Eugene N. Parker was born in Houghton, Michigan, in 1927. After receiving a B.S. degree from Michigan State College in 1948 and a Ph.D. from the California Institute of Technology in 1951, he held various positions at the University of Utah from 1951 to 1955. In 1955, he joined the University of Chicago, where John Simpson and others were beginning to challenge the then-prevalent concept of interplanetary space being largely empty, traversed by a few fast-moving particles. With only a few in situ observations in the immediate neighborhood of the Earth, theorists had to rely on a variety of ambiguous observable geophysical and astronomical phenomena.
In 1958, Parker published his theory of the solar wind, in which the solar corona expands supersonically to the outer reaches of the solar system, now the foundation of modern solar-terrestrial research and solar-planetary relationships. Prior to Parker’s work, the existence of a continuous, but slight, flow of particles from the Sun was suggested by a variety of circumstantial evidence. The idea of such a vigorous, dense, and dynamically complex outflow was so radical for its time that it drew criticism and disbelief from most of the scientific community. In 1960, Soviet scientists reported suggestive observations by Lunik 2; in 1961, Explorer 10 data provided convincing confirmation, followed by Mariner 2 observations in 1962 between the orbits of Earth and Venus. Studying the detailed structure and dynamics of the solar wind animated much of the scientific exploration of the inner solar system during the 1960s, and the concept, extended to other stars, became one of the most important foundations of modern astrophysics.
Not just because of his theoretical work but also because of his active participation in advisory committees and his organizational work within the American Geophysical Union, Parker has been one of the most influential architects of the exploration of interplanetary space during the past four decades. His AGU awards include the John Adam Fleming Medal in 1968 and the William Bowie Medal in 1990. He was elected to the National Academy of Sciences in 1967 and in 1989 received the National Medal of Science. The astronomical community also recognized his contributions with the Henry Norris Russell lectureship and the George Ellery Hale Award (American Astronomical Society) and the Sydney Chapman Medal of the Royal Astronomical Society.
—Joseph N. Tatarewicz
University of Maryland Baltimore County