Ernst Mach
DOI: 10.1063/PT.5.030899
It’s the birthday of Ernst Mach, who was born in 1838 in Brno in what is now the Czech Republic. Mach studied physics and medicine at the University of Vienna. His early research combined both sciences: He investigated the perception of light and sound. Using a technique called schlieren (streak) photography, Mach imaged bullets in flight and discovered the shock waves they make as they travel through air. To physicists, Mach is also known for his principle of inertia, which hypothesizes that local inertial frames are determined by the large-scale distribution of matter. Although general relativity does not incorporate it, Mach’s principle did inspire Albert Einstein and others.
Date in History: 18 February 1838
