3.1 Aether Retreat
The concept of aether was used in ancient philosophy and medieval science as a thin transparent material that fills the upper spheres where planets move and revolve. This concept was invoked again in the late 18th century as a medium for the propagation of light waves, just like sound which needed a medium to propagate. This medium was called: luminiferous aether, meaning: light-bearing aether, or simply: aether, and also can be written as: ether.
The concept of aether was contradictory, because it required the existence of an invisible and infinite material that does not have any interaction with physical objects. On the one hand, aether had to be a perfect fluid in order to fill all space, but on the other hand it has to be millions of times more rigid than steel, in order to support the high frequencies of light waves. It also had to be massless and without viscosity, otherwise it would affect the motion of planets. Additionally, it had to be completely transparent, non-dispersive, incompressible, and continuous at a very small scale.
As Maxwell wrote in Encyclopedia Britannica: “Aethers were invented for the planets to swim in, to constitute electric atmospheres and magnetic effluvia, to convey sensations from one part of our bodies to another, and so on, until all space had been filled three or four times over with aethers.... The only aether which has survived is that which was invented by Huygens to explain the propagation of light.” Schlafly (2011)
In the 19th century, there had been active discussion concerning the state of motion with respect to aether, whether it is dragged by or entrained within moving matter. According to aether dragging hypothesis, no relative motion exists between the Earth and aether, while in the second view there should be some relative motion, and thus the speed of light should depend on the speed of this motion that is called “aether wind”, which should be measurable by instruments at rest on the Earth’s surface. In 1818, Augustin Fresnel (1788-1827) proposed that the aether is partially entrained by matter, but in 1845 George Stokes (1819-1903) suggested that aether is completely entrained within or in the vicinity of matter. Both of these contradictory models were apparently confirmed by some experiments; the first by Hippolyte Fizeau in 1851 and the second by Michelson and Morley between 1881 and 1887.
Therefore, the existence of aether had been questioned and criticized by most physicists, but there was no other theory to replace it. However, many other complex experiments had been carried out in the late 19th century to try to detect the motion of the Earth through the aether, but all returned null results.
Subsequently, some alternative theories were proposed to explain aether dragging. The best in this regard is Lorentz aether theory, which provided an elegant solution to how the motion of an absolute aether could be undetectable. In his theory of aether, Lorentz introduced the idea of length contraction, and Poincaré later was able to express it in mathematical equations, but shortly after that, the new theory of Special Relativity generated the same equations without ever referring to aether.
However, the success of Special and General Relativity marked the end of aether theories, although Einstein himself said that his model could itself be thought of as an aether, since empty space in Relativity has its own physical properties. In 1951, Dirac reintroduced the concept of aether in an attempt to address the perceived deficiencies in current models, thus in 1999 one proposed model of dark energy has been named: quintessence, or the fifth fundamental force. As a scalar field, the quintessence is considered as some form of dark energy which could provide an alternative postulate to explain the observed accelerating rate of the expansion of the Universe, rather than Einstein’s original postulate of cosmological constant.
Nevertheless, as we have already introduced in chapter I above, and will discuss further in chapter V, the continuous creation in the inner levels of time explains the constancy and invariance of the speed of light, and revives the classical concept of aether in a new manner that does not require it to have any effect on motion, because it is now the flat background space that is created dynamically in the inner levels of time, and matter particles are its condensed or excited states, which cause local curvature in this flat space. Space-time is therefore dynamic as in General Relativity, but now it is intrinsically granular as expected by Quantum Field theories.
The classical concept of aether was rejected because it required ideal properties that could not be attributed to any hypothetical medium that was thought to be filling the otherwise empty space background. With the new dynamic creation, however, those ideal properties of aether can be explained, because it is no longer something filling the space background, but it is the empty space itself, that is created dynamically in the inner levels of time.