Purcell, Edward Mills (1912–1997)

US physicist. He was awarded, with Felix Bloch, the Nobel Prize for Physics in 1952 for the development of the nuclear magnetic resonance (NMR) method of measuring the magnetism of atomic nuclei in solids and liquids. This method hinges on the fact that any magnetic nuclei will absorb radio-frequency radiation by a resonance effect when in a magnetic field. Measurement of the absorption provides information on the properties of the nuclei and their molecular environment. The technique is now used in chemistry as a powerful analytical tool. Purcell continued applying nuclear magnetic resonance to help develop the radio telescope.

In astronomy, Purcell was the first to detect the microwave emission from neutral hydrogen in interstellar space at the wavelength of 21 cm/8 in. This discovery made possible the mapping of a large part of our Galaxy and the calculation of the temperature and motion of gas in interstellar space.

Purcell graduated in electrical engineering from Purdue University in 1933 and gained his doctorate from Harvard in 1938, having also spent a year studying physics in Germany at the Technische Hochschule in Karlsruhe. He became a full professor of physics at Harvard University in 1949. During the war years, 1941–45, he worked on the development of radar at the Massachusetts Institute of Technology Radiation Laboratories. He was awarded the US National Medal of Science in 1979.