The apparatus Heinrich Hertz used to investigate electromagnetic waves: (far left) a spool-shaped Rühmkorff spark coil as voltage source, (center) the air gap between two aligned spheres for the spark to traverse, (right) the wireless receiver of the signal generated by the jumping spark. Photograph after 1886, photographer unknown. KIT Archives 28010/I 3152 (reproduction of an original in Deutsches Museum, Munich).
Nowadays, life without a smart phone, portable computer, and countless other wireless communication devices is hardly conceivable anymore. Wireless telegraphy, radio, and television were already shaping the era during the twentieth century. Heinrich Hertz (1857–1894) had set the stage with his research in Karlsruhe into the nature of electromagnetic waves. In 1885, this young private lecturer accepted his first professorship at Karlsruhe Polytechnic, where he had the opportunity to conduct experiments. During Hertz’s tenure at Karlsruhe, student enrollment was exceptionally low, due to the economic crisis known as the Great Depression, which started in 1873 and persisted into the 1890s. In November 1886, Hertz artificially generated a spark not in a laboratory, but in the main building on Kaiserstraße in a lecture hall now named after him. He successfully detected the electromagnetic pulse emitted into the air a few meters away, creating a wireless transmission between a transmitter and receiver. Hertz focused solely on basic research and showed little interest in practical applications. It wasn’t until the mid-1890s that radio technology began to be used in communications by Hertz’s predecessors on the Karlsruhe chair, Ferdinand Braun and Guglielmo Marconi. Both received the Nobel Prize for their work in 1909. Hertz had already died of blood poisoning in 1894 at the age of 36. However, in 1930, the physical unit for oscillation frequency was named after him. Nearly every electrical device used in daily life now bears Hertz’s name with the indicated alternating current frequency “50 Hz” required for its operation. kn
That electricity and magnetism are interrelated was already known from observations in the mid-nineteenth century. Scientists were only debating about how. One key controversial issue was whether the effect occurred instantaneously, like a lever’s action regardless of distance, or whether it propagated as a wave at a finite velocity. James Clerk Maxwell formulated his fundamental equations of electromagnetism in 1864 but could not prove their validity. Heinrich Hertz had been studying electromagnetism already as Hermann von Helmholtz’s assistant at the University of Berlin. After two years in Kiel, at the age of 28, he saw an opportunity to pursue his favorite research focus at Karlsruhe Polytechnic as successor to Ferdinand Braun. Only there did he gain access to essential instruments — primarily from Braun’s laboratory — and a sufficiently spacious facility was made available to him that is now called the Hertz lecture hall. Using his refined and newly developed equipment (spark inductor, Hertzian dipole, etc.), he proved within just three years the existence of electromagnetic waves and elucidated numerous related phenomena, which his many acclaimed detailed publications document. Heinrich Hertz was undoubtedly brilliant; one might ask, however, whether such a career trajectory would have been possible in our current academic environment. Hertz completed his physics studies and doctorate in under three years and secured a professorship just five years later at Karlsruhe Polytechnic. He spent his four most productive years conducting hands-on laboratory research there in addition to his teaching load. One wonders if such an achievement would be feasible in an era of accreditation programs, reduced funding, and extensive bureaucracy. Had he not died in 1894, Hertz would certainly have received the Nobel Prize but that award only existed from 1901 on. If there is an even greater distinction for a scientist, then it is, becoming the namesake of a physical unit. In this sense Heinrich Hertz is certainly the most famous former member of Karlsruhe Polytechnic resp. KIT. Thomas Zwick