Marietta Blau (29.04.1894-1970) was an Austrian physicist and a member of the Vienna Academy of Sciences. She was born in Vienna. She graduated from the University of Vienna (1919). In 1924—38 she worked at the Institute for Radium Research (Vienna). In 1939 she emigrated to the USA, where in 1948-50 she worked at Columbia University, in 1950—55 at Brookhaven National Laboratory and in 1955—60 at the University of Miami. In 1960 she returned to Vienna.
Her research concerned radioactivity, cosmic-ray physics, nuclear physics and nuclear photographic emulsions. She was the first to observe proton tracks in an emulsion (1925). Independently of others she made the first emulsions for nuclear research (1932). She was the first to use photographic plates to study cosmic rays (1936). Together with H. Wambacher she was the first to observe the formation of “stars” in cosmic-ray tracks (1937).