Since Doppler causes an increase or decrease of frequency at the observer, and the energy of a photon is directly proportional to frequency, then the effect in the observer reference frame is that the photon has increased or decreased in energy.  Nothing particularly magical to it.

I know, but such view point seems not so widely shared as expected . And since it is the frequency perceived by the observer, it is not so evident that such increment is a net increment of energy of the atom/photon absorber at the expenses of some kinetic energy of the absorber itself, in the laboratory frame.

I think that the Doppler effect, as derived from general transformations of waves, where the characteristic wave phase is zero, and derived as a consequence of the Lorentz transformation, and further that there is no "rest system" for the wave, yet it is an expression for the equivalence of all privileged systems, imparts that there is no energy shift associated with the general phenomenon.

The actual absorption process is of course outside STR and the absorber (being at rest) would absorb the frequency of the actual photon as measured in the rest frame of the absorber.

Dear Erkki,

thanks for your precious  opinion.

One thing I would add though: the lorentz/fitzgerald factor  can easily descend from the classical doppler effect obtained from energy/momentum conservation. The gamma factor comes out when in the approaching (or dethatching) sound wave solution, the moving emitter and moving absorber relations have to be naturally unified, since no medium to discriminate who is moving respect to, can exist in the general case for light in vacuum.

The Doppler effect represents another important question that generates problems in Special Relativity. In fact in SR the speed of light and of photons is independent of the reference frame and of the relative speed while shifts of frequency and wavelength depend on the relative speed. It is manifest that in the considered physical event observed photon has greater or smaller energy than emitted photon by the source according as the relative speed between source and observer is a speed of approach or of departure. The relative motion produces a delta of energy that has to be added or decreased with respect to the initial energy of emitted photon. This fact is very hard to explain and understand in SR where the Doppler effect, like so many other physical events, has an exclusively kinematic nature depending on the change of space-time through Lorentz's transformations and factor.

Yes Daniele,

this is the sort of circular argument in which one risks to entangles when talking about relativistc effects...

Dear Stefano,

              For a third view, please look at Chapter 5 of L. Brillouin's book, "Relativity Reexamined (Academic Press, 1970, New York), where you would find a discussion on Quantized Doppler Effect, that suggests a correction to the classical Doppler Effect of special relativity. The discussion is based on energy-momentum conservation. You will also find a new approach to Special Relativity, where the path is:

Mass-energy relation => Atomic Clock => Doppler Effect => Lorentz Transformation.

Hi Stefano,

I think the question you ask is fundamental to our understanding of the photon, the Doppler effect, the red-shift, and our perspective of physics in terms of what a photon is and our interpretation of the photon’s state & behaviour in various experiments that are already well documented by prominent and recognised physicists. My “end-of-the-story” is that the photon’s frequency doesn’t change from the perspective of “Physics in 5 dimensions”, however you can switch between the classical view of physics in 4 dimensions and “Physics in 5 dimensions” and check for yourself the options open for us to interpret.

Your question raises all sorts of issues, as mentioned in part in other answers already posted to your question, and deserves serious attention. The changes in perspective possible, although slight, have a big impact on our view of physics and highlights the importance of research into alternative views of physics that remain however compliant with the current fundamentals of physics.

I am in danger of boring you and others with my reference to “Physics in 5 Dimensions”, but you have raised this key issue, and it deserves attention, where my example of “Physics in 5 Dimensions” is but one new perspective, either significant or not, that may encourage others to entertain their own ideas and follow new paths based on the issue of the Doppler effect, photons and the energy aspects involved.

For those with courage of endurance, you can download the book “Physics in 5 dimensions” from my ResearchGate account and look up the following sections:

13.3 Photons treated as particles in the Mössbauer Effect - page325

13.3.1 Scanning the Mössbauer peak - page 334

13.3.2 Conservation of momentum when a nucleus emits a gamma ray with recoil - page 337

13.3.3 Conservation of energy when a nucleus emits a gamma ray with recoil - page 339

13.3.4 Common ratio of gamma ray parameters resulting from the Doppler effect - page 341

13.3.5 Photon frequency in 4- and 5-dimensional space - page 342

13.3.6The Doppler Effect and Wavelength Redshift - page 344

13.3.6.1 The Doppler Effect in 4-dimensional space - page 344

13.3.6.2 The Doppler Effect for a photon is always a “redshift” in 5-dimensional space - page 345

16.3.4 The Doppler Effect, Mössbauer Effect and the Pound & Snider Experiment. - page 406

Chapter 17 Structure of the Universe - page 458

17.1 Physics of the Doppler Effect in 4- and 5-dimensional space - page  460

17.2 5-dimensional space Astronomical/Cosmological Redshift - page 462

17.3 4-dimensional space Astronomical/Cosmological Redshift - page 463

17.4 5-Dimensional space and the Structure of the Universe - page 468

17.4.1 Finite physical boundary and unlimited time - page  468

17.4.2 Built-in redshift - page 469

17.4.3 Distances between objects and observer. - page 470

17.4.4 Creation and Loss of Matter in the Universe - page 470

17.5 Summary: Structure of the Universe - page  471

 I hope this offers some “light” at the end of the tunnel!

Dear Alan,

I will have a careful look at your book, because when I see that somebody worked with the  mossbauer effect it gives me a "good charge"...

13.3.2 Conservation of momentum when a nucleus emits a gamma ray with recoil - page 337.. this is quite interesting...

Reading the Mossbauer nobel lecture didn't make me confortable...

He wrote and said: "the momentum of the cristal after the nuclear recoiless  emission/absorption is negligibly small"

I know that the Crystal reacts as a whole and already you "Rudolf Mossbauer" have to explain me this marvellous quantum collective effect which you don't even mention,  but you also say that the momentum which is very small indeed...is negligible....but negligible respect to what??? THis is Physics and if there is not a sum of terms in which something can be neglected..there is no other way to state that something is negligible.....

Either I can exctract some energy from vacuum or the vacuum itself reacts really as a Whole not the Crystal..like an infinite mass wall and absorbs the momentum without exchanging any energy...

Anyway this is another story...

Both of the alternatives Stefano gives are correct.  In a quick scan I didn't notice an answer that points that out.  If I missed one, sorry.

In the rest frame of the absorber, the absorber has initially zero kinetic energy.  If the photon is 100% absorbed (which I adopt for simplicity), then afterward the absorber is no longer in its initial rest frame.  In that initial frame, it now has a momentum equal to that of the photon.  It has some kinetic energy corresponding to that momentum.  Any surplus balance of photon KE becomes some kind of excitation or thermal energy in the absorber, depending on the specific mechanics of the interaction.

In any other rest frame, both absorber and photon have some KE and some momentum.  I presume that you would figure the resultant momentum of the absorber by conservation of momentum, and that again the left over energy would go into the absorber as excitation (potential) or thermal energy.  The amount of total energy is conserved before and after.  But the amount of total energy in this second case is different.

Again I presume that if you perform a proper reference frame transformation from the 2nd to the 1st case, the absorbed energy would transform appropriately and there would be agreement.

To me, Doppler is not mysterious.

Valentin, you've mixed two questions.  For a given absorber, all reference frames conclude the same degree of absorption, whatever that is, though they calculate it differently. 

Robert,

"In the rest frame of the absorber, the absorber has initially zero kinetic energy.  If the photon is 100% absorbed (which I adopt for simplicity), then afterward the absorber is no longer in its initial rest frame."

The photon is forcibly 100% absorbed, since this is quantum mechanics, there are no leftovers, or it is not absorbed at all.

Here you are talking about a secondary effect which occurs especially for high energy quanta. What you are talking about is the symmetric phenomenon of the recoil.

If you are making an hypothesys about a static observer, ok...

 "Any surplus balance of photon KE becomes some kind of excitation or thermal energy in the absorber, depending on the specific mechanics of the interaction."

if you are talking about a massive material object the Thermal energy is acceptable..

if we talk about instead of an interaction atom/photon, isolated, there is no possiblity for Thermal energy, no additional degress of freedom of fermions can be given, only space-time can help.

The only possibility for the scattering process is the Lorentz factor which allows the energy/momentum conservation and from which it is evident an additional local action of the space-time.

Remi,

"However in GR, a photon rising or falling in a gravitational potential can be said to have something "taken" or "added" to it much as a ball thrown in the air loses KE and then gains KE when it falls"

Sorry but this is not correct. It only depends on the characteriscs of the absorber atoms which are different at different levels in a gravitational field by the amount predicted by GRT. Photons do not lose or gain energy when they travel in a gravitational potential, they are massless when they travel and aren't photons anymore when they are absorbed as masses.

"In the SR scenario the basic Galilean construct is complicated a bit by length contraction and time dilation but classical picture of intercepting or receding from wavecrests of something existing independently in space-time is still the same sort of premise."

I don't think that with the wave representation there is a way out. THe wave is already a collective phenomeon and its representation can be  used well for transmission lines and antennas as solution of Maxwell equations, I would not ask more than this. The analitical power for local interactions with matter has to be left to quantum physics.

I would say that the two points of view are not reconcilable :

REAL, actual transformation of kinetic energy into electromagnetic energy, once stopped the absorber atom A can make more work, emit a more energetic photon,  than the atom E at rest which emitted the radiation A absorbed.

APPARENT, due only to reference systems,  the same thing seen from different points of view, there is no actual transformation of energy.

Yes but as pointed out in this paper the energy loss is not real. Or rather the absorbed photon at higher gravitational potential has the same possibility to perform a work as it was at lower gravitational potential, In other words it is exactly  the same photon.

Article Gravitation, photons, clocks

Dear Harihar,

"Quantized Doppler Effect, that suggests a correction to the classical Doppler Effect of special relativity."

In what consists the third view you suggest?? Yes there is a correction regarding the recoil of the emitter also showed by Schrodinger but this is only a further complication.

The dichotomy between "apparent" and "real" is the product of a wrong theory: Special Relativity that is based on Lorentz's transformations and factor. At first Poincarè and Lorentz demonstrated empirically those transformations with the only purpose to save the absolute reference frame and the ether. Later Einstein demonstrated the same transformations with the exactly opposite purpose: the absence of both the ether and the absolute reference frame. That demonstration nevertheless has many controversial points. The result is: two different logic processes that start from two different theses reach the same conclusion.  It is due to the fact that SR is unable to distinguish between physical effects and relativistic effects and that all reference frames are equivalent similarly for which, for instance, two synchronous events physically and really for an observer are asynchronous relatively and really for another observer.  That dichotomy therefore concerns all SR and not only the Doppler effect because SR is unable to answer elementary questions, as for example:

1. Are synchronous in actuality events?

2. Is the Doppler effect a real effect or is it an apparent viewpoint?

3. Is red the yellow ball that moves away as it appears or is it yellow?

In SR all these contrasting realities are similarly right and there isn't answer those questions generating a contradictory logic for which a thing is simultaneously and similarly white and black.

In the Theory of Reference Frames that dicothomy is solved through the "Principle of Reference" that defines among all reference frames a preferred reference frame that doesn't coincides with the absolute reference frame.

Stefano, yes for a single atom there is only excitation energy and KE, whereas the KE would correspond to thermal energy in a massive object.  There may be some angular momentum and associated energy.  Never even thought of that before.

Robert,

"There may be some angular momentum and associated energy.  Never even thought of that before."

you mean angular momentum in the case when the scattering has a certain angle. But let's always assume the simplest configuration where the direction of photon and atoms are the same.. to complicate things there is Always time...

Dependence of frequency (and energy) of photon on velocity of observer is a genuine effect of special relativity. To relate frequency and energy we need quantum mechanics. The transformation of energy-momentum follows from relativistic transformation rule which is derived by assuming constancy of velocity of light. Thus, the energy of photon is frame-dependent. The wavenumber and frequency together also transform in same fashion as momentum and energy and it is derivable again from the transformation rule of relativity. The ratio of energy of photon and its frequency being the Plank's constant has nothing to do with relativity as such. It follows from quantum hypothesis.

There seems to be a lot of confusion about Mossbauer effect. You have to conserve energy and momentum when an object emits a photon (or any other particle). If the object is at rest before emission of photon (in a particular frame), after emission sum of momentum of the object and photon must be equal or the two must have equal and opposite momenta. If the object is very heavy, the recoil velocity is very small since classically momentum is a product of mass of the object and velocity. In the limit of infinite mass of the object, the recoil velocity is zero. This also means (again in nonrelativistic limit) that the recoil kinetic energy of the object is negligible or zero (in infinite mass limit). In that case, the energy of the emitted photon is equal to the energy difference between the two states of the object. This is the principle of Mossbauer effect. The recoiling object does not have negligible momentum (as mentioned by one of the writers) but negligible velocity.

Shashikant Phatak,

"This is the principle of Mossbauer effect. The recoiling object does not have negligible momentum (as mentioned by one of the writers) but negligible velocity."

Yes you are right, it is the speed not the momentum to be negligible. This doew not improve the picture.

Negligible speed respect to what??? Are there sums in which it is inserted in which it is order of magnitude smaller?? This is Physics not generic estimation of something.

The Crystal reacts as a whole.. We are already deep in the realm of QM, since here the speed of light is not sufficient at all in order to reach all the Fe or Ir nucleous in time in order to carry the momentum at once. Phonons travelling at superluminal speed, maybe not phonons...

The even heavier affirmation is that the Crystal  does have to react as an infinite wall!!!

Yes it might be since only in such case the energy conservation is safe in the long run otherwise a tiny energy (due to the negligibly small speed) will be at disposal at any event of emission and absorption.

This implies that the collective nuclear phenomenon  of the Crystal which seems to interest 10^18 nucleous, has to couple near absolute 0, directly with the vacuum, which reacts as a Whole, or like an infinite massive wall.

This subject is not so Crystal-clear as expected, and has implication very far beyond the intrinsic meaning of the doppler effect.

Stefano

Shashikant Phatak ·

"The transformation of energy-momentum follows from relativistic transformation rule which is derived by assuming constancy of velocity of light. "

Just to be very accurate. The relativistic transformations were born  directly from the conservations (The symmetries of Emmy Noether mathematically proven later). I would not reverse the mother with the child.

"The ratio of energy of photon and its frequency being the Plank's constant has nothing to do with relativity as such. It follows from quantum hypothesis."

Yes..we might say that these have nothing to do...that is why the argument is debated. But since energy, as the possibilty to perform a work, is always a must, unless admitting the perpetual motion or extraction of energy from vacuum, it is the case to clarify the subject following such direction.

Valentin Danci wrote "I really doubt it "is a genuine effect of special relativity". Lorentz explained the Doppler effect and the aberration of light by introducing a concept of local time which was later re-interpreted by Poincaré, Larmor and ....." Lorentz's explanation is no more accepted as a correct explanation. The idea of local time is rejected and there is sufficient evidence to show that space and time is as determined in a given frame of reference. The space and time of one reference frame is related to that of other reference frame by the Lorentz transformation. Surely, Lorentz transformation was given by same Lorentz but was rederived by Einstein using principles of relativity.

Noether's theorem tells that space-time symmetry gives rise to conservation of energy and momentum. We have energy and momentum conservation even in nonrelativistic physics. In relativity energy and momentum together are conserved. Noether's theorem does not say anything about what happens from one changes coordinate frames. One needs transformation rule to go from one frame to another and that is given by principles of special relativity.

Shashikant Phatak

"We have energy and momentum conservation even in nonrelativistic physics. In relativity energy and momentum together are conserved."

We applied energy and momentum conservation in physics , and it is thanks to it that we managed to find that the Newton's law regarding momentum is not correct but the relativistic term has to be added. Again reversing the mother with the child.

Relativistc or not, energy in an isolated system is conserved so far... there is another law which has to be complied I'm really afraid,  and it is the maximum entropy principle, which doesn't care of relativity, the energy has to be conserved this is the first statement and the entropy of an isolated system tends to rise.

"Noether's theorem does not say anything about what happens from one changes coordinate frames. One needs transformation rule to go from one frame to another and that is given by principles of special relativity."

Yes you have to chose one, no matter which, and if you don't manage to describe phenomena according to the conservation laws I'm afraid that there are serious problem with the theory describing such phenomena. Yes Noether sees the global problem, it is not interested in the single view point, but from each and every view point the conservations have to be respected.

"Dependence of frequency (and energy) of photon on velocity of observer is a genuine effect of special relativity."

I would say that special relativity can be easly derived from the features of the doppler effect, beginning from the derivation of the Lorentz contraction, like Richard Feynman suggested. Relegating DE like a simple reference frames conversion means to deny its physical meaning, it is for sure something more.

Dear Valentin,

I have looked closer into your writings, where you advance your Neoclassical Theory of Relativity. You can certainly question experiments as being indefinite according to your own taste. That others do the same is no excuse. However, if you decide to remove Einstein’s postulate that I. The velocity of light is the same in all privileged systems, you are no longer talking about Einstein’s theory of relativity. Furthermore blaming Einstein for committing conceptual errors is meaningless as you have introduced a different conceptual framework that do not contain the postulates of STR.

If you want to dismiss the key axiom of STR, because it seems to be against common sense, and that you and a few others do not consider this is a physical fact that is sufficiently confirmed, you must realize that this step leads to consequences that carry you far beyond what your initial efforts can ever anticipate.

Let us just review what we have within STR (and GTR) as a scientific consensus amongst a majority of practitioners. Note that I am not saying that Einstein never committed any mistakes, there is a lot written about this by other writers, nevertheless it seems sofar that Einstein was essentially correct (in the same way Newton was a few hundred years ago).

In addition to postulate I. above the LT transformations follows uniquely from II. The properties of space and time, which consists of the following four well-known axioms, i.e. a) Space and time are homogeneous.  b) Space is isotropic. c) Space is symmetric with respect to velocities. d) The superposition of two positive velocities will again be a positive velocity.

This leads to a consistent theory, STR, that sofar appears to be principally correct and generalizable to GTR. In addition to the benefits of using the GPS daily, relativistic effects are routinely calculated in chemical physics to determine the structure of heavy atoms, etc. etc.

So in my book I am not willing to throw out all the deductive theories of modern physics, its invariance principles, beautiful symmetries, ab initio calculations on nontrivial molecules, advances in condensed matter and complex biological systems, just because you have doubts on the MM experiment, that, despite your detailed analysis do not contain proper accounts of gravitational interactions and possible background effects that in fact is necessary to get the GPS in order.

Preceding comments confirm again the current existence of three viewpoints and of three research directions:

1.  Modern and postmodern physics based on Special Relativity and General Relativity that asserts the full equivalence of all reference frames.

2. Neoclassical physics that searches for getting back to the absolute reference frame that was a fundation of classical physics.

3.  Contemporary physics that, from my viewpoint, is based on the Theory of Reference Frames, known and subscribed by few people, that in every physical situation establishes the existence of a non-absolute preferred reference frame.

It is manifest that only one research direction is right.

"The velocity of light is the same in all privileged systems,"

this is the results of the Michaelson and Moreley experiment. Some consider such property a tautology..This is at the base of Special Relativity.

 The velocity of light in a non local fashion, crossing gravitational potentials in presence of massive bodies varies in speed and direction . This is at the base of Gravitation and it is this feature that gives birth to time-dilation and lenght contraction in Gravitation.

Also in SR the time dilation factor can be seen as the variation the of speed of light in different reference frames...there is this possibility...even if by most this is considered an Heresy.

The slowing down of the procesess in LHC circular accelerator can be seen as a different time-rate in the accelerated system than in the static. But the origin of the time rate difference is a real physical, change, seen as a relative slowing down of the speed of light in the collision/accelerated frame than in the lab-frame. The acceleration increases the energy of the bodies, such energy stresses the space-time which reacts locally slowing down the processes, it is like a safeguard mechanism of the space time, which prevents its violation.

Dear Valentin,

Many thanks for your thoughtful answers. Let me first say that your youtube presentations are the very best I have seen that explains the problems that Einstein’s postulate (if you consider the definition of a privileged system, it becomes the second axiom) leads to. This is what I mean when I say that it appears to be against common sense!

My point here is that from then on your arguments are, at the end of the day, based on your rejection of the postulate mentioned above. It is also somewhat ironic that Einstein did not refer to the MM experiment when deriving his revolutionary result.

It is also important to observe that STR is a consistent theory in itself, although as everybody knows, it is not a true law of nature, as it does not contain gravitational interactions. This statement seems trivial, but nevertheless a lot of criticism appears to mix STR and GTR illogically. To incorporate gravitational interactions in a quantum theoretical framework is not difficult. The problem appears when one wants to quantize gravity and to invoke gravitational waves. There are thus many open problems and the question to me is to advance deductively, but not every scientist seem to know what this means.

Looking into experimental results in detail is a very complex matter, since it requests the full understanding of a lot of physics, math and statistics to know the error bars and above all to be certain about all the perturbations from noise factors to environmental interactions. I would say that the present doubts are not sufficient to remove one of the pillars of SRT.

Regarding the Doppler Effect: as I have said earlier it is a straight forward result of the Lorentz Transformation – no new postulates needed here. It is illogical to discuss this issue and at the same time referring to “absolute-relativistic effects” as the latter belongs to GTR.

Dear Daniele,

As a representative of the consumers of QM and STR-GTR, I do not agree with your stated viewpoint of the “three research directions”, of which your own research manifests the only “right direction”. 

Furthermore I am not willing to give you an interpretative prerogative to dictate and formulate the future directions of science, based on an incomplete analysis of present say physics.

During my time as Editor in Chief of the International Journal of Quantum Chemistry more than 5000 manuscripts passed my hands. Since their authors comprised international authorities in the field of chemical physics, solid-state physics etc., my interpretation was and still is that an overwhelming majority of scientists stand by deductive science based on the pillars of modern physics, i.e. QM and STR-GTR.

This does not mean that valid critique and serious debates regarding the fundaments of science should be neglected, however one should be aware of the consequences of removing one or several of the axioms and postulates that provide the theoretical foundation.

If you want to have a break with STR and GTR, which of the 5 postulates do you want to question and why?

Erkki, if you like to discuss with me, I would prefer you could be clearer. Which are the 5 postulates that you postulate?

Dear Daniele,

I referred to an earlier posting about the derivation of the Lorentz Transformation, LT. Pauli and others discussed the various assumptions that go into the derivation. A more recent study (Löwdin, 1939), see enclosed pdf  from his book “Some Comments on the Foundations of Physics” demonstrates that the 5 postulates below unequivocally leads to the LT.

I. The velocity of light is the same in all privileged systems

II. The properties of space and time, which consists of the following four well-known axioms, i.e. a) Space and time are homogeneous.  b) Space is isotropic. c) Space is symmetric with respect to velocities. d) The superposition of two positive velocities will again be a positive velocity.

So starting with the critique of STR , which postulate above must be rejected?

Dear Valentin,

I think a good way to remove any inconsistencies here is to reformulate the Lorentz Transformation, LT, without the use of Maxwell’s Equations, see e.g. the reference to Pauli in the Lorentz Transformation.pdf enclosed with my answer to Daniele Sasso.

There you will also see in detail how to derive the LT from just the 5 (or 6 if you include the definition of a privileged systems) postulates that I mentioned earlier. Although the speed c of light does not ensue, it is interesting that the axioms manifest a limit velocity that is invariant in any privileged system and which one might identify with “c”.

Note that there is no rest system for the light wave. A more detailed derivation for a general wave will make this distinction clear. The Doppler Effect is an unequivocal and explicit result of LT.

Dear Erkii, thanks for your answer. I read the paper that you have proposed. I am sorry, but I have observed numerous imprecisions and mistakes in that paper.

For example I read: "in these axioms (of classical physics) there are a number of undefined quantities as e.g. the concepts of force, mass, etc..." It needs a great imprudence to write those quantities are undefined when we know many physical properties of those quantities: physical definition, correlations with other physical quantities, measurement methods, units of measurement, etc...

I agree then fully with Valentin Danci that " Really, that whole construction has no logical(and I add "physico-mathematical") validity". I disagree nevertheless with Valentin about the existence of the absolute reference frame.

With regard to five postulates I agree with postulates 2.a  and  2.b that in the Theory of Reference Frames are properties of the empty space. Relative to the postulates 2.c and 2.d I reaffirm the velocity is a vector quantity and consequently its behavior is governed by the vector calculus. With regard to the postulate 1. it is a direct consequence of the demonstration for which my judgement about is the same as the demonstation.

Dear Valentin,

Per-Olov Löwdin, who wrote the book I referred to, was my teacher and supervisor for my PhD work. He is one of the founders of Quantum Chemistry, a discipline that combines physics, chemistry and biology. He was originally educated as a theoretical physicist and did e.g. spend time with Pauli in Zürich before being appointed to the first Chair of QC in Sweden.

He always challenged us not to believe anything until we had studied the sources and found our own understanding, but he also instilled in us a reverence for a deductive approach to science. This imparts a distinction of mathematics from natural science, i.e. that math is a language for succinctly expressing the knowledge of nature (physics) and then to use the deductive element consistently in the evolution of understanding.

One of the best examples (except of course the axioms of Euclid) is the formulation of STR as we are debating here. It is not always trivial to “translate” simple self-evident postulates like “homogeneity of space time” to mathematics, but it is worthwhile to try to adopt such a process of thinking.

You have obvious difficulties with e.g. the concept of space-time homogeneity as well as space isotropy. All I can say is that the first assumption implies that coordinate transformations have the same form independent of the choice of origin, and the second postulation, that we also have an independence regarding the direction of the x-axis – and so the derivation goes.

Your comments that “… quiet introduction of t1, as if it is already assuming that t is different from t1” and later “..inertial frames in motion relative to the absolute space” show that you have not fully understood and incorporated the deductive approach.

Furthermore there should be an obligation to not include unnecessary assumptions for the actual derivation – a sort of reference to Occam’s razor. In fact Newton did “sin” here since his first law is a consequence of the second – but I guess he is forgiven by now.

So I can only recommend you to study this further. I think one generally has an advantage to have been grilled through hard and competitive university courses and the pressure to “score” in grad school, with excellent possibilities to freely express ones arguments; as compared to self studies (even if one is an outstanding student).

No doubt an autodidact may be tempted to disregard “uninteresting stuff” and submerse oneself in “interesting” details and controversies. Nevertheless the latter approach has often been suffering from the temptation to use “common sense arguments” in scaling everyday physical models to cosmos and to the microscopic domain. On the other hand, such traps may still of course not prohibit anybody to “hit a homerun”, but the probability diminishes as science evolves.

Dear Ekki,

"In fact Newton did “sin” here since his first law is a consequence of the second – but I guess he is forgiven by now"

This statement appears to be true but not quite. The first law gives the definition of an inertial frame. One needs to have a reference coordinate frame to do measurements in mechanics. The first law says that a body continues in its state of motion IF there is no force acting on it. This statement is valid only in inertial frames and not in accelerated or rotating frames.

Dear all,

according to Galilean transformations:  All the systems proceeding with constant relative speed are good for doing experiments (INERTIAL)  with the helps of sticks and clocks [L],[T], and with linear transformations in v it is possible to pass form K to system K'.

Nobody could have expected that  Maxwell equations did not respond directly to the coordinate conversion of Galilei, for such reason the Aether was supposed to exist later disproved by the MM experiment. The conversion law between coordinate systems in presence of light could only be performed by applying the Lorentz transformations, (covariance of EM by lorentz transformations).The Einstein's quantum leap consisted into extending the lorentz transformations, (kinematics), to dynamics, with the SRT.

In order to be able to express phenomena in the K' coordinate system from a K coordinate system, being v their relative speed, it was necessary to find the alternative to Galilei's transformations.

BUT WE HAVE TO MAKE A VERY SHARP DISTINCTION:

The measurement of the relative speed is crucial:

a) relative speed measured by two generic systems relevant to the emitter and the absorber (EM waves measurement only, frequency variation)

b) relative speed in the laboratory frame of the emitter and observer is measured. (information of position with time)

When two bodies are  in deep space the only way to make measurements of thier relative speed in order to transfer the description of physics from one to another is by Exchanging  EM waves, photons.  Such way implies necessarily the direct use of the relativistic DE. In such configuration the DE and the Lorentz transformations are different descriptions of the same thing. The only information which the observer needs, in order to assess the relative speed is the frequency of the emitter.

When this process is brought in a laboratory,  seen from an external observer  the relative speed is asessed according to relative positions of the emitter absorber with time within the lab frame, not by frequencies of photons.

It is easy to apply the conservation laws, and to realize that DE implies transformation of Kinetic energy into electromagnetic energy, for the approaching configuration, and opposite for dethatching configuration.

Regardless of the view point used, the energy conservation is  respected, and as a consequence the energy transformation kinetic to EM and vice versa occurs accordingly, always present with a very good approximation.

I would say that relativistc Doppler  and Lorentz transform are a sort of the same thing formally,  I have to add though that the Lorentz transform and SRT have to have actual serious implications in "energy transformation" beyond the coordinate transformation and time dilation which are their recognised features. 

I would want to do some consideration on two important concepts relative to the debate that from my viewpoint is going into the hearth of the question: the Doppler effect and the speed of light.

1. It needs to say the Doppler effect was discovered much time before Special Relativity and classical physics interpreted that effect in the order of the absolute reference frame and of ether. That interpretation nevertheless had un inconvenience: it generated an asymmetry in formulas according as the observer was moving or the source, the relative speed being equal. Einstein first in Special Relativity gave a symmetrical formulation of that effect through Lorentz's transformations. This is a big merit of Einstein. In the Theory of Reference Frames, that is based on different transformations in the space-time-mass domain, the Doppler effect is still symmetrical with respect to source and observer but different formulas are valid.

2.  The Galileian relativity went into crisis because of the Ampere-Maxwell equation in the order of Maxwell's equations because from that equation classic physicists deduced the speed of light was always c with respect to ether and to the absolute reference frame. The Michelson- Morley experiment proved it wasn't true. Fitzgerald, Poincarè, Lorentz and others strove to save ether applying strange properties to ether, like length contraction and local time, and they reach like this the so called Lorentz transformations. Einstein denied the existence of ether, that he considered superfluous, but then through a demonstration, that was very similar like Erkii's teacher, he deduced the same Lorentz transformations. Like this Special Relativity and the postulate of constancy of the speed of light were born. There is nevertheless an alternative way to Special Relativity and to classic physics and it resides into a different interpretation of the Ampere-Maxwell equation and of the Michelson-Morley experiment. This interpretation is based on the Principle of Reference that establishes the light moves with speed c only with respect to the non-absolute preferred reference frame in every physical situation and this is different from ether. The consequence is that there is a "physical speed" of light that is always constant with respect to the local preferred reference frame and a "relativistic speed" that instead depends on the relative speed.

Dear Valentin,

A little bit of history will never hurt. Remember the popular metaphor (Newton said it but it is in fact older):  regarding” dwarfs standing on the shoulders of giants”. A little modesty is never wrong.

I am disappointed that your essential reply to my postings has been: “here is a logical fallacy named "appeal to authority". If you read my message carefully, you will find that it is an appeal to reason!

I am sorry to say again and again, that you do not have the slightest understanding of deductive processes, which are particularly important in scientific work. You are young and seem to have a brain better than most – use it!

Since you are the one who challenges STR (and GTR) you have the obligation to answer the questions that your physical portrait leads to, in order to be trustworthy.

I have even given you some pedagogical notes including a high school derivation of the LT. At least you can tell me what you have found wrong in this development. As you correctly realized your first reactions to it did not contain anything specific, except an overall feeling that it must be wrong?!

Again, if you want to challenge STR, including LT, you must be able to tell me whether the derivation of LT apply the mathematics erroneously or if the physical axioms are wrong – above all do not mix math and physics!?

Erkii, please let you verify the concept of linearity at pages 10 and 11 of the paper that you have proposed.

Dear Daniele,

"It needs to say the Doppler effect was discovered much time before Special Relativity and classical physics interpreted that effect in the order of the absolute reference frame and of ether. That interpretation nevertheless had un inconvenience: it generated an asymmetry in formulas according as the observer was moving or the source, the relative speed being equal. Einstein first in Special Relativity gave a symmetrical formulation of that effect through Lorentz's transformations. "

Yes, indeed, the Doppler effect was born before and applying the MM experiment results the Lorentz factor comes out naturally. It is the mechansim of testing the Lorentz transformations.

  it is much more:

a) the current relativistic doppler relation [(1+v/c)*gamma] is a simplified version in which quantum effects, like recoil of the sources and observer are not considered, given for granted the fact that masses relevant to the absorbed photons are negligible compared to the mass of the absorber. Such masses of absorbed photons comes not be negligible at all when considering a single atom/photon interaction with gamma photons.

b) The energy which is transformed during the doppler process is kinetic (motion) into electromagnetic (mass) in the approaching configuration, the opposite occurs in the dethatching configuration, the observer speeds up (kinetics) at the expenses of the energy of the photon (absorbed mass).

These phenomena are remarkable since there is a process of equalisation of energies: the kinetic which tends to concentrate to the same point (approaching)  is lowered and some more mass is formed, EM energy increases. On the contrary when there is a dethatching situation the kinetic energy of the atom is increased, the photon/atom becomes less massive, EM energy absorbed is diminished.

Relegating Doppler effect to something apparent, or just related to Lorentz transformations, or just a change of View point, is a very simplistic way to make Physics and I dare to say it is wrong....

Dear Valentin,

"Then further, the author (Löwdin ?) finds that:

          x1 = h(v){x - vt}             (I.2.6)

and after a few sign manipulations and the use of 2 other systems:

          x = h(v){x1 + vt1}          (I.2.7)

So how come the mysterious function h(v) is assumed to be the same (i.e. invariant) for the inverse transformation?"

The way there is no really priviledged RF, I have to pass in the "same way back and forth" in every system, simmetrically, if nothing else is postulated, it is the "least postulate principle" (Joking...but not so much).

"Also please note the quiet introduction of t1, as if it is already assuming that t is different from t1. So, something abstract as h(v), not even defined yet (!), is forcefully deemed invariant, while time is forcefully considered as not being invariant already?"

This is something which in another thread some others are discussing...

Well it would be arbitrary to assume that t=t' using the same t, hence it is more general to use different "t".

What are you mentioning would have been possible but quite unconfortable, T stays the same as absolute time and the Lorentz factor becomes a more complicated weighting factor. The events are compared, the interval between the events is given by the variable behaviour of the space time.

But since the Doppler effect requires the Lorentz factor to exists like that and that is the factor coming out from experiments with charges, it is the case to use it...

I would rather say  that  it is not TIME which is affected but the way atomic clocks measure it, the sequence of the events is exactly the same for everybody,  but it is the pace of the processes to be affected. The consequence of a limited speed for energy/momentum (c) brings to this..quite different from the Newtonian infinite speed view point.

With the Lorentz transformations math has taken the lead and this is not so good. They sort of interpret the symmetries of NOETHER's theorem, but hide something important which describes the physical properties of the space time.

Nowadays some make an effort to digest the fact that what it is called  "time dilation" is not an apparent effect but a real slowing down of the processes due to the reaction of the space-time to the increased  content of energy (stress-tensor) in such region.

Dear Stefano, the Doppler effect is a shift of wavelength and frequency due to the relative speed between source (emitter) and observer (absorber). What you are considering isn't the Doppler effect but a relativistic effect that exists also in the absence of  Doppler effect. I think you are considering the Lamb effect. In fact when the relative speed is zero the Doppler effect there isn't while the Lamb effect exists anyway. Then if you think to solve the Lamb effect in the order of Special Relativity changing the Lorentz factor I would want to inform you that it has been solved in the order of the Relativistic Deterministic Quantum Physics.

This first view seems odd to me and out of sorts with the law of relativity. That being said, how could one tell the difference if the outcome was the same? That's always the true question in physics.

E = h*c/lamda at the detector side regardless of the source, so I would say that it is an energy shift. The shift should only happen due to the relativistic movement of the source with regards to the detector.

"Dear Stefano, the Doppler effect is a shift of wavelength and frequency due to the relative speed between source (emitter) and observer (absorber)."

who denies it, but the implications of such relative motion is not only due to "relativistc effects", the first order doppler term is a net energy/momentum Exchange.

Daniele,

You seem to have a problem with the derivation of the LT, in particular the occurrence of the function h(𝜐). I better clear this up before total chaos develops.

Enclosed, please find a more detailed derivation.

Again math has not "taken the lead". Math is a language for expressing the laws of physics!

Erkii, I learned math is a language for expressing the laws of physics from my theachers. But also they taught me that not always good intentions produce good results. Anyway I will reply when I will read your new paper.

Valentin,

The postulate II. d. says: Space is symmetric with respect to velocities. Please read carefully!

Erkii, let you persevere with your basic mistakes of mathematical physics. You think mathematics is a manipolatory play of abstract symbols. You don't know the concept of linear system, you calculate a relationship among symbols in a particular case and then extend it to the general case. In relativity it is not important  that the "space is symmetric with respect to velocities" but it is important that the velocity isn't symmetric with respect to the physical phenomenon that one is considering. The most manifest case is just the Doppler effect that has a different behavior according as the speed is v or -v. You don't want accept the speed is a vector quantity and persevere with considering it is a scalar quantity.

Valentin,

So now your finally challenging the “velocity postulate”. However, your conception of velocity is too restricted to be useful.

First the postulate should be used as done in the rest of the proof – please continue reading.

Second, when you start analysing STR for particles, matter waves and EM waves, you must have a definition that is relevant. You have probably heard about phase- and group velocities and what their characteristics are.

In the framework of the variables (operators) energy and momentum and their conjugate entities space-time, one defines the velocity as dE/dp=𝜐, which is consistent with STR and Newton.

Please go back to the drawing board.

Daniele,

Mathematics is a language! It can be misused as we can mislead our neighbours with lies and trickery. This is of course the fault of the user not the language itself, even if there are paradoxes, not to mention Gödel’s theorem(s), but this is another issue.

Our issue is still the derivation of LT (from which Doppler follows). Introducing irrelevant topics like the Lamb shift etc. is nothing but trickery from your part.

I refer to my answer to Valentin – get back to the drawing board!

Dear Erkki,

"Mathematics is a language! It can be misused as we can mislead our neighbours with lies and trickery."

I was only pointing out that sometimes it is given the priority to math in order to get the results right, but the actual physical meaning is missed.

The Lorentz transformations are at the base of the four vector notation of SRT which is quite close to the expression of the relativistic doppler effect in free space considering everything acting along, let's say, the x axis. I have to see if with the four vector it is possible to consider recoiling energy which is a wider argument than the simple relativistic doppler effect, let's say a quantum-relativistic doppler effect..

Valentin, what you write is correct. As per a critical analysis of both the modern concept of relativity (SR, GR) and the Michelson-Morley experiment I have demonstrated a new system of transformations among physical quantities of two reference frames that have vector relative velocity, with any direction and intensity. Consequently they are valid not only for inertial reference frames that move with constant relative velocity along the same axis. These equations are:                                                          

                 P[x,y,z,t] = P'[x',y',z,t'] + INTEGRAL[(vdt) between 0 and t]

                                              dt = modt'/m'                                           

Like you see, there is also mass in these equations besides time and space coordinates. If you intend to examine and to expand on those transformations I ask you to do it with critical mind.

PS. Equations are in an unusual format because of the internal word processing of RG, and if you ask me I can send you a pdf format.

I was hesitant about which papers to advise, then I chose two papers:

https://www.researchgate.net/publication/210918310_Relativity_and_Quantum_Electrodynamics_in_the_Theory_of_Reference_Frames_the_Origin_of_Physical_Time

https://www.researchgate.net/publication/256391945_Physico-Mathematical_Fundamentals_of_the_Theory_of_Reference_Frames

Article Relativity and Quantum Electrodynamics in the Theory of Refe...

Article Physico-Mathematical Fundamentals of the Theory of Reference Frames

Valentin,

The gradual uncovering of your misconceptions is more and more contributing to the general picture why you and your supporting buddy have succeeded to be so wrong!

The Doppler effect is a result of LT. I have presented a simple derivation of LT from 5 basic axioms (read them again since you seem to forget them!) I have sent you supporting derivations when you got stuck.

The Lorentz Transformation (the name is Lorentz not Lorenz) is simple beautiful and provides a cornerstone for further theoretic advances. There is an analogy with Euclid’s postulates. You can rightly challenge the parallel axiom and then derive non-Euclidian geometric versions – all in agreement with deductive reasoning. But your strategy is not to get involved in any such reasoning!

The postulate, II.c, says “space is symmetric with respect to velocities” and in the material enclosed earlier, it is demonstrated how this axiom is used in the proof. Your reaction “Physics doesn't have any “velocity postulate”!” On what planet are you hiding?

Then you continue: “except for Einstein's second postulate, which your demonstration tries in vain to prove by inventing other absurd vague postulates”. First I am not trying to prove Einstein’s postulate – it is an axiom in a deductive process. The vague postulates are the ones of Einstein, Pauli and others and practically speaking most derivations of STR are based on similar assumptions!

The most surprising and ill-formulated and misleading statement is “Physics just measures/determines velocities”. Physics means knowledge of nature and “knowledge of nature” does not measure anything. Physicists doing science through research, accumulate knowledge by systematic observation, deliberate experiment (here we measure) and rational theory.

Science is the art of knowledge and the practice of this skill is supposed to be logical in character leading ideally to theories of deductive type. Hence, when you “put all your eggs” in the hat of Héctor Múnera, who challenges the MM experiment, looking for contributing errors in the 1887 experiments of MM, and finding possible ways to secure a non-null result that seem to lie about one tenth of the earths velocity around the sun, you disregard modern advances of laser inferometry, e.g. Lunar Laser Ranging and the Laser Interferometer Gravitational-Wave Observatory. This is one of the many summersaults that you carelessly and accidentally bring about!

Even if no gravitational waves will be discovered the GW-Observatory provides outstanding technologies at the same time, the derailed STR and GR, give us GPS, which would not work in a Galilei framework. Besides I did not seen any mentioning of gravity in Hector M:s analysis.

On top of that you finally express: “I don't see any relevance of "phase-and group velocities” How in the whole world can you even mention and criticise MM:s experiment without knowing the fundamentals of wave propagation?! In order to discuss the Doppler effect you must be able to adapt the LT to wave propagation, and the present appeal to reason gives us a simple general extension of velocity that is commensurate with all kinds of waves and the axioms of STR.

Finally, you seem to have a weird approach to physics. In general we have the human sensibilities of space and time. A physical event is formulated in terms of energy and momentum and portrayed in space-time – or conversely we equip space-time with energy-momentum. You need both to dance and the velocity is the derivative of the energy with respect to the momentum.

 It is extremely awkward to debate with you, since I have to explain everything to you. I recommend you to go back to the drawing board. Take some elementary physics courses, enlist in Grad School or do something sensible! 

I doubt your mathematical ability to turn your project into something useful. I doubt your muddled view about math and physics. I doubt your view to derail the importance of deductive theories. I doubt your pathetic and immature beliefs. I doubt your naïve faith in “common sense” in situations like the microscopic domain or the cosmological arena. To quote Cartesius: I do not doubt that that I doubt? I apologize for the reflexive statement that later made Nietsche, Heidegger and Gödel famous.

Valentin,

I am 70+ and still passionate about science! I like to challenge and I learn from it, I like to be challenged and I continue to learn from this.

You are young and apparently not passionate enough to stand up for your beliefs. I am disappointed and think you are a coward!

I can only imagine your success if you could repeat your youtube moves displaying the Lorentz equivalent of your Neo-classical Relativity with the limit velocity c= 1m/s; 5m/s; 10m/s etc. For you this would display the non-common sense results of LT and for those of us, believing in LT, the weirdness of nature at cosmological scale. Whatever one thinks it should be a success!

Dear all,

I thank you for your partecipation first of all.

I appreciated your comments, thanks to Erkki a scientist veteran,  open and knowlegeable person, and I appreciate Valentin for his big non common effort trying to explain the effect of light with animations. I suspect that there is something which does not work but I have to find the time to see the details of one of Valentin's animations.

It is difficult to accept  that the four vectors energy-momentum and the Lorentz transformations, and light speed argument,  something overtested also in accelerators and many other experiments may contain significant mistakes..Dirac, Feynman, Fermi, Majorana, Eisenberg, and many other nobel prizes  didn't make exceptions in these, using them and finding their marvellous results...

Regarding Einstein I found instead exceptions on the form and predictions of GRT  by Kalman, Thirring, Feynman,  Fock, Synge, and others and I'm realising that their exception have a sound foundation, as suggested me also by Yurij Barishev.

In such case though GRT passed some tests, it still has to pass the one regarding the energy conservaton in a proper way...for this reason Field Gravitation of Poincarè, Kalman, Thirring and Feynman is a much better theory because it accounts for the gravitational energy properly. But this is another story...

In GRT Einstein is certainly questionable since resonable doubts by Nobel Prizes have been raised in 100 years, for other things it is gets really hard.

The effort made by Valentin denotes his ability in something  which is very powerful  in order to make people understand effectively, but patience has to be put in trying to model the reality properly.

I support Erkki for his recall to Science, but would be interesting to make detailed exception in at least one of the videos, recalling the experiments performed during the history of science...

Stefano,

Thanks for your words. I do not know if the Doppler issue was completely worked out in agreement with everyone. Nevertheless it started some heated discussions on Einstein’s mistakes and asserted lack of knowledge.

I am sorry that Valentin interpreted my critique as a war on words and a competition of authority. Instead he should have applauded an opportunity to have his work red and criticised by someone who does not share his repeated criticisms of Einstein’s conceptual errors and risky ignorance – and I disrespect his recent efforts to change his wording into evaluating his behaviour as an idealistic dialogue to be respected. If so his first responsibility should have been to read my enclosed derivations and answered appropriately to my critique of his writings. He did not.

I agree whole-heartedly with you, as I have also expressed myself several times, that it is difficult to accept quote that the four vectors energy-momentum and the Lorentz transformations, and light speed argument, something overtested also in accelerators and many other experiments may contain significant mistakes unquote.

I also agree that there are obvious problems with Einstein’s equivalence principle as modern cosmological observations lead to severe paradoxes, but this is nevertheless quite understandable since there is no consensus regarding the marriage between relativity and quantum mechanics. Even if Einstein made some minor mistakes the latter conundrum should not be put on his account as he unfortunately was not comfortable with quantum mechanics.

Finally my recall to science is very simple, perhaps it should have motivated a separate thread. I have again and again made an appeal for reason commensurate with a deductive scientific process.

My interpretation to the deafening silence to this obvious and imperative request is that most of RG members feel that this is too high a level of ambition to ask for today.

If so, there is little point to challenge unconventional interpretations and creative suggestions, since eventual discussions will only appear to be a war of words and a competition for authority. Does anybody seriously believe that science can evolve in such a climate?

Sorry for speaking my mind but I am awfully disappointed!

Dear Erikki,

my aim was  to regain attention on the main argument of the thread, that's all, and to make people not to waste their energies in not very "in theme" discussions.

Regarding the Doppler effect the things will go on since as you said we didn't come to a shared point yet, and I have still something to say too..

Referring to Einstein , sometimes if somebody is known  as a sort of "total Genius" we tend to minimise his mistakes, or forget. Science does not have to have mithological figures. But if in 100 years  something has been intensively used and not questioned by the brightest mind at least I have to trust it, and in this case Valentine has to pay a lot of attention before declaring something with a real risk to be disqualified.

Hystory is full of pepole who thought they had the holy grail in their hand but then nothing valuable was actually found. Science has been paved of absurd theories.

"If so, there is little point to challenge unconventional interpretations and creative suggestions, since eventual discussions will only appear to be a war of words and a competition for authority. Does anybody seriously believe that science can evolve in such a climate?"

 Erkki, this is not the climate where Science with capital "S" has to evolve, we don't have to have  such drifts.

"Instead he should have applauded an opportunity to have his work red and criticised by someone who does not share his repeated criticisms of Einstein’s conceptual errors and risky ignorance "

yes...I agree

 I will continue with the analisys of the doppler effect...

Dear Stefano,

I wish you a good reading of Valentin’s Neoclassical Theory of Relativity. The presentation is well done, in particular the YouTube animations. I think there is here a lost opportunity since the simulations could be extended to interesting LT versions with various values of the velocities, seen from the platform and the train and then for extended Galilean transformations.

There seems to be a somewhat large group of people on RG that reject STR and GR. Many of them are in one way or another followers of Herbert Dingle, who wrote “Science at the  Crossroads” 1972. He was an influential scientist, Professor at the Imperial College, Founder of the British Society of the History of Science and even President of the Royal Astronomical Society.

His sudden campagne against Einstein was met with surprise and even chock and many of his friends and contemporaries, including Einstein, Synge, Born etc. tried to show him that he was wrong, but without result. In many of the discussions on RG one can see the guidance and inspiration from Dingle.

Another actor on the physics scene is your country-man Ruggero Maria Santilli, who has the unpleasant habit to sue individual persons, editors and institutions (including the Nobel Committee) who does not agree with him – he calls contemporary physics a Great Conspiration.

In these circumstances I do not see any point in dividing science into “small” or “capital” S. The only tactics to me are to employ Deductive Science or abbreviated DS!

Dear Eric,

I had mentioned FGT Field gravitation theory, what is RG (I'm ignorant sorry),??

Yes I have to go deeper with Dingle's,  in every "not correct conclusions" may hide  intelligent insights. I've heard about Santilli...I don't really know what to think...

__________________________________________________________

Going back to Doppler effect so far I say:

a) the Doppler effect of radiation is based on a quantum physical effect and as such has to be considered and the general model has to be built in such framework.

b) the  relativistic Doppler (1+v/c)*gamma and (1-v/c)gamma, is a simplification of the real case of interaction between moving sorce/observer and radiation. 

The hypothesys of low frequency radiation or stiffness of bulk of matter, assures that some details of momenta exchange between radiation and matter can be neglected (recoil). In such case the Lorentz Transformations/four vector energy momentum, properly approximate the phenomeon of Doppler of EM radiation.

c) It is easy to derive the Lorentz factor directly, without passing through SR. It is enough to use a simplified matter/EM-quantum scattering hv, neglecting here too the recoils,  finding the classical DE in the two versions and then assuming the relativity of motion in order to put at work the Lorentz factor.   

The fact that such derivation is not common at all is maybe due to the fact that Lorentz discovered the electrodynamic factor years before 1900 the year when Planck made his very famous experiment and discovered EM quanta.

As a consequence the energy momentum four vector of SR can be deduced from the Doppler Effect, . The four vector is also a direct consequence of a mere coordinate conversion, since Lorentz transformations is considered as such.

d) Regarding the energy issue, it is clear that in the laboratory frame the energy has to be conserved being us in an isolated system.

 As a consequence of energy  and momentum conservation the variation in lab frame at low speeds of scattering atom/photon coresponds to a different energy photon absorbed. Some kinetic energy in lab frame of atom/photon, gets transformed in EM energy of quanta and vice versa.

The atom A moves (slowly) in the lab frame towards a still source S, emitting at a certain frequency fs. The atomA absorbs and emits only at higher frequency fh, intrinsic property, but its relative speed is sufficient and the photons emitted a fs are absorbed.

The atom A is stopped and then radiates the photons absorbed at  fh,  his allowed frequency, in the lab frame. The difference of energy between such photons radiated both still in the lab frame, can be performed and is h*(fh-fs)= delta E, it represents an actual energy difference, something which is able to make a "little" work. Such tiny energy was, before the absorption, some of the kinetic energy of the moving atom.

Stefano,

The derivations of the DE, whether being a result of LT and a (four dimensional) wave vector (transforming like a four vector under LT) or going directly through EM waves are fortunately consistent.

An alternative treatment (commensurate with the above) is John Bell’s article: How to Teach Special Relativity in Progress in Scientific Culture Vol.1. No 2, Summer 1976 (Ettore Majorana Centre for Scientific Culture), where he is demonstrating the analogy between Maxwell’s equations and Lorentz invariance.

What you say make sense in the framework of energy conservation. However, there is another deep problem lurking here, viz., the Minkowski metric, which is indefinite, alters the properties of the Energy variation principle. Instead of being an extremum law it is now “only” stationary. This problem becomes more problematic in GR, since the energy law, momentum law and the force law are not compatible any more, with consequences for the dynamics.

Note added in proof: I was born in Finland so my name is Erkki, but it means Erik or Eric. RG was just a reference to Research Gate – sorry.

Dear Erkki (sorry for Eric),

this discussion about energy conservation is central and of paramount importance. I'm having a sort of this discussion also in another thread, with some mathematicians who do physics giving little importance to it, not very aware of the consequences of their considerations.

"However, there is another deep problem lurking here, viz., the Minkowski metric, which is indefinite, alters the properties of the Energy variation principle."

What is quite difficult to demonstrate is that in an isolated system energy is "not conserved", and energy is the possibility for a system to perform a work. So far nobody managed to show that this property was infringed. 

To admit an extraction out of "space-time fabric" of the capacity to produce  work ,  has to be very carefully demonstrated experimentally, breaking the pillar even of the Heisemberg indetermination principle, which prevents that vacuum energy assumes a priviledged direction (entering the 4D) in quantum electrodynamics.

The Lorentz contraction was born in order to comply to energy and momentum conservations separately. All the theories have been tested under these assumptions, and many were discarded, NOETHER'S theorem was a way to explain mathematically these conservations (momentum, angular m...) as the properties of a continuous manifold.

Feynman himself said that the variational principle of EULER-Lagrange orHamilton-jacobi which embodies the Noether's prescription are necessary ingredients for a good theory to come out.

That the way energy is calculated had to change after the discover of the Lorentz factor is simply due to the fact that in an isolated system the energy conservation had to be complied and the only way to make energy conservation come out, not admitting leaks of the space-time fabric,  was simply  to add changes on how energy was calculated...

Quantum electrodynamics, scattering in every experiment with QM are based on conservations one of which is energy.

I consider energy absolutely fundative and as the base, so far, of a choerent description of reality as we know it through physical models.

I'm not surprised at all that QM and GRT didn't merge  yet in a coherent theory and something else had to be found even if not successfully.

How can two theories merge, if fundative principles contained in one is not respected in the other???

Dear Arno,

I didn't deny that the doppler effect is a consequence of reference frames.. what I can say is that maybe the conversion of reference frames for light was considered a neutral conversion by default, so nobody seemed to care to show it was,  and it is maybe not a neutral conversion digging properly.

Dear Arno,

I just wanted to point out that the blueshif/Redshift is doppler or gravitational.

The doppler shift is a net conversion of energy Kinetic--> EM (mass) or vice versa, depending on approaching or dethatching.

The gravitational Redshift corresponds as Fock correctly affirmed  only into the relativistic part of the Doppler effect or transverse, which is the gamma factor in the clock's theory. In the gravitational redshift the perception is different of the same photon, since the measurement of the frequency in hv is influenced by the gravitational field.

https://archive.org/stream/TheTheoryOfSpaceTimeGravitation/Fock-TheTheoryOfSpaceTimeGravitation#page/n203/mode/2up/search/red+shift

Dear Arno,

what I say is not in disagreement with Lorentz. It simply adds some additional meaning which goes Beyond the simple coordinate, frame conversion.. it is an energy type conversion...motion which goes into EM energy --> mass...

Remind that E=mc2 is a consequence of relativistic energy-momenta...

Dear Arno,

I've read your article, and I agree with you with the fact that RDE is used to determine speeds once the emitter frequency is known.

I know that Redshift of galaxies are due to a cosmological Redshift which in most cases has a component which are not explainable by gravitational Redshift or doppler Redshift but are due to space-time fabric expansion..

Regarding Doppler effect of EM quanta or relativistic doppler effect of rediation in a general way, I'm still of the idea that Giuseppe Giuliani (the one who wrote the paper under discussion) cannot be wrong in his interpretation.

For flat space time the Poincarè Group guarantees the energy conservation and momentum conservation  in a laboratory frame. This is the base of the experimentally verified Quantum Physics. 

The derivation of the quantum DE of Em radiation, according to energy conservation (interaction between atoms and EM quanta), has to be certainly correct.

The interpretation about the transformation of kinetic energy of atoms  into EM energy/mass (as a consequence of energy conservation)  if it is correct in an Galilean laboratory frame in deep space it is anyway correct.

The Lorentz transformations and the derived Four vector energy momentum are formalism from which the most common relativistic effect relation can be derived. THis is Limited to low energy quanta but  possible with high energy quanta in configurations included in the Mossbauer effects.

The four vector energy-momentum represents an approximation of the real Quantum relativistic doppler effect with low energy quanta and matter.

Removing such approximations the DE in the general case is a double atom-photon interaction, including the recoil of the emitter  and absorber atoms in a more complicated relation, partially provided in a old paper of Erwin Shrodinger.

I believe people are unnecessarily complicating things. Doppler effect is  genuine effect arising when observer is moving with respect to the source. It exists even in pre-relativistic physics. Example is change in the pitch of sound wave  when observer is moving with respect to the source (change in pitch of whistle of railway engine when observer moves towards or away from the engine). One difficulty one has with sound waves is we need the medium in which the waves are produced. So, in calculations we have to take into account of motion of source as well as observer in the medium.

Light does not need a medium so what matters is only relative velocity of source and observer. One can do a calculation where one considers light as a wave. So, here we have frequency and wave number of light wave forming a four vector which transforms according to rules of relativity.

One can also do a calculation in simpler way if one takes recourse to QM and considers energy and momentum of light quantum (photon) in terms of frequency and wave number. Then one uses energy-momentum transformation rule to relate these quantities from source frame and observer frame. We don't have to talk of absorption and emission of light (photon) here. If one can somehow measure frequency (or energy) of light in the two frames, they should be related by relativity formula and indeed they are. When one observes Doppler shifts of spectral lines of stars (there is a shift because of motion of atoms in stars), one does not talk about observer or source except for their relative motion. 

If on wants to be absolutely correct (up to infinite precision), one needs to consider recoil effects. When an atom emits a photon, and in the process deexciting, one needs to conserve energy and momentum in the emission process. The atom has some energy before deexcitation. This energy includes rest mass of the atom which includes its excitation energy (this follows from relativity --- mass and energy being equivalent). When the atom deexcites and a photon is emitted, the energy in final state is energy of photon, mass of deexcited atom and recoil kinetic energy of the atom (we are assuming that the initial atom is stationary --- this need not be so). We have to conserve both energy and momentum together. Thus, photon energy is slightly smaller than the difference in energy levels of the atom. For atomic transitions, this energy difference is extremely small, much smaller than the natural width of spectral lines so one never bothers about it. For nuclear transition, it is not so small and one needs to worry about it.

Note two things. First, the actual quantum process of deexcitation is irrelevant in this discussion. We are using energy-momentum conservation which is more fundamental and no violations are seen. Second is we are not talking of Doppler effect here. We don't have to. Energy-momentum is conserved is ALL frames. Doppler effect is about transformation of energy and momentum. If we insist on talking of Doppler effect, we have to consider motion of the atom before and after emission and its energy and momentum (which follows relativistic transformation rule). Thus, we can talk of Doppler effect without referring to the object tat emits the photon. Hope this clears the picture.

"If we insist on talking of Doppler effect, we have to consider motion of the atom before and after emission and its energy and momentum (which follows relativistic transformation rule). "

Yes this is the most general case of Doppler effect of EM quanta and is the one which has to be considered from which any other relations derive.

In any case the doppler of EM radiation configures as an actual transformation of kinetic energy of the  EM exchangers to EM energy/mass of the absorber, the versus depending on approaching or dethatching of such photon exchangers.

I will provide at this purpose a double path doppler example, tecnique used in the Gravity probe A experiment with maser photons, in order to show that what is actually obtained in the same RF ,after cancelling the relativistic effects, is just a net increase of confined EM energy which is subtracted to the kinetics of the bodies in the approaching configuration.

The Doppler effect in all versions, for light, electromagnetic waves, single photons, energy quanta at any frequency, sound waves, is always and only a relativistic effect due to the relative velocity between source (emitter) and observer (absorber). It is manifest that also in the DE fundamental laws of conservation have to be respected, like the conservation law of energy and the conservation law of momentum. The consideration of other effects is positive but it needs to avoid to confuse those effects with the DE. For a critical interpretation of the DE in the order of the Theory of Reference Frames I advise the reading of the following papers:

 https://www.researchgate.net/publication/260085529_Relativistic_Effects_of_the_Theory_of_Reference_Frames

https://www.researchgate.net/publication/256391945_Physico-Mathematical_Fundamentals_of_the_Theory_of_Reference_Frames

Article Relativistic Effects of the Theory of Reference Frames

Article Physico-Mathematical Fundamentals of the Theory of Reference Frames

Dear Daniele,

yes it is.. but the relation derived from the Lorentz transformations is a particular case of doppler effect of EM radiation under restricted hypotheses and makes everything seems only a coordinate transformation and there is something else too..

If I make it seem as a pure consequence of a coordinate transformation, would be like relegating the actual phenomenon to an "apparent" phenomeon...which is not

Stefano,

the relative speed between two reference frames isn't an apparent phenomenon but it is a real fact. Two inertial reference frames aren't two equivalent systems in all physical aspects, but only in relativistic aspects, because the relative speed between two reference frames implies also a different kinetic energy. Dear Stefano, I think you will become a free and independent scientist when you will free yourself from the Lorentz transformations.

Daniele,

I'm not nostalgic about Lorentz transformations. The thing is that while Galileo transformations are ways to see the same thing from different points of view, Lorentz are supposed to be like that too...but it seems they are not only that...

Valentin,

"If I understand correctly, you'd extend the considerations of the DE to include also the accelerations of the emitter and/or absorber,"

I didn't mean that, but I'm going to do it in a particular way...

I also wanted to say that Shrodinger first, then 100 years later Redzic made the extension to a quantum physical effect.

Stefano, whether Galileo's transformations or Lorentz's transformations (and I add also TR's transformations) have the same purpose: mathematical laws of variation of coordinates of space and time for different inertial reference frames in order to respect the principle of relativity. Lorentz's transformations have actually a further intention: they theorize a deformation of space and time in order to respect also the second postulate on the constancy of the speed of light that therefore is an extraneous matter to relativity and to physics.

Exploiting a Radar doppler connection it is possible to compare the differences in the same inertial reference frame of energy of a photon undergoing the doppler effect:

 Eem (back and forth)= Eo [ 1+ beta / (1- beta) ]. This is the correct relation between  the energy of the photons at the emission and after the radar connection.

Delta [Eem (back and forth)] = 2*  Eo (beta(1+beta))...

The question is now, is it possible to say that each path is half the energy??

or rather Delta Eem (forward path) = Eo (beta(1+beta)) ??

Stefano, if you like to have my opinion on this work I would need to know better experimental details..

My answer is no.

Why not, the relations are the same, it is always in both cases an approaching configuration...why should in the returning path the energy difference be different of the one of the forward path??