author
Erwin Freundlich
1885–1964
A key early tester of Einstein’s ideas, this German astronomer helped turn general relativity from theory into something the sky itself could check. His career carried him from Berlin and Potsdam to Istanbul, Prague, and St Andrews, linking major chapters in 20th-century astronomy.
1 Audiobook
The foundations of Einstein's theory of gravitation
by Erwin Freundlich
About the author
Born in Biebrich am Rhein on May 29, 1885, Erwin Finlay-Freundlich was a German astronomer and astrophysicist whose work became closely tied to the rise of Einstein’s general theory of relativity. He studied at the University of Göttingen under Felix Klein, then joined the Berlin observatory world, where he became one of the scientists most committed to testing Einstein’s predictions through observation.
Freundlich is especially remembered for promoting astronomical tests of relativity, including work connected with gravitational redshift and eclipse observations. One famous 1914 eclipse expedition was disrupted when World War I began, but his broader effort helped establish astronomy as a proving ground for modern physics. He also played a major role in the creation of the Einstein Tower in Potsdam, built to support solar observations linked to these questions.
His later career took him across Europe: he worked in Istanbul and Prague before becoming John Napier Professor of Astronomy at the University of St Andrews, where he led the observatory and remained an important figure in astrophysics. He died in Wiesbaden on July 24, 1964.