World Quantum Day: Why April 14, and What Actually Happens
World Quantum Day falls on April 14 because 4.14 is the rounded value of Planck’s constant in electron-volt seconds — a physicists’ in-joke that became a 83-country outreach movement. Here is the verified origin story, the arithmetic behind the date, who actually organizes it, and how it differs from the UN’s International Year of Quantum.
