Aether theories

Alchemy, natural philosophy, and early modern physics proposed the existence of a medium of the aether (also spelled ether, from the Greek word (αἰθήρ), meaning "upper air" or "pure, fresh air" ^[1]), a space-filling substance or field, thought to be necessary as a transmission medium. The assorted aether theories embody the various conceptions of this "medium" and "substance". This early modern aether has little in common with the aether of classical elements from which the name was borrowed.

Although hypotheses of the aether vary somewhat in detail they all have certain characteristics in common. Essentially it is considered to be a physical medium occupying every point in Space, including within material bodies. A second essential feature is that its properties gives rise to the electric and magnetic phenomena and determines the propagation velocity of their effects. Therefore the speed of light and all other propagating effects are determined by the physical properties of the aether at the relevant location, analogous to the way that gaseous, liquid and solid media affect the propagation of sound waves.

The aether is considered the over-all reference frame for the Universe and thus velocities are all absolute relative to its rest frame. Therefore, in this view, any physical consequences of those velocities are considered as having an absolute, i. e. real effects.

Recent aether theories (see section below on protoscience links) of velocity effects, phenomenon of gravitation and planetary motion (i.e. the angular momentum), creation of proton, of stars (neutron stars too) and planets, etc., exist but are not generally accepted by the mainstream scientific community.

John Bell, interviewed by Paul Davies in "The Ghost in the Atom" has suggested that an aether theory might help resolve the EPR paradox by allowing a reference frame in which signals go faster than light^[2]. He suggests Lorentz contraction is perfectly coherent, not inconsistent with relativity, and could produce an aether theory perfectly consistent with the Michelson-Morley experiment. Bell suggests the aether was wrongly rejected on purely philosophical grounds: "what is unobservable does not exist" [p.49]. Einstein found the non-aether theory simpler and more elegant, but Bell suggests that doesn't rule it out. Besides the arguments based on his interpretation of quantum mechanics, Bell also suggests resurrecting the aether because it is a useful pedagogical device. That is, many problems are solved more easily by imagining the existence of an aether.