3-41. Karl Schwarzschild

Karl Schwarzschild (1873–1916) got an early start in astronomy and celestial mechanics in Frankfurt, thanks to his father’s acquaintance with the mathematician Paul Epstein. His first two papers on double star orbits were published when he was only sixteen years old. In 1891, Schwarzschild studied at the University of Strasbourg, and in 1893 moved to the University of Munich, where he defended a thesis on equilibrium figures of rotating fluid masses written under the direction of Hugo von Seeliger (Schwarzschild 1896, 1898).

From 1896 to 1899, Schwarzschild was an assistant at the Kuffner Observatory in Ottakring (near Vienna), where he worked on photometric techniques, a subject on which he presented his Habilitation in 1899 at the University of Munich, entitled “Beiträge zur photographischen Photometrie der Gestirne”.

In 1901 Schwarzschild was named associate professor of astronomy at the University of Göttingen, and director of the Göttingen Observatory. A year later, he was promoted to full professor. In Göttingen, Schwarzschild participated in research seminars with the leading lights of mathematics and theoretical physics, including his colleagues David Hilbert, Hermann Minkowski, Emil Wiechert, Karl Runge, Woldemar Voigt, and Felix Klein, and a number of brilliant doctoral students and Privatdozenten, including Max Born and Walter Ritz. In April, 1909, he attended Poincaré’s Wolfskehl lectures in Göttingen, but left later in the year to direct the Potsdam Observatory.

In 1913, Schwarzschild became a member of the German Academy of Science in Berlin. When war broke out, he volunteered, and was assigned to the Eastern Front, where he contracted a rare skin disease, from which he died in 1916.

Beginning with his dissertation, Schwarzschild engaged with Poincaré’s work in celestial mechanics on several occasions, and paid tribute to both its power, and opacity. The letter that we publish here is his response to Poincaré’s memoir on the stability of the pear-shaped figure (Poincaré 1902), that developed out of Poincaré’s exchange with George Howard Darwin.

Like Poincaré, Schwarzschild took a keen interest in Kapteyn’s announcement of his two-stream theory of star flows in the Milky Way (1906). He published an alternative, unitary model of the proper motion of stars, based on an ellipsoidal velocity distribution (Schwarzschild 1907).

Poincaré did not mention Schwarzschild’s theory in his Lessons on Cosmogonical Hypotheses (Poincaré 1911), which may have led Schwarzschild to deplore, in his book review, Poincaré’s preference for French authors. He also sharpened Poincaré’s critique of Arrhenius’ hypothesis of a cyclical universe, which ran counter to the second law of thermodynamics.

Schwarzschild expressed admiration for Poincaré’s critical approach. In his discussions of cosmogonical hypotheses, Schwarzschild wrote, Poincaré had not “destroyed these ideas by criticism, but laid bare their core and even represented many of them in a clearer way than their authors” (Schwarzschild 1913).

In virtue of his wide-ranging scientific contributions, Schwarzschild was compared to Poincaré by Eddington, who described him as a sort of “guerilla leader”, in that Schwarzschild’s “attacks fell where they were least expected” (Eddington 1917, 319). For a contemporary overview of Schwarzschild’s life and work by a close collaborator, see Hertzsprung (1917); see also the DSB (Dieke 1975), and Schwarzschild’s Collected Papers (Voigt 1992a, 1992b, 1992c).

Time-stamp: "28.01.2016 23:04"