Greenstein is remembered by his colleagues for his groundbreaking work on quasi-stellar objects, known as quasars, and White Dwarfs, which are remnants of destroyed stars. His advances provided evidence for the existence of black holes.
His love of astronomy also led him to determine many of the magnetic, nuclear and chemical properties of stars and galaxies.
Greenstein received his doctorate in 1937 from Harvard’s fledgling graduate astronomy department before receiving a grant to work at the University of Chicago. In 1948, Greenstein accepted a post at the California Institute of Technology (Caltech), where he helped to found its optical astronomy graduate program.
In the 1960s, at the apex of his career, Greenstein was a member of an advisory body that helped form the Harvard-Smithsonian Center for Astrophysics.
“It was very intoxicating and exciting to talk to Jesse because he was in touch with everything that was going on in astronomy,” said Robert P. Kirshner ’70, professor of astronomy and the assistant director of the Harvard-Smithsonian Center for Astrophysics. “He was a great, inspiring guy, and he was always very warm and encouraging.”
Greenstein was born in New York City in 1909. When he was eight-years-old, his grandfather gave him a brass telescope, which ignited his obsession with stars. As a child, he built his own astronomical equipment, including a spectroscope, an instrument used to examine wavelengths of light.
After attending the Horace Mann School for Boys, Greenstein entered Harvard at age 16. Following his graduation in 1929, Greenstein put astronomy on hold to work in his family’s real estate business, helping them through the early years of the Great Depression.
Greenstein returned to Harvard as a graduate student in 1934.
While at Harvard, Greenstein collaborated with former Harvard Astronomy Professor Fred L. Whipple on a paper that attempted to explain the origin of radio signals in outer space.
“He was a very fine astronomer,” said Whipple. “We were good friends when he was a graduate student.”
After receiving the National Research Council Fellowship grant in 1937, Greenstein started work at the University of Chicago’s Yerkes Laboratory. Two years later he joined the astrophysics department at the University of Chicago where, during World War II, he did research in optical design.
But it was during his years at Caltech that Greenstein made his most lasting contributions to the field of astronomy.
He founded the school’s graduate program in astronomy and spent more than 1,000 nights observing the skies from the Hale telescope at Caltech’s Palomar Observatory. He wrote, on average, eight and a half papers per year during his time at Caltech.
Along with his Caltech colleague Maartin Schmidt, Greenstein made significant strides in understanding quasars, the most distant stellar formations visible from the Earth.
While he pursued a number of aspects of astronomy, Greenstein devoted much time to his lifelong study of White Dwarfs.
“Jesse did more than anyone to establish the characteristics of these in the 1930s. He will most probably be remembered for that,” said Jonathan E. Grindlay, chair of Harvard’s astronomy department.
Grindlay, who credits Greenstein with opening new avenues in the field of astronomy, said that even after Greenstein left Harvard, he remained involved in Harvard’s astronomy department.
He served as a member of a visiting committee that came to lecture at Harvard during the 1960s and 1970s.
“He was very interested in what students were doing, very interactive with the department,” Grindlay said. “He was just a real inspiration.”
Kirshner, who teaches Science A-35, “Matter in the Universe,” first met Greenstein as an undergraduate astronomy concentrator during one of Greenstein’s visits to Harvard. Kirshner met up with Greenstein again during his own graduate studies at Caltech.
Kirshner said he remembers being impressed by Greenstein’s “tremendous presence.”
He was, according to Kirshner, a man who “treated you like you were the next best thing. He had a manner of treating you, a totally powerless pawn, as an equal, even though you weren’t.”
Even after his retirement in 1979, Greenstein continued to observe the stars, making his last trip to the Palomar Observatory in 1983, at the age of 85.