Keeping track on a compact disc is light work
Malcolm G Cornwall · Physics World · 1993
Imagine flying down the M1 at 3000 mph and at a height of 50ft, without deviating more than an inch or two in height and alignment from the central barrier. The equivalent of this, but on a scale ten thousand times smaller, is achieved routinely by the laser "stylus" in a domestic compact disc player. And that's just one of the feats of precision engineering and applied physics that make possible the recording and reproduction of almost perfect sound from a small glistening disc of aluminium-coated polycarbonate plastic.