8. EARTH'S ETHER AND THE POSSIBILITY OF ASCERTAINING ITS EXISTENCE
 
   For a long time many scientists have been occupied with the question of the ether's existence as a carrier of electromagnetic radiation, which fills all the cosmos. Thanks to many experiments, although some of them were explained incorrectly, the ether slowly but surely fading away from the science stage. The theory of relativity inflicted a final blow. Thus, such an absolute quiescent ubiquitous ether faded away, but some questions about certain electromagnetic phenomena have been left unanswered. One of those questions is how electromagnetic radiation or the narrower part of that radiation spectrum - light, is transmitted or propagated through the cosmos. The fact that vacuum has electromagnetic characteristics also, in some way, points to the existence of an ether in shape of an electromagnetic field.
   The phenomenon of light aberration leads to the idea that the earth could have its own ether, in the way that it has its own magnetic field. What is it really all about? In 1725, Bradley noticed a deflection or an aberration of light while he was observing the stars, which had occurred as a consequence of the earth's motion around the sun.
   When we observe a star by means of a telescope, then the telescope is not pointed exactly at the star, but at a small angle in relation to that direction. The magnitude of that angle depends on the angle made by the seeming direction earth - star with the direction of the earth's motion. The greatest deflection appears when = 90°. In that case the aberration angle is about 20.496". The effect is such that the light which comes from the stars seems to deflect 20.496" in the direction of the earth's motion. Because of this the telescope should be placed at that angle in relation to the actual direction in order to observe the star. This angle has been defined by the equation
(8.1)

where is the speed of the earth's motion around the sun and is the velocity of light.
   Aberration of light rays, caused by an ether wind, has not been perceived in optical experiments with the earth's light sources. Why? Because there is no cosmic ether on the earth, but only the earth's ether, which moves together with the earth. So, there are no ether winds on the earth and there is no aberration of such light rays.
   The theory of relativity explains the phenomenon of aberration in the mathematical way, based on the Lorentz transformation, but doesn't give a satisfactory physical explanation. Because of this, the explanation has been taken with reserve. Especially, when it is known that this transformation, in case of Michelson's experiment, proved contraction of one branch of the interferometer although it didn't exist.
   If an analogy is made between deflection of sound waves, due to the motion of the air as the carrier of the sound and the aberration of light then one is led to speculate that there is also a carrier of light, and because of its motion, the light, which propagates within it, is deflected. In other words, the aberration proves the existence of earth's ether which the earth carries with it.
   The question now appears to be whether an experiment can confirm or deny the existence of the earth's ether? An old ubiquitous quiescent ether doesn't exist. This has been ascertained by means of the new interferometer. But it is fortunate that with such an interferometer the existence of the earth's ether can be confirmed. The new interferometers give such a big shift of the interference fringes, that, a very small relative velocity can be successfully measured with them.
   Michelson wanted to measure the speed of earth's motion relative to the quiescent cosmic ether, in order to prove the ether's existence. In our case let us place a compact new interferometer on an airplane in order to measure the airplane's velocity relatively to the earth's ether. But before that, for any case, we have to use the same interferometer on the earth to see if the earth's ether rotates together with the earth. If it rotates then there cannot be any shift of the interference fringes when measurements are made on the earth. But if it does not rotate, or if earth does not completely pull it at rotation, which is almost impossible there will be a certain shift which also proves the existence of the earth's ether.
   Thanks to the new interferometer there are more ways to measure the existence of the earth's ether. Here below are descriptions of the two ways.
   Let us imagine that a space ship catches up to the earth at its rotation around the sun, which has a relatively small velocity in relation to the earth. This space ship has to land on earth at some place near the Equator, where the radial velocity on the earth is = 40000 / 86400 = 0.463 km/s or = 1666.67 km/h, due to the rotation of earth. To the observer from the earth it will seem that the space ship flies towards the West at a speed of 1667 km/h. This is so because of the earth rotation towards the East.
   Let us suppose that someone on the ship wants to confirm the existence of the earth's ether by using a new interferometer. When the ship was far from the earth, the ether could not be discovered, as would be the case with the earth's magnetic field, but as the ship gets closer to the earth the interferometer would discover the ether at rotation through 180° from the position where the laser radiates in the direction of the earth's rotation to the opposite direction. In both positions the direction of the laser radiation is normal to the direction of the ship's motion, so that this motion has no influence on the interferometer indication.
   The above cited procedure would be accomplished with the airplane and interferometer inside it. The interferometer has to be placed in the same position as in the space ship and it has to have the laser radiation in the direction of the earth's rotation and then, after its rotation, in the opposite direction.
   The plane would fly along the Equator towards the West at the velocity of 1667 km/h. At that velocity the shift at the interferometer with the side = 0.1 m, has to be

which is very close to the double wave length of the HeNe laser radiation. If the airplane was flying at a velocity of 840 km/h the shift would be equal to the wave length of the laser radiation, what could be easily measured.
   In order to reduce the influence of vibration in the plane on the measurement, it is the best that the interferometer be compact, for example, in a shape of a glass cube whose edges are 10 - 15 cm. Then the shift would be even greater for about 1.5 times.
   Of course, the airplane flight may take place at some other place or with other velocity.
   Another way of confirming the existence of the earth's ether by use of a new interferometer, is by flying over the South or North pole. The path of that airplane flying over a pole should be the same as the path of space ship at flying over a pole. The beam of laser radiation has to be normal to the direction of the airplane motion. In order to confirm the existence of the earth's ether it is not necessary to rotate the interferometer. Changes in the interference state will appear at flying over the pole, due to the change of the direction of the earth's rotation in relation to the airplane, that is in relation to the interferometer.
   If the existence of the earth's ether is confirmed it becomes clear that the light velocity relatively to the source may be greater than the light velocity in the vacuum. This appears, for example, when the earth's ether takes over the radiation from the direction of a star, which coincides with the direction of the earth's motion. Then the light velocity in relation to its source - a star, is equal to the sum of the incoming light velocity and the velocity of the earth motion. If the earth's motion is of opposite direction from the direction of the incoming light, then the light velocity in the earth's ether, in relation to the source of light, will be the difference between these two velocities. In both cases the light velocity in the earth's ether will be 300000 km/s, as if nothing had happened. Actually, the only change that takes place is the change of the light wavelength due to the Doppler shift, as in the case of sound in the closed car discussed in chapter 3. So, if the earth did not have its ether, then the speed of light, in relation to some point on earth, would depend on the direction of the motion of that point in relation to the star, as the source of light. The same is true in the case of a light source on the earth. To make this easier to understand, let us imagine the Michelson - Morley experiment with sound waves in an open wagon and a closed one. In the experiment with the closed wagon we would find out that there is no interference shift, no matter how fast the wagon traveled in relation to the embankment and outer environment. That is so because the environment - air, which carries sound, travels together in the closed wagon. However, on an open wagon there will be interference shift of sound waves, even when the source of sound waves is placed on the open wagon, which we can claim with certainty on the basis of well known experience. Thus, we come to the conclusion that the result of Michelson - Morley experiment proves the existence of the earth's ether.
   Confirming the existence of ether has an enormous and multiple significance. Among other things it would present the end of the theory of special relativity, which is based on the constancy of light velocity. If earth's ether exists, then the other ethers of a cosmic bodies exist too. All of them fill up the cosmos and each one has an influence on light which propagates through them.
 
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