By the time of James Clerk Maxwell, the luminiferous aether, which was now only hypothesized to serve as a medium of light, had assumed logically impossible mechanical properties. The logical contradictions inherent in this post- Maxwell aether had to do with two fundamental assumptions:
That light must be a transverse wave to explain birefringence, polarization, and the electromagnetic nature of light.
To explain the phenomenon of stellar aberration, and to satisfy the derivation of Maxwell's electromagnetic equations (speed of light as constant), the aether must be monolithic.
These assumptions of a monolithic, transverse wave propagating aether, led theoretical considerations, experiments and new theories that culminated in its official rejection by Einstein in 1905 upon the publication of his Special Theory of Relativity and explanation of the photoelectric effect in that year.
Theoretical Considerations The first theoretical consideration had to do with the mechanical properties of the aether. To support a transverse wave the aether had to have impossible restoring forces. Since the aether lacks the electromagnetic bonds that act as a restoring force, for say, a transversely waving string where one end is fixed to a wall, the only way for it to propagate disturbances is through one-to-one collisions. It is impossible to conceive of how the aether particles involved in transverse motion, could move up and down, crest to trough, on its axis perpendicular to the direction of the wave, through collisions alone. How would the aether particles, without a wall to rebound from, change direction once it reached its apex at the crest or trough? It only could if it behaved like a solid.
The second theoretical consideration had to do with the monolithic nature of the aether and planetary motion. How was it possible for a planet to move through the aether, which had to extremely dense to support the high frequencies of light, without constantly losing momentum from the friction, or "aether drag"?
Experiments The experiments that demonstrated the phenomena of birefringence, polarization and the electromagnetic nature of light all seemed to conform the necessity of the transverse propagation of light through the aether. All of these experiments required that light, rather than propagating in one plane as a longitudinal wave, propagate in all planes perpendicular to the direction of the wave.
A monolithic aether that the earth either drags or not cannot account for the phenomenon of Stellar Aberration.
The Michelson-Morley experiment failed to detect a monolithic aether.
New Theories Neither Einstein's Special Theory of Relativity nor his explanation of the photoelectric effect required the existence of an aether. Because his theories rejected the aether, with its impossible mechanical properties and being undetected, they were rapidly regarded simpler, and therefore, more desirable theories.
Einstein's Special Theory of Relativity did not need to posit the existence of a universal frame of reference (the aether). Since it assumed, with Maxwell, that the speed of light is a constant, all frames of reference were deemed relative.
Einstein's explanation of the photoelectric effect assumed that light is a photon, or particle, making a transmitting medium of aether unnecessary.
Einstein's General Theory of Relativity explained the phenomena of gravity also without recourse to an aether.
New Problems Initially, Einstein's theories seemed to greatly simplify theories of light and gravity. However, it soon became apparent that his conclusions created many logic-paradoxes in physics that ironically brought physics to the same state of the previous troubled aether theory: assumptions with no logical equivalent in the world as we see and know it. With no recourse to the aether, the only explanation of quantum and gravitational phenomena necessitates such logical impossibilities as the following:
A wave-particle duality of light and matter. (Double-slit experiment + Einstein's Photon)
The wave portion of the duality is propagates through a mediumless space. (Special Theory Relativity)
Matter does not exist in exact places at any specific given time: they exist as probability-states. (Uncertainty Principle)
"Forces" that are neither space nor matter act instantaneously over a distance. (Gravity, Magnetism, Strong and Weak Forces)
"Fields" that are neither space nor matter effect the motion of matter .(Electromagnetism, Gravity of General Theory of Relativity).
Particles can be in two places at one time. (Double-slit experiment)
Matter can exist in two states simultaneously; and persist so until observed (QT).
Particles can travel in time. (QED)
The conservation of energy. (QED)
The world is not deemed real until it is measured. (QT)
Events do not occur simultaneously; or, time is relative. (STR)
The length contraction (distortion) and increase in mass of matter moving near c are purely relative. (STR)
The is an unobservable fourth dimension of space. (GTR and String Theory)
The two main theories of modern physics, quantum theory, and the general theory are irreconcilable. The attempts at reconciling them have produced theories like string theory, which must assume there are 26 dimensions to space.
Violations of Basic Principles of Logic
The principle of contradiction: the same thing cannot both be and not be.
The principle of excluded middle: the thing must be either this or that.
The principle of causality: that an effect must have a cause.
The New Aether Theory In an ironic turn, a revised theory of the aether greatly simplifies physical theory. It unifies gravity, electromagnetism, magnetism and the atom in one unified theory via the fluid dynamics of the aether without violating any of the principles of logic or posing any dimensions beyond three.
As I will explain, all phenomena of nature can be attributed to the density fluctuations of the aether.
The Troubled History of the Aether in Physical Theory