Henry Faul

Born in Prague on July 17, 1920, he moved to the United States as a teenager and studied geology at the Massachusetts Institute of Technology. During World War II, he worked with Enrico Fermi's team and later on the Manhattan Project in Chicago, Los Alamos, and Washington, D.C., experiences that connected his scientific training to some of the most consequential research of the century.

After the war, he built a career in geophysics and nuclear geology, using radioactive methods to study the age and history of rocks. He edited Nuclear Geology and published works including Nuclear Clocks, helping explain how radioactive decay could be used to measure geological time in a clear, accessible way.

In 1966 he became professor and chair of geology at the University of Pennsylvania, where he was remembered as an energetic leader and teacher. He died in Philadelphia on September 16, 1981. Readers may also know him from It Began with a Stone, a history of geology published after his death, which reflects his lasting interest in telling the broader story of how people came to understand the Earth.