1857-1894

German physicist who discovered the electro-magnetic radiation known as radio waves in 1888. Having studied with Hermann von Helmholtz, Hertz began experimenting with James Clerk Maxwell's theory of electromagnetic waves at Karlsruhe Polytechnic in Berlin (1885-1889). He verified the theory's prediction that a fourth type of radiant energy (other than visible light, infrared, and ultraviolet) could propagate in space between two objects. He discharged a spark, with its transport reflected by a second weaker spark at a distance, proving the progressive propagation in space of electromagnetic waves—radio waves called Hertzian waves. He went on to measure the length and velocity of electromagnetic waves and, by their characteristics of transverse form, vibration, reflection, refraction, and polarization, proved they were like light and heat energy-which proved that light was indeed an electromagnetic wave.