Relativity Theory after 2019: Many-Minds Relativity.

Recent posts show that adoption of the 2019 SI meter Standard makes Einstein's Special Theory of Relativity SR void of physics, since its basic postulate of the same speed of light for all (inertial) observers, after 2019 simply is an agreement or standard to be followed by all (inertial) observers and not a statement about physics. 

The version of relativity theory, which makes sense as a theory about physics under the 2019 SI meter standard, is Many-Minds Relativity MMR.

In MMR Newton's 2nd Law takes the following form for a stationary observer O following the 2019 SI Standard assuming normalisation to unit speed of light: 

• $\frac{m}{1+v}a=F$       (N2)

where $v(t)=\frac{dx}{dt}$ is velocity with $x(t)$ position, $a(t)=\frac{dv}{dt}$ is acceleration, $m$ is mass, $F(t)$ force and $t$ time (measured by a 2019 SI Standard caesium clock). This describes the motion along an $x$-axis of a body of mass $m$ subject to a force $F(t)$, receding from O if $v>0$ and approaching O if $v<0$ with $v>-1$. 

We see that (N2) appears, compared to the usual 2nd Law $ma=F$, with smaller mass $\frac{m}{1+v}$ if $v>0$ and bigger mass if $-1<v<0$. 

Under a constant force $F=1$, this allows a recession velocity $v(t)$ to increase exponentially with $t$ eventually attaining a speed (much) bigger than the speed of light, while in approach with $F=-1$, $v(t)>-1$. The recession case connects to the Nobel Prize in Physics in 2011 "for the discovery of the accelerating expansion of the Universe".

If now since 2019 SR is void of physics, this makes the element of SR present in Einstein's General Theory of Relativity GR also void of physics. What remains of GR is then the Equivalence Principle which GR shares with Newtonian Mechanics NM. Maybe then NM + MMR is enough? Since both SR and GR are very difficult to understand for most people, this could be greeted as a relief?

The shift to 2019 SI Standard appears to give fundamentally new perspectives on modern physics. 

PS1 Recall that the SR version of Newton's 2nd Law takes the form 

• $\frac{m}{\sqrt{1-v^2}}a=F$ 

which has the same form in recession and approach and in particular keeps $v<1$ as if the speed of light cannot be surpassed, which is not what is observed for far away galaxies receding with $v>10$.

PS2 Recall that GR is incompatible with quantum mechanics, which is a main trouble of modern physics, while NM+MMR is compatible with quantum mechanics.