22. ABERRATION
 
   In 1725 James Bradley discovered the aberration of stars, that is the stellar aberration. He found that the displacement, measured as an angle between the real and seeming direction of light rays from a star, is small and in the direction of the observer's motion. In addition he discovered that the aberration is the consequence of the finite speed of light and the transverse motion of the observer. If we disregard the aberration caused by the movement of the solar system, then we are left with the annual aberration due to the orbital motion of the earth around the sun and the diurnal aberration due to the rotation of the earth.
   Annual aberration is, for practical purposes, constant at = 20.496", which corresponds to the orbital speed of the earth around the sun = 29.79 km/s. The diurnal aberration depends on latitude. Its maximum is = 0.32" at equator and at a latitude of 45° (Belgrade) its magnitude is = 0.226".
   At the present there are two quite different explanations of the phenomena of aberration, the classical and the relativistic. The first is based on the corpuscular nature of light alone, and the second is based on the wave nature of light alone. This places both explanations in doubt. Besides, according to the classical explanation of aberration the light rays reach the observer from the real position of the observed star, whereas, according to the relativistic explanation the light rays reach the observer from the direction of the seeming position of the star.
   Because of these differences it is essential to scrutinize both explanations and also a third possible explanation which is based on the existence of the earth's and sun's ether and their relative motion.
 
22.1 The classical way of determining the angle of aberration
 
   According to the classical explanation aberration happens as a consequence of the finality of the speed of light and an observer's motion. Other possible causes, according to this explanation, do no exist. The classical way of determining the angle of aberration is based on the given explanation and it is derived in the following manner.
   Let us assume that the observer moves in a straight line at a constant speed from point towards point , and a ray of light from star , towards point at a speed , as shown in Fig. 22.1. Let the distance be proportional to the speed of light in the same manner as the distance is proportional to the observer's speed so that . In this condition light will come from point to point in the same time as it will take the observer to move from point to point . If we place a telescope so that its objective lens is at point , and the eye piece at point , then the observation of the star would be impossible for the following reason. Until the light from point on the objective lens reaches point , the eye piece moves to point , because of the motion at speed , and from there the observation is impossible. To make the observation possible the eye piece should be placed in point . Then, in the time needed for the light to pass from the lens from point to point , the eye piece from point will reach point , which will enable the normal observation of the star. Hence, to be able to observe a star, a telescope should be turned at a certain small angle from the real angle towards the star, and in the direction of the motion of the observer, that is the telescope. That small angle of turning is called the angle of aberration.

Fig. 22.1

Classical equation for determining the angle of aberration, derived according to the Fig. 22.1, is

(22.1)

where is the real position of the star, is the seeming position of the star, is the angle of aberration which is derived using classical equations, is the speed of an observer and is the angle between the real direction towards the celestial body and the direction of the speed at which the observer moves. In this calculation , that is it is always true that when the observer moves to the right.
   Thus, the classical explanation of aberration is based on the corpuscular nature of light. It is assumed that the telescope should be turned at an appropriate angle from the real direction to the celestial body so that the light corpuscle, entering the objective lens, can fall in the center of the eye piece, which, during the passage of the light corpuscle through the telescope, moves in the direction of the telescope's motion. However, this explanation clashes with the result of the famous Michelson - Morley's measurements.
   Until now there has been no explanation why the angle of aberration does not change when a telescope is filled with water or some other matter whose index of refraction is bigger than the index of refraction of air or vacuum. As we know, according to the classical explanation the angle of aberration depends on light speed and the speed at which the telescope moves. When the telescope is filled up with water then the speed of light in it is less by around 1.33 times, and the speed of the telescope's motion remains the same, and because of that, and according to the given explanation and the Fig. 22.1, the angle of aberration should be bigger. However, it remains the same. The explanation for this is found maybe in the new explanation of Fizeau's test result given in chapter 14. Namely, the direction of photon motion inside of a such telescope stays the same when the telescope is filled up with water because water carries the photons in the direction of telescope motion in the time segment while it is absorbed in water during its passage through the telescope.
 
22.2 The relativistic way of determining the angle of aberration
 
   Aberration is considered as a proof of the correctness of the special theory of relativity. However, closer analysis brings this proof into serious doubt.
   The relativistic explanation of aberration is based on the wave form of light and the motion relative to those waves. Thereby it is assumed that the light coming from stars is in the form of plane wave.
   The relativistic method of determining the angle of aberration is as follows.
   Let there in the unmoving coordinate system propagated plane waves of light with the phase given by expression

(22.2)

   The phase of these same waves in moving coordinate system , which moves uniformly relative to the system along the -axis at speed , is given by expression

(22.3)

where , , , , , are the angles of the normal to the front of plane waves with the corresponding axes of the systems and respectively, or the angles of direction of light ray with the corresponding axes of the corresponding system.
   The expressions (22.2) and (22.3) are invariant and the Lorenz transformation can be applied to them. By application of this transformation in relation to the system we get

and from there

hence

(22.4)

where is the angle formed by the light ray or the normal of the plane of the plane wave with the -axis, is the angle formed by the same normal with the -axis and is the speed of motion of the system relatively to the system , that is the speed of the observer in the direction of and -axes. Since the and -axes are parallel, then is the angle formed by the direction to the real position of the star with the direction of motion of the observer, and is the angle formed between the direction to the seeming position of the star and the direction of the observer's motion. Consequently, the equation for the aberration angle, derived by the relativistic method, is

(22.5)

22.3 Objections to the relativistic approach to determining the angle of aberration
 
   The angle of aberration derived by the relativistic method is in accordance with the results of measurement and is equal to the angle obtained by classical procedure. That circumstance is taken as proof of the correctness of the theory of relativity. Nevertheless, in spite of this agreement there are certain objections which refer primarily to the low speeds of the observer's motion at which that agreement is good, to the relativistic explanation of the cause of aberration and to the way the equation of aberration angle is derived.
   However, the agreement of the angle of aberration calculated by relativistic procedure with its angle calculated according to classical methods is good only at extremely low velocities of the observer relative to the speed of light, such as the orbital velocity of the earth which is about 30 km/s. The agreement begins to break down at greater velocities. For example, the angle of aberration calculated using relativistic Eqs. (22.4) and (22.5), for an observer moving at when the angle of the real position of the star is = 90° is = 53.13°. The angle calculated using the classical Eq. (22.1) under the same conditions as before is = 38.66°. As can be seen, the difference = 14.47° is considerable.
   Consequently, we cannot claim that the agreement between the two methods of calculating aberration is good when it only occurs using extremely low velocities for the observer relative to the speed of light. Similarly we cannot assert that the relativistic way of calculating the angle of aberration is correct for higher relativistic velocities.
   The relativistic way of deriving the equation for aberration angle uses the Lorenz transformation of coordinates with the equation for propagation of plane light waves. Using the other transformation of coordinates, given in this book, and with the exception of transformation No. 5, different angles of aberration are obtained.
   When we use the transformation of coordinates No. 5, given by the Eqs. (12.25), which is derived for the plane wave, we obtain the same equation for aberration angle as when the Lorenz transformation is applied and that being so independently of whether and are expressed via and or vice versa.
   It is interesting to note that the application of two quoted transformations in deriving the equation for the Doppler effect give completely different equations, which was shown in the previous chapter. It is even more interesting that these completely different equations are used (via and ) for deriving the equations for angle of aberration and that they give the same final result, that is the same equation of aberration angle.
   With the relativistic method of determining angle of aberration the unmoving system is connected to the plane waves which come from the observed star. So, at first sight it seems that the system is at rest, and that the speed of the system relatively to it is around 30 km/s. However, in reality it is not so.
   Let us imagine that the observed star, is a pulsar from which every second a directed beam of light of short duration comes to earth. Let at some moment = 0 the axis of that beam corresponds to the -axis of the system and the pulsar travel in the direction of the -axis at the speed of, for example, 200 km/s. Under these conditions the axis of the next beam pulse of the pulsar's emission will be at a point on the -axis, at the distance of 200 km from the -axis, that is from the origin of the system . If at the moment = 0 the origin of the system was at the origin of the system , then after a second the origin of the system will be at a point on the -axis at 30 km distance (under the condition that = 30 km/s) from the origin of the system .
   From this it follows that the relative speed between the system and the axis of the beam is 170 km/s and that the system moves in the negative direction and oppositely to the course of aberration. Therefore, if the principles of relativity are respected, the system should be connected to the star, and the system to the observer. However, if this was done then the result of such a calculation would be way off the reality.
   The derivation of the relativistic equation is performed with the help of two inertial systems, which move relatively, and under the condition that the speed of light, from the same source, is the same in both systems. This condition has meaning only in the case when each of the two systems has its own ether, which carries the light. Such is the case with relativistic determining of the angle of aberration.
 
22.4 A new explanation of aberration
 
   The existing classical explanation of aberration is unsatisfactory because it is based on the corpuscular nature of light alone and its explanation by wave theory is impossible.
   In the case of a light source on earth all three aberrations would occur; solar, annual and diurnal. However, it is well known that, in this case there is no aberration at all [11]. Until now no satisfactory explanation for this phenomenon has been suggested.
   There is no satisfactory explanation of the fact that a telescope filled with water exhibits the same aberration as one filled with air. Some scientists have tried to explain this phenomenon using Einstein's theorem on speed addition, but this cannot be correct since the theorem was derived for conditions of vacuum, not water.
   The question of light propagation through the cosmos has remained unexplained since Michelson's famous experiment and the rejection of the very idea that an ether may exist.
   According to the classical explanation aberration happens as a consequence of the observer's motion, that is as a consequence of the telescope's motion in relation to the direction of the light rays from the observed star, which are passing through the telescope. However, the result of the Michelson - Morley's experiments disputes that classical explanation of aberration. It has been established, by those experiments, that there were no motion of the interferometer and its parts in relation to the used rays - beams of light, as it is described in the chapter 5. Consequently, the telescope does not move too in relation to the light rays from the star, which are passing through the telescope. From this also results that the used light rays come to the telescope from the direction of the seeming position of the observed star, but not from the direction of the real position of the star, as it is stated in the classical explanation of aberration. Accordingly, the result of the Michelson - Morley's experiments and aberration are irrefutable proof of the earth's ether existence.
   In the long run the correct and logical explanation of aberration and other previously mentioned, unexplained phenomena may come to be based on the existence of the earth's and sun's ether and their relative motion.
   The sun has its ether which fills the space bigger than the space of the solar system. The earth also has its ether which fills a considerably smaller space. It is similar to the magnetic fields of these two cosmic bodies.
   The light from the sun or some other cosmic body passes through the sun's ether before it comes into the earth's ether. The earth with its ether travels around the sun, and thus through the sun's ether. The relative motion of these two ethers is the cause of aberration of light when passing from one ether into the other.
   The sun rotates around its own axis. The velocity of the angular rotation of the sun's surface is 2.865·10^-6 rad/s [21]. The velocity of the angular rotation of the inner part of the sun, which generates the sun's ether, and of the ether itself is 3.99·10^-7 rad/s.
   Thus the velocity of motion of the sun's ether in the earth's orbit is two times higher than the velocity of the earth in its motion round the sun. Aberration, therefore, originates when the light rays move from one ether to the other which move relative to one another. This happens in the same way as it would were the sun's ether quiescent and the earth's ether moved at orbital velocity, but in the opposite direction to its real course. This explanation is in accordance with the course of aberration too. Aberration would have the opposite course in case of a pull of the hypothetical quiescent cosmic ether by the earth's motion.
 
22.5 Did Bradley make a mistake in determining the course of diurnal aberration?
 
   Diurnal aberration is small and negligible in comparison with annual aberration. Its measurement is complex and difficult to achieve. Therefore, in Bradley's time, and for a long time after, the magnitude and the course of diurnal aberration could not be measured owing to the lack of good telescopes and the complexity of measurement. As a result diurnal aberration was calculated using Eq. (22.1) and its course was taken to be the same as annual aberration.
   Bradley observed that the maximum displacements in the seeming position of stars occurred when the earth was in positions 1 and 3 as shown in Fig. 22.2

Fig. 22.2

   When orbital and rotational velocity are in the same course (position 1 in Fig. 22.2) then, as is generally accepted, the total aberration would be the sum of the annual aberration and the diurnal aberration as shown in Fig. 22.3 and the measured seeming angle would be given by equation

(22.6)

in which is the angle of seeming position and is the angle of the true position.
   At position 3 in Fig. 22.2 the course of rotational velocity is opposite to that of the orbital velocity, so that the total aberration is the difference between the annual and diurnal aberration, as shown in Fig. 22.4. The seeming angle is then given by

(22.7)

   Use of Eqs. (22.6) and (22.7) gives

(22.8)

(22.9)

   In order to find the real position of the star we must know the diurnal aberration. As was said before, this was obtained using the classical Eq. (22.1) for the calculation of aberration and the direction was taken according to the course of annual aberration. After that it was possible to test the validity of the Eqs. (22.6) (22.7) (22.8) and (22.9). Someone doing this could be convinced that all was correct when in fact it could be incorrect.

Fig. 22.3	Fig. 22.4

   Now let us imagine that the diurnal aberration has the same magnitude as before, but in the opposite course. This situation corresponds to the existence of the sun's and earth's ether and their relative motion. Then the situation in Figs. 22.3 and 22.4 would be as in Figs. 22.5 and 22.6 respectively.
   According to Fig. 22.5 the measured seeming angle would be

(22.10)

and according to Fig. 22.6

(22.11)

Using Eqs. (22.10) and (22.11) we obtain

(22.12)

and

(22.13)

   Consequently, the annual aberration would not be changed, but the angle of the real position would be smaller by making the angle of the real position

(22.14)

Fig. 22.5	Fig. 22.6

   It is not at all simple to ascertain the course of diurnal aberration. For example, we can measure the seeming angles and and using Eqs. (22.1) and (22.9) we can calculate the magnitude of the diurnal aberration and the angle of the real position respectively. After that we can attempt to ascertain the course of the diurnal aberration by the measurement of the seeming angles and when the earth is at position 2 and 4, as shown in Fig. 22.2. Following the accepted opinion that the course of aberration is always the same as a course of the observer's motion we shall wrongly believe that is the angle of the real position of an extremely distant star and we shall see that it is really

(22.15)

   So we shall believe that all is correct, even though the diurnal aberration has the opposite course and is not the angle of the real position.
   As a matter of fact, when the star under consideration is extremely distant we should use

(22.16)

   However, this equation gives the same result as Eq. (22.15). Therefore we can not determine the course of the diurnal aberration by using the measured angles of aberration , , and .
   The measurement of small angles in astronomy, such as diurnal aberration, close to the horizontal plane is difficult and insecure because of atmospheric and other influences. Therefore, the measurement of the diurnal aberration and determination of its course have probably never been made.
 
22.6 Ascertaining the course of the diurnal aberration by means of astronomical observation
 
   The correctness of the two above stated hypotheses is possible to test by means of a simple astronomical observation of a star's seeming motion when its seeming position, at the beginning of the observation, is in the direction of the earth's axis of rotation. By choosing such a starting point the observation is considerably simplified. The direction of the incoming light rays in this case is at a right angle in relation to the direction of the observer's velocity of motion. As a result the influence of the thickness of the earth's ether, which is unknown, is excluded.
   For the sake of easier explanation of this method we shall assume that the astronomical telescope does not invert the image. We shall also ignore the annual aberration and the change of its course during the observation since these will not influence the result of the analysis. In this way we analyse change in the seeming position of the star that is the result of diurnal aberration alone.

Fig. 22.7

   The procedure of the observation and analysis is as follows: At 18:00h, or some other time in the evening the observer aims the telescope at a star the seeming position of which, at that moment, is in the direction of the earth's axis of rotation. The telescope is positioned so that the image of the star is in the centre of the cross-sights. If we connect the coordinate system to the cross-sights so that the horizontal bar corresponds to the -axis and the vertical to the -axis, then the image of the observed star is also at the centre of the coordinate system.
   If earth's ether does not exist the image of the star will shift from point to the centre of the cross-sight, that is the centre of the coordinate system, as shown in Fig. 22.7a. But if the earth's ether exists the image of the star will shift from point to the centre of the cross-sights due to the diurnal aberration which is, in this case, in the opposite course relative to the course of the observer's motion. So the image of the star may be at point or at point , depending on whether the earth's ether exists or not. We do not know at what point the star is because we do not know if the earth's ether exists. This needs to be established through further analysis.
   During the next 05h59'01" (to 23h59'01") the telescope shifts from position to position , because of the earth's rotation. At the same time the coordinate system (the cross-sights) changes orientation by 90° relative to its orientation in position . The new position is shown in Fig. 22.7b. The image of the star at point , in Fig. 22.7a moves to point and, due to diurnal aberration, moves further to position . If the earth's ether exists then the image of the star at point would shift to point , and from there, due to diurnal aberration in the opposite course, to point . The distance between these two possible positions of the star's image along the -axis and the -axis are .
   During the next 05h59'01" (to 05h58'02") the telescope moves from position to position . The situation then will be as shown in Fig. 22.7c. The image of the star at point , as shown in Fig. 22.7b, will move to point , shown in Fig. 22.7c and the image at point will move to point . The coordinate system will have rotated by 90° relative to its orientation in position . In this position of the telescope the distance between two possible positions of the star's image in the coordinate system (the cross-sights of the telescope) is . Such small angles are detectable by modern astronomical telescopes.
   In Fig. 22.8 the curves of the movement of the star's image are shown, in the cross-sights of a telescope at latitude 45° trained constantly in the direction of the earth's axis of rotation. The observation starts at 18:00h. The curve indicated by a full line indicates the pattern of movement when there is no earth's ether and the dotted line is the pattern to be expected if the earth's and sun's ether exist and move relative to one another. In drawing these curves it has been taken into account that astronomical telescopes invert the image and that the course of the annual aberration changes during the observation.

Fig. 22.8

22.7 Possible errors in determining the earth's axis of rotation if the earth's and sun's ether exist
 
   The appearance of the image of the observed star at points and in the cross-sights, presented in Figs. 22.7b and 22.7c, according to the method of observation described, would be the proof that earth's and sun's ethers existed. At the same time it would be the proof that aberration is the result of the relative motion of those two ethers. Nevertheless, if this does not take place, and the image of the observed star appears at points and , this still does not mean that the course of diurnal aberration is the same as the course of the observer's motion, that is, it does not prove that earth's and sun's ethers do not exist.
   The direction of the earth's axis of rotation could be determined by the astronomical observation of the position of a star distant, at a greater or lesser angle, from the direction of the earth's axis of rotation. Then it is taken that the course of the diurnal aberration is the same as the course of the rotational motion of the telescope. If earth's and sun's ethers exist, however, then the direction of the earth's axis of rotation will have been incorrectly determined by such a procedure. The real direction of the earth's axis of rotation in relation to a direction determined in such a way differs by an angle equal to double the value of diurnal aberration for the observatory from which the observation was performed.
   To make this problem easier to understand, let us examine the possibility of making a mistake in determining the direction of the earth's axis of rotation.
   When we aim a telescope at a star, then the image of that star appears at the centre of the cross-sights, which corresponds to point in Fig. 22.9. That position of the image of the star corresponds to the seeming position of the star. If only diurnal aberration existed then point in Fig. 22.9 would correspond to the real position of the star.
   If there were no aberration then we would see the stars in their real positions. If, under those conditions, we aimed a telescope at a star so that its image fell in the centre of the cross-sights and left it for 24 hours, then the image of the star would describe the circle 1 shown in Fig. 22.9.

Fig. 22.9

   If only diurnal aberration existed, then the image of the observed star, under the same conditions, would describe a circle the centre of which would be the same as the centre of circle 1. The direction of the earth's axis of rotation would pass through the centre of circle 1. That centre is on the section of the line and line . The line is normal to the direction of the rotational motion of the observatory at the beginning of the observation and after the rotation of the earth at an angle of 180°.
   However, if earth's and sun's ethers exist then the image of the observed star is in the real position at point of the cross-sight, as shown in Fig. 22.9. If we now apply the same procedure, as in the previous case, then we find that the earth's axis of rotation passes through point , which is the centre of circle 2, that is, through the section of line and . The angular distance separation and is equal to . As a result it is clear that every observatory could make an error in determining the direction of the earth's axis of rotation, equal to double the diurnal aberration at that observatory.
   From the above it results that, if the sun's and earth's ethers exist, every observatory would make a different error in determining the direction of the earth's axis of rotation, that error being equal to at every observatory. This situation presents us with the possibility of establishing whether these ethers really exist.
   So, for example, the diurnal aberration at the site of the St Petersburg observatory (latitude 59.90°) is = 0.1598". The possible error in determining the direction of the earth's axis of rotation at this observatory may be = 0.3195". The diurnal aberration at the site of the Paris observatory (latitude 48.86°) is = 0.2096" so the possible error in the determination of the direction of the earth's axis of rotation may be = 0.4192". From this it results that the difference in the determined directions of the earth's axis of rotation between these two observatories might be 0.0997" which means that we can establish the existence of the sun's and earth's ethers by comparing the direction of the earth's axis of rotation as determined at these two observatories. Naturally this is only valid when the two observatories determine the direction of the earth's axis of rotation independently and with sufficient accuracy.
   If the direction of the earth's axis of rotation has been correctly determined in a different way then the procedure detailed above can be used to show that the sun's and earth's ethers exist.
 
22.8 One possibility for a demonstration of the existance of the sun's ether
 
   The construction and the description of the new interferometer for the demonstration of the existance of the earth's ether are given in the chapter 6 of this book. Two methods for that demonstration, by use of the above mentioned interferometer, are given in the chapter 8.
   The existance of the sun's ether can also be proved, but on the base of a shift of the spectral lines in the spectrum of radiation of some star. For this purpose one should take the spectrum of radiation of some convenient star, from the three points on the earth's orbit (see Fig. 22.10), as follows:
   a) from the point when the earth approaches to the chosen star,
   b) from the point in which the rays from that star form the right angle with the direction of the earth's orbital motion and
   c) from the point when the earth removes from the chosen star

Fig. 22.10

   The marks in Fig. 22.10 are: is the sun, is the earth, is the earth's orbital velocity, are the light rays from the chosen star and is the velocity of the sun's ether in the region of the earth's orbit. The wavelenghts of radiation from the chosen star, in the point , do not depend on the existance of the above mentioned ethers, because the motions of those ethers are normal to the direction of the light rays propagation. Therefore, the wavelenght of some chosen line in the spectrum of the received light, in the point , in case of the nonentity of the ethers, should be

(22.17)

where is the speed of light, and is the wavelenght in the point . However, if the sun's ether exists as a carrier of an electromagnetic radiation, and if its hypothetical velocity of motion, in the region of the earth's orbit, is two times higher than the earth's orbital velocity, then the wavelenght of the chosen line in the spectrum of the received radiation from the chosen star, in the point , is

(22.18)

The difference of the wavelenghts and is

(22.19)

The wavelenght of the chosen line in the spectrum of the received light in the point , in case of the existance of the sun's ether, should be

(22.20)

so that

(22.21)

   However, in the case of the nonentity of the ether should be

(22.22)

and

(22.23)

that is

(22.24)

   Above presented method does not give supposed result. Therefore, it was impossible to discover the existance of the sun's ether and its motion up to now.
   The wavelenghts of electromagnetic radiations from the star, measured on the earth, practically do not depend on that whether or not the earth's and sun's ether exist. Reason for that is the change of the wavelenghts of electromagnetic radiations on their entrance into the sun's and earth's ether. However, there are no changes of the wavelenghts only when the direction of radiation is normal to the direction of the ether motion, as it is shown in figure 22.10 for the case of radiation motion to the point .
   In the direction of the point , in the same figure, the sun's ether, as a carrier and a receiver of electromagnetic radiation, moves to the observed star by velocity = 60 km/s. Therefore, the wavelenght of the observed line in the spectrum of the coming radiation, measured in the sun's ether, should be

(22.25)

   In the direction to the point sun's ether, as a carrier and a receiver of electromagnetic radiation, removes from the observed star by velocity . In that case the wavelenght of the observed line in the spectrum of the coming radiation, measured in the sun's ether, should be

(22.26)

   However, the sun's ether, as a carrier and a source of radiation, removes from the earth and from the point towards the observed star by velocity . Therefore, the wavelenght of the observed line in the spectrum, measured in the earth's ether and at the point on the earth, should be

(22.27)

   If the sun's and earth's ether do not exist then, because of the earth's motion toward the observed star by velocity , the wavelenght of the observed line, measured at the point on the earth, should be

(22.27a)

   The sun's ether, as a source of radiation, approaches to the point on the earth by velocity , so that the wavelenght of the observed line in the spectrum, measured in the earth's ether and at the point on the earth, should be

(22.28)

   If ethers do not exist then the wavelenght of the observed line in the spectrum, measured at the point on the earth which removes from the observed star by velocity , should be

(22.28a)

   So, as it can be seen from Eqs. (22.27) and (22.27a), and also from Eqs. (22.28) and (22.28a) the results pratically are the same, and do not depend on that whether or not ethers exist. However, some small differences exist, but they are so small () so that they can not be detected by current equipment.
   However, the existance of the sun's ether and its motion can be detected by means of new interferometer placed in the cosmic flying vehicle. Interferometer, for that purpose, have to be small dimensions and weight. The sheme of that interferometer is given in picture 22.11

Fig. 22.11

where is a laser with the collimator, is the beamsplitter, is the plate - glass for the splitting and the shift of the laser beams which interfere, is an indicator of the interference and the shifts of the interfered stripes and are absorbers of radiations.
   The surfaces of the front side and back side of the plate - glass have to be polished and planparallel. The reflection of the front and back side of the plate - glass should be so chosen in order to get convenient relation between the intesity of useful beam and the intesity of parasitic beams, which originate by many reflections between the front and back side of the plate - glass. For example, if we want the relation to be 17 then the reflection of the front side should be about 20% and back side about 30%.
   The velocity of motion of the sun's ether near to the earth and outside of the earth's ether is approximatelly 60 km/s. If the thickness of the plate - glass would be 2 mm and the refraction index of glass 1.5 then the shift between interferented beams would be

at the turn of the interferometer for 180 degrees from the direction of the sun's ether motion. At the turn over 10 degrees the shift would be