Lorentz's theory of ethers

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The Lorentzian ether theory (also New Mechanics, Lorentzian electrodynamics, Lorentzian electron theory, after the English "Lorentz ether theory" also often abbreviated LET) was the end point in the development of the idea of ​​the classical light ether , in which light waves are analogous to water waves and sound waves in one Spread medium . The theory was mainly by Hendrik Lorentz and Henri Poincaré developed and then through the mathematically equivalent, but in the interpretation of space-time much more in-depth special relativity by Albert Einstein and Hermann Minkowski replaced.

Problem

The assumption of an aether at rest seems to contradict the result of the Michelson-Morley experiment , in which the proof of a movement of the earth relative to this aether failed. In Lorentz's theory of ethers, this contradiction is resolved by introducing Lorentz transformations . Here, however, the length contraction and time dilation are understood as processes to which scales and clocks moving relative to an ether are subject, while space and time remain unchanged. This means that these effects are viewed as asymmetrical, i.e. moving scales are actually shorter and clocks actually run more slowly. A moving observer assesses stationary rulers identically as shorter and stationary clocks as slower, but this assessment is interpreted as a deception, since the moving observer gains it by using falsified standards and clocks. The symmetry of the observations and thus the obvious validity of an apparent principle of relativity is interpreted as a consequence of a rather coincidental symmetry of the underlying dynamic processes. However, it prevents the possibility of determining one's own speed relative to the aether, and thus makes it a fundamentally inaccessible quantity in theory. According to a principle of thrift ( “ Occam's razor ” ) pronounced by Ockham, such quantities should be avoided as much as possible, which is one reason why this theory is considered outdated and is rarely supported.

In the special theory of relativity, however , length contraction and time dilation are a consequence of the properties of space and time and not of material measures and clocks. The symmetry of these effects is a consequence of the equivalence of the observer, which is the basis of the theory as a principle of relativity. All quantities of the theory are experimentally accessible.

Historical development

Hendrik Antoon Lorentz, 1916, portrait by Menso Kamerlingh Onnes

Basic concept

Ethers and electrons

The Lorentz theory of ethers, which was mainly developed between 1892 and 1906 by Lorentz and Poincaré, was based on the further development of Augustin Jean Fresnel's theory of ethers, the Maxwell equations and the electron theory of Rudolf Clausius . Lorentz introduced a strict separation between matter ( electrons ) and aether, whereby in his model the aether is completely immobile and is not carried along by moving bodies. Max Born then identified the Lorentz ether with the absolute space of Isaac Newton . The state of this ether can be described in the sense of Maxwell-Lorentz'schen electrodynamics by the electric field E and the magnetic field H , whereby these fields were understood as excitation states or vibrations in the ether caused by the charges of the electrons . So here an abstract electromagnetic ether takes the place of the older mechanical ether models. In contrast to Clausius, who assumed that the electrons act on each other through action at a distance , Lorentz, as a mediator between the electrons, assumed this electromagnetic field of the ether, in which effects can spread at the maximum speed of light. For example, Lorentz was able to theoretically explain the Zeeman effect from his theory , for which he received the Nobel Prize in 1902 . At about the same time as Lorentz (1897, 1900) Joseph Larmor drafted a similar theory of electrons or ethers, which, however, was based on a mechanical ether.

Corresponding states

A fundamental concept of the theory was the "theorem of the corresponding states" introduced by Lorentz in 1895 for quantities (i.e. for velocities that are low compared to the speed of light), from which it follows that an observer moving in the ether has approximately the same observations in his " fictitious "field makes like an observer resting in the ether in his" real "field. This theorem was extended to all orders of magnitude by Lorentz (1904) and completed in accordance with the relativity principle of Poincaré (1905, 1906) and Lorentz (1906, 1916).

Length contraction

A major challenge to this theory was the Michelson-Morley experiment carried out in 1887 . According to the theories of Fresnel and Lorentz, a movement relative to the ether should have been determined with this experiment, but the results were negative. Albert A. Michelson himself suspected that the result speaks for a complete entrainment of the ether, but other experiments, the aberration and the Maxwell-Lorentz'sche electrodynamics were hardly compatible with a complete entrainment.

A solution was suggested when Oliver Heaviside further developed Maxwell's electrodynamics in 1889 and noticed that the electrostatic field around a moving, spherical body was shortened by a factor in the direction of movement (the so-called Heaviside ellipsoid). Following this, George Francis FitzGerald (1889) suggested (but only qualitatively) and independently of him Lorentz 1892 (already worked out quantitatively) that not only the electrostatic but also the molecular forces during the movement through the ether are influenced in this way in an unknown way that the interferometer arrangement lying in the direction of movement is shorter by an approximate factor than the part perpendicular to it. In 1895 Lorentz himself suggested various possibilities for bringing about the relative shortening:

  • The interferometer contracts in the direction of movement and does not change its length perpendicular to it.
  • The length of the interferometer remains the same in the direction of movement, but dilates perpendicular to it.
  • The interferometer contracts in the direction of movement and at the same time dilates to a somewhat greater extent perpendicular to it.

The Lorentz contraction of the length l 0 measured in the ether in the direction of movement (without expansion perpendicular to it) with the precise factor according to was only given later by Larmor (1897) and Lorentz (1904): An observer who moved with the earth would be affected by this contraction, which in If the movement of the earth around the sun is only 1 / 200,000,000, do not notice anything as all scales are also affected by this effect.

Although the connection between electrostatic and intermolecular forces was by no means necessary and the theory was soon referred to as " ad hoc " and by Lorentz himself as "strange", Lorentz could at least cite the connection with the shortening of electrostatic fields as a plausibility argument in favor of the hypothesis. It is important that this contraction only affected the distance between the electrons, but not the electrons themselves, which is why the original contraction hypothesis was also called the "intermolecular hypothesis". The electrons themselves were not included in the contraction by Lorentz until 1904. For the further development of the contraction hypothesis, see the section Lorentz transformation .

Local time

An important part of the theorem of the corresponding states was the local time introduced by Lorentz in 1892 and 1895 , where t is the time coordinate used by an observer resting in the ether and t 'is the value used by an observer moving to the ether. ( Woldemar Voigt also used the same local time as early as 1887 in connection with the Doppler effect and an incompressible medium). But while for Lorentz the contraction in length was a real, physical effect, for him the local time initially only meant an agreement or a useful calculation method. With the help of the local time and the mathematical formalism of its corresponding states, Lorentz was able to explain the aberration of light , the Doppler effect and the dependence of the speed of light in moving liquids measured in the Fizeau experiment , without a "partial entrainment" of the ether (in the sense of Fresnel's ether theory ) to have to accept. However, it was initially not recognized that the existence of the time dilation follows from the local time . This was defined by Larmor in 1897, when he found by combining the local time with the factor that periodic processes of moving objects in the ether took place more slowly than with stationary objects. This also emerged from the work of Lorentz in 1899, who recognized that if one related the vibrations of a moving, oscillating electron to the mathematical local time, it would appear to run more slowly.

Unlike Lorentz, Poincaré saw local time as more than a mathematical device. So he wrote in a philosophical essay in 1898 :

“We have no immediate intuition for simultaneity, just as little as for the equality of two periods of time. If we think we have this view, it is a delusion. We adhere to certain rules that we mostly apply without being accountable to ourselves [...] So we choose these rules, not because they are true, but because they are the most convenient, and we can summarize them and say: The The simultaneity of two events or their succession and the equality of two periods of time must be defined in such a way that the wording of the natural laws becomes as simple as possible. "

In 1900 he interpreted the local time as the result of a synchronization carried out with light signals. He assumed that two observers A and B moving in the ether synchronize their clocks with optical signals. Since they believe that they are at rest, they assume that the speed of light is constant. So all they have to do is take into account the times of flight and cross their signals to check that their clocks are in sync. On the other hand, from the point of view of an observer resting in the ether, one clock runs towards the signal and the other runs away from it. The clocks are therefore not synchronous, but only show the local time . But since the observers have no means of deciding whether they are moving or not, they will not notice the error. In 1904 he illustrated the same method in the following way: A sends a signal to B at time 0, which indicates t on arrival . And B sends a signal to A at time 0, which indicates t on arrival . If t gives the same value in both cases , the clocks are synchronous. Therefore, in contrast to Lorentz, Poincaré understood local time as well as length contraction as a real physical effect. In contrast to Einstein, who used a similar procedure in 1905, which is now known as Einstein synchronization , Poincaré stuck to what he believed to be the “more convenient” idea that the “true” time is only displayed by clocks resting in the ether.

Lorentz transformation

While local time could only explain the negative aether drift experiments for velocities of the first order, it soon became necessary (e.g. because of the Trouton Noble experiment ) to explain the undetectability of the aether for all orders of magnitude. The mathematical instrument for this was the Lorentz transformation . This was partly derived by Voigt as early as 1887, but this so-called Voigt transformation used an incorrect scale factor. In 1895 Lorentz had similar equations with local time for quantities to v / c . Joseph Larmor (1897) and Lorentz (1899, but with an undetermined factor) finally these equations extended for sizes of order v ² / c ² and gave them a form which is used with the equivalent today. In 1904 Lorentz came very close to a theory in which all forces between molecules, whatever their nature, are subjected to the Lorentz transformation in the same way as electrostatic forces - i.e. that is, he was able to demonstrate the extensive independence of physical effects from the motion of the earth. He extended his contraction hypothesis and explained that not only the space between the electrons, but also the electrons themselves are subject to contraction. A problem of length contraction when applied to the electrons themselves, however, was pointed out by Max Abraham (1904): According to the electromagnetic theory, a system of contracted electrons could not remain stable and an additional non-electrical energy is required, their Existence of Abraham was doubted. In order to refute this objection, Poincaré (1905) introduced the so-called “Poincaŕe tensions”. This is an external pressure which should explain not only the stability of the matter but also the existence of the length contraction itself. (For Abraham's criticism and the Poincaré tensions, see also the section EM rest mass and EM energy .)

According to Paul Langevin (1905) this extension of the theory of Lorentz and Larmor actually leads to the physical impossibility of discovering a motion to the ether. However, as Poincaré showed on June 5, 1905, Lorentz had not succeeded in showing the complete Lorentz covariance of the electromagnetic equations. He corrected the flaw in Lorentz's application of the equations (e.g. in connection with the charge density and velocity) and showed the group property of this transformation, spoke of the “postulate of the complete impossibility of determining an absolute motion” and spoke of the possibility of a theory of gravity (including gravitational waves ) that corresponded to these transformations. (Whereby essential parts of this work were already contained in two letters which Poincaré wrote to Lorentz around May 1905. In the first letter Poincaré corrected the electrodynamic equations of Lorentz, and in the second he justified and formulated the group property of the Lorentz transformation relativistic addition theorem for velocities .)

Where

Where is a function of which has to be set equal to 1 in order to get the group property. He also set the speed of light to 1.

A significantly expanded version of this document (also known as the Palermo Work) was transmitted on July 23, 1905, but was not published until January 1906, which was also due to the fact that the journal in question only appeared twice a year. (Einstein published his work on electrodynamics exactly between the two by Poincaré.) In connection with his conception of gravitation, Poincaré showed that the combination is invariant and introduced the expression as the fourth coordinate of a four-dimensional space - he was already using four-vectors before Minkowski . He spoke of the "postulate of relativity"; he showed that the transformations are a consequence of the principle of least effect and he demonstrated their group property in more detail than before, coining the name Lorentz Group (“Le groupe de Lorentz”). However, Poincaré later noted that a reformulation of physics in a four-dimensional language was possible, but too cumbersome and therefore of little use, which is why he did not pursue his approaches in this regard. This was only done later by Minkowski.

Mass, energy and speed

JJ Thomson (1881) and others noted that electromagnetic energy contributes to the mass of charged particles by what has been referred to as electromagnetic or "apparent" mass. Another derivation comes from Poincaré (1900), who used the impulse of electromagnetic radiation to be able to maintain the principle of maintaining the movement of the center of gravity , and in doing so found the relationship .

It was also noted that the mass increases with speed. Different authors such as Thomson, Searle, Abraham, Bucherer gave different values, whereby a distinction was made between the longitudinal mass in the direction of movement and the transverse mass perpendicular to it. Lorentz found the following relationships for this in 1899 (with an indefinite factor) and 1904:

,

Where

These relationships were checked with the Kaufmann-Bucherer-Neumann experiments on cathode rays , which were, however, controversial for a long time. Many researchers now believed that all of the mass and forces are of electromagnetic origin. But this idea had to be abandoned because Abraham showed that non-electromagnetic binding forces are required to stabilize Lorentz's electron. He also calculated that different results would be obtained when calculating the longitudinal mass based on the energy or its momentum. To solve this problem, in 1905 and 1906 Poincaré introduced a potential of a non-electromagnetic nature (Poincaré tensions), which contributes to the energy of the body and thus explains the 4 ⁄ 3 factor. However, he still assumed that only the electromagnetic energy contributed to the mass. This assumption was replaced by Einstein's equivalence of mass and energy , according to which all energy, not just electromagnetic, contributes to the mass of bodies.

Gravity

Lorentz's theories

In 1900 Lorentz tried to explain the phenomenon of gravitation on the basis of Maxwell-Lorentz electrodynamics. First he proposed a mechanism based on Le Sage gravity . He assumed that the ether was filled with extremely high frequency EM radiation, which exerts enormous pressure on the body. If this radiation is now completely absorbed, the shielding between the bodies actually creates an “attraction” following the law of distance . However, this was the same problem as with the other Le Sage models: If it is absorbed, the energy has to go somewhere, or an enormous amount of heat would have to be produced , which is not observed. Lorentz therefore rejected this model.

In the same work he then tried to explain gravity as a kind of electrical differential force. Like Ottaviano Fabrizio Mossotti and Karl Friedrich Zöllner before him, he started from the idea that the attraction of two different electrical charges is a fraction stronger than the repulsion of two charges of the same name. The result would be nothing other than universal gravity, whereby according to this theory changes in the gravitational field propagate at the speed of light. However, this leads to a conflict with Isaac Newton's law of gravitation , in which, as Pierre-Simon Laplace has shown on the basis of the aberration of gravitation , the speed of propagation should be a multiple of the speed of light. Lorentz was able to show that in this theory, due to the structure of the Maxwell equations, only negligible deviations from the law of gravity occur in the order of magnitude . However, it received a value that was far too low for the perihelion twist. In 1908 Poincaré also examined Lorentz's theory of gravity and classified it as compatible with the principle of relativity, but, like Lorentz, criticized the inaccurate information on the perihelion rotation of Mercury. Lorentz himself, however, rejected his own model in 1914 because he did not see it as compatible with the principle of relativity. Instead, he saw Einstein's work on gravitation and the principle of equivalence as the most promising way of explaining it.

Poincaré's Lorentz-invariant law of gravitation

In 1904 Poincaré stated that in order to maintain the principle of relativity, no signal must be faster than the speed of light, otherwise the above synchronization rule and thus the local time would no longer apply. At that point in time, he understood this as a possible objection to the compatibility of the principle of relativity with the new theory. However, in 1905 and 1906 he calculated that changes in the gravitational field can propagate at the speed of light and that a valid law of gravity is still possible, provided that such a theory is based on the Lorentz transformation. Later, Minkowski (1908) and Arnold Sommerfeld (1910) also tried to develop a Lorentz-invariant law of gravity based on Poincaré's approach, but this was made superfluous by the work of Einstein.

Principles and conventions

Henri Poincaré

Constancy of the speed of light

Already in his philosophical treatise on the time measurements (1898) Poincaré wrote that astronomers as Ole Rømer in interpreting the measurement of the speed of light by means of the moons of Jupiter from the postulate must assume that the light is constant in all directions at the same speed. Otherwise other laws like the law of gravitation would be much more complicated. (However, it is not completely clear here whether, according to Poincaré, this postulate is valid for all reference systems.) The speed of propagation must also be taken into account when determining the simultaneity of events. Poincaré finally carried out this procedure in 1900 when he interpreted Lorentz's local time, with local time (in addition to the contraction hypothesis) being necessary for the observed validity of the principle of relativity, as Poincaré emphasized several times. And in 1904 he summarized the connection between Lorentz's theory and the speed of light in this way:

“From all these results, if they are confirmed, a completely new method would emerge, which would be mainly characterized by the fact that no speed could exceed that of light, just as no temperature could fall below absolute zero. For an observer who is carried along in an unconscious movement, no apparent speed could exceed that of light either, and this would be a contradiction if one did not remember that this observer does not use the same clocks as a stationary observer , but clocks that show the 'local time'. […] Perhaps we should also devise a completely new mechanism, which only vaguely hovers in front of us, in which, since resistance increases with speed, the speed of light would be an insurmountable limit. The usual mechanics would simply remain a first approximation, which would remain true for not very high speeds, so that one would still find the old dynamic under the new ... But I would like to add expressly at the end that we are not that far yet and that nothing has yet been proven that they [the principles of ordinary mechanics] will not emerge victorious and untouched from the battle. "

Relativity Principle

As early as 1895 Poincaré assumed that the Michelson-Morley experiment seems to show that it is impossible to measure an absolute movement or the movement of matter relative to the ether. And although most physicists believed this to be possible, Poincaré stuck to his opinion in 1900 and alternately used the terms “principle of relative motion” and “relativity of space”. At the same time, however, he criticized the artificiality of the assumptions designed as required in order to save this principle. Finally, in 1902, he used the expression "Principle of Relativity" for it. In 1904 he paid tribute to the work of mathematicians who saved this principle with hypotheses such as local time, but he again criticized the "accumulation of hypotheses". He defined this principle (according to Miller, modified from Lorentz's theorem of the corresponding states) as follows: " The principle of relativity, according to which the laws of physical processes should be the same for a stationary observer as for someone moving in uniform translation, so that we have or cannot have any means of distinguishing whether we are in such a movement or not. "

With reference to these objections by Poincaré, Lorentz tried to formulate a more coherent theory and wrote in 1904: “ Certainly there is something artificial about the establishment of special hypotheses for every new test result. It would be more satisfactory if one could show, with the help of certain basic assumptions, that many electromagnetic processes are strictly, i. H. are independent of the movement of the system without any neglect of higher order terms. "

Although Poincaré showed in 1905 that Lorentz had not completed his work, he attributed this postulate to him: “  Il semble que cette impossibilité de démontrer le mouvement absolu soit une loi générale de la nature [..] Lorentz a cherché à compléter et à modifier son hypothèse de façon à la mettre en concordance avec le postulat de l'impossibilité complète de la détermination du mouvement absolu. C'est ce qu'il a réussi dans son article intitulé [Lorentz, 1904b]  »(German:“ It seems that this impossibility to determine the absolute motion of the earth is a general law of nature. [..] Lorentz tried his hypothesis to complete and modify it in order to bring it into agreement with the postulate of the complete impossibility of determining an absolute motion. This he succeeded in his article [Lorentz, 1904b] ")

In 1906 Poincaré referred to this as the "Postulate of Relativity" ("Postulate de Relativité"). And although he stated that this postulate could perhaps be refuted (and in fact, he mentioned that the discovery of the magnetic cathode rays by Paul Villard (1904) endangers the theory), it is still interesting to consider the consequences if the postulate without limitation is valid. This also implies that all forces of nature (not only electromagnetic) are invariant under the Lorentz transformation.

In 1921, Lorentz also praised Poincaré's achievements in establishing the principle of relativity: «  … je n'ai pas établi le principle de relativité comme rigoureusement et universellement vrai. Poincaré, au contraire, a obtenu une invariance parfaite des équations de l'électrodynamique, et il a formulé le «postulat de relativité», termes qu'il a été le premier an employer.  »(German:" ... I have not established the principle of relativity as rigorous and universally valid. Poincaré, on the other hand, has achieved the perfect invariance of the electromagnetic equations, and he formulated "the postulate of relativity", whereby he was the first to use these terms. ")

The role of the ether

Poincaré wrote in 1889, in line with his philosophy of conventionalism : “ We care little whether the ether really exists; that is the business of the metaphysician; It is only essential for us that everything takes place as if it existed, and that this hypothesis is convenient for explaining the phenomena. By the way, do we have another reason for believing in the existence of material objects? This, too, is only a convenient hypothesis, only it will never cease to exist, while one day the ether will no doubt be rejected as useless. "

In 1901 he also denied the existence of an absolute space or an absolute time: “ 1. There is no absolute space and we only understand relative movements; nevertheless the mechanical facts are often pronounced as if there were an absolute space to which they could be related. 2. There is no absolute time; if one says that two times are the same, then that is an assertion which in itself has no meaning and which can only be obtained by agreement. 3. Not only do we have no direct view of the equality of two times, but we do not even have that of the simultaneity of two events which take place in different scenes; I have set this out in an essay entitled: la Mesure du temps. "

Poincaré continued to use the term ether and justified the use of the ether in 1900 by stating that it had to be explained where the light beam actually is after it has left the source and before it reaches the receiver. Because in mechanics a state must be exactly determined by the previous state. So in order not to have to give up the simplicity or convenience of the mechanical laws of nature, a material carrier is required. And while emphasizing the relative and conventional character of space and time, he believed that classical convention was "more convenient" and went on to distinguish between "true" and "apparent" time. For example, in 1912 he wrote on the question of whether the usual conventions of space and time really need to be changed: “ Are we forced to reshape our conclusions? Certainly not! We accepted an agreement because it seemed comfortable to us, saying that nothing could force us to give it up. Today some physicists want to accept a new agreement. Not that they are forced to; they feel that this arrangement is more convenient; that's all. Anyone who does not hold this view can, with full justification, stick with the old one so as not to be disturbed in their usual ideas. I believe, between us, that it will be done for a long time. "

And Lorentz also wrote in 1913: “ Suppose there is an ether; then one of all systems x, y, z, t would be distinguished by the fact that the coordinate axes and the clock rest in the ether. If you combine this with the idea (which I would be reluctant to give up) that space and time are something completely different and that there is a 'true time' (simultaneity would then exist independently of the place, corresponding to the fact that the idea is infinite for us high speeds are possible), it is easy to see that this true time must be indicated by clocks resting in the ether. If the principle of relativity were to have general validity in nature, one would certainly not be in a position to determine whether the reference system just used is that particular one. "

The transition to the theory of relativity

Special theory of relativity

Albert Einstein, 1921, photograph by Ferdinand Schmutzer

While some of the explanations related to Lorentz's electron theory (e.g. that matter consists exclusively of electrons, or that there are only electrical interactions in nature, or the explanations of gravitation) are clearly refuted, many statements and results of the theory are equivalent with statements from the special theory of relativity (SRT, 1905) by Albert Einstein . Here Einstein succeeded in deriving the Lorentz transformation and the other parts of the theory solely from the assumption of two principles, namely the principle of relativity and the constancy of the speed of light. These principles were also used in part by Poincaré and Lorentz, but they did not recognize that they are sufficient to establish a closed theory without using an ether or any assumed properties of matter. First Poincaré and then Lorentz taught the complete mathematical equality of reference systems and recognized that different spatial and time coordinates are actually measured. However, they continued to attribute the effects of the Lorentz transformation to dynamic interactions with the ether, differentiated between the "true" time in the stationary ether system and the "apparent" time in relatively moving systems, and mentioned the ether in their writings until the end. The fundamental re-evaluation of space and time in the context of a scientific theory was reserved for Einstein.

Einstein's presentation of the SRT was expanded in 1907 by Hermann Minkowski , whose four-dimensional space-time enabled a very natural interpretation of the interrelationships of the theory (whereby the fundamental aspects of four-dimensional space-time as described above were already anticipated by Poincaré). The naturalness and usefulness of the presentation by Einstein and Minkowski contributed to the acceptance of the SRT and to the decrease in interest in Lorentz's ether theory. Lorentz himself argued in 1913 that there was no great difference between his ether theory and the rejection of a preferred reference system and that it was therefore a question of taste which theory one admitted to. However, in 1907 Einstein criticized the ad hoc character of the contraction hypothesis because it was only introduced to save the ether, with an untraceable ether as the foundation of electrodynamics being unsatisfactory. In 1908, Minkowski also described the contraction hypothesis as part of Lorentz's theory as a “gift from above”; but although Lorentz's theory is completely equivalent to the new conception of space and time, Minkowski was of the opinion that the relationships become much more understandable in the context of the new space-time physics.

Equivalence of mass and energy

As Einstein (1905) derived from the principle of relativity, there is actually an inertia according to the energy , or more precisely, that electromagnetic radiation can transfer inertia from one body to another. But in contrast to Poincaré, Einstein recognized that matter experiences a loss of mass when it is emitted - that is, the energy stored in the matter and corresponding to a certain mass and the electromagnetic energy can be converted into one another, which is what the actual equivalence of Gives mass and energy . Poincaré's radiation paradox can be solved comparatively easily with this equivalence. If it is assumed that the light source loses mass at the emission according to, the contradiction dissolves without having to accept any balancing forces in the aether.

Similar to Poincaré, Einstein was able to show in 1906 that the theorem of the conservation and movement of the center of gravity is also valid for electrodynamic considerations, if the inertia of the (electromagnetic) energy is assumed. Here, too, he did not have to introduce fictitious masses like Poincaré, but only needed to show how the emission and absorption of energy lead to the transfer of inertia, so that no perpetual motion machine can arise. He referred to the work of Poincaré and assessed its content as formally largely consistent with his own text. Einstein wrote in the introduction:

"Despite the fact that the simple formal considerations that have to be carried out to prove this assertion are mainly contained in a work by H. Poincaré², for the sake of clarity I will not rely on that work."

With Einstein's approach, the contradiction between the task of the conservation of mass and the reaction principle, mentioned by Poincaré, can be resolved, since the conservation of mass is now a special case of the conservation of energy .

general theory of relativity

According to the general theory of relativity (ART) developed by Einstein , which made the explanations of gravitation by Lorentz and Poincaré superfluous, including gravitation in the relativity principle means that Lorentz transformations and the constancy of the speed of light are only locally definable and valid. Einstein himself said in a speech (1920) that within the framework of the ART, space cannot be thought of without gravitational potential and that physical qualities adhere to space itself. Therefore one could speak of a "gravitational ether" in the sense of an "ether of the general theory of relativity". He wrote:

“What is fundamentally new about the ether of the general theory of relativity compared to the Lorentzian ether consists in the fact that the state of the former is determined at every point by legal connections with matter and with the etheric states in neighboring places in the form of differential equations, while the state of the Lorentzian ether in the absence of electromagnetic fields it is not conditioned by anything but it and is the same everywhere. The ether of the general theory of relativity goes over into the Lorentzian one by replacing the space functions that describe it with constants by ignoring the causes which determine its state. One can also say that the ether of the general theory of relativity emerged from the Lorentzian ether through relativization. "

priority

There is some speculation that the special theory of relativity was the work of Poincaré and Lorentz, and not of Einstein. See the article: History of the special theory of relativity

Recent developments

New Lorentzianism

Although the idea of ​​a preferred reference system is largely rejected by experts, some “ Lorentzian ” or “ neo-Lorentzian ” models (English: neo-Lorentzian relativity ) were developed after Lorentz and Poincaré . These theories were mainly advocated in the 1950s by Herbert E. Ives and Geoffrey Builder , among others , and by Simon Jacques Prokhovnik in the decades that followed . Corresponding to the original Lorentzian theory of aether, an aether at rest was assumed, whereby the speed of light is only constant relative to this, and consequently it should be direction-dependent in moving inertial systems. If, in addition to the directional dependence, the effect of length contraction is postulated, the existence of time dilation also follows. Therefore it is not possible (unless additional parameters of the theory are changed) to experimentally determine the anisotropy of the speed of light. Experiments like those of the eccentric Bulgarian physicist Stefan Marinow , which supposedly provided confirmation of their directional dependence, were rejected by experts as useless.

In 1996 Helmut Günther also developed a Lorentzian model of a universal ether. This is based on the fact that quasi-relativistic effects such as length contraction in plastic deformations and dislocations in crystal structures or in pendulum chains in connection with solitons were found. This is because the Sine-Gordon equation on which these phenomena are based is Lorentz-invariant. Other Lorentzian models are discussed in Brandes et al. discussed.

However, all these models are hardly discussed further in the professional world, since a theory in which the ether is practically undetectable due to a kind of conspiracy of various effects, a very low degree of probability is assigned. See also criticism of the theory of relativity # ether and absolute space .

Test theories of special relativity

Some test theories of the special relativity theory , with which possible deviations from the Lorentz invariance are to be assessed, contain the Lorentzian ether theory as a limiting case. So far, precision measurements have fully confirmed the validity of the Lorentz invariance.

literature

For an exact list with the sources for all other authors, see History of Special Relativity # Literature

Works by Lorentz, Poincaré, Einstein

  • Lorentz, Hendrik Antoon: De l'influence du mouvement de la terre sur les phénomènes lumineux . In: Archives néerlandaises des sciences exactes et naturelles . 21, 1886, pp. 103-176.
  • Lorentz, Hendrik Antoon: Considerations on Gravitation . In: Proceedings of the Royal Netherlands Academy of Arts and Sciences . 2, 1900, pp. 559-574.
  • Poincaré, Henri: Théorie mathématique de la lumière , Volume 1. G. Carré & C. Naud, Paris 1889. Partial reprint of the foreword in “Science and Hypothesis” (1902), chap. 12.
  • Poincaré, Henri: The measure of time . In: The Value of Science (Chapter 2) . BG Teubner, Leipzig 1898/6, pp. 26–43.
  • Poincaré, Henri: Sur les principes de la mécanique . In: Bibliothèque du Congrès international de philosophie . 1901, pp. 457-494. . Reprinted in “Science and Hypothesis” (1902), chap. 6-7.
  • Poincaré, Henri: Science and Hypothesis . Xenomos, Berlin 1902/2003, ISBN 3-936532-24-9 . .
  • Poincaré, Henri: The Value of Science . Xenomos, Berlin 1905a / 2003, ISBN 3-936532-23-0 . .
  • Poincaré, Henri: The New Mechanics . In: The foundations of science (Science and Method) . Science Press, New York 1908/13, pp. 486-522. . German translation in "Wissenschaft und Methode" (1908), third book.
  • Poincaré, Henri: Science and Method . Xenomos, Berlin 1908b / 2003, ISBN 3-936532-31-1 . .
  • Poincaré, Henri: La Mécanique nouvelle (Lille) . In: Comptes rendus des Sessions de l'Association Française pour l'Avancement des Sciences . , Paris 1909, pp. 38-48.
  • Poincaré, Henri: La Mécanique nouvelle (Göttingen)  (= six lectures on selected subjects from pure mathematics and mathematical physics). BG Teubner, Leipzig and Berlin 1910, pp. 41–47.

Secondary sources

  • Katzir, Shaul: Poincaré's Relativistic Physics: Its Origins and Nature . In: Physics in perspective . 7, 2005, pp. 268-292. doi : 10.1007 / s00016-004-0234-y .
  • Miller, Arthur I .: Albert Einstein's special theory of relativity. Emergence (1905) and early interpretation (1905-1911) . Addison-Wesley, Reading 1981, ISBN 0-201-04679-2 .
  • Whittaker, Edmund Taylor: A History of the theories of aether and electricity Vol. 1: The classical theories , 2nd edition. Edition, Nelson, London 1951.

Sources for recent work

  • Prokhovnik, SJ: Neo-Lorentzian relativity . In: Journal of the Australian Mathematical Society . 9, No. 2, 1965, pp. 273-284.
  • Prokhovnik, SJ: The empty ghosts of Michelson and Morley: A critique of the Marinov coupled-mirrors experiment . In: Foundations of Physics . 9, 1979, pp. 883-896.
  • Brandes et al .: Einstein's and Lorentzian interpretations of the special and general theory of relativity . VRI, 1997, ISBN 3-930879-05-0 .
  • Günther, H .: Limiting speeds and their paradoxes . BG Teubner, Stuttgart-Leipzig 1996, ISBN 3-8154-3029-1 .
  • Mansouri R., Sexl RU: A test theory of special relativity. I: Simultaneity and clock synchronization . In: General. Relat. Gravit. . 8, No. 7, 1977, pp. 497-513.
  • Sendker, Werner Bernhard: The so different theories of space and time. The transcendental idealism of Kant in relation to Einstein's theory of relativity, Osnabrück, 2000 ISBN 3-934366-33-3
  • Wolf et al .: Recent Experimental Tests of Special Relativity (2005): arxiv : physics / 0506168 ; and Relativity tests by complementary rotating Michelson-Morley experiments (2007): arxiv : 0706.2031

Individual evidence

Primary sources
  1. ↑ Lorentz (1892a)
  2. ↑ a b c d Lorentz (1895)
  3. ↑ a b c d e Lorentz (1904b)
  4. ↑ a b c d e Poincaré (1906)
  5. ↑ a b c d e Poincaré (1905b)
  6. ↑ Lorentz (1916)
  7. ↑ Michelson (1887)
  8. ↑ Lorentz (1892b)
  9. ↑ a b Lorentz (1899)
  10. ↑ a b Poincaré (1898); Poincaré (1905a), Ch. 2
  11. ↑ a b Poincaré (1900b)
  12. ↑ a b c d e Poincaré (1904); Poincaré (1905a), Ch. 8
  13. ^ Letter No. 1, May 1905 ( Memento of April 16, 2009 in the Internet Archive )
  14. ^ Letter No. 2, May 1905 ( Memento of April 16, 2009 in the Internet Archive )
  15. ↑ Lorentz (1900)
  16. ↑ Poincaré (1908a); Poincaré (1908b), 3rd book
  17. ↑ Lorentz (1914)
  18. ↑ Poincaré (1895)
  19. ↑ a b Poincaré (1900a); Poincaré (1902), Ch. 10
  20. ^ Poincaré (1902), Ch. 13
  21. ↑ Lorentz (1921), pp. 247-261
  22. ↑ Poincaré (1889); Poincaré (1902), Ch. 12
  23. ↑ Poincaré (1901a); Poincaré (1902), Ch. 6
  24. ↑ Poincaré (1913), Ch. 2
  25. ↑ a b Lorentz (1913), p. 75
  26. ↑ Einstein (1908a)
  27. ↑ Einstein (1905b)
  28. ↑ Einstein (1906)
  29. ↑ Einstein (1922)
Secondary sources
  1. ↑ Whittaker (1951), 386ff
  2. ↑ Born (1964), 172ff
  3. ↑ Brown (2001)
  4. ↑ Miller (1981), 70-75.
  5. ↑ Janssen (1995), chap. 3.5.4
  6. ↑ Darrigol (2005), 10-11
  7. ↑ Janssen / Mecklenburg (2007)
  8. ↑ Walter (2007), chap. 1
  9. ↑ Janssen / Mecklenburg (2007)
  10. ↑ Miller (1981), 359-360
  11. ↑ Walter (2007)
  12. ↑ Galison (2002)
  13. ↑ Miller (1981): 186-189
  14. ^ Miller (1981), 79
  15. ↑ Katzir (2005), 275-288
  16. ↑ Walter (2007), chap. 1
  17. ↑ Darrigol (2005), 15-18
  18. ↑ Janssen (1995), chap. 4th
  19. ↑ Walter (1999)
  20. ↑ Darrigol (2005), 18-21
  21. ↑ Miller (1981)
  22. ↑ Janssen (1995)
Recent work
  1. ↑ Prokhovnik (1965)
  2. ↑ Prokhovnik (1979)
  3. ^ Günther (1996)
  4. ↑ Dietrich (2001)
  5. ↑ Brandes (1997)
  6. ↑ Wolf (2005)

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This article was added to the list of excellent articles on February 22, 2008 in this version .