On Sat, 12 Mar 2011 14:54:02   Adam Cox wrote

[Snip] Personally, I favor what can best be described (unfortunately) as
Aether 

theory,[/snip]

 

Adam,

 

Nothing unfortunate in ether theory, My theories are based on a Neo
Lrentzian ether. It isn’t disproved just simply not as favored as

Special relativity A friend of mine on HSG wrote the thread below on this
subject.

Regards

Fran

 

 

Ether and the Theory of Relativity
<http://forum.hydrino.org/viewtopic.php?f=5&t=75&sid=40801b82e00598a889df277
21932fc60&start=300#p9176>   by JohnEB  on September 11th, 2010, 9:49 am

Generally, it is thought that Einstein eliminated the ether and did not
believe in it. This is not true.
An Address delivered on May 5th, 1920, in the University of Leyden

The following is from the book “SIDELIGHTS ON RELATIVITY” by Albert
Einstein:

ETHER AND THE THEORY OF RELATIVITY

How does it come about that alongside of the idea of ponderable matter,
which is derived by abstraction from everyday life, the physicists set the
idea of the existence of another kind of matter, the ether? The explanation
is probably to be sought in those phenomena which have given rise to the
theory of action at a distance, and in the properties of light which have
led to the undulatory theory. Let us devote a little while to the
consideration of these two subjects.

Outside of physics we know nothing of action at a distance. When we try to
connect cause and effect in the experiences which natural objects afford us,
it seems at first as if there were no other mutual actions than those of
imrsa c ;ate contact, e.g. the communication of motion by impact, push and
pull, heating or ind.ut;- ing combustion by means of a flame, etc It is true
that even in everyday experience weight, which is in a sense action at a
distance, plays a very important part. But since in daily experience the
weight of bodies meets us as something constant, something not linked to any
cause which is variable in time or place, we do not in everyday life
speculate as to the cause of gravity, and therefore do not become conscious
of its character as action at a distance. It was Newton’s theory of
gravitation that first assigned a cause for gravity by interpreting it as
action at a distance, proceeding from masses. Newton’s theory is probably
the greatest stride ever made in the effort towards the causal nexus of
natural phenomena. And yet this theory evoked a lively sense of discomfort
among Newton’s contemporaries, because it seemed to be in conflict with the
principle springing from the rest of experience, that there can be
reciprocal action only through contact, and not through immediate action at
a distance.

It is only with reluctance that man’s desire for knowledge endures a dualism
of this kind. How was unity to be preserved in his comprehension of the
forces of nature ? Either by trying to look upon contact forces as being
themselves distant forces which admittedly are observable only at a very
small distance—and this was the road which Newton’s followers, who were
entirely under the spell of his doctrine, mostly preferred to take ; or by
assuming that the Newtonian action at a distance is only apparently
immediate action at a distance, but in truth is conveyed by a medium
permeating space, whether by movements or by elastic deformation of this
medium. Thus the endeavour toward a unified view of the nature of forces
leads to the hypothesis of an ether. This hypothesis, to be sure, did not at
first bring with it any advance in the theory of gravitation or in physics
generally, so that it became customary to treat Newton’s law of force as an
axiom not further reducible. But the ether hypothesis was bound always to
play some part in physical science, even if at first only a latent part.

When in the first half of the nineteenth century the far-reaching similarity
was revealed which subsists between the properties of light and those of
elastic waves in ponderable bodies, the ether hypothesis found fresh
support. It appeared beyond question that light must be interpreted as a
vibratory process in an elastic, inert medium filling up universal space. It
also seemed to be a necessary consequence of the fact that light is capable
of polarisation that this medium, the ether, must be of the nature of a
solid body, because transverse waves are not possible in a fluid, but only
in a solid. Thus the physicists were bound to arrive at the theory of the ”
quasi-rigid ” luminiferous ether, the parts of which can carry out no
movements relatively to one another except the small movements of
deformation which correspond to light-waves.

This theory—also called the theory of the stationary luminiferous
ether—moreover found a strong support in an experiment which is also of
fundamental importance in the special theory of relativity, the experiment
of Fizeau, from which one was obliged to infer that the luminiferous ether
does not take part in the movements of bodies. The phenomenon of aberration
also favoured the theory of the quasi-rigid ether.
The development of the theory of electricity along the path opened up by
Maxwell and Lorentz gave the development of our ideas concerning the ether
quite a peculiar and unexpected turn. For Maxwell himself the ether indeed
still had properties which were purely mechanical, although of a much more
complicated kind than the mechanical properties of tangible solid bodies.
But neither Maxwell nor his followers succeeded in elaborating a mechanical
model for the ether which might furnish a satisfactory mechanical
interpretation of Maxwell’s laws of the electro-magnetic field. The laws
were clear and simple, the mechanical interpretations clumsy and
contradictory. Almost imperceptibly the theoretical physicists adapted
themselves to a situation which, from the standpoint of their mechanical
programme, was very depressing. They were particularly influenced by the
electro-dynamical investigations of Heinrich Hertz. For whereas they
previously had required of a conclusive theory that it should content itself
with the fundamental concepts which belong exclusively to mechanics (e.g.
densities, velocities, deformations, stresses) they gradually accustomed
themselves to admitting electric and magnetic force as fundamental concepts
side by side with those of mechanics, without requiring a mechanical
interpretation for them. Thus the purely mechanical view of nature was
gradually abandoned. But this change led to a fundamental dualism which in
the long-run was insupportable. A way of escape was now sought in the
reverse direction, by reducing the principles of mechanics to those of
electricity, and this especially as confidence in the strict validity of the
equations of Newton’s mechanics was shaken by the experiments with 13-rays
and rapid kathade rays.

This dualism still confronts us in unextenuated form in the theory of Hertz,
where matter appears not only as the bearer of velocities, kinetic energy,
and mechanical pressures, but also as the bearer of electromagnetic fields.
Since such fields also occur in vacuo—i.e. in free ether— the ether also
appears as bearer of electromagnetic fields. The ether appears
indistinguishable in its functions from ordinary matter. Within matter it
takes part in the motion of matter and in empty space it has everywhere a
velocity ; so that the ether has a definitely assigned velocity throughout
the whole of space. There is no fundamental difference between Hertz’s ether
and ponderable matter (which in part subsists in the ether).

The Hertz theory suffered not only from the defect of ascribing to matter
and ether, on the one hand mechanical states, and on the other hand
electrical states, which do not stand in any conceivable relation to each
other ; it was also at variance with the result of Fizeau’s important
experiment on the velocity of the propagation of light in moving fluids, and
with other established experimental results.

Such was the state of things when H. A. Lorentz entered upon the scene. He
brought theory into harmony with experience by means of a wonderful
simplification of theoretical principles. He achieved this, the most
important advance in the theory of electricity since Maxwell, by taking from
ether its mechanical, and from matter its electromagnetic qualities. As in
empty space, so too in the interior of material bodies, the ether, and not
matter viewed atorlistically, was exclusively the seat of electromagnetic
fields. According to Lorentz the elementary particles of matter alone are
capable of carrying out movements ; their electromagnetic activity is
entirely confined to the carrying of electric charges. Thus Lorentz
succeeded in reducing all electromagnetic happenings to Maxwell’s equations
for free space.

As to the mechanical nature of the Lorentzian ether, it may be said of it,
in a somewhat playful spirit, that immobility is the only mechanical
property of which it has not been deprived by H. A. Lorentz. It may be added
that the whole change in the conception of the ether which the special
theory of relativity brought about, consisted in taking away from the ether
its last mechanical quality, namely, its immobility. How this is to be
understood will forthwith be expounded.

The space-time theory and the kinematics of the special theory of relativity
were modelled on the Maxwell-Lorentz theory of the electromagnetic field.
This theory therefore satisfies the conditions of the special theory of
relativity, but when viewed from the latter it acquires a novel aspect. For
if K be a system of co-ordinates relatively to which the Lorentzian ether is
at rest, the Maxwell-Lorentz equations are valid primarily with reference to
K. But by the special theory of relativity the same equations without any
change of meaning also hold in relation to any new system of co-ordinates K’
which is moving in uniform translation relatively to K. Now comes the
anxious question :—Why must Yin the theory distinguish the K system above
all K’ systems, which are physically equivalent to it in all respects, by
assuming that the ether is at rest relatively to the K system ? For the
theoretician such an asymmetry in the theoretical structure, with no
corresponding asymmetry in the system of experience, is intolerable. If we
assume the ether to be at rest relatively to K, but in motion relatively to
K’, the physical equivalence of K and K’ seems to me from the logical
standpoint, not indeed downright incorrect, but nevertheless inacceptable.

The next position which it was possible to take up in face of this state of
things appeared to be the following. The ether does not exist at all. The
electromagnetic fields are not states of a medium, and are not bound down to
any bearer, but they are independent realities which are not reducible to
anything else, exactly like the atoms of ponderable matter. This conception
suggests itself the more readily as, according to Lorentz’s theory,
electromagnetic radiation, like ponderable matter, brings impulse and energy
with it, and as, according to the special theory of relativity, both matter
and radiation are but special forms of distributed energy, ponderable mass
losing its isolation and appearing as a special form of energy.

More careful reflection teaches us, however, that the special theory of
relativity does not compel us to deny ether. We may assume the existence of
an ether ; only we must give up ascribing a definite state of motion to it,
i.e. we must by abstraction take from it the last mechanical characteristic
which Lorentz had still left it. We shall see later that this point of view,
the conceivability of which I shall at once endeavour to make more
intelligible by a somewhat halting comparison, is justified by the results
of the general theory of relativity.

Think of waves on the surface of water. Here we can describe two entirely
different things. Either we may observe how the undulatory surface forming
the boundary between water and air alters in the course of time ; or
else–with the help of small floats, for instance—we can observe how the
position of the separate particles of water alters in the course of time. If
the existence of such floats for tracking the motion of the particles of a
fluid were a fundamental impossibility in physics—if, in fact, nothing else
whatever were observable than the shape of the space occupied by the water
as it varies in time, we should have no ground for the assumption that water
consists of movable particles. But all the same we could characterise it as
a medium.

We have something like this in the electromagnetic field. For we may picture
the field to ourselves as consisting of lines of force. If we wish to
interpret these lines of force to ourselves as something material in the
ordinary sense, we are tempted to interpret the dynamic processes as motions
of these lines of force, such that each separate line of force is tracked
through the course of time. It is well known, however, that this way of
regarding the electromagnetic field leads to contradictions.

Generalising we must say this :—There may be supposed to be extended
physical objects to which the idea of motion cannot be applied. They may not
be thought of as consisting of particles which allow themselves to be
separately tracked through time. In Minkowski’s idiom this is expressed as
follows :—Not every extended conformation in the four-dimensional world can
be regarded as composed of world-threads. The special theory of relativity
forbids us to assume the ether to consist of particles observable through
time, but the hypothesis of ether in itself is not in conflict with the
special theory of relativity. Only we must be on our guard against ascribing
a state of motion to the ether.

Certainly, from the standpoint of the special theory of relativity, the
ether hypothesis appears at first to be an empty hypothesis. In the
equations of the electromagnetic field there occur, in addition to the
densities of the electric charge, only the intensities of the field. The
career of electromagnetic processes in vacuo appears to be completely
determined by these equations, uninfluenced by other physical quantities.
The electromagnetic fields appear as ultimate, irreducible realities, and at
first it seems superfluous to postulate a homogeneous, isotropic ether-
medium, and to envisage electromagnetic fields as states of this medium.

But on the other hand there is a weighty argument to be adduced in favour of
the ether hypothesis. To deny the ether is ultimately to assume that empty
space has no physical qualities whatever. The fundamental facts of mechanics
do not harmonize with this view. For the mechanical behaviour of a corporeal
system hovering freely in empty space depends not only on relative positions
(distances) and relative velocities, but also on its state of rotation,
which physically may be taken as a characteristic not appertaining to the
system in itself. In order to be able to look upon the rotation of the
system, at least formally, as something real, Newton objectivises space.
Since he classes his absolute space together with real things, for him
rotation relative to an absolute space is also something real. Newton might
no less well have called his absolute space “Ether ” ; what is essential is
merely that besides observable objects, another thing, which is not
perceptible, must be looked upon as real, to enable acceleration or rotation
to be looked upon as something real.

It is true that Mach tried to avoid having to accept as real something which
is not observable by endeavouring to substitute in mechanics a mean
acceleration with reference to the totality of the masses in the universe in
place of an acceleration with reference to absolute space. But inertial
resistance opposed to relative acceleration of distant masses presupposes
action at a distance ; and as the modern physicist does not believe that he
may accept this action at a distance, he comes back once more, if he follows
Mach, to the ether, which has to serve as medium for the effects of inertia.
But this conception of the ether to which we are led by Mach’s way of
thinking differs essentially from the ether as conceived by Newton, by
Fresnel, and by Lorentz. Mach’s ether not only conditions the behaviour of
inert masses, but is also conditioned in its state by them.

Mach’s idea finds its full development in the ether of the general theory of
relativity. According to this theory the metrical qualities of the continuum
of space-time differ in the environment of different points of space-time,
and are partly conditioned by the matter existing outside of the territory
under consideration. This space-time variability of the reciprocal relations
of the standards of space and time, or, perhaps, the recognition of the fact
that ” empty space ” in its physical relation is neither homogeneous nor
isotropic, compelling us to describe its state by ten functions (the
gravitation potentials gµv), has, I think, finally disposed of the view that
space is physically empty. But therewith the conception of the ether has
again acquired an intelligible content, although this content differs widely
from that of the ether of the mechanical undulatory theory of light. The
ether of the general theory of relativity is a medium which is itself devoid
of all mechanical and kinematical qualities, but helps to determine
mechanical (and electromagnetic) events.

What is fundamentally new in the ether of the general theory of relativity
as opposed to the ether of Lorentz consists in this, that the state of the
former is at every place determined by connections with the matter and the
state of the ether in neighbouring places, which are amenable to law in the
form of differential equations ; whereas the state of the Lorentzian ether
in the absence of electromagnetic fields is conditioned by nothing outside
itself, and is everywhere the same. The ether of the general theory of
relativity is transmuted conceptually into the ether of Lorentz if we
substitute constants for the functions of space which describe the former,
disregarding the causes which condition its state. Thus we may also say, I
think, that the ether of the general theory of relativity is the outcome of
the Lorentzian ether, through relativation.

As to the part which the new ether is to play in the physics of the future
we are not yet clear. We know that it determines the metrical relations in
the space-time continuum, e.g. the configurative possibilities of solid
bodies as well as the gravitational fields ; but we do not know whether it
has an essential share in the structure of the electrical elementary
particles constituting matter. Nor do we know whether it is only in the
proximity of ponderable masses that its structure differs essentially from
that of the Lorentzian ether ; whether the geometry of spaces of cosmic
extent is approximately Euclidean. But we can assert by reason of the
relativistic equations of gravitation that there must be a departure from
Euclidean relations, with spaces of cosmic order of magnitude, if there
exists a positive mean density, no matter how small, of the matter in the
universe. In this case the universe must of necessity be spatially unbounded
and of finite magnitude, its magnitude being determined by the value of that
mean density.

If we consider the gravitational field and the electromagnetic field from
the standpoint of the ether hypothesis, we find a remarkable difference
between the two. There can be no space nor any part of space without
gravitational potentials ; for these confer upon space its metrical
qualities, without which it cannot be imagined at all. The existence of the
gravitational field is inseparably bound up with the existence of space. On
the other hand a part of space may very well be imagined without an
electromagnetic field ; thus in contrast with the gravitational field, the
electromagnetic field seems to be only secondarily linked to the ether, the
formal nature of the electromagnetic field being as yet in no way determined
by that of gravitational ether. From the present state of theory it looks as
if the electromagnetic field, as opposed to the gravitational field, rests
upon an entirely new formal motif, as though nature might just as well have
endowed the gravitational ether with fields of quite another type, for
example, with fields of a scalar potential, instead of fields of the
electromagnetic type.

Since according to our present conceptions the elementary particles of
matter are also, in their essence, nothing else than condensations of the
electromagnetic field, our present view of the universe presents two
realities which are completely separated from each other conceptually,
although connected causally, namely, gravitational ether and electromagnetic
field, or—as they might also be called—space and matter.
Of course it would be a great advance if we could succeed in comprehending
the gravitational field and the electromagnetic field together as one
unified conformation. Then for the first time the epoch of theoretical
physics founded by Faraday and Maxwell would reach a satisfactory
conclusion. The contrast between ether and matter would fade away, and,
through the general theory of relativity, the whole of physics would become
a complete system of thought, like geometry, kinematics, and the theory of
gravitation. An exceedingly ingenious attempt in this direction has been
made by the mathematician H. Weyl; but I do not believe that his theory will
hold its ground in relation to reality. Further, in contemplating the
immediate future of theoretical physics we ought not unconditionally to
reject the possibility that the facts comprised in the quantum theory may
set bounds to the field theory beyond which it cannot pass.

Recapitulating, we may say that according to the general theory of
relativity space is endowed with physical qualities; in this sense,
therefore, there exists an ether. According to the general theory of
relativity space without ether is unthinkable ; for in such space there not
only would be no propagation of light, but also no possibility of existence
for standards of space and time (measuring-rods and clocks), nor therefore
any space-time intervals in the physical sense. But this ether may not be
thought of as endowed with the quality characteristic of ponderable media,
as consisting of parts which may be tracked through time. The idea of motion
may not be applied to it.

 

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