1 0 0 D O C . 5 7 C O M M E N T O N A N D E R S O N
Published in Astronomische Nachrichten 219 (1923): 19–20 (No. 5233).
Anderson 1923a, which is dated 29 March 1923 and was published on 17 April 1923. Wilhelm
Anderson (1880–1940) was a doctoral student in astronomy at the University of Dorpat (now Tartu)
in Estonia. In his paper he discusses light refraction in the solar atmosphere, on the assumption that
the solar corona is an electron gas. Taking the gas density to be inversely proportional to the distance
r from the solar center, he finds that the amount by which light is refracted is also inversely propor-
tional to r. The same dependence holds for gravitational light deflection.
Because the index of refraction of an electron gas is smaller than unity, in Anderson’s model
light would be refracted away from the Sun. See also Anderson’s reply (Anderson 1923b) and Ein-
stein’s response to it (Doc. 234).