Speed of Light vs 2019 SI Standard

The 2019 SI Standard defines length scale in meter by travel time of light assuming a preset speed of light of exactly 299792458 meter/second with time measured by a standard caesium atomic clock.

The SI Standard thus views propagation of light along a spatial $x$-axis as an electromagnetic wave phenomenon governed by Maxwell's wave equations in a medium or aether identified with the $x$-axis thus with an aether which is stationary with respect to the $x$-axis. The distance between two stationary points A and B on the $x$-axis is measured by sending a light signal from A and measuring the time for the reflected signal at B to return to A and then translating to distance by the preset speed of light. 

This is how an instrument like a Rangefinder at A determines the distance to a point B assuming that A and B are stationary on an $x$-axis joining A and B. A radar works the same way.

If the distance between A and B is large, it may be difficult to identify a reflected signal, and in this case the source may be equipped with a clock and emit a light signal with time of emission encoded, which when received by A with a synchronised clock will record travel time and so distance. This allows B to move with respect the $x$-axis, while the instrument is always stationary, which effectively means that the $x$-axis is tied to the instrument receiving the light signal. 

Consider now an $x^\prime$-axis gliding on top of the $x$-axis with constant speed $w$ as an inertial system with the length scale along the $x^\prime$-axis determined in the same way, that is via a Rangefinder tied to the $x^\prime$-axis. This means that the length scales on the $x$-axis and the $x^\prime$-axis are determined in the same way and thus will be the same if 

• The speed of light is the same in all inertial systems.              (P)

Let us now check if this is the case in the light of the 2019 SI Standard, by inspecting the physics of a Rangefinder tied to an $x$-axis, which is the physics described by Maxwell's equations expressed in $x$-coordinates, which describes propagation of waves in a medium/aether identified with the $x$-axis. This is the physics explored in Many-Minds Relativity MMR.

Note that (P) is the same as the main postulate of Einstein's Special Theory of Relativity SR, which Einstein does not motivate but assumes as a Postulate from which he then concludes many strange effects like time dilation and space contraction forced by the Lorentz transformation.

The main difference between SR and MMR is that (P) in SR is a postulate with strange consequences, while (P) in MMR is simply an adopted SI Standard, which has no strange consequences and which can be motivated on physical grounds as indicated below. We now proceed to see how SR and MMR differ.   

We will then compare with propagation of sound in still air represented by an $x$-axis described by the same form of wave equation. We consider the relation between an emitter B and receiver A of sound waves, which can be viewed as a resonance phenomenon in a stationary medium where an oscillator at B interacts with the medium and so puts an oscillator at A in motion, just like two tuning forks at distance interacting by resonance in still air as medium. 

We similarly view interaction by a light source and a receiver as a resonance phenomenon carried by electromagnetic waves along an $x$-axis or aether tied to the receiver. We then face the possibility of different inertial systems or different aethers. MMR thus describes propagation of light in a many-aether system to be be compared with sound waves in a single-aether system as still air. 

To see the key difference between SR and MMR consider a light signal emitted at time $t=0$ at $x=0$ on a $x$-axis, and a light signal emitted at the same time at $x^\prime =0$ on a $x^\prime$-axis gliding on top of the $x$-axis and coinciding at $t=0$.  

In MMR the signals are different because they are carried by resonance in two different aethers, one connected to the $x$-axis and the other to the $x^\prime$-axis, and (P) is fulfilled thanks to the SI Standard. 

In SR these two light signals are identified to be the same, which lacks physics and so requires time dilation and space contraction to fulfil (P) according to the Lorentz transformation. 

MMR relies on the SI Standard expressing (P), which can be motivated as a resonance phenomenon in different inertial systems/aethers.  

SR has no reference to the SI Standard and so must seek satisfaction of (P) through unphysical Lorentz transformation. 

Conclusion: SR/Lorentz transformation is obsolete after 2019. Physics no longer has to be strange to satisfy needs of SR. The key is resonance between emitter and receiver of light carried by an aether identified with an $x$-axis at rest with the receiver as the essence of MMR in full agreement with the 2019 SI Standard. Eliminating SR/Lorentz transformation from modern physics may open to progress which has been blocked by the incompatibility between Newtonian mechanics and the Lorentz transformation.