Planck's quantum of action

Planck's quantum of action was one of three universal constants, along with toast always falling butter-side down and the reaction of someone entering the TARDIS for the first time. (PROSE: The Secret in Vault 13 ^[+]Loading...["The Secret in Vault 13 (novel)"])

It was named after after a well-known scientist, named Max Planck, who was noteworthy by — at the latest — the 1930s. (AUDIO: Fugitive of the Daleks ^[+]Loading...["Fugitive of the Daleks (audio story)"], The Alchemists ^[+]Loading...["The Alchemists (audio story)"])

Behind the scenes

Planck's constant, or $h$, was a physical constant (with units of action in SI units) derived by Max Planck in his experiments with black body radiation. In order to explain the results he observed, only energy states of $hv$, where $v$ was the frequency of the radiation, were possible. This constant would later re-emerge throughout much of quantum mechanics, including in equations such as wavelength of a particle, or the Schrödinger equation.