Searching for the Ether: Leopold Courvoiser’s Attempts to Measure the Absolute Velocity of the Solar System
ROBERTO DE ANDRADE MARTINS Physics Department, State University of Paraiba (UEPB), Brazil roberto. andrade .martins@gmail .com
Leopold Courvoisier (1873-1955) was an observer at the Berlin / Babelsberg astronomical observatory from 1905 up to his retirement in 1938. Most of his work was traditional astrometrical observation resulting in the publication of several star catalogues. A relevant part of his publications was devoted, however, to another subject: the attempt to detect the motion of the solar system through the ether.
Most of Courvoiser's search for measurable effects of the ether was based upon two “principles”. According to him, (1) the angles of incidence and reflection of light could be different, relative to the proper reference system of the mirror, if it moved through the ether; and (2) the Lorentz contraction of the Earth due to its motion through the ether produced observable effects relative to the Earth’s reference system. Both “principles”, of course, violate the principle of relativity. Courvoisier presented theoretical arguments attempting to show that there should exist second order measurable effects. He searched for those effects using both astronomical observations and laboratory experiments and claimed that he had measured a velocity of the solar system of about 600 km/s. This paper presents a description and analysis of Courvoiser’s ether researches.
Leopold Courvoisier was bom on 24 January 1873 in Rihen near Basel (Switzerland).1 His father Ludwig Georg Courvoisier was a physician and was in charge of the surgery chair of the University of Basel. Leopold (or Leo, as he was usually called) passed away in the same city where he was bom, on 31 December 1955. However, most of his professional life was spent in Germany.
Courvoisier exhibited an interest for astronomy since he was 15 years old. In 1891 he began his university studies, first in Basel and later in
1 For biographical information, see Courvoisier's obituary: Nikolaus Benjamin Richter, “Leopold Courvoisier”, Astronomische Nachrichten, cclxxxiv (1957), 47-48.
Searching for the Ether
Strasbourg - at a time when this city belonged to Germany. In 1897 he completed his dissertation, on the absolute height of the pole as observed from Strasbourg (“Die absolute Polhöhe von Straßburg”). The next year he became an assistant observer at the Königstuhl astronomical observatory near Heidelberg, under Karl Wilhelm Valentiner. In 1900 he obtained his Doctor degree in Straßburg. From 1905 onward he worked at the Berlin / Babelsberg observatory as an astronomical observer, under the direction of Karl Hermann Struve. In 1913 the Berlin observatory moved to its new site, in Babelsberg,2 and one year later Courvoiser became its chief observer and professor. He worked at Babelsberg up to his retirement in 1938, when he was 65 years old. In 1943 he moved to his birthplace, where he kept making observations and publishing papers up to his death. Back to Switzerland, he was the editor of several of Leonhard Euler's astronomical works.
Courvoisier’s main astronomical contribution was a large series of routine astrometrical observations and the production of star catalogues. Volumes 5, 6 and 7 of Poggendorff s Biographisch-literarisches Handwörterbuch provide references of about 10 large works (astronomical catalogues) besides nearly 100 minor contributions by him.3 However, Courvoisier’s work was not restricted to common astrometrical observations. From his tedious measurements there soon came out evidences that he regarded as disproof of the theory of relativity.
Coursoisier did not accept the theory of relativity. He believed there was an ether, and attempted to measure the absolute velocity of the solar system relative to this medium. From 1921 to his death, Courvoisier published a series of over 30 papers where he described the theoretical basis of his search and the several experimental techniques he used in attempting to detect the motion of the Earth relative to the ether. Some of his measurements used astronomical observations; other measurements depended on other physical effects (gravitational, etc.). As a result of his observations he claimed that he had measured a velocity of the solar system of about 600 km/s in a direction close to 75° right ascension and +40° declination.
2 The history of the Berlin / Babelsberg observatory is described in Julius Dick, “The 250th anniversary of the Berlin observatory”, Popular astronomy, lix (1951), 524-35.
3 Paul Weinmeister (ed.). J. C. Poggendorff s biographisch-literarisches Handwörterbuch für Mathematik, Astronomie, Physik, Chemie und verwandte Wissenschaftgebiete (1904 bis 1922), vol. 5 (Leipzig, 1926); Hans Stobbe (ed.), J. C. Poggendorff 's biographisch-literarisches Handwörterbuch für Mathematik, Astronomie, Physik mit Geophysik, Chemie, Kristallographie und verwandte Wissenschaftgebiete (1923 bis 1931), vol. 6 (Leipzig, 1936-1938); Rudolph Zaunick and Hans Salie (eds.), J. C. Poggendorff biographisch-literarisches Handwörterbuch der exakten Wissenschaften (1932 bis 1953), vol. 7 (Berlin, 1956-1962).