Background
Seth Barnes Nicholson was born on November 12, 1891 in Springfield, Illinois, United States. He was the son of William Franklin Nicholson, a school principal and farmer, and of Martha Ames.
Seth Barnes Nicholson was born on November 12, 1891 in Springfield, Illinois, United States. He was the son of William Franklin Nicholson, a school principal and farmer, and of Martha Ames.
Although encouraged to study science by his father, who had a master's degree in geology, he did not become intensely interested in astronomy until he entered Drake University in Des Moines, Iowa, in 1908. He studied astronomy with D. W. Morehouse, best known for his 1908 discovery of the exceptionally bright comet that bears his name. As an undergraduate Nicholson devoted his research time to comets and minor planets. In 1911 he and a fellow astronomy student, Alma Stotts, published a report of the computed orbit of the minor planet Ekard, discovered in 1909. Nicholson also was a physics instructor during his senior year. Nicholson graduated from Drake in 1912 and then was appointed a fellow in the graduate program in astronomy at the University of California at Berkeley. He received the Doctor of Philosophy in 1915.
Beginning in the fall of 1913, Nicholson was instructor in astronomy at Berkeley for two years.
In 1914, while serving as an assistant at the Lick Observatory, Nicholson was directed to observe the recently discovered eighth satellite of Jupiter. He took an unusually long exposure of Jupiter VIII to ensure a superior photographic plate, and discovered yet another Jovian satellite at approximately the same distance from the planet. Calculating the orbital characteristics of Jupiter IX provided Nicholson with his doctoral dissertation. In 1938 he again observed Jupiter (this time with the 100-inch Mt. Wilson telescope) in an attempt to reconfirm the discoveries of the nine known moons.
Nicholson joined the staff of the Mt. Wilson Observatory. Because this facility was devoted primarily to solar research during its early years, much of his work focused on the sun.
Working with George Ellery Hale and other solar astronomers, he conducted long-term studies of solar spectra and surface features, providing an excellent record of sunspots and other solar phenomena.
During the 1920's and 1930's Nicholson labored with Edison Pettit to adapt the vacuum thermocouple to measure temperatures of astronomical bodies. They used their new technique to establish the lower temperature of sunspots (compared with the solar surface), the low density of the Martian atmosphere, and the high surface temperature of Mercury. They also made extensive measurements of the rapid changes in the moon's surface temperatures during lunar eclipses, providing significant information about its surface and subsurface structure.
Although primarily a research scientist, Nicholson was active in the dissemination of astronomical knowledge. Between 1911 and 1963 he published 267 articles in scientific periodicals. He often lectured at the University of California during the summer and, after his retirement in 1957, served as western coordinator for the visiting professors program of the National Science Foundation and American Astronomical Association.
He was always in demand as a speaker because of his rare ability to present recent astronomical discoveries in a manner comprehensible to laymen. Although severely ill at the time, he listened to the award ceremonies via a special telephone link between the San Diego meeting and his hospital room in Los Angeles, where he died.
Nicholson married Alma Stotts on May 29, 1913. They had three children.