Caputh, near Berlin, 1 March 1931

Excitement at new observations by the Mount Wilson observatory, with implications for the age of the universe.

A trip to America has been very interesting, although tiring: 'The people at the Mount Wilson observatory are excellent. They have recently discovered that the spiral nebulas are almost equally distributed in space and show a powerful Doppler effect in proportion to their distance, which incidentally follows easily from the theory of relativity ... The snag is however that the expansion of matter suggests an origin in time going back 10¹⁰ or 10¹¹ years. Because any other explanation of the effect runs into great difficulties, the situation is very exciting'. Einstein is impressed by Besso's proposal for a toxicological institute, and suggests that he forward it, with Einstein's recommendation, to the Institut international de coopération intellectuelle in Paris.