Aether Come-Back

Modern physics was initiated in the late 19th century in a search for an immaterial medium as aether/vacuum carrying light as an electromagnetic wave phenomenon described by Maxwell's equations. But no such aether/vacuum could be identified, which opened for Einstein's Special Theory of Relativity simply denying any need of an aether.  

But the search of an aether has continued with today the Cosmic Microwave Background Radiation CMB emerging as a possible candidate, but without conclusion.

Maxwell's equations are formulated in terms of electric and magnetic fields depending on a spatial coordinate in a Euclidean coordinate system effectively serving as an aether, and a time coordinate.

There are then as many aethers as Euclidean systems, each system being specified by origin and orientation, thus opening to a many-aether theory (suggested by Cunningham in  the 1910s) as a possibility accepting that no unique aether can be identified.

This idea is investigated in Many-Many Relativity assuming coordinate systems to be fixed at receivers of light. 

This connects to the analysis of radiative transfer of heat from (warm) source to (cold) receiver as a resonance phenomenon with temperature dependent high-frequency cut-off. This is the essence of light communication between source and receiver as analysed in Computational Black Body Radiation. 

Note that Maxwell's equations require specification of a Euclidean coordinate system and that the choice captures different physics. The basic idea is to connect coordinate systems to receivers. This is natural in particular when light sources are distant, like collecting the light from a distant star in a telescope.  

The essence is resonance between source and receiver carried by standing electromagnetic waves in a vacuum as a coordinate system fixed to the receiver (allowing moving source). In particular, this means that the speed of light is independent (same Maxwell equations) of motion of both source and receiver. 

In a system with many sources and receivers possibly moving, there will be no unique coordinate system and thus there will be a need to harmonise different descriptions, see Many-Many Relativity