Marietta Blau, PhD, was an Austrian physicist who developed photographic emulsions that could be used to capture the tracks of speeding subatomic particles. This method could also be used to accurately study reactions caused by cosmic ray events. In 1937, working with her colleague Hertha Wambacher, Blau found the first hard evidence of the disintegration of the nuclei of a heavy atom by the impact of another particle. This discovery launched the field of particle physics. Blau was forced to leave Austria in 1938 due to the country’s annexation by Nazi Germany, causing a severe break in her career. She was nominated several times for the Nobel Prize in Physics, and once for the Nobel Prize in Chemistry, but never won. In 1950 the Nobel Prize in Physics was awarded to Cecil F. Powell, who had built on Blau’s work and perfected the photographic emulsion method, using it to discover pions in cosmic rays.

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