Eugene Newman Parker (June 10, 1927 – March 15, 2022) was an American solar and plasma physicist. In the 1950s he proposed the existence of the solar wind and that the magnetic field in the outer Solar System would be in the shape of a Parker spiral, predictions that were later confirmed by spacecraft measurements. In 1987, Parker proposed the existence of nanoflares, a leading candidate to explain the coronal heating problem. Parker obtained his PhD from Caltech and spent four years as a postdoctoral researcher at the University of Utah. He joined University of Chicago in 1955 and spent the rest of his career there, holding positions in the physics department, the astronomy and astrophysics department, and the Enrico Fermi Institute. Parker was elected to the National Academy of Sciences in 1967. In 2017, NASA named its Parker Solar Probe in his honor, the first NASA spacecraft named after a living person. Biography Parker was born in Houghton, Michigan to Glenn and Helen (MacNair) Parker on June 10, 1927. He received his Bachelor of Science degree in physics from Michigan State University in 1948 and a Doctor of Philosophy from Caltech in 1951. Parker spent four years at the University of Utah before joining the University of Chicago in 1955, where he spent the rest of his career. He held positions in Chicago's physics department, astronomy and astrophysics department, and the Enrico Fermi Institute. Parker was elected to the National Academy of Sciences in 1967. Hypotheses In the mid-1950s, Parker developed the theory of the supersonic solar wind and predicted the Parker spiral shape of the solar magnetic field in the outer Solar System. His theoretical modeling was not immediately accepted by the astronomical community: when he submitted the results to The Astrophysical Journal, two reviewers recommended its rejection. The editor of the journal, Subrahmanyan Chandrasekhar, overruled the reviewers and published the paper anyway. Parker's theoretical predictions were confirmed by satellite observations a few years later, especially the 1962 Mariner 2 mission. Parker's work increased understanding of the solar corona, the solar wind, the magnetic fields of both the Earth and the Sun, and their complex electromagnetic interactions. He published several textbooks, including Cosmical Magnetic Fields in 1979, and one on magnetic fields in X-ray astronomy in 1994. Seeking to address the coronal heating problem, in 1987 Parker proposed that the solar corona might be heated by myriad tiny