Orest Khvolson

Orest Khvolson was a Russian physicist who made seminal contributions to radiative-transfer theory and, in 1924, described the ring image a distant star would form when its light bends around an intervening mass — the phenomenon later called gravitational lensing, or the 'Chwolson ring.' He also wrote a widely used physics textbook. His father, the orientalist Daniel Chwolson, was a Jewish-born convert, giving Orest documented Jewish paternal ancestry.