Why Newton was Replaced by Einstein, and Back

Newton's Inverse Square Law NL was until the 1960s the prime example of the power of mathematical thinking visible to everybody: All of celestial mechanics can be described and computed from NL  necessarily valid from principles of conservation in any existing Universe. 

What happened in the 1960s was that Einstein's General Theory of Relativity GR, presented already in 1915, finally was adopted to serve as one of the two pillars of modern physics (the other one Quantum Mechanics QM) and so replace Newton the icon of classical physic by Einstein as icon of modern physics. 

But this transition took place only after Einstein's death in 1955, because of the very complex mathematics of GR understood by few if any making it useless in any from of practical physics. 

However in the propaganda of the cold war it served well to strengthen the world dominance of US science formed by physicists imported from Germany during WWII inventing the atom bomb. Replacing Newton by Einstein served as a demonstration of power, and all the earlier skepticism to GR could be put under the rug. And of course the Sovjet Union followed. Einstein was put in first place, but only after his death since during his life time he appeared as an "absent-minded eccentric maybe too fond of fame". 

Today the cold war is back, Einstein is still on top of the list of fame, while the rapidly developing technology of warfare is using Newton to come to expression. 

There is only an homage to Einstein GR left as an initial offset of satellite clocks in the GPS system, which in operation is annihilated by continuous synchronisation to a master clock on Earth. 

Maybe there is reason to return to a new critical analysis of Newton vs Einstein without the fame dominating the discussion.  

The discussion could start comparing Newton's absolute space against which Einstein's relative space took stand. 

Is it true that Newton's theory of gravitation needs a notion of absolute space against which absolute velocity can be measured? Does Newton say that velocity is absolute? Certainly not! Nobody would come up with such an idea. Of course velocity of an object is always measured relative to something else.

So Newton says that velocity is relative. On the other hand Newton says that rotation as accelerated motion is detectable by forces of tension arising from acceleration. Newton's rotating bucket can thus be viewed as a form of absolute rotation which does not need any outside reference. 

Note that there is a special form of accelerated motion which is not so easily detected by presence of forces and that is free fall under gravitation where all parts of your body feel the same force and no tension arises. But that is not true for a bigger object where tidal forces occur because the gravitational force is not uniform.

So the argument that Newton says that velocity is absolute and so has to be replaced by Einstein's relativity, is not correct. The argument that Newton's theory of gravitation is a necessity in any existing Universe, is very strong. The question is if there are modern physicists willing to face this reality.