My answer to that question is that I am trying to tell you very many things in a very compact/compressed form, unfortunately I can not take the time and effort to go into minute details of every aspect of what I am trying to tell, so, instead, I’ll point out some things that I find very interesting in the relativistic universe.
You wrote that: “Einstein showed us mass and energy are intimately related, they are two aspects of the same thing” . I agree with that statement, but Einstein’s theory does not explain exactly how mass and energy are related, in other words: If energy and mass are two separate entities how do they combine to form the mass/energy unit? Or another way of asking the question is: What is “mass,” and what is “energy”?
One thing I am trying to tell you is that the formula that I posted here gives a better definition, or understanding, of the structure of mass and energy and how they are combined.
I also agree that time and space can not be separated, I also agree that space and time can change, but I disagree with the statement that the speed of light always is the same. I agree that there is a universal constant associated with the speed of light, but it is not the speed itself that is constant, but the acceleration that the photons obtain when leaving the source.
That is what the posted “simple” mathematical formula represents.