Edward Mills Purcell was born on August 30, 1912, in
Taylorville, Illinois, the son of Edward A. Purcell and Mary Elizabeth Mills. Purcell received his
B.S. in Electrical Engineering from
Purdue University in 1933, followed by his
M.A. (1935) and his
Ph.D. (1938) in Physics from
Harvard University. He was a member of the Alpha Xi chapter of the
Phi Kappa Sigma fraternity while at Purdue. After spending the years of
World War II working at the
MIT Radiation Laboratory on the development of microwave radar, Purcell returned to Harvard to do research. In December 1945, he discovered
nuclear magnetic resonance (NMR) with his colleagues
Robert Pound and Henry Torrey. NMR provides scientists with an elegant and precise way of determining chemical structure and properties of materials, and is widely used in physics and chemistry. It also is the basis of
magnetic resonance imaging (MRI), one of the most important medical advances of the 20th century. For his discovery of NMR, Purcell shared the 1952 Nobel Prize in physics with
Felix Bloch of
Stanford University. Purcell also made contributions to
astronomy as the first to detect radio emissions from neutral galactic hydrogen (the famous
21 cm line due to
hyperfine splitting), affording the first views of the spiral arms of the
Milky Way. This observation helped launch the field of
radio astronomy, and measurements of the 21 cm line are still an important technique in modern astronomy. He has also made seminal contributions to
solid state physics, with studies of spin-echo relaxation, nuclear magnetic relaxation, and negative spin temperature (important in the development of the laser). With
Norman F. Ramsey, he was the first to question the
CP symmetry of particle physics. Purcell was the recipient of many awards for his scientific, educational, and civic work. He served as science advisor to Presidents
Dwight D. Eisenhower,
John F. Kennedy, and
Lyndon B. Johnson. He was president of the
American Physical Society, and a member of the
American Philosophical Society, the
National Academy of Sciences, and the
American Academy of Arts and Sciences. He was awarded the
National Medal of Science in 1979, and the
Jansky Lectureship before the
National Radio Astronomy Observatory. Purcell was also inducted into his Fraternity's (
Phi Kappa Sigma) Hall of Fame as the first Phi Kap ever to receive a Nobel Prize. Purcell was the author of the innovative introductory text
Electricity and Magnetism. The book, a
Sputnik-era project funded by an NSF grant, was influential for its
use of relativity in the presentation of the subject at this level. The 1965 edition, now freely available due to a condition of the federal grant, was originally published as a volume of the
Berkeley Physics Course. The book is also in print as a commercial third edition, as Purcell and Morin. Purcell is also remembered by biologists for his famous lecture "Life at Low
Reynolds Number", in which he explained forces and effects dominating in limiting flow regimes (often at the micro scale). He also emphasized the time-reversibility of low Reynolds number flows with a principle referred to as the
Scallop theorem. Purcell died on March 7, 1997, in
Cambridge, Massachusetts, aged 84. == Recognition ==