Ether – less Special Relativity cannot be sound alternative to Lorentz theory.
Special Relativity assumes isotropy of one – way speed of light in all relatively moving frames.This isotropy follows from Einstein synchrony convention, that makes the one-way speed equal to the two-way speed.
Michelson - Morley experiment confirms, that in moving laboratory round trip speed of light appears to be isotropic, but this experiment says nothing about one - way speed of light. Measured isotropy of two - way speed of light in moving laboratory is due to distortion of interferometer (Lorentz - contraction).
It should be noted, that one – way speed of light is anisotropic relatively to a rim of rotating ring (Sagnac Effect). The ring can be of arbitrarily large diameter. It is experimentally confirmed fact. Hence, speed of light is anisotropic relatively to any laboratory on the Earth surface.
The only correct answer to this question is that if we assume that the speed of light is isotropic in one reference frame (and synchronize clocks Einstein – way), it is necessarily anisotropic in the other, relatively moving one and one must employ anisotropic (Reichenbach's) synchrony convention which is also self- consistent.
My answer to this question demonstrates, that time dilation is not reciprocal and only absurd synchronization leads to reciprocal time dilation.
If you consider which theory is more elegant and simple, just keep in mind that resolution of twin paradox in frameworks of Lorentz Theory and the ether – less Special Relativity demonstrates ugliness of the latter. Resolution of the Twin paradox in Lorentz Theory fits into one page, while raving fans of ether – less relativity still put forward hypotheses, each his own one.
The same goes to Bell’s spaceship paradox. Explanation why the thread breaks (or spaceships scatter from each other) is very simple in the framework of Lorentz theory.
Champeney and Moon time dilation test demonstrates absence of reciprocal time dilation for two observers that are placed on opposite sides of rotating ring. It is clear why – because their clocks dilate at the same magnitude and this dilation chancel each other. Neither rotating observers, nor purely inertial ones that coincide with rotating at the moment of measurement would not measure any reciprocal time dilation ( See fig. 4 in this article)
Minkowski formalism cannot be sound alterative to the Ether; it simply turns simple things into complex ones: it’s just a matter of time when this annoying concept will just be dumped, I believe that the following comment here indicates that this moment is getting closer:
‚@Dale If one fills all space time with particle fields on which operators work, and posits that this is the underlying reality, as most theoretically inclined people do, what is it but a reemergence of an aether? It just fulfills the function of an aether, for signals, in this case particles.‘