User talk:Harald88/sandbox2

Farrel's outline
Salon.com article (note John Farrel is a journalist, not a physicist):

- Petr Beckman - self-published book "Einstein Plus Two"; Galilean Electrodynamics

- German anti-semitism

- Albert Michelson

- Herbert Ives

- Tom Van Flandern

(* Dingle, Aspden,...)

CRITICISM OF THE THEORY OF RELATIVITY
- * Warning: the following is just a text dump that is not yet suited to be read, except for the first few sections * -

Criticism of the theory of relativity refers to activities of scientists who disagree with the way the theory of relativity is promoted. These 'dissidents' or 'nonconformists' criticize real or apparent inherent contradictions and/or inconsistencies of orthodox relativity, often focusing on either the Special theory of relativity (SRT) or the General theory of relativity (GRT). Occasionally counter-proposals are offered. Such criticisms and research activities have also been coined "anti-relativity", a label that fits some but not all criticism. Typical publication platforms are journals like Apeiron, Galilean Electrodynamics, Hadronic Journal and Physics Essays.

Different types of criticism
Some mainstream criticism comes from quantum physics as quantum physics is difficult to reconcile with relativity

The dissidents may be sub-divided into various groups.

Dissidents criticize the state of the art of modern relativity either from empirical, from logical or from mere general epistemological grounds. A common point of attack is the concept of time employed in modern relativity, where time is represented as one dimension of four-dimensional Spacetime (in contrast to classical space-time). The group concerned about this includes presentists, process physicists, philosophers and others who have adopted the viewpoint that time is a result of the mind.

Most dissidents offering counter-proposals can be classified into 'aether-realists' and 'emissionists'. 'Aether-realists' advocate one of the three (different) 'aether hypotheses' concerning the luminiferous aether, which were put forward around the middle of the nineteenth century by Fizeau. 'Emissionists' adhere to some modification of the ballistic emission theory originally proposed around 1900 by Walter Ritz.

Representative Dissidents
One prominent dissident has been the Jewish British "Time Lord" Louis Essen (1908-1997), who had been involved in the development of the first cesium atomic clock. For several decades he had been responsible for the British national standard of time, and he was under his international collegues well known for his refusal to take account of the time dilatation factor in clock synchronisation.

Quite a number of dissidents does not attack the formal theory of relativity itself, but rather the relativistic metaphysics such as is implicated in the publications by Einstein and/or Minkowski. A prominent member of this group was the British philosopher Herbert Dingle. He was frequently misunderstood of being a strict opponent of relativity, especially because his use of the term "Special Relativity" associated Einstein's interpretation of it. (For a striking example of his arguments plus a rebuttal by Mc Crea, see Nature 216 (1967), pp.119-121 and 122-124).

Depending on the interpretation of what is meant with the word "theory of relativity", a number of famous scientists who did not share Einstein's views (such as Lorentz, Poincaré, Langevin, Ives and Dirac) are sometimes called "anti-relativists", even though they supported the theory of physics that is called Special Relativity.

To the present anti-relativistic scene belong the astronomer Tom Van Flandern as well as the American physicist J. Paul Wesley who authored several books and who refers to Special relativity theory as "the special relativity nonsense".

Reception of Experimental Evidence
In response to the seemingly overwhelming and incontrovertible evidence in support of the relativity principle (which supporters of SRT claim to be comparable to the empirical support for the conservation of energy, for example), some opponents assert that the experimental results have been falsified, or that contrary findings have been suppressed or ignored, or that the experimenters' expectations have unconsciously guided the experiments to the expected results and colored their interpretation.

On the one hand, regarding these assertions, scientists satisfied with SRT claim that nearly all the crucial experiments which form the empirical basis of SRT (e.g., Michelson and Morley) actually gave results that were directly contrary to what the experimenters and theorists of the time anticipated, but under the assumption that Fizeau's 2nd aether hypothesis be valid. The latter premise, which corresponds to the assumption of an absolute space existing independently of the material bodies it contains, had been fashionable prior to the event of SRT. On the other hand, dissidents have doubts because absolute space as an independent light guiding structure cannot be observed. According to them, there is no need whatsoever to first assume the existence of absolute space, in order to invent afterwards sophisticated theories which apparently "explain" the absence of certain phenomena which one originally had hoped to observe. Moreover, dissidents assert that a null result can "prove" almost nothing and they emphasize that much the same null results would be observed if Fizeau's 1st aether hypothesis were valid. Fizeau's 1st aether hypothesis implicates that each material body carries its individual light guiding structure around with it, an idea promoted by Heinrich Hertz, Max Planck and others.

The defenders of SRT, who accept that first absolute space is introduced into the theory admired by them and then further strange hypotheses like 'length contraction' (Lorentz contraction) and 'time dilatation' are added in order to cope with unexpected null results, stress that Isaac Newton's book on mechanics contains a "Scholium", where absolute space has been (vagely) defined. Opponents of SRT comment that Newton better should not have written this "Scholium" because the laws of Newtonian mechanics work without any particlur space concept in just the same way. [edit]

Michelson and Morley
The response to the null result of the Michelson and Morley experiment is not unique. Some opponents, like Reginald Cahill, claim that the experiment did not actually produce a null result, while other dissidents accept the null result because it does not conflict with their own theory. [edit]

Dayton Miller
Dayton Miller in the 1930's reported finding what corresponds to an ether-drift of 11 km/sec. Most scientists believe that the small variations in interference fringes reported by Miller were due to instrumentation errors, and they point out that an "ether drift" of this magnitude is not consistent with any coherent ether theory, and, more importantly, that countless repetitions of similar experiments with far more precise equipment have consistently yielded a null result within experimental tolerances. Others such as Reg Cahill point out what they consider to be essential differences; in particular, Miller's device tested the Fizeau effect for gas. This is however not taken seriously by most other scientists, as no convincing explanation is provided for why Fresnel dragging in gas would break Lorentz symmetry.

It's notable that Miller's work is regarded by most scientists as an archtypical example of "the experimenter effect", because his reported non-null result was consistent with his prior expectation of a non-null result (as opposed to Michelson, whose result was the opposite of what he expected). On the other hand, Maurice Allais in the late 1990's claimed to have found a subtle pattern in Miller's data that he (Allais) believes was both unexpected and unnoticed by Miller. If so, one could not attribute this subtle pattern to the "experimenter effect". However, Allais' claims have not been validated by the scientific community, and he was unable to get his writings on this subject published in a peer reviewed physics journal. This is not surprising, since nearly all reputable physics journals have adopted a policy of not accepting anti-relativity papers.

The Speed of Gravity
Tom van Flandern maintains that experimentally the speed of gravity is considerably greater than the speed of light. This contradicts special relativity's universal speed limit. However, his interpretation of these experimental results is rejected by reputable physicists, who have explained in detail the fallacies underlying van Flandern's contention. Furthermore, van Flandern's claims entail the rejection not only of relativity and quantum mechanics, but of classical electromagnetism as well (not to mention ordinary fluid mechanics), since he contends that electromagnetic effects propagate faster than light, a proposition which grossly conflicts with commonplace observation. In addition, the "errors" he describes in general relativity have led reputable scientists to conclude that he simply mis-understands the theory.

Objections from Logical Grounds
The public has wrong impressions on the mutual respectance of experimental physicists and theoretical physicists and also on the weight of their competence. It tends to value the theoretician higher - who appreciates this - and does not believe the experimenter. Some experimenters with a high level of knowledge in theoretical physics (e.g., R.H. Dicke) object strongly against being called a "theoretician", however, the main reason being that the phantasy of a theoretician is less well trained by current contact with reality. Because of his advantage,an experimenter spots logical errors in the structure of a theory more easily (which sounds paradoxically). To take an example, many textbooks on SRT describe clock type of synchronisation procedures, sometimes even involving clocks of train stations, but always light pulses, in order to demonstrate how easily it in reality is to deduce the fundamental formulae of SRT, the Lorentz transformation. The next step is then to predict with the help of the Lorentz transformation "relativistic" phenomena with an extraordinarily high precision, such as the optical Doppler effect. An experimenter distrusts the internal logic of this approach, because if clocks shall be synchronised with the help of light pulses, the optical Doppler effect would have to be known already in advance. If this is from one reason or the other not necessary, then the experimenter expects a clear and precise answer to the question why this is so.

In front of the public, the theoretician has here an advantage, because the public judges that this is a theoretical question and, therefore, the theoretician should be more competent. The theoretician can therefore react with a superior smile in his face - without giving any answer.

The theoretician has here one more advantage: The public concludes that the theoretician must have been right, because, after all, he arrived at the correct final answer. But this again is a pre-occupation because the 'inventor' of the 'novel theory' can have known the important final result in advance and his sole 'original contribution' can have consisted in the construction of a network of hypotheses and assumption, merely designed to carmouflage the plagiate Relativity Priority Dispute.

In this ugly game of unintended or intended intellectual intrigue, the experimenter is hopelessly lost, and the better he is in his profession, the greater the likelyhood that he becomes a dissident. Ernst Gehrcke and Louis Essen were dissidents of this type.

Other Arguments against Modern Relativity
A common complaint about modern relativity is that it is counter intuitive. Supporters of modern relativity typicall react on complaints of this kind as follows: "For example, if Bill and Ted were in motion parallel to the path of a light pulse, but at different speeds, the pulse would have the same speed in terms of both Bill's and Ted's inertial rest frame coordinate systems. This seems counter-intuitive, until we realize how the rest frame inertial coordinate systems of Bill and Ted differ both spatially and temporally. Human intuition is well-adapted to the skew between the time axes of relatively moving systems of reference, but not to the skew between the spatial "planes". The ability to grasp these combined skews, and to visualize their consequences, seems to be closely correlated with mathematical aptitude, which is distinctly lacking in most individuals questioning the final state of the art of modern relativity".

Some critics of modern relativity contend that quantum entanglement conflicts with relativity. Supporters of SRT argue this is not a valid criticism, because quantum entanglement does not entail any information or mass-energy transmitted faster than the speed of light. Other critics claim relativity is falsified by the observed motions of the arms of spiral galaxies. Supporters answer to this argument, that this is not a valid criticism of relativity per se, because galactic motions conflict with Newtonian gravity as well as general relativity, so the apparent conflict is not specifically related to relativity. (The apparent conflict is based on estimates of the mass contained in galaxies, which may be under-estimated when based purely on the luminous matter. Possible candidates for Dark Matter and other theories are actively being researched.)

Critics of relativity also refer to the fact that, in Quantum electrodynamics, the photon can be regarded as having a non-zero amplitude to be exchanged over a time-like interval. In fact, so-called virtual particles represent time-like exchanges. Supporters being convinced of the correctnes of SRT reply that these do no represent actual faster-than-light conveyance of either energy or information, so (again) there is no actual conflict with relativity.

One common argument against the full validity of general relativity is that the theory is incompatible with quantum mechanics. Many scientists suspect that one or the other (or both) of these fundamental theories will need to be revised in order to arrive at a quantum theory of gravity. This is an active field of research.

Embarrassments of the Establishment
Orthodox relativists argue that the theory of relativity attracts more opposition than other physics theories (such as quantum mechanics) for three main reasons. First, unlike quantum mechanics, the theory of relativity is accessible on all levels. It deals directly with the concepts of space, time, and motion, with which everyone is familiar, and it is easy to have an opinion about propositions involving these concepts, even if one does not understand relativity at all.

Second, unlike quantum mechanics, the theory of relativity is associated in the popular mind with one single individual (Albert Einstein), which makes it easy to personalize any objections to the theory. It is much easier to loudly declare "Einstein Was Wrong!" than it is to declare "Planck and Einstein and Bohr and Heisenberg and Schrodinger and Born and Jordan and Dirac and Pauli Were Wrong!". The men known to be involved in the development of quantum mechanics span a wide range of nationalities, religions, politics, and personalities, so it is difficult to carry over antagonisms from those areas into objections against quantum mechanics. In contrast, any antagonisms against the personality of Einstein can be carried over as fuel for nonconformity. The original Anti-Relativity Club ("Anti-Einstein-Liga", as Einstein dubbed it) was formed in Germany between the World Wars, and included Lenard, Stark, and a few other noted members. The motivations of that group, objecting to "Jewish Science", have been impugned subsequently.

Third, and perhaps most importantly, the word "relativity" is easily conflated with the concept of "relativism", even though the theory of relativity has nothing whatsoever to do with relativism. In fact, many prominent workers in the field of relativity (including Einstein, Sommerfeld, Minkowski, and Klein) argued that the concepts involved in the theory of relativity would be more accurately conveyed by naming it The Theory of Invariants, or The Theory of the Absolute World (as suggested by Minkowski). If one of these names had been adopted, instead of the misleading word "relativity", there would doubtless be much less polemic against Einstein's marvellous and beautiful doctrine.

As mentioned at the beginning of this article, opponents of modern relativity can publish only in a limited number of physics journals. They attribute this 'conspiracy' to a variety of causes and motivations. Some believe (and loudly proclaim) that it is due to sheer stupidity on the part of physicists, to the extent that they (Nobel-prize-winning physicists) cannot understand what is obvious to a child. Others attribute it to "brain-washing" carried out by the academic system, but this begs the question of what motivates the academic system to do this. The most common explanation given by nonconformists for the pro-relativity conspiracy is that many physicists have a vested interest (both financial and emotional) in relativity, and are simply too proud, stubborn, greedy, and venal to admit the manifest erroneousness of relativity when it is clearly explained to them by amateurs. Naturally, physicsts deny that there is any conspiracy, and contend that the principle of relativity is so widely accepted in scientific circles simply because it provides the best (i.e., most unified, coherent, heuristically productive) account of phenomena.

Main Source of Embarrassment
From the viewpoint of dissidents the embarrassments of the establishment about nonconformity revals somethimg on the degree of convincement of orthodox relativists in their own doctrine, or on what Einstein's doctrine really has to offer. Nobody would be taken serious, who, say, refuses to accept the Pythagorean law, nor would anyone ever begin to zealot privately or in public if an indivudal would take for him or herself the decision to reject that law. The person doing so would simply not be taken serious. So, argue the nonconformists, why are the dissidents taken so very serious by the relativistic establihment? Do the conformists fear 'Berthold Brecht's law', according to which The compact minority is always right?

The main reason for the embarrassments of the relativistic establishment is without any question the fact that its members are recognized by almost the complete human society worldwide (including governments, media and public institutions) - with one exception: The dissidents look upon the relativistic establishment as a case of an insulated, self-sufficient demi-monde, a group of intellectuals, which finds it fashionable to deviate from logic and which should be subjected to some kind of 'de-einstein-ification' re-education type of programme.

More Cultural Causes of Nonconformity

If motivations of individuals who object against orthodox relativity merely from non-physical reasons, including objections against the Einstein cult and the like, are disregarded, then the major source of nonconformity obviously boils down to the high degree of 'belief', which anybody has to accept who wants to become a member of the relativistic establishment. From the viewpoint of nonconformists, in particular SRT has speculative qualities associated with it, which remind of a religion. "Why do we believe in relativity?", ask proudly teachers of relativity, who are convinced that they have understood orthodox relativity. Why does nobody ask, for example: "Why do we believe in Maxwell's equations", although SRT and Maxwell's equations are intimately related with one another?

What Albert Einstein has said, or has not directly said but perhaps might have meant, so the dissidents, has to be true from the very beginning, independently of whether it actually had been said by him and independently of whether or not it is true. "Brain-washing" is a term which implicates that there is some indoctrination going on, and that the teachers know in advance what they are doing. An accusation of this kind is not meant here, however. To which kind of curiosities the blind belief in Einstein's words or writings leads, can best be seen in the book Theoretical Physic by Joos, which was first published in 1932 and has been re-edited and translated since then many times. According to orthodox relativistic doctrine, classical physics has to have no transverse Doppler effect at all. Einstein himself, however, has never asserted this. But, since the relativistic establishment 'believes' - now since one century - that with a short note published in the year of 1907 its hero might have meant an experimentum crucis, in any textbook on SRT, including the chapter in Joos' book, it is asserted that for the case of lateral observation in classical physics the Doppler shifted frequency of oscillation be strictly given by f ' = f. There exists also textbooks in which this assertion is formulated as a "test question" for students. If the student wants to become a respected und full member of the relativistic establishment, and if he does not want do endanger his professional career, he is forced to give this answer although the answer is evidently false. In the book of Joos this leads to a direct contradiction, because about ten pages earlier Joos treats the classical Doppler effect correctly. (The answer f' = f is enforced in some textbooks by means of a didactic trick, namely by resorting to the plane wave approximation. The students are then, however, not told that this invalid 'proof' involves an approximation.)

Creditability of the Scribes

Elementary particle physicists regard themselves, as it were, as the 'modern aristocrates' (Werner Heisenberg). The theoreticians in this field apply the Lorentz transformation, which has the strange interpretations of 'Lorentz contraction' and 'time dilatation' associated with it. Mainly because of the latter circumstance the opposition sees in these research workers merely scuril swarms of mislead and indoctrinated scribes. Typical strongholds of these 'relativistic scribes' are research centres like CERN (Switzerland), DESY (Germany) and SLAC (California). Some decades ago, an other 'genius' had found employment in the German institute. He was capable to take in his head the root out of large numbers with very many decimal places. He even delivered proof of this extraordinary capability in German public television. He only needed a blackboard or a piece of paper and something to write. His capability was discussed in news papers, such as the news magazine Der Spiegel, where also his portrait was shown on the front page. The physiognomic resemblence of DESY's gènio secondo with the original (in brackets or not and with a meaning whatsoever) was striking.

In the media the story on the 'new genius` was told over a considerable time span. Several years later news papers reported that the man had been found shot dead in Brussels.

After further years had elapsed, a non-scientist with second name Freiherr von Richthofen and with quite a normal profession, who probably had never heared of the 'genius' just mentioned, demonstrated in German public television, how everybody could undertain groups of spectators with the art of taking in his head the root out of very large numbers with many decimal places. He demonstrated this in a friendly and relaxed manner on a blackboard, being visibly delighted that he could show this in public. There exists a fairly simple algorithm which allows this to do and which Richthofen had found in some textbook.

The opposition may ask - not entirely without any justification: How can things like this happen in an institution like DESY, a major residence of the international relativistic establishment which is so sure about its scientific superiority and its critical attitude?

Galilean Relativity
Opponents attacking the usual interpretations attributed to SRT have a strong point, because Lorentz type of transformation formulae were first deduced by Woldemar Voigt, and Woldemar Voigt arrived at his result by substituting the general form of the Galilei transformation in a differential wave equation. Thus, there can hardly be a serious contradiction between the Galilei transformation and the formulae of the Lorentz transformation. There are only different opinions on interpretations.

In order to be able to 'understand' SRT, it is of paramount importance to first re-ensure oneself of the fact that the transverse Doppler effect of classical optics of moving bodies is formally just the same as the transverse Doppler effect predictable with the help of the Lorentz transformation. One should, however, not use Wolfgang Pauli's book on relativity for this comparison, because Pauli presents the wrong formula. But any other textbook on SRT can serve for this purpose.

Once it is realized that the 'two' transverse Doppler effect are exactly the same, it becomes immediately obvious that a real departure of the predictions of classical optics of moving bodies does occur essentially solely in the special case of longitudinal observation (when source and observer are positioned on the same geometrical line), in which case the departure is maximum. What could be the reason for this departure of the 'classical' prediction from the 'relativistic' one? Now, it happens that from mere historical reasons the term 'classical' optical Doppler effect is badly chosen and misleading, bcause Doppler's original optical Doppler theory holds true in reality solely for longitudinal waves (such as sound waves), but not precisely for transverse waves, such as electromagnetic waves. For longitidinal observation of transverse waves it is only an approximation. (When Doppler first established his optical Doppler theory, the discovery that light consists of transverse waves was only about a quarter of a century old, and Doppler was not really convinced of light's transverse character. But even if he had accepted the transversality of light, the time was not yet ripe for asking such questions as to whether there could perhaps be a minor difference between the Doppler effect of transverse waves and the Doppler effect of longitudinal waves.) In other words, the small discrepancy of predictions between the old and the new, 'relativistic' theory must be caused by light's transversality.

The evolution of theoretical physics does not take place solely along straight lines, but also along side ways. That the Doppler effects are different for longitudinal and for transverse waves had been known already in the year of 1886 (or even earlier) to Woldemar Voigt. Attention had been drawn to this circumstance again in an article publishwd by E. Kohl in Annalen der Physik of the year 1903. But apparently thereafter it somehow had been forgotten again. Because of the latter fact modern textbooks on classical physics contain a systematic error which consists in not strictly distinguishing between the Doppler effect of transverse waves and the Doppler effect of longitudinal waves.

This has also to do with the fact that a fairly simple velocity aberration type of aberration phenomanon had been overlooked by physics teachers, which can qualitatively be described as 'velocity aberration of angular velocity'. It is the latter phenomenon which enters the scenery as soon as transverse waves are observed with highly accurate measuring devices, such as Doppler receivers. It is the phenomenon responsible for all obscure effects which in the framework of SRT are circumstantially and wrongly attributed to 'time dilatation'. No such thing as 'time dilatation' does exist in reality. It exists solely in the imagination of the relativistic establishment

What has been said hitherto raises the question of whether the 'Lorentz transformation' should not be renamed into Voigt transformation. As a matter of fact, there does not exist only one single Voigt transformation but rather an ensemble of them, and one member of this ensemble should correspond to the Lorentz transformation. The number of Voigt transformations, which could be distinguished in principle, may be obtained from the number of different Doppler scenarios which one would like to admit for the consideration. Thus, if Fizeau's 1st aether hypothesis were valid, one would not have to distinguish between cases where the source and/or the receiver move(s), contrary to what is necessary if Fizeau's 2nd, absolute space type of aether hypothesis would be better compatible with nature.

Modern Galilean relativity (MGR) is the contemporary version of the classical discipline of optics of moving bodies, which was superseded around the turn to the 20th century by the special theory of relativity developed by Lorentz, Poincaré and Einstein. It is a research area of those who wish to re-surrect Galilean kinematics.

Doppler effect and Galilean transformation
Concerning the so-called transverse Doppler effect, as Krause claims, teachers of relativity have since one century been involved in shameless and direct betrayal of students in asserting in textbooks that the transverse Doppler effect is a unique prediction of special relativity and has been entirely unknown in the discipline of optics of moving bodies. He argues that since the transverse Doppler effect is known since the year of 1842, the argument propagated by special relativity, that classical optics of moving bodies follows from special relativity in the limit $$\frac{v}{c} \rightarrow 0$$, breaks down.

Post-Lorentzian Galilean theories
In Modern Galilean relativity two historical schools can be distinguished. 'Aether-realists' advocate one of the three (different) aether hypotheses concerning the luminiferous aether, which were put forward around the middle of the nineteenth century by Hippolyte Fizeau. 'Emissionists' adhere to some modification of the ballistic emission theory originally proposed a century ago by Walter Ritz. Due to its many problems, that theory is no longer considered an active branch of modern Galilean relativity.

Most modern Galilean theories lack the predictive power of Special relativity while some are hard to concord with experiments that support Lorentz invariance; thus they are widely ignored by mainstream physicists.

Luminiferous aether
In the case of electromagnetic waves which propagate through a vacuum region encapsulated within a closed box, the contrary experience had been made that absolutely nothing could be done (nothing could be 'removed') in order to achieve that the wave propagation ceases. The conclusion was that, consequently, there obviously must exist an immovable, absolute space type of luminiferous aether which is not affected by the motion of the bodies.

Max Planck suggested that the aether surrounding a body could perhaps be kept at its place by the active gravitational forces exerted by that body on the aether surrounding it. This picture implies, however, that the aether has a corpuscular structure.

The theory of special relativity may be regarded as an 'abstract realization' of a theory based on Fizeau's 1st aether hypothesis. This can be seen, for example, from the symmetry of relativistic effects with regard to source and receiver motion. The Croatian critic Stephan Mohorovicic, who himself adhered to Newton's concept of 'absolute space', has called special relativity a "Monadology". In natural philosophy, a monadology is considered to be the complete opposite of an absolute space type of picture of the universe.

Relevance of the Michelson experiment
Experiments designed to register the motion of the luminiferous aether with respect to a moving platform on which a Michelson interferometer is installed, are based on the premise of the stationary aether hypothesis.

Despite this "null result", occasionally even physicists adhering to the Galilean tradition still offer 'physical explanations' of the null result of the Michelson experiment.

An altwrnative phenomenological interpretation of the Michelson experiment is that its null result is in support of Fizeau's 1st aether hypothesis, an interpretation which is sometimes also adopted by contemporary physicists feeling obliged to the Poincaré-Lorentz-Einsteinian 'special theory of relativity'.

Mainstream counter-critiques
Mainstream critics point out that Einstein's special theory of relativity is an extension of the principles of Galilean relativity or invariance from classical mechanics to include Maxwell's equations and thereby optics.

In the mainstream view, therefore, any attempt to formulate a new aether theory by recourse to Galilean relativity, is doomed since Galilean invariance is already incorporated into special relativity under the name Lorentz invariance; any putative aether is considered to be devoid of mechanical properties, unobservable and hence superfluous. It is held that any non-superfluous aether theory would yield predictions that are incompatible with Lorentz invariance and thereby Maxwell's equations; however the latter is empirically very well attested.

Consequently the concept of a "Galilean" aether or space has not been used in the Theory of Relativity, Quantum mechanics, or other modern theories of physics.

Suggested further reading

 * Carus, P. (1913) The Principle of Relativity in the Light of the Philosopy of Science; with an Appendix containing a Letter from James Bradley on the Motion of the Fixed Stars, Open Court, Chicago.
 * Dingle, H. (1972) Science at the Cross Roads, Western Printing Services'', Bristol.
 * Essen, L. (1971) The Special Theory of Relativity: A Critical Analysis, Oxford University Press (Oxford science research papers, 5).
 * Isenkrahe, C. (1921) Zur Elementaranalyse der Relativitätstheorie - Einleitung und Vorstufen, Vieweg, Brausnschweig.
 * Jong-Ping Hsu and Yuan Zhong Zhang (2001) Lorentz and Poincaré Invariance - 100 Years of Relativity, World Scientific, Singapure.
 * Lämmerzahl, C. (2005) "Special Relativity and Lorentz Invariance", ''Ann. Physik 14 (1-3), 71-102.
 * Laue, M. von (1928) "Die Optik der bewegten Koerper", in: Handbuch der Experimentalphysik (W. Wien und F. Harms, Hrg.), Bd. 18: Wellenoptik und Polarisation, Akademische Verlagsgesellschaft, Leipzig, I. Kapitel.
 * Lévy, J. (2003) From Galilei to Lorentz ... and beyond - Principles of a fundamental theory of space and time, Apeiron, Montral.
 * Ruder, H., Soffel, M., und Herold, H. (1998) Experimente zur Relativitätstheorie, Vieweg, Braunschweig.
 * Selleri, F.(ed.) (1998) Open Questions in Relativity, Apeiron, Montreal.
 * Theimer, W. (2005) Die Relativitätstheorie - Lehre, Wirkung, Kritik, Edition Mahag, Graz (Austria), 2. Auflage.


 * P. Brosche und D.-E. Liebscher (1998), "Fallstricke beim Thema Aberration"
 * John J. O'Connor and Edmund F. Robertson (1996), "A Brief History of Special Relativity"
 * T. Roberts, S. Schleif et al. (2000), "What is the experimental basis of Special Relativity"

Fizeau's three aether hypotheses
In order to clarify the relation between the luminiferous aether, the bodies and the motion of the bodies, one and a half centuries ago Hippolyte Fizeau suggested that one of three 'aether hypotheses' should be true: 1)The aether is inseparably attached to the molecules of the bodies and moves together with them, 2) the aether is completely free and is not affected by the motion of the bodies, or 3) only one part of the aether participates in the motion of the bodies and the residual part is completely free.

Alternative formulation of Fizeau's three aether hypotheses
In modern physics, a structure in the vacuum, with respect to which light's phase velocity c is constant, is called an 'inertial frame of reference'. Because of this, Fizeau's three aether hypotheses may also be re-formulated as follows: 1) The inertial frame of reference is inseparably attached to the molecules of the bodies and moves together with them, 2) the inertial frame has an existence on its own and is not affected by the motion of the bodies, or 3) some adequate combination of hypotheses 1) and 2) applies in nature.

General comments
Fizeau's 1st aether hypothesis associates a picture where any molecule is accompanied by an individual waveguide of infinite extension, which penetrates all other waveguides existing in the vacuum. Obviously, an individual waveguide of this kind must be inhomogeneous. This nonlinear property is required in order to ensure that the individual waveguides may be distinguished from one another.

Fizeau's 2nd aether hypothesis implicates the diametrically opposite picture of an homogeneous rigid waveguide of infinite extension, which exists independently of the ponderable matter which it contains. This is the aether in H. A. Lorentz's sense, to which all previous critiques of aether theories refer. (Contrary to Lorentz's aether, a co-moving aether in the sense of Fizeau's 1st aether hypothesis has no classical counter-part, i.e., it cannot be visualized as a self-consistent substance similar to a chemical substance.)

The attitude of modern physics toward aether theories has been discussed by A. Einstein in a lecture presented in 1920 at the University of Leiden. For a more recent discussion see, e.g., Anatoly A. Logunov's book "Henri Poincaré and Relativity Theory".

Common properties of the aether in all three hypotheses
Independently of which of the three aether hypotheses put forward by Fizeau is compatible with nature, it is assumed that the aether has infinite spatial extension.

The aether is a non-corpuscular structure, not a substance in a chemical sense, which supports the propagation solely of transverse waves, i.e., it is a structure which excludes the propagation of longitudinal waves. Its performance resembles, therefore, that of an elastic incompressible medium.

The partial differential equations describing wave propagation in an elastic incompressible medium have been used in 1887 by Woldemar Voigt to deduce, with the help of the Galilean transformation, relativistic transformation relations which according to H. A. Lorentz are fully equivalent to the transformation equations employed in special relativity.

Fizeau's second aether hypothesis
Because of its inherent conceptual simplicity, the idea of an infinte homogeneous light aether has been a widely accepted one. It was made popular in particular by the writings of H. A. Lorentz. After the event of the theory of special relativity, the idea of the homogeneous aether was still advocated by Max Abraham. Today, the idea is still taken into consideration by dissidents of special relativity.

An argument in favour of the infinite homogeneous aether, which is popular especially among critics of the theory of special relativity, is that it is compatible with Isaac Newton's concept of 'absolute space' discussed in a  'Scholium' of his book on mechanics. However, Newton's concept of absolute space is not a necessary prerequisite of Newtonian mechanics. This can best be seen from the circumstance that in well known textbooks on theoretical mechanics no reference whatsoever is made to the concept of 'absolute space'.

A major objection against the absolute space type of luminiferous aether originates from the fact that it is not observable in nature: It is impossible, in principle, to separate space and matter in such a manner, that an infinite empty space can be observed. Apart from this, the hypothetical physical separatability of the bodies on the one hand, and of physical space on the other hand, would lead to a tautology of the concepts of space and matter, because in the interior of an atomic particle the physical phenomenom of spatial extension would be counted twice.

Another objection has to do with the simplicity of Bradley's theorem for the velocity aberration of star light, which allows it to determine the aberration of the normal of the wavefront, when the observer's velocity $$\vec{v}$$ is known. The argument is that, if there would exist an infinite homogeneous aether, the aberration law would have to be considerably more complicated than it really is, because in addition the relative motion of the light source with respect to the aether would have to be accounted for. Bradley's theorem alone would then no longer suffice to infer from the direction of the arriving wavefronts of the star light the direction of the true position of the star observe

Fizeau's three aether hypotheses
In order to clarify the relation between the luminiferous aether, the bodies and the motion of the bodies, one and a half centuries ago Hippolyte Fizeau suggested that one of three 'aether hypotheses' should be true: 1)The aether is inseparably attached to the molecules of the bodies and moves together with them, 2) the aether is completely free and is not affected by the motion of the bodies, or 3) only one part of the aether participates in the motion of the bodies and the residual part is completely free.

Alternative formulation of Fizeau's three aether hypotheses
In modern physics, a structure in the vacuum, with respect to which light's phase velocity c is constant, is called an 'inertial frame of reference'. Because of this, Fizeau's three aether hypotheses may also be re-formulated as follows: 1) The inertial frame of reference is inseparably attached to the molecules of the bodies and moves together with them, 2) the inertial frame has an existence on its own and is not affected by the motion of the bodies, or 3) some adequate combination of hypotheses 1) and 2) applies in nature.

General comments
Fizeau's 1st aether hypothesis associates a picture where any molecule is accompanied by an individual waveguide of infinite extension, which penetrates all other waveguides existing in the vacuum. Obviously, an individual waveguide of this kind must be inhomogeneous. This nonlinear property is required in order to ensure that the individual waveguides may be distinguished from one another.

Fizeau's 2nd aether hypothesis implicates the diametrically opposite picture of an homogeneous rigid waveguide of infinite extension, which exists independently of the ponderable matter which it contains. This is the aether in H. A. Lorentz's sense, to which all previous critiques of aether theories refer. (Contrary to Lorentz's aether, a co-moving aether in the sense of Fizeau's 1st aether hypothesis has no classical counter-part, i.e., it cannot be visualized as a self-consistent substance similar to a chemical substance.)

The attitude of modern physics toward aether theories has been discussed by A. Einstein in a lecture presented in 1920 at the University of Leiden. For a more recent discussion see, e.g., Anatoly A. Logunov's book "Henri Poincaré and Relativity Theory".

Common properties of the aether in all three hypotheses
Independently of which of the three aether hypotheses put forward by Fizeau is compatible with nature, it is assumed that the aether has infinite spatial extension.

The aether is a non-corpuscular structure, not a substance in a chemical sense, which supports the propagation solely of transverse waves, i.e., it is a structure which excludes the propagation of longitudinal waves. Its performance resembles, therefore, that of an elastic incompressible medium.

The partial differential equations describing wave propagation in an elastic incompressible medium have been used in 1887 by Woldemar Voigt to deduce, with the help of the Galilean transformation, relativistic transformation relations which according to H. A. Lorentz are fully equivalent to the transformation equations employed in special relativity.

Fizeau's second aether hypothesis
Because of its inherent conceptual simplicity, the idea of an infinte homogeneous light aether has been a widely accepted one. It was made popular in particular by the writings of H. A. Lorentz. After the event of the theory of special relativity, the idea of the homogeneous aether was still advocated by Max Abraham. Today, the idea is still taken into consideration by dissidents of special relativity.

An argument in favour of the infinite homogeneous aether, which is popular especially among critics of the theory of special relativity, is that it is compatible with Isaac Newton's concept of 'absolute space' discussed in a  'Scholium' of his book on mechanics. However, Newton's concept of absolute space is not a necessary prerequisite of Newtonian mechanics. This can best be seen from the circumstance that in well known textbooks on theoretical mechanics no reference whatsoever is made to the concept of 'absolute space'.

A major objection against the absolute space type of luminiferous aether originates from the fact that it is not observable in nature: It is impossible, in principle, to separate space and matter in such a manner, that an infinite empty space can be observed. Apart from this, the hypothetical physical separatability of the bodies on the one hand, and of physical space on the other hand, would lead to a tautology of the concepts of space and matter, because in the interior of an atomic particle the physical phenomenom of spatial extension would be counted twice.

Another objection has to do with the simplicity of Bradley's theorem for the velocity aberration of star light, which allows it to determine the aberration of the normal of the wavefront, when the observer's velocity $$\vec{v}$$ is known. The argument is that, if there would exist an infinite homogeneous aether, the aberration law would have to be considerably more complicated than it really is, because in addition the relative motion of the light source with respect to the aether would have to be accounted for. Bradley's theorem alone would then no longer suffice to infer from the direction of the arriving wavefronts of the star light the direction of the true position of the star observe