The Role of the Lorentz Transformation in Modern Physics

The trade mark of modern physics as relativistic physics is the Lorentz Transformation LT connecting observations in two Euclidean coordinate systems moving with constant velocity $v$ with respect to each other (inertial systems), to be compared with the Galilean transformation of classical Newtonian physics, with difference scaling with $\vert v\vert ^2$, assuming normalisation of the speed of light to 1. 

In most cases $\vert v\vert <<1$ and then the relativistic effects are very very small, yet they serve as prime evidence of major advancement brought by modern physics in the sense that the effects are of an entirely new kind including time dilation and space contraction resulting from the fact that LT mixes space and time, which is not seen in classical physics. 

The relativistic effects of modern physics are thus presented as being very very small, except possibly in very very extreme cases like "colliding black holes", yet very very important by opening to a whole new world of strange relativistic effects all based on LT.

Recent posts have pointed to the following facts: 

1. LT was introduced by Lorentz to accommodate observations indicating that the speed of light is the same in all inertial Euclidean coordinate systems.
2. The meter length  scale in each Euclidean coordinate system is according to the 2019 SI Standard  to be determined in terms of travel time of light with the speed of light specified to be exactly 299792458 meter/second, with second defined by standard caesium clock.  

We understand that with the 2019 SI Standard the speed of light is the same in all Euclidean coordinate systems by definition/standard: The length scale in each Euclidean coordinate system is determined so that the speed of light is exactly 299792458 meter/second.

This means that the original mission of LT has been taken over by the 2019 SI Standard, and the real question is now to what extent observations in different inertial systems can be made to agree. There is full agreement on the speed of light by definition/standard but not on velocities and distances in general. This is the objective of Many-Minds Relativity.

Summary: LT has no longer any role to play under the 2019 SI Standard. The speed of light is the same in all inertial systems by definition/standard. There are no effects of time dilation since a caesium clock cannot be affected by inertial motion. Physics without LT may open to a unified theory viewed to be impossible with LT.