A stipend by the Austrian Association of University Women made it possible for her to do research also in Göttingen and Paris (1932/1933) at the Curie Institute.

For this work, Blau and her former student Hertha Wambacher received the Lieben Prize of the Austrian Academy of Sciences in 1937.

It was her greatest success when, also in 1937, she and Wambacher discovered "disintegration stars" in photographic plates that had been exposed to cosmic radiation at an altitude of 2,300 metres (≈7,500 feet) above sea level.

Because of her Jewish descent, Blau had to leave Austria in 1938 after the country's annexation by Nazi Germany, a fact which caused a severe break in her scientific career.

[7] Conditions in Mexico made research extremely difficult for her, and she seized an opportunity to move to the United States in 1944.

She headed a working group analyzing particle-track photographs from experiments at CERN and supervised a dissertation in this field.