Invited Talk - Plenary

Thursday, 14 September 2023, 09:00   (H 0104 / virtual plenum)

Karl Schwarzschild and Ejnar Hertzsprung in Potsdam: 1910-1916

Adriaan Raap

Respectively, on the 8th and the 9th of October of this year it will be 150 years ago that Ejnar Hertzsprung and Karl Schwarzschild were born in that order. Both astronomers would finally pave the way to astrophysics together.
In 1909 Karl Schwarzschild, being the director of the Gauss-Observatory and the youngest professor in astronomy at the University of Göttingen, recognized the talents of Ejnar Hertzsprung in measuring and classifying the spectra of stars. Therefore, he offered him at first an extra-ordinary professorship in Göttingen and then both moved to the Great Refractor of the Astrophysical Observatory of Potsdam in 1910.
This lecture will provide answers to such questions as to: where and when the first Hertzsprung-Russell diagram was published? Why, nonetheless, did they prefer the Telescope on Mt. Wilson in California? Why volunteered Schwarzschild in the German Army in August 1914? Why did he leave the Zeppelin-weather-station in Namur 1915? What were the secrets of the foot-artillery division of General von Schabel which he joined thereafter? Where wrote Schwarzschild his articles on the theory of relativity, on quantum mechanics and ballistics during the war? Where and when did the outbreak occur of his autoimmune disease leading to his early death? Why Ejnar Hertzsprung had to leave Potsdam in 1919?