Charles F. Ehret
Charles Frederick Ehret (March 9, 1923 – February 24, 2007) was an American molecular biologist and World War II veteran who worked for 40 years at Argonne National Laboratory in Lemont, Illinois. He studied how electromagnetic radiation affects bacteria like bacillus megaterium with Edward Powers and explored how time shifts influence paramecia, rats, and humans.
Ehret earned degrees from the City College of New York and the University of Notre Dame. He coined the term circadian dyschronism and helped popularize the word zeitgeber (time giver) in the 1980s on morning TV programs. He contributed to jet lag guidance, including the Jet Lag Diet and The Cure for Jet Lag with Lynne W. Scanlon.
Ehret also built what was once described as the world’s largest spectrograph—a 100-foot rainbow used to study color. He served in the Army’s 87th Infantry Division during World War II, earning the Purple Heart and Bronze Star. He died at his home in Grayslake, Illinois.
This page was last edited on 2 February 2026, at 08:06 (CET).