Chapter 10. Epola Wave Propagation and Interaction with Matter

10.1 Absorption and dissipation of epola waves by random vibrations

The physical conditions under which vibrations of epola particles form an epola wave motion were discussed in Section 7.1. We shall now discuss the physical processes which an established epola wave or its representative – the electromagnetic wave – undergoes while propagating in the epola. The inevitably present factor disturbing all epola wave motions are the random vibrations of epola particles around their lattice sites (Section 5.11).

In our formulation of the Huygens principle (Section 7.1), we explained that when an epola particle is reached by an epola wave, it is forced to vibrate with the frequency of the wave; therefore. the particle becomes the center of a new spherical epola wave. Suppose that an epola wave-front reaches a certain lattice site. However, the epola particle is not there but, due to the random vibrations, it is momentarily further out. Then it is reached by the wave-front at a slightly later moment. If the particle is in front of its lattice site, then it is reached by the wave slightly earlier. In both cases, the energy transferred to the particle by the wave is less than the amplitudinal value in the wave. Hence, the continuation of the wave, initiated by the particle, will have less energy. Such events at large result in absorption, which transfers some wave energy into the energy of random vibrations of epola particles.

We see that epola particles, which are momentarily further out of their lattice sites, receive the wave signal slightly later than the particles in their lattice sites. Particles in front of their lattice sites receive the wave signals slightly earlier than particles which are in their lattice sites. The delays and advances have the local effects of reducing and increasing frequency. These opposed effects do not cancel out completely. The general trend to reduce energies involved in physical processes leads here to some net reduction in frequency, thus to non-linear absorption. The simplest example of non-linear absorption is the reduction in vibrational frequency of a pendulum in such energy-absorbing media as compressed air, water, oil, or honey.

Yet another process is the deflection of the wave. The basic physical interaction here occurs when the wave-front reaches a lattice site whose particle is out to the right or left. In such case, there is no delay in energy transfer but a change in the shape of the wave-front, initiated by the deflected particle. This also means a change in the direction of the ray, which is perpendicular (normal) to the wave-front. In bulk, such processes lead to the dissipation of the wave motion.

10.2 Fading of long-wave electromagnetic radiation due to epola random vibrations

The linear and nonlinear absorption and the dissipation of epola wave energy due to the interaction with epola random vibrations, discussed in Section 10.1, affects, in principle, all spectral ranges and all frequencies. However, the effect is significant only in low-frequency electromagnetic radiation. The lower the frequency of the wave, the larger is the radius of the half-wave deformation cluster, and the number of randomly vibrating epola particles in the cluster is larger. A larger number of randomly vibrating particles results in a stronger absorbing and diverting action.

The nonlinear absorption in the long-wave electromagnetic radiation reduces the frequency of the wave and increases the wavelength, increasing the number of absorbing particles in the half-wave deformation cluster. This results in an increased non-linear absorption and further frequency reduction, and so on, until a zero frequency or infinite wavelength, i.e., until the epola wave motion fades away completely. Then all the energy of the epola wave (the electromagnetic radiation) is turned into the energy of random vibrations of epola particles.

The fading out of low-frequency epola waves can best be observed on the 60 Hz electromagnetic waves radiated by the wires of our alternating current power-lines. In the immediate vicinity of such a line, even a pocket transistor radio (battery-operated) detects the radiation and sounds the characteristic hum. Moving away with an appropriate receiver, one obtains a lower signal and may distinguish a lower pitch. The distance at which the signal fades away completely depends also on the sensitivity of the receiver.

A precise measurement of the dependence of the amplitude and frequency of the 60 Hz radiation on the distance from the radiating wire (or sheet) might yield the experimental evidence for the absorption by epola random vibrations. For this, we should eliminate as much as possible the air, which could also be suspected as an absorber of the 60 Hz radiation. Therefore, the experiments should be carried out in the best achievable vacuum and/or cleanest deionized air.

Non-linear absorption, with wavelength-increase as function of the distance to the receiver, is observed in long-wave (3 km) radio-communication on distances of a thousand km. On such distances, the absorption may mostly occur in masses of wet air and it is hard to say what part of it is due to epola random vibrations.

10.3 Distances between particles in atomic bodies

Solid and liquid atomic bodies consist of host atoms, forming the molecules of the body, impurity atoms (dopants), "free"* electrons and/or free "holes"**. They also contain various kinds of structural defects: vacancies, grain and twin boundaries and surface layers, which differ from the bulk of the body in structure and sometimes also in chemical composition. The sizes of the atoms are ~100 pm and the distances between the nuclei of neighboring atoms are ~300 pm. In gases at normal conditions, the molecules arc ~10 times farther apart. Inside the atoms, the distances between the orbital electrons and their remoteness from the nucleus depend on their number. With 20 orbital electrons (as in $\mathrm{Ca}$), the average distance between them is ~25 pm. This distance is proportionally smaller in heavier atoms.

The distances between the orbital electrons inside the atoms are smaller than the distances between any other particles of the atomic body. But even these distances are thousands of times larger than the distance between epola electrons and positrons. The epola lattice constant is $l_0 = 4.4 \ \mathrm{fm}$, so that in the volume of an atom, there are $10^{13}$ epola unit cubes of volume ${l_0}^3$, or $10^{13}$ epola particles, and in a cubic cm, there are $10^{37}$ epola particles, and only $10^{23}$ atoms of the atomic body, i.e., $10^{14}$ epola particles for each atom. Therefore, in the epola space, atomic bodies appear as highly diluted and weakly bound conglomerates of nuclei and electrons, thousands and up to hundred thousand of epola units apart from each other.

10.4 Electrons and holes in metals, semiconductors and insulators

Atoms of metals easily release their valence electrons, which can move quite freely inside the metal. In active metals, the concentration of these 'free' electrons may reach $10^{23}$ per $\mathrm{cm^3}$, meaning that almost every atom has released a valence electron. Therefore, the metal consists of positive ions of the host atoms and of a 'gas' of 'free' electrons or the "electron gas". The average distance between the electrons in the electron gas is therefore similar to the distance between the nuclei of the ions, i.e., ~500 pm. In less active metals, the density of the electron gas can be $10^{21} / \mathrm{cm^3}$, so that the mean distance between electrons is increased to ~1 nm. The high density of free electrons in metals results in the high electrical conductivity of metals. In some less active metals, especially in "semimetals", electric currents can also be carried by free holes.

The ionization energy of a host atom in a semiconductor is much higher than in metals. However, atoms of various dopants are easily ionized in the semiconductor. Therefore, in most of the semiconductors, the "free" electrons and holes originate mostly from the impurity atoms or dopants, and from structural defects in the material. In n-type semiconductors, the electrical conduction is due to "free" electrons, and in p-type semiconductors, it is due to free holes. The concentrations of these charge-carriers vary in semiconductors from above $10^{18} / \mathrm{cm^3}$ down to $10^{12} / \mathrm{cm^3}$. Accordingly, the average distance between the charge carriers is 10 nm to 1 $\mathrm{\mu}$m. These concentrations can increase in semiconductors by orders of magnitude, due to heat, pressure, irradiation, application of electric fields, and other external factors. This is what makes semiconductor materials so important in modern technologies.

In insulators, the ionization energy of host atoms is higher than in semiconductors. In addition, impurity atoms do not reduce their ionization energy in the host-atom matrix of the insulator as drastically as they do in the semiconductor matrix. Therefore, the concentration of free electrons and holes is lower than $10^{12} / \mathrm{cm^3}$ and the mean distance between charge carriers is larger than 1 $\mathrm{\mu}$m.

10.5 Interaction of electromagnetic radiation with the free electron gas

The interaction between electromagnetic radiation and the free electron gas depends on the diameter of the half-wave deformation cluster of the epola wave, represented by the radiation, and on the average distance between the electrons in the electron gas. It then seems obvious that epola waves with half-wave cluster diameters shorter than this distance should be able to penetrate through the electron gas and interact with the atoms or ions of the body. Hence, the electron gas in metals should be penetrable for radiation of wavelengths shorter than 1 nm, i.e., to X-rays of energies above 1.24 keV. In semiconductors, the electron gas should become penetrable to wavelengths shorter than 1 $\mathrm{\mu}$m. However, beeause of the much lower concentration of the electron gas, longer wavelengths are also able to diffract into the bulk of the semiconductor, and are not eliminated, as in metals. In insulators, the concentration of 'free' electrons is small; they make small contributions to the reflectivity and absorption and their role is not significant. Hence, radiation of all wavelengths penetrates into the insulators and interacts with their atoms.

The reflectivity of metals in all spectral ranges up to X-rays is the highest among known materials and is almost entirely due to the electron gas in them. This can be ascribed to the experimentally-known strong correlation between electrons and electromagnetic radiation. It can easily be explained, because in the epola model, electromagnetic radiation is due to vibrating electrons and positrons, and the transfer of energy and momentum is most complete between particles of equal mass. Therefore, "free" electrons, reached by the vibrations of particles in the surrounding epola, are swept into these vibrations unconditionally. This occurs, whether the vibration energy is allowed to the electron or forbidden. The difference is only in the time delay before re-emission.

A forbidden energy would bring the electron into an energy-state identical with the state of another electron in the dense electron gas of the metal. The accompanying waves of the two electrons would then have to unite, being carried by the same epola particles. This means that the two electrons would become exposed to a part of their Coulombic repulsion, not balanced by the attraction to the positive ions of the metal. The exposure would last for a longer time than in the occasional crossing of paths of two electrons in the electron gas. Therefore, the outcropped Coulomb repulsion between two electrons in one accompanying wave causes the rejection or re-emission of the forbidden energy. This is expressed in the Pauli exclusion principle (Sections 9.3, 9.4).

If the radiation energy is allowed, the 'free' electron keeps and cherishes it, together with the harem of other vibrations in which it participates. The electron transfers and re-emits this energy, accepting new portions of it and losing old ones. As an example may serve the re-emission of the radio and TV waves, received by our metallic aerials. (Because of this re-emission, our neighbors may find out what we are watching or listening to). If the energy is not allowed, then the electron gets rid of it in a very short, practically immeasurable time. Therefore, it looks to the outside world as if the electron did not commit the act of accepting the forbidden energy but reflected it immediately, as demanded by the Pauli principle.

Serious absorption of radiation energy by the electron gas in metals starts at energies just above the 'work function' values, which vary from 1.9 eV in cesium to 5.4 eV in platinum. Absorption of these energies results in the photoelectric effect (Section 3.2). In semiconductors, there is no proximity between the electrons of the electron gas, which would require the application of the Pauli exclusion principle, and the electron gas may absorb any amounts of energy, up to the energies for which it becomes transparent. Therefore, the reflectivity of the electron gas is smaller than in metals, and also its spectral range is narrower, ending in the near infrared.

10.6 Direct and secondary transparency of atomic bodies to epola waves

The epola model allows us to formulate a general rule for the transparency of atomic bodies to electromagnetic radiation. From the epola viewpoint, it is obvious that:

an atomic body is directly transparent to electromagnetic waves, in which the diameter of the half-wave epola deformation clusters is smaller than the distance in the body between such particles or complexes, which resist the passage of the wave.

This rule fits the transparency of the electron gas in metals but is too restrictive in the case of the electron gas in semiconductors. We should therefore add that:

if the concentration of the resisting particles or complexes in the volume of the body is low, then, due to possible diffraction.,correspondingly longer wavelengths may be allowed to pass.

The rule does not consider the inevitable thermal absorption by all particles and complexes of the atomic body, to which all wave-motions are subject. This absorption reduces the transparency of the body, and sufficiently thick bodies may turn opaque. This absorption may also lead to some frequency reduction (Section 10.2).

According to our rule, electromagnetic radiation of wavelength longer than the distance in the body between atoms and complexes which resist its passage is absorbed by these constituents of the body. This absorption may cause some long-term changes in the body, e.g., due to photochemical reactions, or by creating defects, i.e., by removing atoms or ions from their sites, etc. The short-term changes can be photoconductivity and/or photovoltaic effects. However, absorption occurring in atoms may temporarily raise the atoms into higher energy states. Thereafter, the atoms return to their previous states and the radiation is re-emitted. As a final result, the body is transparent to the radiation. This "secondary" transparency does not contradict our rule, because the atoms which absorbed and re-emitted the radiation did not actually resist its passage; they only delayed it. Anyhow, because of this delay, we should distinguish between the secondary transparency and the direct transparency, which occurs without delay.

10.7 Velocity of light in atomic matter

The known values of the velocities of X-rays and gamma-rays in atomic matter are very close to the vacuum light velocity $c$. However, the velocities of visible light in atomic bodies are much smaller than $c$: by 25 percent in water, by 34 percent in glass and by 60 percent in diamond. This discrepancy can be explained by the epola model, on the basis of our transparency rule and the discussion of Section 10.6. X-rays, the half-wave deformation clusters of which are not smaller than the distance between orbital electrons in heavy atoms, may still be absorbed and re-emitted by electrons on the inner-shell orbits of the heavy atoms. Otherwise, the short X-rays and gamma-rays pass in the bodies directly. without delay, hence, with a velocity close to $c$. However, visible radiation is strongly absorbed by the orbital electrons of atoms and then re-emitted by them. The passage of this radiation is delayed and the resulting propagation-velocity of this radiation is reduced. Our conclusion is that:

the primary or direct propagation velocity of electromagnetic radiation in atomic matter is close to the vacuum light velocity $c$; the observed lower velocities of certain spectral radiation ranges in some atomic bodies result from delays caused by the absorption and re-emission of this radiation, mostly by the atoms of the bodies.

Our explanation fits also the density relations between the epola and atomic matter. The mass-density of the epola is $10^{10} \ \mathrm{g/cm^3}$. The density of water is $10^{-10}$ that of the epola density. "Filling" 1 $\mathrm{cm^3}$ of the epola with water means increasing the density by a $10^{-10}$ part. The velocity of bulk deformation waves is inversely proportional to the square root of the density (Section 6.3). Hence, the velocity in water should decrease by a $10^{-5}$ part or by a thousandth of a percent. A further decrease should be due to the distortions introduced in the epola by the electrons and nuclei of the water molecules, which were squeezed in between the epola particles. Some reduction in velocity may also be due to absorption processes. Altogether, we might expect a velocity reduction of much less than one percent. The velocity reduction of X- and gamma-rays is of this order. The observed 25 Percent reduction of the speed of visible light in water could only be due to the discussed absorption – re-emission delays.

10.8 Reduction of light-velocity in distorted epola

In the previous section, we mentioned a possible reduction in light velocity, due to the distortion of the epala by the nuclei and electrons of atoms. Obviously, this reduction cannot be measured inside atomic bodies, not only because it is small but because the separation of velocity reductions by their causes is not feasible in atomic bodies. However, we may expect that these disturbances should exist per se in epola layers immediately adjacent to the surface of the bodies. We may also approximate the thickness of such distorted layers to be a billion of epola lattice units, i.e., a few micrometers.

We therefore suggest a measurement of the velocity of light in a laser beam with the smallest possible cross-section diameter. Thereafter, we would place on both sides of the beam long blocks of the heaviest possible material (platinum desired, but may settle for lead), precisely machined, so that they can form a channel several micrometers wide and measure the velocity of light in it. The measurement could also be performed with the light-beam in an optical fiber.

The proposed measurement may have some cosmological aspects. We mentioned in Section 2.9 that in his 1911 paper, Einstein allowed some change of light-velocity in a gravitationally distorted space, while in 1916, he denied the possibility of such change. Hence, the gravitational redshift was ascribed to frequency reduction only. The distortion of the epola in the narrow channel between the large masses in our proposed experiment is far in value from the gravitational distortion in the vicinity of the Sun but would have the same character, i.e., distortion due to, but outside of, large masses, away from the interaction of their atoms with radiation.

10.9 Interaction of electromagnetic radiation with atomic bodies moving in the Epola

Before analyzing the interaction, we must recall two experimental facts which contradict our natural perception of matter and space, and which we therefore instinctively resist and disregard in our thinking. First is the fact, discovered by Rutherford in 1911, that only a $10^{-15}$ part of the volumes of atomic bodies (including ourselves) is occupied by dense particles. The rest, i.e., practically all the volume, is as empty as the vacuum space and penetrable to dense particles. The second fact, discovered by Anderson in 1932, is that from every point of the vacuum space, free electrons and positrons can be released by submitting 1.02 MeV of energy. Out of this fact, it follows that the vacuum space must be densely populated by bound electrons and positrons, 4.4 fm apart from one another (Chapter 4).

Due to our natural perceptions, we always think of the interaction between a moving body and electromagnetic radiation as of the action of a moving wall, pushing or pulling the radiation, together with whatever it is in: the space, the ether or the electromagnetic field. Hence, the moving body increases or reduces the frequency of the radiation, if not its velocity. It surely is hard to accept, that in the distance belween every two atoms of the body, there are a hundred thousand bound electrons and positrons, the vibrations of which are represented by the radiation. The moving body is just as able to push or pull these bound particles, as a net with square-kilometer-large eyelets can catch sardines.

From the epola point of view, the atomic body is a conglomerate of nuclei and electrons, thousands up to hundred thousand epola lattice units apart, with a billion times smaller mass density, bound to each other hundreds up to hundred thousand times weaker than the epola particles. When the body moves, the interaction of its dense particles with the epola causes epola waves with de Broglie wavelengths, which accompany the motion of each particle, and forces the adjustment of the electron orbits to the motion.

The value $c$ of the velocity of epola waves results from a binding energy which is $10^5$ times stronger than in atomic bodies and from a mass-density which is a billion times larger. Hence, it would take bodies of nuclear matter to change $c$. Bodies of atomic matler cannot change this velocity, neither in their bulks nor in adjacent outsides, except perhaps by a small fraction of a percent. In the epola, the electromagnetic radiation always propagates with the same velocity, independent of whether there are moving atomic bodies in it. Inside the moving or resting atomic body, the quadrillions of epola electrons and positrons, which participate in the electromagnetic wave, propagate the wave motion with the same velocity, until their wave-energy is absorbed.

10.10 Electromagnetic radiation received by a moving body

Let us consider an atomic body moving with a velocity $v$ relative to the epola, in which electromagnetic waves are propagating. The body is much larger than the half-wave deformation cluster of the waves, so that the radiation does not diffract around it. The body is therefore a receiver of the radiation and can serve, with proper auxiliary equipment, as a detector of this radiation. To be specific, let the radiation be in the visible range and the receiver be of any movable size, from a rocket to a few micrometer-thin foil of a square millimeter area.

When the radiation reaches the surface of the moving receiver, it continues to propagate inside with the same velocity $c$, forcing the quadrillions of epola electrons and positrons inside the foil to vibrate with the same frequency $f$, as it was outside. Simultaneously, the 'free' electrons of the receiver, the orbital electrons of its atoms and even the nuclei are shaken with the same frequency $f$. If none of this shaking is accepted, then the radiation behind the body continues to propagate with the same frequency and velocity. If all is accepted and absorbed in the body, whether in the whole thickness or in a certain frontal part of the thickness, then there is no radiation behind the receiver or inside it, behind the absorbing frontal part.

Let us now consider the frequency of the radiation, received by the moving body. During one second, the receiver is approached in the epola by $f$ waves or $2f$ half-wave deformation clusters. If the receiver moves toward the radiation, then it 'swallows' more half-wave clusters, and its 'free' and orbital electrons endure more shakes. If the receiver moves away from the radiation, then during one second, it receives as many fewer waves as it left behind itself, on the distance which it passed in one second.

We may say that if wave propagation with velocity $c$ delivers in one second a number $f$ of waves, then propagation with velocity $v$ of the same frequency would deliver a number of waves as many times smaller than $f$, as $v$ is smaller than $c$; hence, a number $fv/c$. Therefore, the number of waves received in one second by the body moving towards the radiation is $f + fv/c$, while the body moving away from the radiation receives in one second $f - fv/c$ waves. But these numbers are the frequencies $f$ of the radiation received by the moving body, thus:

or, replacing $f' - f = \Delta f$, we have

These are the equations for the Doppler effect. We recall that the velocity $v$ is 'automatically' much smaller than $c$, because atomic bodies would disintegrate at $v \ge 0.01 \, c$. We also do not have to worry about it, because the highest velocity achieved, that of the Voyager, was 52,000 km/h or less than 15 km/s relative to Earth. This could mean a maximum of, maybe, 45 km/s relative to the epola.

10.11 Electromagnetic radiation emitted by a moving body and the Doppler effect

We shall now consider an atomic body, which emits electromagnetic radiation while moving with a velocity $v$ relative to the epola. Let the emitter be close to a point-source, e.g., a high-pressure electric arc, a few mm in size, emitting equally intense radiation in almost all directions. The radiation is due to thermally-excited atoms, the orbital electrons of which transit to lower energy states, forcing epola electrons and positrons into vibrations with the transition energies.

Epola electrons and positrons forced into vibrations transfer the vibrational energy to their neighbors, and this transfer of vibrational energy is the propagation of electromagnetic waves. The velocity of this propagation is the velocity $c$ of epola deformation waves, defined by the binding energy and mass-density in the epola. Thus, it depends solely on the 'local' conditions in the epola itself. We may say that the vibrating epola particles have no 'information' about the conditions and motions of the source, except what is in the energy or frequency they obtained. They also have no information on the velocity of the transfer process in other regions of the epola, which the radiation passed before reaching them. All they have is the energy or frequency to pass on, the inertia, and the binding and proximity to the neighboring particles, which define how fast the energy is passed on.

The sole dependence of the propagation velocity of epola waves on the conditions in the epola causes the radiation, emitted by a moving source, to propagate in all directions in the epola with the same velocity $c$. However, the energies and frequencies of radiation emitted in different directions are different.

Let a particular electron-transition-frequency in the source be $f$. If the source rests in the epola, then all epola particles around the source are reached in one second by a number $f$ of vibrations, as emitted by the source, or by a number $f$ of waves. But when the source moves with velocity $v$, then the epola particles behind the body are reached by less than $f$ vibrations; as many less as there are waves in the distance traveled by the source in one second. If propagation with velocity $c$ delivers $f$ waves in a second, then propagation with velocity $v$ would deliver as many less waves as $v$ is smaller than $c$. And, in the case of $v = c$ (impossible; atomic bodies would disintegrate at $v \ge 0.01 \, c$), none of these vibrations or waves would reach particles behind the body. Hence, the number of waves reaching the epola particles behind the body in one second, or the frequency $f'$ of radiation behind the body is:

Epola particles in front of the moving body are reached in one second by more than $f$ vibrations or waves; as many more as there are waves in the distance traveled by the emitter in one second, i.e., by $fv/c$ waves. Hence, the number of waves reaching the epola particles in front of the body in one second, or the frequency $f'$ of radiation in front of the body is:

Replacing $f' - f = \Delta f$, we have, for frequencies in front and behind the moving emitter,

which is the equation for the Doppler effect. The same formulas were obtained in the previous section for the moving receiver. Both cases, of the moving source and of the moving receiver, may therefore be united, with $v$ representing the velocity of the receiver and the source relative to the epola, keeping in mind that the two are atomic bodies hence, that $v$ cannot exceed a hundredth of $c$.

Our discussion is also applicable to the re-emission and to the reflection of radiation absorbed by an atomic body. Obviously, there is no difference in the propagation of radiation from atoms, whether excited thermally, or by absorbed radiation, or by any other means. The same propagation conditions are also valid for radiation reflected by the electron gas.

In our derivation, we actually used the classical rules for velocity addition, though there is no physical addition of velocities here. The velocity of atomic bodies does not add to the velocity of light, as velocities of nuclear bodies would, and as the velocity of water in the river adds to the velocity of the boat. In general, mathematical treatment worked out for a particular physical process may be legally and successfully applied to the treatment of distinct processes, with gain to both physics and mathematics. The trouble to physics starts when the interpretation of such treatment masks the physical distinctiveness and particulars; as a final result, there might be no physics left.

10.12 Constancy of light-velocity and the Michelson-Morley experiment

We have seen in Section 10.11 that the velocity of light depends solely on the conditions in the epola. Being determined by the epola binding energy and mass density, tremendously large, as compared with atomic bodies, the velocity $c$ cannot be affected by atomic bodies, and only bodies of nuclear matter could cause changes in the epola. Therefore, if the emitter or receiver of electromagnetic radiation are atomic bodies, then the velocity of light $c$ is independent of the motion of the emitter and receiver and is the same in all directions.

This conclusion is in full agreement with the results of Michelson-Morley's experiment, described in Section 1.3. In their experiment, light from a monochromatic source was split into two beams, one parallel to the direction of Earth's motion and the other perpendicular to it. After passing slightly different optical paths, the two beams were brought together, to produce their interference fringe pattern. Then, the whole apparatus was turned by 90°, so that the two beams exchanged the directions of their paths. If there were a difference between the velocities of light along the two paths, then during the exchange of orientation of the two beams, their interference fringe pattern should have been shifted.

Thc experiment was performed at different seasons, locations and elevations, repeated by different workers until 1930, and brought to an accuracy, such that a difference in 1 km/s in the velocity of light could have been detected. However, no difference could be found in the velocity of light in directions along the motion of Earth, perpendicular to it and opposite to it.

Such an agreement of experimental results of Michelson–Morley and their continuators, with the conclusions made on the basis of our model, should be considered as an experimental evidence for the validity of the epola model. All the more, that it is only the epola model which is able to explain the results of this experiment, and to do it in a way which is compatible with all known experiments.

Einstein's conclusions of the Michelson-Morley results are in his Second Postulate of special relativity (Section 2.1):

Light is always propagated in empty space with a definite velocity $c$, which is independent of the state of motion of the emitting body.

Also:

Any ray of light moves in the 'stationary' system of coordinates, with the determined velocity $c$, whether the ray be emitted by a stationary or by a moving body.

If it were allowed to replace the words "'stationary' system of coordinates" by the word 'epola', the words "is always propagated in empty space" by the words 'propagates in the epola', and to insert "atomic" before the word "body.", then Einstein's second postulate could become a pillar of the epola model of space. Except that in the epola model, it does not have to be postulated; it is explained and derived.