Aether and Gravitation Part 24

ART. 94. _Relative Motion of Aether and Matter._--There is hardly any subject of greater importance which is engaging the attention of scientists at the present time, than the question as to what is the relative motion of Matter to the Aether in which it moves.

I venture to premise the successful solution of the problem will be accompanied with the greatest advance to science that has been known for a long time. The problem to be solved may be stated thus: "Does the Aether surrounding a planet or sun or any body in s.p.a.ce move with that body, or does it allow the body to pa.s.s through it?"

Up to the present, opinions on the subject have been varied and conflicting. Some scientists hold that the planetary and other bodies in s.p.a.ce pa.s.s through the Aether without disturbing it, while others hold that part of the Aether is carried along by the moving planet. Fresnel a.s.sumed that the surrounding Aether was carried along by the earth, so that all relative phenomena would be the same as if the earth were at rest. Fizeau, from experiments which he conducted on running water, also came to the same conclusion.

With the old idea of a frictionless medium, some of the present accepted theories are altogether untenable, because, if Aether is frictionless, how can it be carried along with the moving body, unless it is held bound to that body? and how can it be held bound to that body if it is frictionless?

The whole view of the Aether is, however, changed by the conception of the Aether put forward in Chapter IV. Aether is Matter, and being matter it is also gravitative, and therefore is just as much subject to the Law of Gravitation as any other kind of matter, as Young stated in his Fourth Hypothesis (Art. 45).

We will therefore attack the problem of the relative motion of the earth and the Aether around it from this new standpoint. In order to be strictly philosophical, we must base our hypothesis and conception on experience and observation. Where in the whole of planetary phenomena do we find similar conditions which exist between the Aether and the earth?

Such conditions are alone to be found between the atmosphere and the earth. The a.n.a.logy between the atmosphere and the earth, and the Aether and the earth is very striking, as the following comparisons will prove.

The atmosphere (when pure) is invisible, so is the Aether. The atmosphere is atomic, the Aether is also atomic. Both are subject to the same laws of elasticity and density, and both are gravitative, according to our conception of the Aether. Now what is the effect of any large revolving body on a liquid or gaseous medium surrounding that revolving body?

If experience is any guide, we learn that the motion of the revolving body is either partially or entirely transmitted to the liquid or gaseous medium surrounding such a body. So far as our experience teaches us anything, it teaches us that to that rule there is no exception, and no experiment can be devised of any body revolving in water or a gaseous medium as air, without that body imparting its rotation to the water or the air. The atmosphere in relation to the earth is no exception to this rule. We know that the earth has an equatorial circ.u.mference of about 24,000 miles, and that it revolves on its axis once every day, so that at the equator the surface of the earth is whirling round in s.p.a.ce at the rate of 1000 miles per hour.

Try to conceive what the result would be if the atmosphere were stationary at the earth's surface in the equatorial regions. It would mean that any body on its surface would be whirled round at that rate, while the atmosphere, being stationary, would exert a power equal to a wind travelling at the rate of 1000 miles per hour.

Under the influence of such a hurricane, nothing could exist on the surface of the earth at the equator, if the earth revolved on its axis and the atmosphere did not partic.i.p.ate in that motion. But the atmosphere is gravitative, and being gravitative, it is not only held bound to the earth as it revolves on its axis in its onward rush through s.p.a.ce, but accepts the revolving motion of the earth, with the result that as the earth revolves on its axis, the atmosphere revolves also.

Thus a balloon at the equator if allowed to rise several hundred feet above the surface could remain comparatively stationary if held by a rope to overcome its tendency to rise, whereas such an event would be impossible if the atmosphere failed to receive only half of the motion of the earth's surface, as it would still have a power equal to that of a wind blowing at the rate of 500 miles an hour. If, however, we come further north, or go further south, then we find that the surface of the earth does not have the same velocity as at the equator, with the result that the atmosphere has not the same velocity either; consequently it would travel slower in the temperate regions than in the equatorial regions, and slower still at the poles than in the temperate regions.

We know by experiment what the effect of increased velocity has upon any whirling body; it tends to enlarge the body at those parts where the velocity is the greatest, the consequence being that the bulging out of the atmosphere would be greatest at the equator. We find a similar result in the shape of the earth, where the equatorial diameter is greater than the polar diameter, because of the centrifugal force being greatest in the equatorial regions.

We have, therefore, to apply these facts to the aetherial medium which surrounds all planetary and stellar bodies in the same way as the atmosphere does; and which, being also gravitative, is equally subject to the same laws of motion. We have seen, therefore, that not only does the earth revolve on its axis, but that the atmosphere revolves on its axis also, and that the velocity of its revolution is greatest in the equatorial regions, the atmosphere spreading or bulging out in those parts more than in any other part of the earth's surface.

Let us suppose that the atmosphere extends 200 miles above the earth, and that there we come to the pure Aether of universal s.p.a.ce. In view of the fact that Aether is Matter, and therefore gravitative, it is reasonable and logical to conclude that exactly the same result follows in relation to the atmosphere and the Aether at that height, as follows in relation to the earth and the atmosphere 200 miles beneath.

Unless this view is accepted, we should then have our second Rule of Philosophy violated, as we should have matter revolving in more rarefied matter, and failing to impress upon that rarefied condition of matter the motion either partially or wholly which it itself possesses; and such a result being contradictory to all experience cannot be admitted from a philosophical standpoint.

Therefore, the only solution is, that the rotating atmosphere imparts some of its motion to the aetherial atmosphere, which in its turn rotates, and that that rotation is governed by exactly the same conditions as govern the relation that exists between the earth and the atmosphere. Therefore the Aether in s.p.a.ce a.s.sociated with each planet or satellite or sun or star, rotates with the rotating body, and that rotation imparts to the Aether a greater bulging out in the equatorial regions of the aetherial atmosphere than in any other part thereof. It is interesting in relation to this point to note Herschel's view of the effect of the rotation of any body upon the Aether. In his _Outlines of Astronomy_, in a note, p. 358, he states: "Supposing the neighbourhood of the sun to be filled with a material fluid; it is not conceivable that the circulation of planets in it for ages should not have impressed upon it some degree of rotation in their own direction, and this may preserve them from the effects of acc.u.mulated resistance."

In this way we arrive at the conception of the motions of the Aether suggested by Prof. Challis from the magnetic character of the earth, which he thought were due to aetherial currents circulating around it, and we learn that such physical conception of the Aether fully agrees with the explanation of celestial bodies being electro-magnets; because, we have only to add to our rotating Aether that which it has been proved to possess, viz. an electro-magnetic basis, and we have at once the currents of electricity circulating round the earth and other planetary or solar bodies, by which is obtained the true explanation of the permanent magnetism of all celestial bodies.

Now to some minds unconversant with scientific research and knowledge, such a supposition may seem to be incredible, but that incredibility may disappear, when I say that the fact that the Aether is bound to the earth, and goes along through s.p.a.ce with it, has actually been proved by some of the most delicate and successful experiments that have been made in recent times: experiments of which Lord Kelvin has stated that he can find no error or flaw in them. I refer to the scientific experiments of Michelson and Morley of America. For full particulars of these experiments I must refer the reader to the _American Journal of Science_, 1886, vol. 31, or to the _Phil. Mag._, vol. 44.

The conclusion which is arrived at from their experiments is, that the Aether is carried along with the earth as it rushes on its journey through s.p.a.ce. Of course such a result is altogether opposed to the ordinary conception of a frictionless medium, and indeed to any conception of the Aether except to that submitted in this work, which is also in harmony with Young's Fourth Hypothesis (Art. 45).

So that Michelson's and Morley's experiment is a direct experimental demonstration of the fact that Aether is gravitative, and because it is gravitative, it is carried along with the earth, as that planet journeys through s.p.a.ce. It further conclusively proves that not only is the Aether carried along with the earth, but that the Aether circulates round the earth in the same way that the atmosphere circulates round the earth.

This result naturally follows from the experiment, because, if it were carried along by the earth and yet did not rotate with the atmosphere, then we should have a result opposed to all experience and experiment, as these teach us that when a body revolves in a medium which is held bound to that body by Gravitation, the medium so held bound partic.i.p.ates in the rotation of the revolving body.

So that in Michelson's and Morley's experiment we have experimental evidence of the fact, already stated, that the Aether circulates round the earth, and therefore, in view of the electro-magnetic character of the Aether, this circulation results in the production of magnetism in all the planets, and other bodies around which it circulates.

Thus not only does the Aether circulate round the earth, but it also circulates around every other planet, and not only round every other planet, but equally so around every sun and star, as stated in Art. 91.

These results are perfectly consistent with philosophical reasoning, and any other result would be inconsistent with the a.n.a.logies presented to us by the phenomena of the Aether in relation to our earth as ascertained by experiments made by the scientists referred to. Thus for the first time the experiment is brought into harmony with our Philosophy, which up to the present has not been the case, a result which at once stamps the experiment with that validity of truth and fact which will ultimately win for it universal acceptance and favour.

We are now in a position to answer some queries regarding the motions of the Aether asked by Herschel in his work on _Astronomy_, p. 345. These I give with the answers opposite.

QUERIES. | ANSWERS.

| 1. What is the law of density | The Law of Gravitation of the resisting medium which | (Art. 45).

surrounds the sun? | | 2. Is it at rest or in motion? | In motion.

| 3. If the latter, in what | Rotates round the sun.

direction does it move? | | 4. Circularly round the sun | Both, as it circulates round or traversing s.p.a.ce? | the sun while that body | traverses s.p.a.ce.

| 5. If circularly, in what | The plane of the ecliptic.

plane? |

ART. 95. _Physical Explanation of the Vibration in the Electro-Magnetic Theory of Light._--In Art. 78 we learned that light was an electro-magnetic disturbance in the Aether which was propagated through the Aether, with a finite velocity; and from this we gathered that light waves were nothing more or less than electro-magnetic waves, which were radiated from the sun, out into the Aether on every side.

We were unable, however, at that time to give a definite physical conception of the aetherial vibrations, or of the relation of the various types of vibration to each other. Since, however, the development of the Aether from the electric and magnetic standpoint, which has led us up to the fact that the Aether possesses a circulating motion round the sun (Art. 91), the solution of the problem appears probable. I am of the opinion that the physical conception of the various vibrations to each other is now within the region of possibility, and in this article I wish to endeavour to give what seems to me to be a correct and philosophical explanation of this part of the electro-magnetic theory of light, the physical conception of which up to the present has not been generally understood.

The explanation may, or may not, be fully complete, but even if it be not perfectly correct, I am convinced that it will ultimately lead to a satisfactory physical explanation of this part of Maxwell's Theory of Light. In forming a conception as to the physical character of the vibrations in the electro-magnetic theory, we have to remember that there are three distinct vibrations, or motions, concerned in this theory.

[Ill.u.s.tration: Fig: 22.]

1st. There is the direction of propagation.

2nd. There is the direction of the electric vibration which is at right angles to the direction of propagation.

3rd. There is the direction of the magnetic vibration or motion which is at right angles to both of the other two.

Now we have seen that the direction of propagation of any aetherial light ray, is that of a straight line from the sun corresponding to the radius vector (Art. 76). We have also seen that the front of a light wave is really that of a spherical sh.e.l.l (Art. 71).

We have also learned that the electric and the magnetic vibrations are in the wave front, so that these two vibrations, which are at right angles to each other, are to be found on the surface, so to speak, of each aetherial spherical sh.e.l.l, that surrounds the sun with ever-decreasing density, and ever-decreasing elasticity.

Let us try to picture the actual fact by an ill.u.s.tration. Let _S_ be the sun, with concentric spherical aetherial sh.e.l.ls surrounding it (Fig.

22). Then _S_ _A_ and _S_ _C_ will be rays of light being radiated out from the sun, and the magnetic and electric vibrations have to be both at right angles to the line of propagation and in the wave front; the wave front being represented by the circular lines showing the section of the concentric sh.e.l.ls running north and south.

Now how can we picture these two motions at right angles to each other, and yet both at right angles to the line of propagation? First, let us take three straight lines and see how this may be done (Fig. 23).

Let _A_ _B_, _A_ _S_ be two straight lines at right angles to each other, and _A_ _C_ another straight line at right angles to both. This can only be done by making _A_ _C_ perpendicular to the plane of the paper, and can be ill.u.s.trated by supposing that it represents a pencil or pen placed upright on the paper, the point of the pencil being at point _A_. If this be done, then not only will _A_ _B_ and _A_ _C_ be at right angles to each other, but both will be at right angles to _A_ _S_, which corresponds to the line of propagation.

[Ill.u.s.tration: Fig: 23.]

Now refer to Fig. 22, and we shall see that the line _A_ _B_ and the boundary of the sh.e.l.l will practically correspond. So that any section of a spherical wave front will always be at right angles to the ray of light. But we have learned from Art. 89 that these sections of the aetherial spherical sh.e.l.l are really identical with Faraday's Lines of Force, with the result that along any line which stretches from the North pole of the sun to the South pole, there will ever be an electric vibration, which is put into motion by the elasticity of the aetherial vortex atoms. So that on every side of the sun there is ever going on this electric vibration, along the lines of force which correspond to a section of the aetherial sh.e.l.l, the surface of which really const.i.tutes the wave front.

Therefore it can readily be seen, that, as these lines are at right angles to the propagation of the ray of light, the electric vibration is at right angles to the lines of propagation, and is thus in accordance with the result demanded by Maxwell's theory.

We have now to give a physical conception of the magnetic vibration or motion of the Aether, and this has to be at right angles to both the electric vibration and the line of propagation.

In Art. 91 we have learned that the Aether possesses a rotatory motion, by which it rotates round the central body of the solar system, the sun. So that if we take any point, for example, in the path of the ray as _S_{1}, _S_{2}, _S_{3}, and _S_{4}, situated upon some definite equipotential surface or lines of force, and if we will imagine those lines to rotate round the sun, as the sun rotates on its axis, then in time the points will have described half the circle, and will come to the position on the right of the sun indicated by the same Nos. _S_{1}, _S_{2}, _S_{3}, _S_{4}. Thus there has been an aetherial motion at right angles to the electric motion, as the Aether circulates round the sun, because this motion may be represented as taking place from west to east of the sun, while the electric vibration takes place from north to south, or transverse to the line of propagation.

We have, however, learned that the Aether has an electro-magnetic basis, and therefore the rotation of the Aether gives rise to electro-magnetic currents; hence the motion west to east is really the motion of electro-magnetic currents which circulate round the sun. As these are at right angles to the line of propagation, and we have seen that they are at right angles to the electric vibration, it follows that all three are at right angles to each other, which is in accordance with the requirements as laid down by Maxwell.

We have considered these vibrations, first, from the view of the solar system as a whole in its relation to the universal Aether; but the same principle holds good if considered from the aetherial atomic standpoint.