The German physicist Rudolf Heinrich Hertz (1857–1894) was a genius in both science and languages (he learned Arabic and Sanskrit as a youth). Aside from his work on electrodynamics, he conducted research on meteorology and contact mechanics (what happens to objects when they are put against one another).

In 1888 Hertz proved the existence of electromagnetic waves. Although visible light was known to be electromagnetic in origin, Hertz produced electromagnetic waves not visible to the human eye—radio waves—using a wire connected to an induction coil, then detecting them using a loop of wire and a spark gap. Hertz built upon Maxwell’s work, and in 1892 rewrote Maxwell’s equations of electrodynamics in the elegant, symmetric form that is most commonly used today. Hertz’s work is the scientific foundation of all wireless communications, and the unit of electromagnetic frequency, the hertz (Hz), is named in his honor.