Vera Rubin
Vera Florence Cooper Rubin was an American astronomer who pioneered work on galaxy rotation rates. She uncovered the discrepancy between the predicted and observed angular motion of galaxies by studying galactic rotation curves, the first evidence for galaxy rotation problem, one key piece of evidence for dark matter. Measurements by other astronomers using 21 centimeter hydrogen line radio telescopes clinched the case.
Honored during her lifetime for her work, she received the Bruce Medal, the Gold Medal of the Royal Astronomical Society, and the National Medal of Science, among others. The Vera C. Rubin Observatory in Chile is named in her honor. Her legacy is described by The New York Times as "ushering in a Copernican-scale change" in cosmological theory. Prominent theoretical physicist Lisa Randall and others have argued that Rubin was neglected for the Nobel Prize.
Rubin spent her life advocating for women in science, and mentored aspiring female astronomers.
Early life and education
Vera Cooper was born on July 23, 1928, in Philadelphia, Pennsylvania. She was the younger of two sisters born to a Jewish family with roots in Eastern Europe. As recalled by Vera, her father Pesach Kobchefski was born in "Vilna, Latvia", and at the age of seven immigrated with his mother and three siblings to Gloversville, New York, reuniting with his father who had immigrated a year or two earlier. Pesach soon anglicized his name to Pete Cooper, and as an adult studied electrical engineering and worked at Bell Telephone. He married Rose Applebaum, a second generation American born to a mother who had immigrated from Bessarabia to Philadelphia. They met at Bell, where Rose worked until they married.In 1938 the family moved to Washington, D.C., where ten-year-old Vera developed an interest in astronomy while watching the stars from her window. "Even then I was more interested in the question than in the answer," she remembered. "I decided at an early age that we inhabit a very curious world." She built a crude telescope out of cardboard with her father, and began to observe and track meteors. She attended public school at the Coolidge Senior High School, graduating in 1944.
Ignoring advice she had received from a high school science teacher to avoid a scientific career and become an artist, the young aspiring astronomer chose instead to pursue her undergraduate education at Vassar College. Vassar, then an all-women's school, was famous for its association with the pioneering 19th century astronomer Maria Mitchell, discoverer of Comet 1847 VI and a professor at Vassar from the time of the founding of its observatory in 1865.
At Vassar College, Rubin was a member of the honors society Phi Beta Kappa. She earned her bachelor's degree in astronomy in 1948. Despite Vassar's historic reputation for groundbreaking science in the field, Rubin was the only graduate in astronomy that year.
Graduate studies
Rubin attempted to enroll in the astronomy program at Princeton, but was barred due to her gender. She was accepted to Harvard's program, but declined the offer on the basis that she was getting married, and her future husband, a graduate student in physics, was based at Cornell University.Cornell was not known during this period for the excellence of its astronomy department, composed as it was of only four members. It did, however, boast an excellent physics faculty, and much of the coursework for Rubin's degree was taught within this department. Noted physicist Philip Morrison and future Nobelists Hans Bethe and Richard Feynman worked with Rubin during this period.
At Cornell, she worked with astronomer Martha Carpenter on galactic dynamics and studied the motions of galaxies. From this work, Rubin made one of the first observations of deviations from Hubble flow. Though her conclusions – that there was an orbital motion of galaxies around a particular pole – were later disproven, the idea that galaxies were moving held true and sparked further research. Additionally, Rubin's research provided early evidence of the supergalactic plane.
This information and the data she compiled were controversial for their day. Against her advisors' hesitations, she gained permission to present at the annual meeting of American Astronomical Society. Not only was her material in a form that left it open to speculation that it was premature and incompletely supported, she had given birth to her first child three weeks previously and was not a member of the society. These circumstances did not go unnoticed. Her presentation to the AAS in December 1950 received front page headlines. The talk received – to Rubin's personal recollection – universally negative feedback and the paper was not published.
She completed her work at Cornell with the award of her 1951 master's degree.
Rubin studied next at Georgetown University, where she earned her Ph.D. in 1954, although much of her classwork was completed with Georgetownian Francis Heyden. Her dissertation, completed in 1954, concluded that galaxies clumped together, rather than being randomly distributed through the universe, a controversial idea not pursued by others for two decades.
Career
For the next decade, Rubin held various short-term academic positions in the greater DC area. She served for a year as an instructor of Mathematics and Physics at Montgomery College, Maryland. Then from 1955 to 1965 she worked at Georgetown University as a research associate astronomer, lecturer, and finally, assistant professor of astronomy.In the latter position, from 1963, Rubin began a year-long collaboration with Geoffrey and Margaret Burbidge, during which she made her first observations of the rotation of galaxies while using the McDonald Observatory's 82-inch telescope.
She joined the Carnegie Institution of Washington in 1965 as a staff member in the Department of Terrestrial Magnetism. There she met her long-time collaborator, instrument-maker Kent Ford.
During her work at the Carnegie Institution, Rubin applied to become the first female astronomer permitted to observe at the Palomar Observatory in 1965.
An initiating faculty member of the Vatican Observatory Summer School, Rubin continued this relationship through subsequent decades, providing dedication remarks for the opening of the VATT, the Vatican's telescope on Mount Graham.
Rubin retired from the Carnegie Institute in 2014 as Senior Fellow of Astronomy in the Department of Terrestrial Magnetism.
Research
At the Carnegie Institution, Rubin began work related to her controversial thesis regarding galaxy clusters in tandem with Kent Ford, making hundreds of observations using Ford's image-tube spectrograph. This image intensifier allowed resolving the spectra of astronomical objects that were previously too dim for spectral analysis. A decade of observations coalesced in the shared discovery of the Rubin-Ford effect, with publication first appearing in 1976.Rubin–Ford effect
The Rubin–Ford effect, an apparent anisotropy in the expansion of the Universe on the scale of 100 million light years, was discovered through studies of spiral galaxies, particularly the Andromeda Galaxy, chosen for its brightness and proximity to Earth. The idea of peculiar motion on this scale in the universe was a highly controversial proposition. It was dismissed by leading astronomers but ultimately shown to be valid. The effect is now known as large scale streaming.Galactic motion
Rubin and Kent also briefly studied quasars, which had been discovered in the early 1960s and were a popular topic of research. Wishing to avoid controversial areas of astronomy, including quasars and galactic motion, Rubin began to study the rotation and outer reaches of galaxies, an interest sparked by her collaboration with the Burbidges.Rotational curves
She investigated the rotation curves of spiral galaxies, again beginning with Andromeda, by looking at their outermost material. She observed flat rotation curves: the outermost components of the galaxy were moving as quickly as those close to the center. She further uncovered the discrepancy between the predicted angular motion of galaxies based on the visible light and the observed motion. Her research showed that spiral galaxies rotate quickly enough that they should fly apart, if the gravity of their constituent stars was all that was holding them together; because they stay intact, a large amount of unseen mass must be holding them together, a conundrum that became known as the galaxy rotation problem.Rubin's results came to be cited as evidence that spiral galaxies were surrounded by dark matter haloes.
Rubin's calculations showed that galaxies must contain at least five to ten times more mass than can be observed directly based on the light emitted by ordinary matter. Rubin's results were confirmed over subsequent decades, and became the first persuasive results supporting the theory of dark matter, initially proposed by Fritz Zwicky in the 1930s. This data was confirmed by radio astronomers, the discovery of the cosmic microwave background, and images of gravitational lensing. However, Rubin did not rule out alternative models to dark matter also inspired by her measurements. She and her research were discussed in the 1991 PBS series, The Astronomers.
Counter-rotation
Another area of interest for Rubin was the phenomenon of counter-rotation in galaxies. Her discovery that some gas and stars moved in the opposite direction to the rotation of the rest of the galaxy challenged the prevailing theory that all of the material in a galaxy moved in the same direction, and provided the first evidence for galaxy mergers and the process by which galaxies initially formed.Activism for women in astronomy
During her work at the Carnegie Institution, Rubin applied to observe at the Palomar Observatory in 1965, despite the fact that the building did not have facilities for women. Reluctantly granted access, she was informed "your time on the observatory is limited, because we don't have a women's bathroom," a common period ruse to avoid allowing women access to these stations. According to Carnegie president Eric Isaacs, Rubin "solved the problem pretty simply by cutting out a little paper skirt and taping it to the stick figure image of a man which was on the men's room door. And she turned around and said, 'now you have a ladies' room' and then she got to work."Throughout her graduate studies, Rubin encountered discouraging sexism; in one incident she was not allowed to meet with her advisor in his office, because women were not allowed in that area of Georgetown, a Catholic university. Motivated by her own battles to gain credibility in a field dominated by male astronomers, Rubin encouraged girls interested in investigating the universe to pursue their dreams. She was described by Sandra Faber and Neta Bahcall as one of the astronomers who paved the way for other women in the field, as a "guiding light" for those who wished to have families and careers in astronomy. Rebecca Oppenheimer also recalled Rubin's mentorship as important to her early career.
When Rubin was elected to the National Academy of Sciences in 1981, she became only the second woman astronomer in its ranks. She, alongside Burbidge, advocated for more women to be elected to the NAS, selected for review panels, and represented in academic searches. She said that despite her own election to the NAS, she continued to be dissatisfied with the low number of women who were elected each year, and she further said it was "the saddest part of life".
Throughout her life, Rubin faced discouraging comments on her choice of study but persevered, as she was supported by family and colleagues. In addition to encouraging women in astronomy, she was a force for greater recognition of women in the sciences and for scientific literacy.