|Fig. 1: A plaque for Marietta Blau that translates to: "Marietta Blau graduated from this school in 1914. As a nuclear physicist she pioneered the development of the photographic method of particle detection. This technique led to the discovery of disintegration stars. Blau had to leave Austria in 1938." (Source: Wikimedia Commons)|
Marietta Blau was an Austrian physicist who was born on April 29, 1894 in Vienna to a Jewish family.  She had an interest in math and the sciences from a young age and even graduated high school in the top ranks of her class. In 1914, she started her studies at the University of Vienna in physics.  It is also important to note that universities in Austria only started admitting women in 1897, though by the time Blau entered college, female college students were no longer a novelty. 
At this period in time, Austria was enjoying a role as a center for radioactivity research.  After graduation, Blau worked as a researcher for an X-ray tubes manufacturer in Berlin for two years and then as an assistant at the Institute for Medical Physics at the University of Frankfurt, where she learned about the applications of photography to physics.
She moved back to Vienna in 1923 to care for her ill mother and joined the Institut für Radiumforschung, a prominent research institute on radioactivity.  Here, she developed the photographic emulsion technique for studying cosmic rays and measured about 10,000 proton tracks. In 1937, Blau and her partner Hertha Wambacher discovered disintegration stars, which are the tracks of massive nuclear disintegrations.  With this finding, they could determine the energies of incident neutrons, and they were awarded the Ignaz L. Lieben-Preis, which was Austria's most prestigious prize.
As a woman and being of Jewish descent in the early 1900s, Blau was denied a professional career. When Blau and Wambacher were writing the report on their discovery of disintegration stars, her Nazi peers at the Radium Institute asked her to sign Wambacher's name before hers.  When Germany annexed Austria in 1938, she was forced to leave to Norway and then to Mexico, and in 1944 she moved to America after Albert Einstein helped her find a position.
In 1950, Cecil Powell received the Nobel Prize for his discovery of pion in emulsions, and though his work was largely based on Blaus method, she did not receive any recognition and was therefore obscured for her contributions.  Even when Erwin Schrödinger nominated Blau and Wambacher for recognition, the Nobel physics committee dismissed his report, saying that Blau and Wambachers work were founded on someone else's idea. Sime calls the committee's report a hatchet job, intended to justify a decision already made. 
She became a professor at the University of Miami in 1955, where she founded the department for particle physics, and retired to Vienna in the 1960s when her health started to deteriorate. When she died from lung cancer early 1970, there were no obituaries for her in any scientific journal. It was as though she had been forgotten.
In recent years, there has been more research on her life and as a result more acknowledgements. The Instituto Politecnico Nacional in Mexico City organized a festival to commemorate Blau in 2005, and the University of Vienna named a new classroom after her that same year.  Plaques (Fig. 1) have also been installed to honor her. Though nothing can be done now to undo the discrimination she suffered, Marietta Blau's life and work is now starting to come to light, enabling people to recognize her sizeable contributions to physics.
© Regina Nguyen. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 R. L. Sime, "Marietta Blau: Pioneer of Photographic Nuclear Emulsions and Particle Physics," Phys. Perspect. 15, 3 (2013).
 R. Rosner, "The Life of Marietta Blau - Austrian Physicist and Pioneer of Particle Physics," Bridges, 14, (2007).