Category Archives: Science

Eddington 1927: Velocity through the Aether

October 6, 2024 – 8:20 AM

Reference: The Book of Physics

Note: The original text is provided below.
Previous / Next

Summary

A preferred frame of space would be one corresponding to an observer absolutely at rest. It was assumed not to exist. [NOTE: A black hole with infinite inertia at the center of the galaxy may provide such a frame, but this was neither known to Newton nor to Einstein.]

The wave theory assumes light to be a disturbance in an ethereal medium. Einstein denied the existence of aether in the sense that light did not need a medium to propagate through as it was not a disturbance. Later Einstein reinstated aether as a substance that filled the space along with the electromagnetic energy and matter. It had its own characteristics that were yet to be determined.

Einstein established equivalence between energy and matter, thus identifying both as substances. Today this ethereal medium is described through a complexity of mathematical symbols and equations that have been interpreted in different ways. But, in reality, it is a substance much like energy and matter. This is consistent with what Faraday had postulated. (See Faraday 1846: Thoughts on Ray Vibrations)

.

Comments

The Theory of Substance states that substance is anything that is substantial enough to be sensed. We can sense matter, energy and thought. The postulated aether may be thought, but that is yet to be established. The invariant property of substance is “consistency” which is called mass/inertia for matter. It is defined by frequency for energy; and it is relatively zero for aether.

We may say that aether, energy and matter provide a spectrum of substance of increasing inertia (consistency). The higher is the inertia, the lesser is the velocity. A body of infinite inertia, such as, a black hole at the center of the galaxy, shall be very close to having the state of rest. By relating inertia to velocity we can separate science fiction from science. For example, we cannot ever have matter traveling at the speed of light.

The inverse relationship between velocity and consistency provides us with a scale of absolute motion as well as absolute inertia for matter, energy and aether. Every material body may be plotted somewhere on this scale. This scale extends to atomic realm and beyond. The postulated aether at the other end of the scale shall have zero consistency and infinite velocity.

The space between atoms, which is filled by electromagnetic energy coincides with the space through which the whole material body is moving. In short, the space is filled by aether, energy or matter. There is no empty space.

.

Original Text

The theory of relativity is evidently bound up with the impossibility of detecting absolute velocity; if in our quarrel with the nebular physicists one of us had been able to claim to be absolutely at rest, that would be sufficient reason for preferring the corresponding frame. This has something in common with the well-known philosophic belief that motion must necessarily be relative. Motion is change of position relative to something-, if we try to think of change of position relative to nothing the whole conception fades away. But this does not completely settle the physical problem. In physics we should not be quite so scrupulous as to the use of the word absolute. Motion with respect to aether or to any universally significant frame would be called absolute.

No aethereal frame has been found. We can only discover motion relative to the material landmarks scattered casually about the world; motion with respect to the universal ocean of aether eludes us. We say, “Let V be the velocity of a body through the aether”, and form the various electromagnetic equations in which V is scattered liberally. Then we insert the observed values, and try to eliminate everything that is unknown except V. The solution goes on famously; but just as we have got rid of the other unknowns, behold! V disappears as well, and we are left with the indisputable but irritating conclusion: 0 = 0.

This is a favourite device that mathematical equations resort to, when we propound stupid questions. If we tried to find the latitude and longitude of a point north-east from the north pole we should probably receive the same mathematical answer. “Velocity through aether” is as meaningless as “north-east from the north pole”.

This does not mean that the aether is abolished. We need an aether. The physical world is not to be analyzed into isolated particles of matter or electricity with featureless interspace. We have to attribute as much character to the interspace as to the particles, and in present-day physics quite an army of symbols is required to describe what is going on in the interspace. We postulate aether to bear the characters of the interspace as we postulate matter or electricity to bear the characters of the particles. Perhaps a philosopher might question whether it is not possible to admit the characters alone without picturing anything to support them—thus doing away with aether and matter at one stroke. But that is rather beside the point.

In the last century it was widely believed that aether was a kind of matter, having properties such as mass, rigidity, motion, like ordinary matter. It would be difficult to say when this view died out. It probably lingered longer in England than on the continent, but I think that even here it had ceased to be the orthodox view some years before the advent of the relativity theory. Logically it was abandoned by the numerous nineteenth-century investigators who regarded matter as vortices, knots, squirts, etc., in the aether; for clearly they could not have supposed that aether consisted of vortices in the aether. But it may not be safe to assume that the authorities in question were logical.

Nowadays it is agreed that aether is not a kind of matter. Being non-material, its properties are sui generis. We must determine them by experiment; and since we have no ground for any preconception, the experimental conclusions can be accepted without surprise or misgiving. Characters such as mass and rigidity which we meet with in matter will naturally be absent in aether; but the aether will have new and definite characters of its own. In a material ocean we can say that a particular particle of water which was here a few moments ago is now over there; there is no corresponding assertion that can be made about the aether. If you have been thinking of the aether in a way which takes for granted this property of permanent identification of its particles, you must revise your conception in accordance with the modern evidence. We cannot find our velocity through the aether; we cannot say whether the aether now in this room is flowing out through the north wall or the south wall. The question would have a meaning for a material ocean, but there is no reason to expect it to have a meaning for the non-material ocean of aether.

The aether itself is as much to the fore as ever it was, in our present scheme of the world. But velocity through aether has been found to resemble that elusive lady Mrs. Harris; and Einstein has inspired us with the daring skepticism—”I don’t believe there’s no sich a person”.

.

By vinaire | Also posted in Physics Book | Comments (8)

Eddington 1927: Relative and Absolute Quantities

October 6, 2024 – 8:06 AM

Reference: The Book of Physics

Note: The original text is provided below.
Previous / Next

Summary

This chapter by Eddington does not provide a clear understanding of relative and absolute quantities. A relative quantity is measured from a relative reference point. An absolute quantity is measured from an absolute reference point.

Relative motion occurs between two objects. Their relative motion is the same with respect to each other. This works for two material objects; but it does not work for light and a material object. We can say that the speed of light is 186,000 miles per second relative to earth; but we cannot say that the speed of earth is 186,000 miles per second relative to light. Common sense tells us that earth has inertia and it cannot move that fast. So, the concept of relative motion breaks down for light.

The theory of relativity uses “inertial frame of reference.” That means it restricts itself to the domain of matter.

.

Comments

Common sense tells us that the greater is the inertia, the more difficult it is to move something. We may, therefore, postulate that a body of infinite inertia will have no motion, and a body of zero inertia will have infinite motion. This gives a sense of absolute motion in terms of inertia. Here we are looking at a deeper truth.

.

Original Text

I will try to make clear the distinction between absolute and relative quantities. Number (of discrete individuals) is absolute. It is the result of counting, and counting is an absolute operation. If two men count the number of people in this room and reach different results, one of them must be wrong.

The measurement of distance is not an absolute operation. It is possible for two men to measure the same distance and reach different results, and yet neither of them be wrong.

I mark two dots on the blackboard and ask two students to measure very accurately the distance between them. In order that there may be no possible doubt as to what I mean by distance I give them elaborate instructions as to the standard to be used and the precautions necessary to obtain an accurate measurement of distance. They bring me results which differ. I ask them to compare notes to find out which of them is wrong, and why? Presently they return and say: “It was your fault because in one respect your instructions were not explicit. You did not mention what motion the scale should have when it was being used.” One of them without thinking much about the matter had kept the scale at rest on the earth. The other had reflected that the earth was a very insignificant planet of which the Professor had a low opinion. He thought it would be only reasonable to choose some more important body to regulate the motion of the scale, and so he had given it a motion agreeing with that of the enormous star Betelgeuse. Naturally the FitzGerald contraction of the scale accounted for the difference of results.

I am disinclined to accept this excuse. I say severely, “It is all nonsense dragging in the earth or Betelgeuse or any other body. You do not require any standard external to the problem. I told you to measure the distance of two points on the blackboard; you should have made the motion of the scale agree with that of the blackboard. Surely it is common sense to make your measuring scale move with what you are measuring. Remember that next time.”

A few days later I ask them to measure the wavelength of sodium light—the distance from crest to crest of the light waves. They do so and return in triumphal agreement: ”The wave-length is infinite”. I point out to them that this does not agree with the result given in the book (.000059 cm.). “Yes”, they reply, “we noticed that; but the man in the book did not do it right. You told us always to make the measuring scale move with the thing to be measured. So at great trouble and expense we sent our scales hurtling through the laboratory at the same speed as the light.” At this speed the FitzGerald contraction is infinite, the metre rods contract to nothing, and so it takes an infinite number of them to fill up the interval from crest to crest of the waves.

My supplementary rule was in a way quite a good rule; it would always give something absolute—something on which they would necessarily agree. Only unfortunately it would not give the length or distance. When we ask whether distance is absolute or relative, we must not first make up our minds that it ought to be absolute and then change the current significance of the term to make it so.

Nor can we altogether blame our predecessors for having stupidly made the word “distance” mean something relative when they might have applied it to a result of spatial measurement which was absolute and unambiguous. The suggested supplementary rule has one drawback. We often have to consider a system containing a number of bodies with different motions; it would be inconvenient to have to measure each body with apparatus in a different state of motion, and we should get into a terrible muddle in trying to fit the different measures together. Our predecessors were wise in referring all distances to a single frame of space, even though their expectation that such distances would be absolute has not been fulfilled.

As for the absolute quantity given by the proposed supplementary rule, we may set it alongside distances relative to the earth and distances relative to Betelgeuse, etc., as a quantity of some interest to study. It is called “proper-distance”. Perhaps you feel a relief at getting hold of something absolute and would wish to follow it up. Excellent. But remember this will lead you away from the classical scheme of physics which has chosen the relative distances to build on. The quest of the absolute leads into the four-dimensional world.

A more familiar example of a relative quantity is “direction” of an object. There is a direction of Cambridge relative to Edinburgh and another direction relative to London, and so on. It never occurs to us to think of this as a discrepancy, or to suppose that there must be some direction of Cambridge (at present undiscoverable) which is absolute. The idea that there ought to be an absolute distance between two points contains the same kind of fallacy. There is, of course, a difference of detail; the relative direction above mentioned is relative to a particular position of the observer, whereas the relative distance is relative to a particular velocity of the observer. We can change position freely and so introduce large changes of relative direction; but we cannot change velocity appreciably—the 300 miles an hour attainable by our fastest devices being too insignificant to count. Consequently the relativity of distance is not a matter of common experience as the relativity of direction is. That is why we have unfortunately a rooted impression in our minds that distance ought to be absolute.

A very homely illustration of a relative quantity is afforded by the pound sterling. Whatever may have been the correct theoretical view, the man in the street until very recently regarded a pound as an absolute amount of wealth. But dire experience has now convinced us all of its relativity. At first we used to cling to the idea that there ought to be an absolute pound and struggle to express the situation in paradoxical statements —the pound had really become seven-and-sixpence. But we have grown accustomed to the situation and continue to reckon wealth in pounds as before, merely recognizing that the pound is relative and therefore must not be expected to have those properties that we had attributed to it in the belief that it was absolute.

You can form some idea of the essential difference in the outlook of physics before and after Einstein’s principle of relativity by comparing it with the difference in economic theory which comes from recognizing the relativity of value of money. I suppose that in stable times the practical consequences of this relativity are manifested chiefly in the minute fluctuations of foreign exchanges, which may be compared with the minute changes of length affecting delicate experiments like the Michelson-Morley experiment. Occasionally the consequences may be more sensational—a mark-exchange soaring to billions, a high-speed β particle contracting to a third of its radius. But it is not these casual manifestations which are the main outcome. Clearly an economist who believes in the absoluteness of the pound has not grasped the rudiments of his subject. Similarly if we have conceived the physical world as intrinsically constituted out of those distances, forces and masses which are now seen to have reference only to our own special reference frame, we are far from a proper understanding of the nature of things.

.

By vinaire | Also posted in Physics Book | Comments (0)

Eddington 1927: Chapter 1 Summary

October 5, 2024 – 9:27 AM

Reference: The Book of Physics

Note: The original text is provided below.
Previous / Next

Summary


Eddington is interpreting the electrical theory of matter to mean that the motion of the measuring equipment will result in Fitzgerald contraction and that would influence the measurements. He believes that this would occur even when no accelerations are involved. He, therefore, concludes that the Newtonian length of an object cannot be determined. And, therefore, the present-day physics is based on fictitious measurements. This has now resulted in the whole structure of classical physics tumbling down. 

.

Comments

In truth, there are no problems in measurements unless very high accelerations are involved. But, in those cases, the resulting contractions can be calculated and corrections made.

.

Original Text

This thought will be followed up in the next chapter. Meanwhile let us glance back over the arguments that have led to the present situation. It arises from the failure of our much-trusted measuring scale, a failure which we can infer from strong experimental evidence or more simply as an inevitable consequence of accepting the electrical theory of matter. This unforeseen behaviour is a constant property of all kinds of matter and is even shared by optical and electrical measuring devices. Thus it is not betrayed by any kind of discrepancy in applying the usual methods of measurement. The discrepancy is revealed when we change the standard motion of the measuring appliances, e.g. when we compare lengths and distances as measured by terrestrial observers with those which would be measured by observers on a planet with different velocity. Provisionally we shall call the measured lengths which contain this discrepancy “fictitious lengths”.

According to the Newtonian scheme length is definite and unique; and each observer should apply corrections (dependent on his motion) to reduce his fictitious lengths to the unique Newtonian length. But to this there are two objections. The corrections to reduce to Newtonian length are indeterminate; we know the corrections necessary to reduce our own fictitious lengths to those measured by an observer with any other prescribed motion, but there is no criterion for deciding which system is the one intended in the Newtonian scheme. Secondly, the whole of present-day physics has been based on lengths measured by terrestrial observers without this correction, so that whilst its assertions ostensibly refer to Newtonian lengths they have actually been proved for fictitious lengths.

The FitzGerald contraction may seem a little thing to bring the whole structure of classical physics tumbling down. But few indeed are the experiments contributing to our scientific knowledge which would not be invalidated if our methods of measuring lengths were fundamentally unsound. We now find that there is no guarantee that they are not subject to a systematic kind of error. Worse still we do not know if the error occurs or not, and there is every reason to presume that it is impossible to know.

.

By vinaire | Also posted in Physics Book | Comments (0)

Introduction (Relativity)

July 17, 2024 – 6:35 AM

Reference: Einstein 1920: Relativity

Einstein starts with considering the coordinates of space and time that have so far been considered in an abstract mathematical sense, and applies to them the principles of palpability of physics. Matter, in spite of being very rigid, expands and contracts when heated and cooled. Can the rigid coordinates of space also expand and contract under the influence of time? So started the thought that went into building a fantastic theory of relativity.

The theory of relativity presents a fascinating view of the physical universe. It presents the covariance of space, time and substantiality in the form of a four-dimensional world. Under the influence of time, space seems to acquire the palpability of substance. The concept of substance includes both the rigidity of matter and the fluidity of energy. For example, Matter becomes concentrated energy, and energy becomes diluted matter. The concept of inertia that applied to matter in classical mechanics, now gets generalized into the consistency of space. The variability of this consistency makes space appear as energy and matter in a gravitational field.

The comments at the end of this book present the following model of the universe based on Einstein’s theory of relativity:

The space has substantiality, which gives it a measure of consistency. When the consistency is extremely small, the space appears as fluid energy that has a very high velocity. When the consistency is extremely large, the space appears as rigid matter that has a very low velocity. In between, the space appears as the gravitational field of variable consistency and velocity. The velocity has an inverse relationship with consistency. It is the balance of inherent motion of matter floating in a sea of energy that is perceived as the phenomenon of Gravity.

The spectrum of energy/matter based on the property of consistency suggests a vortex type pattern, which is seen repeated in nature at all scales. For example, the atoms display this pattern where the electrons form a vortex, at the center of which there is an extremely dense and small spinning nucleus. The “gravitational field” at this level appears as charge.

At the level of the solar system, planets revolve, as if they are caught up in a vortex of gravity, at the center which is a massive and spinning sun. In their turn, the spinning planets form the center of smaller vortices of gravity in which their moons are caught up.

On a much larger cosmic scale, we have solar or star systems that are caught up in a vortex of gravity which appears as a galaxy. At the center of the galaxy is an extremely dense and small spinning black hole.

All these vortices at different scales seem to be overlapping and producing a very complex pattern in which the inherent motions of the heavenly bodies balance each other in a cosmic dance. We may thus visualize the universe having a “solid” spinning center made up uncountable number of galaxies with a great periphery of curving light far away of unimaginable proportions.

This “vortex universe” is devoid of solid masses in about 99% of its volume; but that volume is filled with palpable energy. The universe may be considered to be finite yet unbounded because it seems to curve upon itself.

.

By vinaire | Also posted in Einstein | Comments (0)

Preface (Relativity)

July 16, 2024 – 8:07 PM

Reference: Einstein’s 1920 Book

This Book summarizes Albert Einstein’s RELATIVITY: THE SPECIAL AND GENERAL THEORY, originally published by Henry Holt and Company, New York (1920).

Einstein’s Special Theory of Relativity addresses the effect of the finiteness of the velocity of light on the space coordinates. A much more comprehensive General Theory of Relativity then explains gravity by postulating a four-dimensional continuum that has acquired the properties of extension and durability.

This book summarizes the original presentation above one section at a time. The summary contains Einstein’s ideas in their purity.

The summary is accompanied by comments, also one section at a time, that provide a new interpretation of Einstein’s ideas. This interpretation gradually builds up a model of the universe that makes Einstein’s theory of relativity easier to understand.

It is my hope that more people will get the pleasure of really understanding this brilliant theory of relativity that was completed by Einstein in 1915.

.

By vinaire | Also posted in Einstein | Comments (0)