Scientists Create 'Fastest Man-Made Spinning Object'

dryriver sends this news from the BBC: "A team of researchers claims to have created the world's fastest spinning man-made object. They were able to levitate and spin a microscopic sphere at speeds of up to 600 million revolutions per minute. This spin speed is half a million times faster than a domestic washing machine and more than a thousand times faster than a dental drill. The work by the University of St Andrews scientists is published in Nature Communications. Although there is much international research exploring what happens at the boundary between classical physics and quantum physics, most of this experimental work uses atoms or molecules. To do this they manufactured a microscopic sphere of calcium carbonate only four millionths of a meter in diameter. The team then used the minuscule forces of laser light to hold the sphere with the radiation pressure of light — rather like levitating a beach ball with a jet of water. They exploited the property of polarization of the laser light that changed as the light passed through the levitating sphere, exerting a small twist or torque. Placing the sphere in vacuum largely removed the drag due to any gas environment, allowing the team to achieve the very high rotation rates. In addition to the rotation, the team observed a 'compression' of the excursions or 'wobble' of the particle in all three dimensions, which can be understood as a 'cooling' of the motion. Essentially the particle behaved like the world's smallest gyroscope, stabilizing its motion around the axis of rotation."

Re: Dental drill, 600k RPM?

[Anonymous Coward]

600,000 RPM is 10,000 revs/s. Depending on the nature of the whine, the bulk of the energy may be at harmonics, but given anything short of absolute perfect balance and symmetry, there will definitely be some at the fundamental. Most people have no problem hearing 10 kHz, and many young people will pick up the first harmonic at 20KHz.