Isn't the aether existent?

Question

Before you say I'm wrong consider this, Einstein is supposedly the first person to get completely get rid of the various aether models that were proposed. But didn't Einstein actually prove them right in the sense that things move through a medium called time (i.e. Minkowski space). After all we can measure it just like any other physical thing. It might not be considered spacial but that seems pretty arbitrary because we are defining from our perspective. Am I just splitting hairs? Is this not true?

I'm obviously not a physicist but I'm reading Feynmans Lectures to get a general idea of things (I'm not on the special or general relativity parts yet) but I'm just trying to get a bit of intuition.

Answer 1

It's important to state exactly what one means by "aether" when saying that aether theories are discredited.

Specifically, the notion of medium that one can in principle detect one's motion relative to is what has been ruled out by experiment. Mediums such as water for acoustic waves fall into this category: the acoustic wave equation changes its form when one is in uniform motion relative to the medium. In contrast, Maxwell's equations do not change their form in this way.

All experiments so far support Galileo's relativity principle - that there is no experiment that one could do making measurements within one's own laboratory that could detect the uniform motion of the laboratory relative to another frame. To understand more deeply exactly what Galileo means here, see the allegory of Salviati's Ship. Most of the 19th century notions of an aether tell against this principle because, as for the motion relative to the water, they would give us an easy way to tell whether we were moving relative to the medium.

However, an aether fulfilling Galileo's principle is not ruled out experimentally. Indeed there was one aether theory, namely Lorentz Aether Theory which is identical in its experimental predictions to special relativity. User ACuriousMind summarizes this theory, and why SR is preferred, in his answer here.

General Relativity brings home the notion that "empty space" is not a void vividly and in a very in-your-face way: in GR "empty space" has definite properties[1] that differ from place to place: for example: its geometry - and outcomes of experiments to detect this geometry - can vary with a nonconstant curvature tensor. Modern quantum field theory goes further: empty space is a real, "material" entity, and modern physics conceives of it as being made of quantum fields in their ground state: modern physics has no need for an extraneous and mind bending notion of "empty space" further to the quantum fields that make up reality.

So, although one must be careful with the word aether to exclude anything that violates Galileo's principle and yields Lorentz-invariant predictions as being in conflict with experiment, I personally kind of like the word as a metaphor for empty space to emphasize the 20th century achievements of general relativity and quantum field theory. We can describe how empty space takes different geometry through the Einstein field equations. The quest for quantum gravity can be thought of as seeking to understand the mechanisms and that machinery of empty space that lead to the EFE description: quantum gravity can be thought of as the quest to find out how the Lorentz-invariant "aether" works.

[1]. It's important to note that even in Newtonian physics "empty space" has definite properties so that, from a philosophical standpoint, the distinction between void and empty space is still very real here, but subtler.

Answer 2

Einstein didn't actually get rid of the aether. He said the luminiferous aether was redundant when he was doing special relativity in 1905. But later when he was doing general relativity, he described space as an aether. See his 1920 Leyden Address. He said this: "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 aether". Also see the quote here by Nobel Prizewinner Robert B Laughlin:

"It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed. The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum..."

In addition have a look on the arXiv for papers with aether in the title. There's lots of them. Unfortunately there is a bit of a difference between "popscience physics" and genuine physics. Such is life I'm afraid.

Answer 3

There are many theories that postulate "aether" and to be honest, I never really thought about it, mostly, because that is what was thought to me in school and physics study.

Since I'm 14, I tried to understand general relativity. I understood the formulas, but never the underling reason, it simply did not make sense to me. Einstein solved this riddle for me:

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.

I could not understand it, because it's unthinkable.

The only reason we don't have an aether is, that Einstein could not describe it mathematically.

Now, the problem with most aether theories is, that they think aether as some sort of super-fluid, that never where able to describe physics to the full extend. One problem for example is, that a photon, as some sort of traveling energy, needs a boundary condition, otherwise the energy would dissipate like a normal EM-Wave. Implementing this in a super-fluid is hard or even impossible.

Now, if you don't see it a super-fluid but a self organizing grid like structure, things start to make sense, this is what the "Basic Structures of Matter - Supergravitation Unified Theory" (BSM-SG) from Stoyan Sarg does.

It has a concept of aether (CL-Space) that was never investigated so far.

• it only assumes 2 basic fundamental particles that vibrate and congregate.
• 3 dimensional empty space without physical properties (no light, Newtonian gravity, temperature, ...)
• 1 law of attraction, the supergravitation: SG=G_0 * (m1*m2)/r^3

It does not require mathematical logic nor an uncertainty principle.

This basic assumptions, are enough to derive a model that fits extremely well with all observed phenomena so far while answering many answers of current physics:

• What is dark energy
• What is dark matter
• How is the ZPE implemented
• What is a black hole, or great attractor
• What is the relation between general relativity and the quantum world, how does they relate ?
• What is the real difference in nuclear isomer (Atoms with same proton/neutron numbers but different "Energy")
• How does gravity work
• ...

It is in perfect alignment with SR & GR and explains all currently known quantum mechanical properties without logical breakage.

Unfortunately, the model does not get the scientific feedback it deserves and is widely ignored, not because somebody found a problem (so far), but because it breaks with many long told theories.

For me, after some month diving heavily into this theory, a whole new view on the world emerged and everything makes sense now. I'm absolute certain, that if you would present this model to Einstein, Tesla, Dirac, Maxwell, they all would say: Thats it. But unfortunately, BSM-SG does not allow time travel backwards ;)