Who coined the term astrophysics?
American astronomer George Ellery Hale (1868-1983) founded and directed two major U.S. observatories, oversaw the construction of the world's four largest telescopes (each surpassing its predecessor in size), and made some of the most significant astronomical discoveries of his time. While a student at the Massachusetts Institute of Technology (MIT), Hale was volunteering at the Harvard College Observatory when, in 1889, he invented the spectrohelioscope, a combined telescope and spectroscope. This instrument produces a colorful display of the sun's chemical components. For instance, hydrogen appears red and ionized calcium appears ultraviolet in a spectrohelioscope. He was the founder and director of Yerkes Observatory and Mount Wilson Observatory and was the driving force behind construction of telescopes at those observatories and construction of the Hale telescope at Palomar Observatory. Among other astronomical pursuits Hale conducted solar research; while exploring sunspots he discovered, in their spectra, that magnetic forces were at work. Before this, no indication had been found that magnetic fields exist anywhere other than on Earth. Under Hale's directorship, revolutionary scientific discoveries were commonplace on Mount Wilson. In addition to solving the mysteries of sunspots, Hale and the rest of the observatory staff determined the temperature and composition of numerous stars and advanced out knowledge of the structure of the universe.
In 1902 Hale joined the Carnegie Institution's Advisory Committee on Astronomy and lobbied heavily for his concept of a "new astronomy." This new astronomy involved a combination of traditional astronomy (such as describing a star's motion and brightness) with physics (studying the physical properties of a star, such as leaning how it moves, why it shines, and what it is made of). Hale named this new science "Astrophysics."