Giorgio T.

Thank you. I should have looked there before I posted. Greater minds than mine have thought about this!

Rotating in relation to what? Are we relying on internal signals, the external Universe or the inertial frame? Or is it all of those?

It seems to be possible to detect rotation in an object without reference to anything external. This can be done from within the object with a gyroscope, a ring laser or by detection of centrifugal forces. Is there a state of absolute non rotation?

I realize that you can tell if you are in a rotating frame in many different ways, ring lasers, gyroscope, dropping balls, etc. I find it interesting that as Mr Hafele & keating looked out the window of the aircraft going east the stars were going by at a greater rate that they were when they were going west and the clocks were going slower. Is it simply a coincidence?

So are we back at Mach's principle? The inertial frame requires that it is not rotating in relation to the stars.

In the experiment by Hafele & Keating to prove time dilation the frame of reference for the tests was assumed to be connected to the center of the Earth but I assume it was not rotating with the Earth. Why not assume it was connected and rotating with the Earth?

So the 'spin' represents the rest state angular momentum which is zero?

Ok the term spin used in quantum mechanics does not describe any rotation or angular momentum of the nucleus. The nucleus does however have mass. Do we know if it is spinning? (in the traditional Newtonian world)

One of Clark's laws: "For every expert, there is an equal and opposite expert,"[

Dear Dubbelosix and swansont, Thanks for your replies, You guys are obviously the experts. I am sorry but I have almost no knowledge in your field. Consider the question coming from and old fashioned “Natural Philosopher”. Let me pose the question in a different way with a little thought experiment: I have invented an inertial ray gun and I can aim it at things and control mass. I aim it at an old watch with a balance wheel and turn the inertial mass of the parts to one half - the watch goes twice as fast because the balance wheel loses mass and the spring stays the same. What happens if I do the same with an atomic clock? Will it speed up? Regards

Thanks for your quick answer, Does the kinetic energy of the nucleus then affect the hyperfine frequency and is it a component in the rate stability of atomic clocks ?

In the hyperfine structure of the nucleus the magnetic moment is tied to the spin and the spin is described as angular momentum. Does this indicate that there is inertial kinetic energy in the nucleus?