Very cool! Small fast-spinning objects have practical use as 'spinning rotor pressure gauges'. They're the true pressure transfer standard at very high vacuum.

Very cool! Small fast-spinning objects have practical use as 'spinning rotor pressure gauges'. They're the true pressure transfer standard at very high vacuum. You can buy them. Beams et al. were spinning steel ball bearings at megahertz in the sixties. (For the fourier-inclined, the readout uses a cool trick. They bounce light off the bearing and track the frequency of the ~50th harmonic, increasing the size of the frequency shift.) 600 million RPM is 10 MHz. Beams reached at least 1 MHz, and their circuitry could do 8. http://rsi.aip.org/resource/1/rsinak/v33/i2/p151_s1 http://rsi.aip.org/resource/1/rsinak/v33/i2/p151_s1 Thank you, OP, it's been fifty years since this field has seen a change.