sense, and that is what the SRT interpretation of the Lorentz Transformations is about, because it excluded gravity.
That is the only reason why uniform velocity is indefinable in SRT.
In the real world however, the Lorentz Transformations represent the retardation by the speed of light, but the reciprocity depends on the definition of the velocities, linked to masses, as in the Newtonian interpretation.
That is why one can say that a fast moving rocket passing by the Earth would have its atomic clock retarding, and not vice versa, the Earth having its atomic clock retarding by the rocket passing by.
Hence, the Newtonian definition of velocity, based upon the global picture allows to define the Lorentz Transformations correctly, and they will not be totally symmetric in the case that only one RF moves and the other is standing still.
I am sorry Stefano, the down-voting closes your interesting RG question. I hope the officials take action! More and more down voting kills RG!
Please see section "Acausal Absorber Theory" of the page bellow where it is presented another form of Maxwell's equations from Thomas E. Phipps which are invariant with Galilean transformation. Why this theory is not analyzed nowadays?
http://www.infinite-energy.com/iemagazine/issue59/adissidentview.html
Best regards
@ George Dishman
It is amazing how airily a relativist utters preconceived opinions about a paper which he cannot even read. He calls people who have a profound knowledge of the subject "silly".
The German texts of Einstein are available in English translation. His book with Infeld was even written in English (see reference [6] in http://arxiv.org/abs/1506.09070).
It is not of my business to provide English translations. I am a multilingual physicist, but not an interpreter.
WWE: The German texts of Einstein are available in English translation.
I know, I gave you a link and included the translation.
WWE: It is not of my business to provide English translations.
What, not even a single word request?
OK, it appears you've taken the point, the correct translation is not "constant", nor was constancy Einstein's postulate.
The question of the thread is about the physical meaning of x',y',z', and t' using LT. I agree that if we use them in Maxwell's equations or in the wave equation we can see the interaction between electric and magnetic fields between the two references, deduce the Doppler effect and other phenomena. But the question is still what x',y',z' and t' mean physically. t' does not seem do be really the time in the moving reference and x',y',z' don't seem to give the position of the moving body. Thus there are only artificial parameters that may help to resolve certain problems but they do not have physical meaning, although some of the results obtained with them can have physical meaning.
I totally agree with Dr. Engelhardt about the origin of the LT. This come from the research from several researchers to make the form of Maxwell's equations (and thus the form of the wave equation) invariant for a moving body. Keeping the same form means c=constant.
Best regards
Keeping the same form in different frames requires that c is invariant, not constant. It could have had a smaller (but still invariant) value yesterday and SR would still follow.
However, assuming c is invariant would be a somewhat circular argument. What Einstein noted was that ε0 and μ0 were scalars hence the speed which can be derived from them must be independent of direction, the postulate is really that the speed is isotropic. He makes that clear by postulating that "the speed is independent of the state of motion of the emissive body". Invariance can then be derived from that and the first postulate.
Constancy is another matter, that can only be established observationally though we should bear in mind that it is a value dependent on the choice of coordinates.
Please read carefully the paper of Dr. Engelhardt on the origin of the LT.
Please ask yourself why we should try to make the form of the wave equation invariant if the body is at rest or in motion. Dr. Engelhardt has derived the wave equation for the body in motion and gave also the corresponding dispersion equation: that is all what we need. The variables in this wave equation are really the coordinates of the body and time.
The principle of relativity means that an equation that models a law of nature should holds for any reference. If the wave equation holds for a moving body, there is no reason to try to change its form. Changing its form to make it like the wave equation in a reference at rest means that the phase velocity is invariant (this is the word that you prefer). However the phase velocity is not the same in the two cases (the dispersion equation is not the same).
George:
"You are confusing different requirements. The simplest version of SR applies if the frame is inertial, not the objects. Einstein's paper was entitled "On the Electrodynamics of Moving Bodies" because it dealt with accelerating bodies."
Reference Frames are defined if attached to bodies, including IRFs. The physical meaning of RF is a set of measurements instruments, including the coordinates which are rigidly bound to material bodies.
I may agree with you that one thing is to see what occurs between IRFs and the other is to observe what occurs between generic moving bodies from an IRF.
The famous Einstein paper, you cited, deals mainly with IRFs and the "Dopplersheprinzip" which is between IRFs.
Only at the end of it, it deals with acceleration but he also derives a wrong formula of the "longitudinal and transverse mass".
"This is a good example of why I deprecate the use of relativistic mass, it leads to confusion and errors."
I avoid it as well but the resort to infinite mass is not relevant to that, it is only due to the attempt to model an IRF.
"For an arbitrarily large mass, you can make the change of speed of the mirror arbitrarily low but you cannot eliminate the energy change."
I agree, but here the paradox rises. If I make bounce back and forth a beam between approaching IRFs it will increase its frequency and hence energy violating the consevation laws, since bodies do not change speed by definition of IRFs... so it is not possible in principle to conceive an IRF if it interacts with something else...IRF is an isolated system basically... the original sin is avoided by saying that IRF can occur only within a certain experimental accuracy.
"The motion doesn't need to be inertial, only the coordinate frame in which it is measured."
In the LT the motion is postulated to be inertial and if I assume the exchange of EM waves I get the RDE. I deal with two inertial reference frames attached rigidily to two bodies...this should be impossible in real situation, that is why it can be considered only an approximation.
HB: Please read carefully the paper of Dr. Engelhardt on the origin of the LT.
I think it more productive to read what Einstein said when he derived the LT but looking at Engelhardt's paper a couple of things jump out.
First, just after equation (12), he says:
- "This amounts to requiring that the phase velocity of a wave is independent of the motion of the observer. It is unclear how Voigt arrived at this curious idea."
As I mentioned in my previous post, it can come from the fact that the speed can be calculated by any experimenter from the two scalar constants in Maxwell's Equations, though I'm not suggesting that was Voigt's reasoning.
HB: this is the word that you prefer
I prefer people to use the correct term to match what they mean. The words "constant", "invariant" and "isotropic" all mean different things so one has to be careful, and that is evident next.
The second point I note is from the first paragraph of section 3 in the paper:
- "This is reflected in the little relationship ½(τ0+τ2) = τ1 on page 898. It refers to a situation where a light signal is emitted from the origin of a moving coordinate system at time point τ0, travels towards some point on the x–axis where it arrives at time τ1, and returns to the origin upon reflection at time τ2. Einstein uses this inconspicuous relationship in order to express in a somewhat convoluted way his assumption c = const in the moving system as a precondition for the derivation. The technical term for taking the conclusion to be proved into the premise is called petitio principii."
In fact Einstein is simply applying the second postulate, that the speed is isotropic, hence (τ2-τ1) = (τ1-τ0).
Engelhardt gives the impression that Einstein assumes "c = const" in order to prove "c = const" but that is not the case, Einstein postulated that the speed was isotropic (as he clearly said) and used that to prove the LT, from which it can be seen that it is also invariant so his derivation did not depend on the result as Engelhardt implies. Einstein nether assumed it was constant nor tried to prove it was constant.
Can you see how Engelhardt misuses the terms to imply that the derivation is circular when using the correct terms would make it clear that that was not the case?
SQ: Reference Frames are defined if attached to bodies, including IRFs. The physical meaning of RF is a set of measurements instruments, including the coordinates which are rigidly bound to material bodies.
Exactly but you can choose what body to attach them to.
SQ: I may agree with you that one thing is to see what occurs between IRFs and the other is to observe what occurs between generic moving bodies from an IRF.
That's the key.
GD: "The motion doesn't need to be inertial, only the coordinate frame in which it is measured."
SQ: In the LT the motion is postulated to be inertial and if I assume the exchange of EM waves I get the RDE. I deal with two inertial reference frames attached rigidily to two bodies...this should be impossible in real situation, that is why it can be considered only an approximation.
Ah, you are missing a trick ;-)
You don't need to make the mirror of infinite mass to get an inertial frame, just add a small pebble which is initially co-moving with the mirror but is isolated from any forces. That pebble then defines the frame and the mirror can change its velocity relative to the pebble without disturbing the frame.
The example I gave was using the "centre of momentum" frame. Imagine the mirror is moving right to left relative to the pebble before it reflects the light, and moves left to right relative to the pebble after the reflection at the same speed. Similarly the light was moving from left to right, hit the mirror and was reflected back going right to left at the same frequency in that frame. That obviously conserves both energy and momentum as we require and the velocity of the mirror and frequency of the light can then be obtained in any other frame using the LT.
Once you use that approach, the results are exact, no approximation is needed.
If you refer to the wave equation without using LT, the phase velocities for transmitted and reflected waves should be c and c-v respectively thus we could not have (τ2-τ1) = (τ1-τ0) unless if we suppose that the phase velocity is always c for transmitted and reflected waves. The statement "phase velocity is always equal to c" and LT are tightly interrelated. The origin of LT is this statement and presenting this statement as a consequence of LT is just a closed circle.
HB: the phase velocities for transmitted and reflected waves should be c and c-v respectively
No, you're missing the point. The second postulate says only that the speed of the light must be independent of the speed of the source so the two speeds must be equal in both directions. They could both be c or both be c-v or both be any other speed you like, but they cannot differ if they are to comply with the postulate. That means that (τ2-τ1)=(τ1-τ0), regardless of the actual speed, from which ½(τ0+τ2)=τ1 is trivial algebra.
HB: "phase velocity is always equal to c" ... The origin of LT is this statement
No it isn't, that's only what Engelhardt wants you to think and why is mis-states "isotropic" as "constant". The origin of the LT is that the speed of light moving left to right must be the same as when moving right to left, which is what Einstein actually said, and that is apparent from Maxwell's Equations.
GD:The second postulate says only that the speed of the light must be independent of the speed of the source so the two speeds must be equal in both directions. They could both be c or both be c-v or both be any other speed you like, but they cannot differ if they are to comply with the postulate.
If I understand you the phase velocity for the transmitted wave should be equal to the phase velocity for the reflected wave: but this is not true according to the wave equation for a moving body which no one disagree with.
George
"Ah, you are missing a trick ;-)
You don't need to make the mirror of infinite mass to get an inertial frame, just add a small pebble which is initially co-moving with the mirror but is isolated from any forces. That pebble then defines the frame and the mirror can change its velocity relative to the pebble without disturbing the frame."
In other situations the pebble or the external inertial observer or the lab frame observer can be used. In the case of the RDE or the Moving Mirror, where there is a direct radiation connection and the gist is the radiation connection in itself, the RFs of the emitter and observers are put in relations right with the LT.
If I use the pebble I may define a comoving IRF for sure, but I would not be able to perceive the signal, since it is the mirror which is hit, so in principle I would predict the behavior of the signal according to the LT which is not the actual behavior of the signal which bounces on the mirror.
IF the mirror is of finite mass, the recoil will alter its speed and the bounced radiation will not be the same as if it is calculated by the IRF of the pebble which was comoving with the mirror till the radiation scattering.
"Imagine the mirror is moving right to left relative to the pebble before it reflects the light, and moves left to right relative to the pebble after the reflection at the same speed."
the mirror smashes into the source if it is not stopped by a multiple bouncing back and forth of the radiation...the pebble will see the mirror moving always in the same direction unless the motion is reverted by the same radiation which grew in intensity while the two systems were approaching..
Dear @ Halim,
Your example shows another inconsistency surfacing from the application of LT. The discrepancy is, however, of order v^2/c^2. Relativists usually discuss it away by taking resort to accelerations which are not part of SRT. That's why I have concentrated myself to effects of first order such as
linear Doppler effect against CMB (defining an absolute velocity of the solar system),
stellar aberration (https://www.researchgate.net/publication/244401858_Relativistic_Doppler_Effect_and_the_Principle_of_Relativity?ev=prf_pub)
Sagnac effect (https://www.researchgate.net/publication/261700742_Classical_and_Relativistic_Derivation_of_the_Sagnac_Effect?ev=prf_pub)
Einstein's own refutation of LT is also of first order x v/c^2.
Best regards,
Wolfgang
Article Relativistic Doppler Effect and the Principle of Relativity
Article Classical and Relativistic Derivation of the Sagnac Effect
HB: If I understand you the phase velocity for the transmitted wave should be equal to the phase velocity for the reflected wave:
Bear in mind that we are talking about propagation in vacuo so the refractive index is 1 by definition, and the phase velocity is just c.
HB: but this is not true according to the wave equation for a moving body which no one disagree with.
Anyone who has studied electromagnetism should disagree with that, Maxwell's Equations say the speed is c in any direction irrespective of the speed of the source.
Einstein used that as his second postulate, he wrote "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." You said the return speed was (c-v) but that is obviously not independent of v, nor is it compatible with Maxwell's Equations.
SQ: IF the mirror is of finite mass, the recoil will alter its speed and the bounced radiation will not be the same as if it is calculated by the IRF of the pebble which was comoving with the mirror till the radiation scattering.
Sorry Stefano, I sort of mixed different experiments. Let me try to be clearer.
Suppose you are trying to analyse a light sail driven by a series of pulses of light and we'll look at just one pulse. Suppose the sail is moving at away from the source 0.10c before it is hit by the pulse and 0.12c after the light has been reflected. If you define the pebble to be moving away from the source at 0.11c throughout, then the sail is moving at -0.01c before the impact of the light and at +0.01c after the impact. You need to calculate the speed accurately of course bearing in mind the formula for combining speeds in relativity, I'm just using a crude average to illustrate the approach.
Transforming the incident light to the "pebble frame" gives you the frequency as 'seen' by the sail which will be redshifted compared to the source frequency, the reflected frequency will have the same frequency in the pebble frame and transforming that back to the source frame will again redshift it.
That approach works, there are no approximations, just some tedious algebra, and the reflection is perfectly elastic in the pebble frame. Transforming to the source frame gives you the loss of energy by the light and the gain in kinetic energy of the sail.
Note the light doesn't hit the pebble, by definition it must remain inertial so nothing can affect its motion, it is nothing more than a (hypothetical) reference for the origin of your coordinate system.
Bear in mind also that the emission of the light pulse by the source also imparts some kinetic energy to the source as a recoil, but usually we don't need to worry about that.
GD: Anyone who has studied electromagnetism should disagree with that, Maxwell's Equations say the speed is c in any direction irrespective of the speed of the source.
I would not be as categorical as you. Radar engineers and electromagnetic books do no use this statement. Please see how the Doppler effect is considered by engineers and electromagneticians:
https://en.wikipedia.org/wiki/Doppler_effect
The statement that you present is only used by those who derived LT. The statement is the origin/cause of LT and the statement is also presented as a consequence of LT (this is the circular argument that we were talking about).
This statement is not a consequence of Maxwell's equations (and thus the wave equation). Please see Engelhardt paper on origin of LT: equations (7), (10) and (11) is what you get for wave equation. LT error comes from the idea to change the form of (10) in order to obtain a form as (12).
Imagine that we consider a dielectric medium with index of refraction n. The phase velocity of the plane wave propagating in this medium is c/n. Imagine now that someone come with the idea that the wave equation should have exactly the same form as it is in air with the same phase velocity c. Then this person will come with different parameters x',y',z', and t' in order to keep the same phase velocity c. These parameters have no any physical meaning. Probably the person will be able to obtain similar or same forms for intrinsic impedance and Snell-Descartes law. However no one will accept this theory and no one will give any physical meaning to x',y',z' and t'. So the question is why LT, which is all about the same technique as the one described above, is not even questioned?
HB: The statement that you present is only used by those who derived LT
I am a professional design engineer currently developing an HF radio so I'm well aware of how Maxwell's Equations are used in real life.
HB: The phase velocity of the plane wave propagating in this medium is c/n.
For a vacuum, n=1 by definition so, as I said, the speed is c.
For a dielectric medium n is different to one. Please try to follow the last paragraph which I repeat here:
Imagine that we consider a dielectric medium with index of refraction n (n is considered different to one). The phase velocity of the plane wave propagating in this medium is c/n. Imagine now that someone come with the idea that the wave equation should have exactly the same form as it is in air with the same phase velocity c. Then this person will come with different parameters x',y',z', and t' in order to keep the same phase velocity c. These parameters have no any physical meaning. Probably the person will be able to obtain similar or same forms for intrinsic impedance and Snell-Descartes law. However no one will accept this theory and no one will give any physical meaning to x',y',z' and t'. So the question is why LT, which is all about the same technique as the one described above, is not even questioned?
Please try to follow the fact that Einstein's derivation, which Engelhardt quotes, is in vacuum so discussion of dielectrics is of no relevance.
As I said, if you want to learn how to handle propagation in a medium, you should study Fizeau's experiments on light passing through flowing water which also supported SR.
Of course you can get right results with SR but the question is: is it right to do LT (which is equivalent to the postulate that you presented and which is equivalent to SR)?
I tried to show you that we cannot do that kind of transformation for a dielectric medium (using Maxell's wave equation we get that the phase velocity is c/n without any hypothesis), so why would we do it for the moving body? Why we don't only use the wave equation, without any postulate and any hypothesis from the beginning on the wave equation (if we use the wave equation for the moving body we obtain a phase velocity of c-v which is different to c)?
All the problem is on the postulate and that is where you should ask yourself: why it is accepted as granted? Any postulate should be first demonstrated experimentally.
Let us consider a plane wave A=exp(-j(kx-wt))=exp(-jphi). Suppose that we have a certain wave equation. By using inserting A in this wave equation we can get relation between k and w (dispersion equation), the phase velocity and how phi is varying. The trick of SR is introducing new parameters x' and t' and make an assumption on the phase velocity (the famous postulate). Of course we can obtain probably similar result in terms of the variation of phi, but this is not right.
Dear Thierry
In my knowledge SR is a theory about space and time, no more, no less.
Logunov, based on Poincarè's work, showed that SR is obtained via space-time properties, resulting the most basic and brilliant formulation of SR (it needs only one postulate). There is not necessity to refer to Einstein postulates, which are consequences too.
Lorentz transformations are obtained as isometries, which are independent of matter presence.
The pseudo Euclidean geometry of physical space time (the single postulate of SR), is also the fundament of the universal conservation laws.
So, SR will be a limited or wrong theory if, and only if, at least one conservation law is wrong.
Although most researchers assumes that SRT is not valid in presence of gravity, there are no theoretical neither experimental demonstration of such speculation.
On the other hand, Logunov et al have published a gravitation theory in Minkowski space.
Regards
Caro Hugo,
"So, SR will be a limited or wrong theory if, and only if, at least one conservation law is wrong."
Poincarè and Lorentz based their theory on the aether. The LET also respect the conservation laws and defininig a priviledge frame for the light can overcome the incongruency of retardation of accelerated clocks which is a consequence of the application of LT in SR.
SR implies the conservation laws not viceversa. IF SR fails this does not necessarily imply that the conservations are violated.
HB: Of course you can get right results with SR but the question is: is it right to do LT (which is equivalent to the postulate that you presented and which is equivalent to SR)?
Well if it gives you the right answer, then obviously it is right, you just answered your own question.
HB: I tried to show you that we cannot do that kind of transformation for a dielectric medium (using Maxell's wave equation we get that the phase velocity is c/n without any hypothesis),
By the definition, you get that the speed is c/n in the frame in which the dielectric is at rest.
HB: so why would we do it for the moving body?
To find the speed in any other frame, you would then need to use a transform. The LT gives you the right answer as you said at the beginning.
HB: All the problem is on the postulate and that is where you should ask yourself: why it is accepted as granted? Any postulate should be first demonstrated experimentally.
It is accepted because it has been tested by every method and experiment people can think of repeatedly, and has passed every test.
This postulate has never been validated and it is the origin of all the problem about LT and SR.
If you do not use this postulate you get the right result for the phase velocity and you explain very well all the phenomena related to a moving body. The fact that SR give similar results for these phenomena does not mean that it is right.
Let me give you a simple example
suppose that the solution of a problem give A=2pi * f * t where A, f and t are unknown. Using two other correct equations one find the right values for A, f and t.
Another person that use two incorrect equations find the right value for A but different values for f and t (we suppose these values to be f/b and t*b). Then we can say that both persons have found the right value for A but the second person is wrong about f and t.
For the problem that we are talking about, the incorrect equation is the famous 2nd postulate.
Caro Stefano
I am not talking about Poincarè or Lorentz theories, but rather the Logunov treatment.
SRT and conservation laws have the same fundaments (homogeneity and isotropy of space and uniformity of time).
Homogeneity of space gives the momentum conservation law.
Isotropy of space gives the angular momentum conservation law.
The uniformity of time gives the energy conservation law
While each conservation law refers to a single property (one-to-one correspondence), SR needs all together.
So, in order to invalidate SR as a general theory, it is only necessary the failure of one conservation law. If conservation laws are valid then SRT is also valid.
Of course, if SR fails then one conservation law at least is not valid.
Saluti
HB: If you do not use this postulate you get the right result for the phase velocity
As I have said several times, Fizeau tested the speed in a moving medium by measuring light in flowing water and found that the Lorentz Transforms give the correct result. I suggest you research his work.
Einstein's postulate has been tested a great many times and has always been found to be correct. A recent check is linked.
http://www.nature.com/articles/ncomms9174
Michelson and Morley:
A non-event can never be a proof, because it depends from the assumptions about the real world, while that real world is not even known.
Moreover it may depend from assumptions that are not even formulated. Indeed the assumptions of relativists are neither complete nor exclusive wrt the real world.
One of such assumptions is that aether has a velocity of zero at and in the Earth's surface.
So, Nature's "Direct terrestrial test of Lorentz symmetry in electrodynamics to 10^−18" is a downstraight lie. Again. It is neither direct, nor a valid test.
TDM: A non-event can never be a proof
No theory is ever proved, they can only be falsified, or not.
A null result can however be as valid as a positive. The null result of Michelson and Morley falsified the Galilean Transform. The quoted paper is an entirely valid test of Lorent invariance under the specific conditions.
Dishman. Wrong! A null result is only valid when the total physical context is perfectly known. Example in classical mechanics: a zero mechanical stress inside an ideal metal beam means that no forces act upon it from the outside.
That total knowledge of context is absolutely not the case wrt the present issue.
"No theory is ever proved, they can only be falsified, or not.". That is wrong again!
Falsification is not the sole criterion. A poor-quality theory can maybe prove a few things. However, even if it is not falsified, it can be surpassed by a much more performant theory.
Hence, a poor-quality theory must not mandatorily be falsified in order to be dismissed. Popper is wrong because his reasoning is a binary way of thinking, which does not represent the reality.
GD: As I have said several times, Fizeau tested the speed in a moving medium by measuring light in flowing water and found that the Lorentz Transforms give the correct result. I suggest you research his work. Einstein's postulate has been tested a great many times and has always been found to be correct. A recent check is linked.
First you said that the postulate comes from Maxwell's equations: this is not true. Maxwell's wave equation has the same form as sound wave equation and both disagree with the postulate. Thus from wave theory, the postulate is wrong.
Now you want to use experimental results which are not unanimously interpreted as you are interpreting them.
It is clear that the postulate was based on an assumption and it is strange to admit a theory before validating the assumption. Wave theory already disagrees with this assumption. Voigt was the first researcher to introduce a transformation that implicitly imposes this wrong invariance of the phase velocity (he considered a wave equation that must hold also for sound).
HB: First you said that the postulate comes from Maxwell's equations: this is not true.
Yes it is. The speed of the waves in vacuum in the equations is given by
- c = 1 / √(ε0 μ0)
Both ε0 and μ0 are scalar values with no direction dependence so obviously c cannot depend on direction either. The speed of light in vacuum is isotropic according to the equations and that is what Einstein states as the second postulate.
ME → c isotropic → LT → c invariant
HB: Maxwell's wave equation has the same form as sound wave ...
You must be joking. See Christian's reply.
@GD:
Now you have a 3rd argument: the formula of c as a function of the permeability and permittivity. The speed of sound also depends in the material and we know for sure that the 2nd postulate does not apply for the sound.
The form of the wave equation for sound or electromagnetic wave is the same: Helmotz equation. I wish you can compare both partial different equations and ask yourself: what is the difference in the electromagnetic wave equation that will annulate the effect of v that we see in the phase velocity for the sound equation?
The phase velocity is c-v or c+v depending on the direction. These two equations for the phase velocity are used in the 1905 paper in total contradiction to the 2nd postulate: is it not a clue for you?
I have also answered to CB in the second paragraph.
Sorry, I had a problem with my cellular phone,I had to switch to my computer.
Best regards
Please see my answer above.
I wish you can see what I see: actually you should be happy because since LT become superfluous, I propose you a world where there is no more speed limitation, no space dilation and no time dilation. We could maybe travel in the future at very high speed such that it would be possible to visit other stellar systems.
We still have much more work to do to have a better understanding of the electromagnetic wave and its medium of propagation. This is where we should concentrate ourselves.
Best regards
Christian,
The light medium exists: it is characterized by the permittivity and the permeability. The imaginary parts of these parameters characterize the loss (dissipation) for the propagating wave. The polarization of the wave cannot be a cause for changing the phase velocity.
please see also the second paragraph of my answer above (before the last message of George)
Dear Christian,
If dissipation is a key point, it must be demonstrated with acoustic wave for small distance that the 2nd postulate holds. We know that it does not depend on the distance.
I have summarized the ideas bellow. I am not using partial differential equations since not everybody are familiarized with them. However a minimum knowledge on phase velocity is required:
https://www.researchgate.net/publication/309770230_A_constructive_critical_view_on_special_relativity
Article A constructive critical view on special relativity
HB: "After that many experimental results have shown that it was possible to exceed the speed of light (superluminal phenomena), in order to be in agreement with SR, it was stated that c in LT is not anymore the speed of light but the maximum speed of propagation of the information."
That sounds like Cerenkov radiation.
In reading again this very interesting thread, I get the impression that the question of the purely electromagnetic mass of the electron is somehow important. In due time, it was pointed out that, without some stresses outbalancing the charge, such an electron would fall to pieces. But in 1905 the supporter of the primacy of electromagnetism conceived it in an immaterialist sense akin to Berkeley. To me the following article by Hecht: “Einstein Never Approved of Relativistic Mass”
https://www.researchgate.net/publication/239294361_Einstein_Never_Approved_of_Relativistic_Mass
suggests that perhaps, at first Einstein could have envisaged a purely electromagnetic theory in energetic terms rather than in terms of void space.
Article Einstein Never Approved of Relativistic Mass
Dear Sara,
first of all the relativistic mass is a conjecture of the past. What has been experimentally measured is the relativistic momentum and it is unappropriate to attribute the Lorentz factor to the mass. If I attribute such property to the mass I could also be allowed to attribute it to the background which resists reversibly to the motion of particles.
That the three forces unified, including the Electromagnetism are the base of the matter there is no doubt. Serious doubts are casted on the possibility for them to be also at the base of the mass of the single elementary particle.
There are theories which depict electrons as point like. This was also the Einstein's effort of his last years to make gravitation out of mass singularities. The Heisenberg's UP forbids electrons to be a dimensionless particle since there would be no uncertainty in their position.
The origin of the elementary particle can only be explained as resonances of higher dimension entities, something emerging from the background: which is what Higgs did. The Higgs field with the relevant coupled spinors are entities which explain mass and charge of the fermions.
HB: Now you have a 3rd argument: the formula of c as a function of the permeability and permittivity.
No, that is the first point I raised in response to your post four days ago on page 6 of the thread:
- However, assuming c is invariant would be a somewhat circular argument. What Einstein noted was that ε0 and μ0 were scalars hence the speed which can be derived from them must be independent of direction, the postulate is really that the speed is isotropic. He makes that clear by postulating that "the speed is independent of the state of motion of the emissive body". Invariance can then be derived from that and the first postulate.
HB: The speed of sound also depends in the material and we know for sure that the 2nd postulate does not apply for the sound.
The speed of sound also depends on the speed of the wind, the speed of light does not. There is no "aether wind speed" in Maxwell's equations.
HB: The form of the wave equation for sound or electromagnetic wave is the same: Helmotz equation.
That is wrong, there is no "aether wind speed" in Maxwell's equations. If you want to use the Helmholtz Equation for sound, you also need to incorporate the speed of the wind.
HB: I wish you can compare both partial different equations and ask yourself: what is the difference in the electromagnetic wave equation that will annulate the effect of v that we see in the phase velocity for the sound equation?
Simple, there is no 'v' to be cancelled, there is no "aether wind speed" because there is no aether and that's why the MMX and more recent versions always say the value of v is zero.
HB: The phase velocity is c-v or c+v depending on the direction. These two equations for the phase velocity are used in the 1905 paper
That is wrong, the phase velocity is c, the ends of the rod are moving at v and c-v or c+v is the rate at which the distance between the light and the end of the rod varies. You should try to understand what he says instead of just looking at the equations and making erroneous assumptions about what they mean.
HB: in total contradiction to the 2nd postulate: is it not a clue for you?
Immediately before introducing those terms for the first time at the top of page 5 (in the link attached) he states: "Taking into consideration the principle of the constancy of the velocity of light we find ...". That should be clear enough for you.
http://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf
George Dishman,
You said "Simple, there is no 'v' to be cancelled, there is no "aether wind speed" because there is no aether and that's why the MMX and more recent versions always say the value of v is zero."
That is another Straw man!!! I think you did the calculations by yourself in my theory.. Do you remember that!!!????
The speed v will be cancelled if we translating the retardation in EM according to the reality is observer dependent!!! in this case the result will give you the same result of the aether theory but instead of the aether theory, it is vacuum energy dependent (gauge theory)!!! And by equivalence principle gravity is gauge theory also!!! In this case LT can't describe the motion well!! The real transformation must be vacuum energy dependent. It is a transformation of group by vacuum fluctuations (acceleration), and in this case the uncertainty principle plays the rule, and this transformation expresses about the wave-particle duality by considering space is invariant!! Do you know what is the importance of space is invariant now!!!???
Review how I used the group and the phase in this case and how the uncertainty principle is working according to the phase and the group by the vacuum fluctuations!! Remember Chrenkov radiation is explained in my theory!!! That is impossible to be explained in SRT!!! You understand that well!!! You know why now!!! I advice to review the relationship between what is local and what is global in this case and how the uncertainty principle is the connection between what is local and what is global!!! The certainty is in the uncertainty!!!!
Now you must understand what is the importance of the wave-particle duality in this case!!! You must understand now what is the wave-function and the collapse of the wave-function, and how I used the phase and the group even in my equivalence principle and how I explained Pound and Rebka experiment by making the localisation by collapsing the wave-function (phase). In GR there is no localisation...why!?! And then how I explained light bending by gravity, Shapiro delay, Mercury precession, Pioneer anomaly by the group!! There is no energy momentum problem in my theory same as in GR. Energy and information are conserved!!!
According to aether theory, aether theory does not assume that the time itself is affected by motion; the reading displayed by the moving clocks results from two facts: Due to their movement through the aether, they tick at a slower rate than in the aether frame. The usual synchronization procedures generate a synchronism discrepancy effect. These facts give rise to an alteration of the measurement of time which exactly explains the experimental results. In particular, they enable to solve an apparent paradox that special relativity cannot explain When the measurement distortions are corrected, the time proves to be the same in all co-ordinate systems moving away from one another with rectilinear uniform motion. These considerations strongly support the existence of a privileged aether frame. The consequences concern special relativity (SR) as well as general relativity (GR) which is an extension of SR. We should note that Einstein himself became conscious of the necessity of the aether from 1916, in contrast with conventional relativity. Now I re=explained all of that according to quantum theory by the wave-particle daulity and the uncertainty principle, and I succeeded in that by translating the retardation in EM according to the reality observer dependent!!!
Azzam, I wasn't talking to you, I was answering Halim Boutayeb.
Until you can work out the answers to my questions and fix the errors in your work that I pointed out, you have nothing anyone could ever use.
AKA: Chrenkov radiation is explained in my theory!!!
No it isn't.
AKA: That is impossible to be explained in SRT!!!
The explanation is straightforward, it is light emitted by charged particles that are moving slower than c (as required by SR) but faster than c/n (which is the speed of light) where n is the refractive index.
You clearly know nothing about it again.
George Dishman,
You said "Until you can work out the answers to my questions and fix the errors in your work that I pointed out, you have nothing anyone could ever use."
Like this you use the Straw man!!! There is no errors in my work, and you proved that!!! Try to study well the Helmholtz equation and the Gunter Nimtz experiments!!! I'll not repeat!!!
You said "The explanation is straightforward, it is light emitted by charged particles that are moving slower than c (as required by SR) but faster than c/n (which is the speed of light) where n is the refractive index."
Nonsense!! because the Cherenkov effect can occur in vacuum. In a slow-wave structure, the phase velocity decreases and the velocity of charged particles can exceed the phase velocity while remaining lower than c. In such a system, this effect can be derived from conservation of the energy and momentum where the momentum of a photon should be written as p=h(bar)B (where B is phase constant) rather than the de Broglie relation p=h(bar)k. This type of radiation is used to generate high power microwaves.
In my theory vacuum is not a vacuum same as predicted in QFT. Now you can take the previous explanation of Cherenkov radiation and try to understand my explanation of Chrenkov radiation according to the conservation of the energy and momentum in my theory by the wave-particle duality and the uncertainty principle by translating the retardation in EM by considering the reality is observer dependent!! Now you can understand what is the real explanation of Cherenkov radiation and why SRT can't explain Cherenkov radiation!!! That's also illustrates to you what is the real problem of GR by considering the conservation of energy momentum. That's why if we consider LT we do not know if Lorentz invariance is exact or approximate, and there are other theories that break Lorentz invariance same as in explaining Cherenkov radiation in this case to fix data with SRT!!!!
Dear Stefano,
you are right. Hecht’s paper agrees with you on the relativistic mass. It is not a quantity of matter. I think, that Hecht's paper is well written. In 2011 he also wrote a longer one on all of Einstein’s demonstrations of the relationship between mass and rest energy, and their evolution.
Going back to my previous comment, on p.2 of this thread Engelhardt stated: “Furthermore, Einstein has himself refuted the LT in his book of 1938 as discussed at length in a different thread.” Yet, in 1905 Einstein only had propounded another physical meaning. Thus, initially, the had attributed to Lorentz' transformations a physical (electrodynamical) meaning that he couldn’t keep. Although I am no historian, it seems to me that the evolution of the mass-energy relationship was linked to the geometric representation of the Lorentz transformations.
For a while around 1910 it seemed as if simple algebraic geometry would explain physics. Afterwards, general relativity evolved into a program of geometrization of physics, for example geometrodynamics
(https://en.wikipedia.org/wiki/Geometrodynamics).
As a matter of fact, the standard model is far more abstract and complex than both.
GD:
I know very well Einstein's paper, it is not nice to make judgements. I used to learn every sentences of the paper because I used to see LT as magic equations that show hidden physical laws.
Einstein himself, with his humility, abandoned SR and the second postulate in 1907. I suggest you to read the last reference in my letter, there are very interesting things. This reference has other references showing how Einstein worked on delayed potentials using Galilean translation to resolve the problem of the magnet and the conductor in case of motion, during 7 years before 1905.
It is very important to understand the limit of a theory and not to believe it like a religion. At least you can try to follow what Einstein was thinking after 1905. He said about SR: that was "a good joke that should not be repeated" (last reference).
I friend of mine suggested me another reference. I repeat his text here:
"Petr Beckmann: “Einstein Plus Two” (available on Amazon), basically tries to show, quite successfully, that gravity operates as a medium for light propagation, like a refractive index, so its speed is relative to the gravitational field. He also founded the journal “Galilean Electrodynamics” (or electromagnetic, I don’t recall now).
Einstein apparently also believed that speed of light was affected by gravity, but maybe not the same way Beckmann did. Beckmann did not insist that Einstein was wrong; he just had a different philosophy and it happened to explain a couple of more physics questions, so he just pursued the physics like Einstein did."
AKA: Nonsense!! because the Cherenkov effect can occur in vacuum. In a slow-wave structure, the phase velocity decreases and the velocity of charged particles can exceed the phase velocity while remaining lower than c. In such a system, this effect can be derived from conservation of the energy and momentum where the momentum of a photon should be written as p=h(bar)B (where B is phase constant) rather than the de Broglie relation p=h(bar)k. This type of radiation is used to generate high power microwaves.
ROFL, is that the best you can do Azzam, quoting verbatim something you clearly don't understand from Wikipedia:
https://en.wikipedia.org/wiki/Cherenkov_radiation#Vacuum_Cherenkov_radiation
Note the bit you missed in your copy-and-paste, the particles exceed the phase velocity but still travel slower than c, exactly as I said.
The first link below is the source of the Wikipedia article. Rather than the usual case of the light being slowed by the refractive index of a material, they uses a carefully constructed waveguide to reduce the speed of the signal. There's a beginner article on slow-wave structures in the second link.
Enjoy ;-)
http://adsabs.harvard.edu/abs/1983PZhTF...9.1385B
https://www.microwaves101.com/encyclopedias/slow-wave-structures
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