Ether and Special Relativity

My Special Relativity and space-time theory were modelled on the Maxwell-Lorentz theory of the electromagnetic field.

If K is 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 Special Relativity, the same equations also hold in relation to any new system of co-ordinates K' which is moving relatively to K.

But why must I distinguish the non-moving K system above all moving K' systems, which are physically equivalent to it in all respects, by assuming that the ether is at rest relatively to the non-moving K system?

I think that such an asymmetry in the theoretical structure, with no corresponding asymmetry in the system of experience, is intolerable*.

If the ether were at rest relatively to non-moving K, but in motion relatively to moving K', the physical equivalence of non-moving K and moving K' is unacceptable.

Initially, the solution is that the ether does not exist at all.

The electromagnetic fields:

• are not states of a medium
• are not bound down to any bearer
• are independent realities which are not reducible to anything else, exactly like the atoms of ponderable matter.
• are electromagnetic radiation, according to Lorentz’s theory. This is like ponderable matter bringing impulse and energy with it

According to Special 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.

But afterwards, Special Relativity however does not compel us to deny ether.

We may assume the existence of an ether. But it does not have a definite state of motion to it, i.e. we must remove its immobility.

Think of waves on the surface of water. Here we can describe 2 entirely different things. Either we may observe how:

1. Changes in the water in a pond are shown by its wavy surface, or

2. Changes in the water in a pond are shown by buoys that act as markers

If such buoys were impossible, then we cannot say that water was made up of moving particles. But it would still be a medium.

The electromagnetic field is like water, consisting of lines of force. Each separate line of force is tracked through time. But this way of regarding the electromagnetic field leads to contradictions.

There might be extended physical objects to which the idea of motion cannot be applied. They might not be made up of trackable particles*.

Minkowski expresses this as: Not every extended conformation in the four-dimensional world are composed of world-threads.

In Special Relativity, the ether is made up of unobservable particles. But the ether hypothesis in itself is not in conflict with Special Relativity.

We merely must not ascribe movement to the ether.

To Special Relativity, the ether hypothesis initially is an empty hypothesis.

The equations of the electromagnetic field only have:

• the densities of the electric charge
• the intensities of the field.

Electromagnetic processes in vacua are completely determined by these equations, uninfluenced by other physical quantities.

The electromagnetic fields appear as ultimate, irreducible realities.

At first, it seems superfluous to:

• postulate a homogeneous, isotropic ether-medium
• envisage electromagnetic fields as states of this medium.

But on the other hand, the ether hypothesis is useful in harmonizing the fundamental facts of mechanics.

The mechanical behaviour of body hovering freely in empty space depends on:

• relative positions (distances)
• relative velocities
• its state of rotation
  • This might not appertaining to the body in itself.

In order to look at the rotation of the body as something real, Newton objectivises space. He classes his absolute space together with real things. For him, rotation relative to an absolute space is also something real.

Newton could have called his absolute space as “Ether”.

Besides observable objects, another thing, which is not perceptible, must be looked upon as real in order to enable acceleration or rotation to be looked upon as something real.