Intrinsic Action (Spin)

According to the best available measurements

[Dehmelt, Physica Scripta T22, 102 (1988)],

an upper limit to the radius of the electron is

10^-22 meters (it could be zero !).

If all its charge & mass were concentrated at this

distance, the outer surface must move at 10¹⁰ times

the speed-of-light to produce the measured values

for its angular momentum & magnetic moment !

Clearly this is an INTRINSIC and not a mechanical property.