Further to my last post above. On the International Bureau of Weights and Measures' definition of a second, and the seeming agenda to foist a fait accompli on the value 299792458m/s as the speed of light in vacuum by using the adjective "exactly". In order for this conspiratorial plan to work there MUST BE a further qualification in the definition of the second by adding "at earth surface". This is because Pound and Rebka in their experiment, further corroborated by the Gravity Probe A have demonstrated that Caesium 133 atom will oscillate at a frequency higher than 9 192 631 770 Hz in the vacuum at higher altitude!
According to results from Gravity Probe A, at 10,000km, general relativity predicts that Caesium 133 will oscillate 4.5 parts in 10-10 faster than one on the Earth.
Indeed, given the General relativity equation
tu = td (1 - GM/rc2),
where the subscripts u and d stand for up and down respectively,
an atomic oscillation that takes 1 second on earth surface will take 0.9999999993 seconds in free space, far from gravity. And since frequency is the inverse of period, Caesium 133 will oscillate at 9 192 631 776 Hz in freer space, instead of 9 192 631 770 Hz. Light velocity in free space and not earth surface would be 299792458.2087m/s.
I therefore broadly agree with John Donoghue that once this hidden agenda is abandoned for good, "It would really change 99.9 per cent of physics research".
What next on the agenda to foist the value 299792458m/s on us, since the definition of a second is now shown here to be incomplete?
Akinbo