Finlay Freundlich, Erwin

Born in Biebrich, now a suburb of Wiesbaden . Father - Friedrich Philip Ernst Freundlich, director of the factory, son of a German and a Jewish woman, mother - Scottish Ellen Elisabeth Finlayson ( ⁴⁾ . Erwin's brother, Herbert Max Finlay-Freundlich, became a famous chemist.

In 1910 he graduated from the University of Gottingen and defended his thesis there, his supervisor was Felix Klein . Further Freundlich worked as an assistant at the Berlin Observatory , during this period he became acquainted with the work of Albert Einstein on the new theory of gravitation (General Relativity, GR) and entered into correspondence with him. In letters and in personal meetings, they discussed the development and experimental testing of the Einstein theory of gravitation. Einstein wrote an article in 1911, where he substantiated the deviation of a ray of light in a gravitational field and urged astronomers to test this hypothesis. Finlay-Freindlich expressed concern that it would be difficult to separate the gravitational deviation of light from the refraction of the same ray in the solar atmosphere, and suggested using Jupiter instead of the Sun. Einstein rejected this idea, since, according to his calculations, for Jupiter the deviation would be 100 times smaller than for the Sun, and expressed concern that reliable measurement would become impossible ^[5] .

Subsequently, Finlay-Freindlich actively participated in the discussion of verification of this and other non-classical effects ( redshift and perihelion shift of Mercury ) in both Einstein and alternative theories of gravity ^[6] . In a letter to Sommerfeld (1916), Einstein wrote: “Freindlich was the only colleague who supported me in my aspirations in the field of general theory of relativity” ^[7] . In 1916, Finlay-Freindlich published the book "Fundamentals of Einstein's theory of gravitation", the preface to which was written by Einstein himself ^[8] .

In 1913, Finlay-Freindlich married Käte Hirschberg. The marriage remained childless, and after the death of the wife's sister, they took her children, Hans and Renata, to the upbringing.

In 1914, the scientist traveled to Russia to use the solar eclipse to test the Einstein theory of gravity, but the war prevented it. Freundlich as a citizen of an enemy country was interned and was soon exchanged for one of the captured Russian officers ^[6] .

After the war, Finlay-Freindlich took an active part in the construction of the solar observatory in Potsdam , nicknamed the “Einstein Tower” . After the observatory was commissioned, he was appointed director of the research institute attached to it. In 1926 and 1929, he organized and led an expedition to Sumatra to measure (at the time of the eclipse) the deflection of light rays in the gravitational field predicted by general relativity.

With the Nazis coming to power in Germany, Freundlich was forced to leave the country, since both his paternal grandmother and Kete's wife were Jewish. He spent several years at Istanbul University , where he also organized the construction of an observatory. Then, on the recommendation of Arthur Eddington, he received a professor of astronomy at St. Andrews University (Scotland).

Freundlich, together with Max Born , put forward the hypothesis of “aging of light” in 1953 to explain the cosmological redshift .

In 1959, Freundlich retired and returned to his native Wiesbaden, where he died five years later.

• Analytische Funktionen mit beliebig vorgeschriebenem, unendlich-blättrigem Existenzbereiche, Dissertation, Göttingen, 1910
• Über einen Versuch, die von A. Einstein vermutete Ablenkung des Lichtes in Gravitationsfeldern zu prüfen, Astronomische Nachrichten 193 (1913) 369
• Die Grundlagen der Einsteinschen Gravitationstheorie. Mit einem Vorwort von Albert Einstein, Berlin: Springer, 1916.
• Das Turmteleskop der Einstein-Stiftung, Berlin: Julius Springer, 1927
• (mit Harald v. Klüber und Albert von Brunn) Weitere Untersuchungen über die Bestimmung der Lichtablenkung im Schwerefeld der Sonne, Potsdam: [Astrophysik. Observatorium, Einstein-Inst.], 1933. (Annalen von der Bosscha-Sterrenwacht, Lembang (Java))
• Erwin Finlay-Freundlich, Max Born. Über die Rotverschiebung der Spektrallinien. Theoretische Bemerkungen zu Freundlichs Formel für die stellare Rotverschiebung. - Göttingen: Vandenhoeck & Ruprecht, 1953, S. 96-108 (Nachrichten der Akademie der Wissenschaften in Göttingen, Jg. 1953, Nr. 7)

• General Relativity Tests

• Vizgin V.P. Relativistic theory of gravitation. Origins and formation. 1900-1915 - M .: Nauka, 1981 .-- 352 p.
• Kolchinsky I.G., Korsun A.A., Rodriguez M.G. Freindlich (Finlay) Erwen // Astronomers. Biographical reference. - Kiev: Naukova Dumka, 1977 .-- S. 388. - 416 p.

• Potsdam, Einstein Tower.
• John J. O'Connor and Edmund F. Robertson . Finlay Freundlich, Erwin (English) - biography in the MacTutor archive.
• Hentschel, Klaus. The Einstein Tower An Intertexture of Dynamic Construction, Relativity Theory, and Astronomy , Stanford University Press, Stanford 1997 .
• Obituary . (eng.)
• Erwin Finlay-Freundlich . (German)