I have avoided using the word aether because it is an historic empirical inference out of favor for a century. My own second tier is a natural outcome of my foundational thought experiment leading to the creation of a conceptual space consisting of what i am calling the second tier of matter whose natural scale is that of the electron. First tier matter is scaled at the scale of a neutrino and third tier is scaled at the scale of a neutron.
We have here an excellent chronology of the development of what is been called Aether theory. Sadly it is clear that the authority of Einstein was sufficient to discredit the very word since the beginning of the twentieth century. The same thing has happened to cold fusion.
My own work has produced the inevitability of a second tier of matter. That this acts as the Aether is additionally confirmed by the work reported here. None of this shows the first tier of matter yet and that is actually unlikely for a long time. I can nicely simulate it however in a conceptual space easily replicated in a virtual space conducive to many interesting discoveries and predictions.
- Reginald T. Cahill 
Aristotle believed the heavens (that region beyond the sphere of the Moon) are made of a fifth substance called aether. Unlike the other four substances, which can be transformed into one another, aether is unchanging and indestructible.
The planets, for instance, are carried around by a sea of aether moving in whirlpool fashion, producing what we would call gravitational effects. All space was a sea filled with matter that swirled around in large and small vortices (forming the Cartesian Vortex universe).
Descartes referred to the aether as the “second matter” and “second element.”
In order to explain, without employing magical action-at-a-distance, the transmission of light, heat, and magnetism across the Torricellian vacuum, it was necessary to postulate a subtle medium, or aether, which remained when the air was removed.
Huygens, a follower of Descartes, shared the view that gravity was nothing more than "the action of the aether, which circulates around the centre of the Earth, striving to travel away from the centre, and to force those bodies which do not share its motion to take its place". In 1669, to demonstrate the idea, he conducted a simple experiment that seemed to support the vortex theory of gravity. A whirlpool was induced in a bowl of water; this action caused pebbles to be drawn to the centre of the vortex at the middle of the bowl.
According to this theory, the "ultra-mundane corpuscles," moving at high speed and coming from all directions, are continually impacting on all material objects. Any two material bodies would partially shield each other from the flux of impinging corpuscles and establish a pressure imbalance. This imbalance, then, tends to drive the bodies together, and so, provides a 'push-gravity' explanation for Newton's gravitational force.
Euler was a notable adherent of the aether-wave theory of light, as opposed to Newton’s corpuscular version.
French mathematician and astronomer
Laplace hypothesized that the effect of gravity is propagated with a speed between 7-million and 100-million times that of light. [“Traitè de Mécanique Célèste” 1803; “Exposition du Système du Monde”] This rules out the notion that the flow of the medium itself is involved in Laplace’s cause of gravity.
subsequently guided Augustin Fresnel
In 1817, French physicist, A. Fresnel (1788-1827) introduced the transverse wave theory of light which could account for all the known phenomena of optics; consequently the aether became solid-like and rigid yet allowed the free passage of heavenly bodies. In Fresnel’s view, the aether flowed through the interstices of material bodies even on the smallest scale; but he did allow for matter to have a small dragging effect on the aether.
It should be pointed out that Cauchy (see entry below) was the first, as of 1831, to propose a theory whereby the Earth drags the aether. Stokes adopted the aether-drag concept around 1845.
Theory #2: Aether changed in elasticity.
Theory #3: Then in 1839 Cauchy proposed an aether that was contractile or “labile,” “possessing a negative compressibility.” [Mason, p472] Today we would call this a negative Λ or a simple gravity effect.
This aether is a quasi-material elastic medium. Whether it is ultimately continuous or discrete was left undecided.
Maxwell’s theory treats aether as the preferred frameof reference in which light propagates with constant speed in all directions. Notwithstanding the inclusion of microscopic rotating tubes, aether was viewed as a stationary medium.
Post 1887, aether was real.
Albert A. Michelson (1852-1931)
Edward Williams Morley (1838-1923)
For the first time in history it was proposed that aether has the ability, not merely to change the course of objects (as does gravitational aether), but to change the size of objects. FitzGerald’s aether had the relativistic ability to contract the dimensions of any object: contraction occurring in the direction of motion and in proportion to the speed through the aether!
The validity of this theory was later confirmed. Whenever the experiment was performed in a vacuum the aether-effect on the optical interferometer was (and still is) totally annulled.
In 1905 the same steel-girder apparatus recorded 8.7 km/s.
On a rotating platform, M.G. Sagnac split light from a single monochromatic source into cw and ccw rays that traveled identical paths in opposite directions around the platform. He combined the returning rays to form a visible interference pattern, and found that the fringes shifted as the speed of rotation changed.
In Dec of 1921 the steel base was replaced with a concrete one to exclude any possible magnetic effects. Same result, 10 km/s.
In a non-optical experiment in 1991 (see DeWitte, below) the RA direction of ~5h was dramatically confirmed.
It is interesting and useful to note an essential difference between the Foucault and Allais pendulums. In the former the pendulum’s bob and wire do not turn (relative to the Earth frame) since the bob and wire are not free to pivot, only the nonmaterial swing plane turns; while in the latter the pendulum’s bob-and-rigid-arm assembly is free to turn. The Foucault pendulum measures the Coriolis effect while the Allais pendulum supposedly measures the direction of aether flow.
The experiment lasted 178 days and confirmed that the effect was periodic with sidereal time, not solar time. The aether motion was of extra-solar-system origin —or galactic origin.
There could now be no doubt that the aether wind is of galactic source from beyond the Solar System.
Galaev concluded that the aether is consistent with a medium composed of discrete particles, and that the aether is responsible for electromagnetic waves propagation.
The DSSU model represents the first testable theory using a luminiferous and gravitational aether-space in the context of the non-expanding cellular-universe model.
The M-M and the Miller data were carefully reanalyzed, the new calibration factor was applied, and the full magnitude of the aether drift velocity was at long last revealed.
Aether-space (on the cosmic scale) expands in certain regions and contracts in other regions. This dynamic activity manifests as the cosmic cell structure observed by astronomers.
Cells (of cosmic scale) are self-regulating in size and are in a perpetual steady state of simultaneous expansion and contraction. The cells constitute a Euclidean structure that exists within the non-expanding universe. The DSSU infinite universe is a quasi-static lattice-like structure of unit-universes.
Electromagnetic phenomena are CONDUCTION properties of the aether-space.
Process-aether was shown to produce the contractile effect (Cahill calls it the 3-space self-interaction effect) that had long been attributed to some kind of mysterious unsubstantiated matter.
In effect, Cahill found that dynamic aether is gravitationally more powerful than is Newton’s force and Einstein’s geometrized space.
A DSSU concept (but possibly predates the DSSU revolution).
The increase in path length and its connection to the refraction index is described, in mathematical detail, by Professor Cahill (www.ptep-online.com/index_files/2011/PP-24-04.pdf).
The implications for cosmology are profound.
The implications for cosmology are profound.