How were the pingpong-sized balls of quartz polished (to a perfect sphere)?
These spheres we use, these gyroscope rotors about an inch and a quarter — about the size of a ping pong ball — they are nearly perfect. We believe they are the most perfectly round spheres ever manufactured. They are not completely perfect but they almost are. If you looked at the imperfections in those spheres and you blew it up to the scale of the Earth, the distance between the deepest ocean and the highest mountain would be only a few feet. So they’re very finely machined and polished, but we didn’t use lasers or anything exotic like that. We actually used kind of standard machining techniques, and the way we got the roundness and the flatness on that surface had to do with the polishing technique. We had to invent a special piece of equipment that uses a cam and a rotor type of system to manipulate this rotor, and then we had a special slurry, which is kind of a polishing compound we used to polish it, and we literally polished these things for weeks and for months to make them
