Found by analysis of fission products of irradiated uranium fuel, its discovery is not made public until 1947.
Dorothy Hodgkin and C. H. (Harry) Carlisle publish the first three-dimensional molecular structure of a steroid, cholesteryl iodide.[2][3] In January, Hodgkin also discovers the structure of penicillin, not published until 1949.
November – Assembly of the world's first general purpose electronic computer, the Electronic Numerical Integrator Analyzer and Computer (ENIAC), is completed in the United States, covering 1,800 square feet (170 m2) of floor space, and the first set of calculations is run on it.
February – Raymond L. Libby of American Cyanamid's research laboratories at Stamford, Connecticut, announces a method of orally administering the antibiotic penicillin.[7]
August 12 – The Smyth Report is released by the United States government, informing the public of the basics of nuclear fission and its military and civilian applications, and emphasizing the role played by physics in the development of the atomic bomb.
Bachem Ba 349 Natter is launched from Stetten am kalten Markt. The Natter is the first manned rocket, developed as an anti-aircraft weapon. The launch fails and the pilot dies.[8]
publishes Uno y el Universo ("One and the Universe"), a collection of essays criticizing the apparent moral neutrality of science and warning of dehumanization in technological societies.
First book in the New Naturalist series is published in the United Kingdom, E. B. Ford's Butterflies.