June 6, 1930 – Einstein Made a Mathematical Mistake at Nottingham’s University College in Britain

On June 6, 1930, Albert Einstein visited Nottingham and presented a guest lecture at the university.

Albert Einstein in 1930

A blog devoted to the history of Nottingham University recounts that Einstein’s visit was arranged by Physics Professor Henry Brose. Einstein and Brose met in an internment camp during WWI. Professor Brose was an authority on the theory of relativity and had translated many of Einstein’s books and scientific papers into English. He invited Einstein in 1928 to lecture in Nottingham.

On this day in history, Einstein’s lecture began at 7 p.m. The lecture theater was packed to capacity when Einstein entered the room to expound his theories of relativity which would become the foundations of modern science.

It was recently pointed out, however, that the equations on the Oxford blackboard were taken directly from a key paper on relativistic cosmology written by Einstein in April 1931 and published in the Proceedings of the Royal Prussian Academy of Science on May 9 of that year. The paper is of historic significance because it constituted the first scientific publication in which Einstein embraced the possibility of a cosmos of time-varying radius. But it set the cosmological constant to zero, declaring it redundant, predicting a universe that expands and contracts over time. (The work is sometimes known as the Friedman-Einstein Model of the Universe).

Blackboard used by Albert Einstein at Nottingham June 6, 1930

However, the numerical estimates of cosmic parameters in Einstein’s 1931 paper – and on the blackboard – contained an error with respect to Einstein’s estimates of cosmic density. It appears that Einstein stumbled in converting megaparsecs to centimeters, giving a density of matter that was too high by a factor of a hundred, a cosmic radius that was too low by a factor of ten, and a timespan for the expansion that was too high by a factor of ten. These errors were corrected in a later review of relativistic cosmology written by Einstein in 1945.

A section of blackboard he used to show his calculations at Nottingham and even the chalk he used is preserved in the university’s archives. The blackboard is one of the most iconic objects in the collection of the Museum of the History of Science in Oxford.