“
From a mathematical perspective, every oscillation could be used to tell time. In the real world, only a few are good enough. Most are too noisy, or show different periods when external conditions are slightly varied. The Dow Jones Industrial Average shows oscillations, but you would not want to time an egg with them.
”
”
Daniel B. Forger (Biological Clocks, Rhythms, and Oscillations: The Theory of Biological Timekeeping)