ALBERT EINSTEIN - TYPED LETTER SIGNED 04/23/1932 - HFSID 350540

ALBERT EINSTEIN
Einstein Reviews the Controversy of the Universe. Extraordinary letter with amazing content!

Typed Letter Signed: "A. Einstein". 8¼ x 9½. One page, on personal letterhead. Dated April 25, 1932. Sent to Dr. Ludwig Silberstein. Minor tears at vertical and horizontal folds which do not touch typeface. Surface stains at lower-left edge. Otherwise, fine condition. Includes unsigned photograph and 3 presentation plaques, one of which included an additional translation of the letter. Framed by the Gallery of History to an overall size of 41x25.

Translated from German into English, in full:

Dear Mr. Silberstein!

Naturally I think back to our personal acquaintance. -On the cosmological problem and the term Λ the following remarks:

1.) From the point of view of my latest results in general relativity, the introduction of the Λ term is far more natural than it originally was. This emerges from a work that is right now being printed at the Academy.

2.) In Pasadena this winter I changed my position on the cosmological problem. It turns out that one can do justice to the hitherto known facts without using a Λ term and without introducing a curvature of space. This is briefly laid out in a memo I published together with [Willem de] Sitter at the National Academy in Washington. Because there is a relation between the expansion and the mean density, that corresponds to the order of magnitude estimated by astronomers, we are for the time being unable, from the point of view of experience, to say anything at all about the curvature of space. This only seemed possible as long as one began with the hypothesis supposing the mean density of matter to be constant over time.

With kind regards,
Yours A. Einstein


Albert Einstein (1879-1955) wrote this letter to Dr. Ludwig Silberstein in April of 1952. In this letter, Einstein alludes to the paper he co-authored with Dutch astronomer William de Sitter that year which treats the universe as it exists, not in curved space, but in Euclidean space. Nine months after this letter was written, Hitler came to power in Germany (January 1933) and ten months after that Einstein made the United States his permanent home (October 1933).

Shortly before this letter was written, Einstein had concluded a visit to the United States. The main purpose of his trip was to converse with Edwin Hubble and Milton Humason at the Mount Wilson Observatory near Pasadena California. Their observations spawned questions from foremost theoreticians and astrophysicists as to the validity of Einstein's formula for a stable universe. Faced with this controversy, Einstein sought to compare these new observations with his 1917 view of the universe with which he had virtually founded modern cosmology.

In 1917, Einstein had defined his theoretical view of the actual universe - referred to as "cosmological constant" - which was based on his General Theory. It stated that "...the universe may be regarded as a closed continuum as far as distance measurements are concerned." That same year, de Sitter used his mathematical projections and Einstein's General Theory to provide his view of the universe. "De Sitter's world", however, showed the universe as continually expanding. Einstein and de Sitter's 1932 paper addressed the studies done at the Observatory and revisited the ideas of the universe.

Dr. Ludwig Silberstein (1872-1948), a mathematical physicist from Berlin, published in English, a textbook on Relativity (1914) which he revised in 1924 to include Einstein's General Theory of Relativity. The two met in the early 1920s, shortly after Silberstein's immigration, while Einstein was visiting the United States. Silberstein worked for Eastman Kodak and later taught in Toronto, Canada: Ithaca New York: and Chicago Illinois.