Alumni: John A. O'Keefe, 1941
Ph.D., University of Chicago, 1941

October 13, 1916 - September 8, 2000


John Aloysius O'Keefe was an expert in planetary science and astrogeology with the National Aeronautics and Space Administration (NASA) from 1958 to 1995. He and his co-authors, Ann Eckels and Ken Squires, are credited with the discovery that the Earth had a significant third degree spherical harmonic in its gravitational field using U.S. Vanguard satellite data collected in the late 1950s. The "pear shaped" Earth as it was known became front-page news and was even the subject of a "Peanuts" cartoon. He was the first to propose the idea of a scanning microscope in 1956 and he is the co-discoverer of the YORP effect (short for Yarkovsky-O'Keefe-Radzievskii-Paddock effect), an effect resulting from sunlight which causes a small celestial body such as an asteroid or meteor to spin up or down.