The Impact of World War I on Relativity: A Progress Report

Abstract: From an astronomical and relativistic point of view, the Great War began with the August, 1914 capture and imprisonment of the members of a German eclipse expedition that had gone to the Crimea to look, at the request of Einstein, for bending of starlight by the sun. And it ended in 1919 with the Eddington-inspired measurements of that light bending from Principe and Sobral and with the founding of the International Astronomical Union by scientists from "the countries at war with the Central Powers." In between came unprecedented, and in some ways unequaled, death and destruction. The scientists lost were mostly too young to have made an impact (Henry Moseley and Karl Schwarzschild are exceptions), but many of the best-known of the next generation had, if citizens of the belligerent countries, served on the battle lines, and most of the rest contributed in some other way. It may come as a surprise to find that both theoretical physics and observational astronomy of relevance to general relativity continued to take place and that there was a certain amount of communication of results, information, and even goods in both directions. The early post-war years saw something of a flowering of the subject, before the majority of physicists turned their attention to quantum mechanics and astronomers to stellar physics, though both had already been under consideration during the war. War-based bitterness between French and German scholars was surely part of the context in which Einstein and Henri Bergson faced off on 6 April 1922, in a debate on the nature of time, as part of an Einsteinian visit to Paris that had originally been planned for Fall, 1914.