Full Idea
In the hydrogen atom the electron rotates some 10,000 billion times per second.
Gist of Idea
Electrons rotate in hyrogen atoms 10^13 times per second
Source
Peter Watson (Convergence [2016], 18 'Evolutionary')
Book Reference
Watson,Peter: 'Convergence' [Simon and Schuster 2016], p.439
A Reaction
That's an awful lot. Is it at the speed of light?