Physicists have learned to translate the equations of gravity into the language of electricity. This trick, double copy, works like a dictionary: it replaces the complex geometry of curved spacetime with simple electrical rules. When the method was applied to the simplest black holes, a coincidence emerged: the formula linking their mass, size, and entropy (a measure of disorder) exactly mirrors Gauss's law — the rule by which a charge creates a field around itself. Two different phenomena are described by the same mathematical pattern.

The double copy turns Einstein's equations into Maxwell's equations. Back in the 1970s, Hawking proved that black holes radiate heat. Now, that heat can be 'heard' in the language of electricity.