Edward Mills Purcell was an
AmericanThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
physicist who shared the 1952 Nobel Prize for Physics for his independent discovery (published 1946) of nuclear magnetic resonance in liquids and in solids.
Nuclear magnetic resonanceNuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
(NMR) has become widely used to study the
molecularA molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
structure of pure materials and the composition of mixtures. See also
Magnetic resonance imagingMagnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI)
Biography
Born and raised in
Taylorville, IllinoisTaylorville is a city in Christian County, Illinois, United States. The population was 11,246 at the 2010 census. It is the county seat and largest city in Christian County.-Geography:Taylorville is located at ....
, Purcell received his
BSEEThe Bachelor of Engineering is an undergraduate academic degree awarded to a student after three to five years of studying engineering at universities in Armenia, Australia, Bangladesh, Bulgaria, Canada, China, Denmark, Egypt, Finland , Germany, Hong Kong, India, Indonesia, Ireland, Jordan, Korea,...
in
electrical engineeringElectrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
from
Purdue UniversityPurdue University, located in West Lafayette, Indiana, U.S., is the flagship university of the six-campus Purdue University system. Purdue was founded on May 6, 1869, as a land-grant university when the Indiana General Assembly, taking advantage of the Morrill Act, accepted a donation of land and...
, followed by his M.A. and Ph.D. in physics from
Harvard UniversityHarvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
. He was a member of the Alpha Xi chapter of Phi Kappa Sigma while at Purdue. After spending the years of
World War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
working at the
MITThe Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
Radiation Laboratory on the development of microwave radar, Purcell returned to Harvard to do research. In December 1946, he discovered
nuclear magnetic resonanceNuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
(NMR) with his colleagues Pound and 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 imagingMagnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(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 BlochFelix Bloch was a Swiss physicist, working mainly in the U.S.-Life and work:Bloch was born in Zürich, Switzerland to Jewish parents Gustav and Agnes Bloch. He was educated there and at the Eidgenössische Technische Hochschule, also in Zürich. Initially studying engineering he soon changed to physics...
of
Stanford UniversityThe Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
.
Purcell also made contributions to
astronomyAstronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
as the first to detect radio emissions from neutral galactic hydrogen (the famous
21 cm lineThe hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation is at the precise frequency of 1420.40575177 MHz, which is equivalent to the vacuum...
due to hyperfine splitting), affording the first views of the spiral arms of the
Milky WayThe Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
. This observation helped launch the field of
radio astronomyRadio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
, and measurements of the 21 cm line are still an important technique in modern astronomy. He has also made other seminal contributions to
solid state physicsSolid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy. It is the largest branch of condensed matter physics. Solid-state physics studies how the large-scale properties of solid materials result from...
, 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. EisenhowerDwight David "Ike" Eisenhower was the 34th President of the United States, from 1953 until 1961. He was a five-star general in the United States Army...
,
John F. KennedyJohn Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....
, and
Lyndon B. JohnsonLyndon Baines Johnson , often referred to as LBJ, was the 36th President of the United States after his service as the 37th Vice President of the United States...
. He was president of the
American Physical SocietyThe American Physical Society is the world's second largest organization of physicists, behind the Deutsche Physikalische Gesellschaft. The Society publishes more than a dozen scientific journals, including the world renowned Physical Review and Physical Review Letters, and organizes more than 20...
, and a member of the
American Philosophical SocietyThe American Philosophical Society, founded in 1743, and located in Philadelphia, Pa., is an eminent scholarly organization of international reputation, that promotes useful knowledge in the sciences and humanities through excellence in scholarly research, professional meetings, publications,...
, the
National Academy of SciencesThe National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
, and the
American Academy of Arts and SciencesThe American Academy of Arts and Sciences is an independent policy research center that conducts multidisciplinary studies of complex and emerging problems. The Academy’s elected members are leaders in the academic disciplines, the arts, business, and public affairs.James Bowdoin, John Adams, and...
. He was awarded the
National Medal of ScienceThe National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social sciences, biology, chemistry, engineering, mathematics and...
in 1979. Purcell was also inducted into his Fraternity's (
Phi Kappa SigmaPhi Kappa Sigma is an international all-male college social fraternity. Its members are known as "Phi Kaps", "Skulls" and sometimes "Skullhouse", the latter two because of the skull and crossbones on the Fraternity's badge and coat of arms. Phi Kappa Sigma was founded by Dr. Samuel Brown Wylie...
) Hall of Fame as the first Phi Kap ever to receive a Nobel Prize.
Purcell is the author of
Electricity and Magnetism (1965) — originally
Volume 2 of the
Berkeley Physics CourseBerkeley Physics Course is a lecture course in physics of UC Berkeley professors, first published by Mcgraw-Hill College in 1965 .* Mechanics. Vol. 1 by Charles Kittel, Walter Knight, Malvin A. Ruderman, Authors, J. A. Lewis, Reviewer...
. (A 1984 second edition is meant to stand on its own.) This text is still one of the standard introductory electricity and magnetism textbooks in college physics. Purcell is also remembered by biologists for his famous lecture "Life at Low Reynolds Number", where he explained a principle referred to as the
Scallop theoremThe Scallop theorem states that to achieve propulsion at low Reynolds number in simple fluids , a swimmer must deform in a way that is not invariant under time-reversal....
.
External links