Jacqueline Mitton - Vera Rubin: A Life

On January 6, 2020, the 235th Meeting of the American Astronomical Society (AAS) in Honolulu received the official announcement that the Vera C. Rubin Observatory Designation Act had become Public Law number 11697 in the United States. Never before had a national astronomical observatory been named to honor a woman. So why did Vera Rubin merit this notable distinction?

In December 1950, a young and inexperienced Vera Rubin had attended her first AAS meeting, in Haverford, Pennsylvania, to present some controversial conclusions from her masters thesis. Most of her audience on that occasion were highly critical of the work of the unknown twenty-two-year-old, who had not even started to study for a doctorate. Sixty-nine years later, however, at this 2020 meeting, Rubin is universally acknowledged as one of the most influential female astronomers of her generation, whose life is worthy of commemoration with an unprecedented accolade. After her death at the age of eighty-eight, on December 25, 2016, the Division on Dynamical Astronomy (DDA) of the AAS lost no time in naming its recently created Early Career Prize to honor Vera Rubin, a remarkable individual who contributed to a transformation in astrophysics and championed the status of women in science. The DDA described its decision as particularly fitting since she was not only an extraordinary scientist, but also well known for her kindness towards and encouragement of young scientists.

The official redesignation of what was formerly known as the Large Synoptic Survey Telescope (LSST) project, confirmed into law by the president of the United States on December 20, 2019, was an even more impressive tribute.

Rubin is remembered first and foremost for her pioneering, long-term studies of spiral galaxies. Her stunning and unexpected discoveries helped to convince astronomers that dark matter is a real entity and, further, that it exists in vast quantities. Rubin never claimed that she had discovered dark matter as a concept, although others have mistakenly attributed discovery to her. Cosmologist Fritz Zwicky, writing in 1933, is credited as the first person to suggest there could be such a thing, because known astrophysics could provide no explanation for his observations of how galaxies are moving within their clusters. However, few people paid attention to Zwicky at the time, and the idea lay more or less fallow for almost forty years. From the mid nineteen-sixties, Rubin and her colleague Kent Ford decided to investigate a different kind of motion: how the stars and gas clouds belonging to an individual galaxy revolve around the galaxys center. They had no intention of searching for dark matter but, to her surprise, Rubin found compelling evidence that galaxies are immersed in vast halos of it. In fact, it emerged that some ten times more of this mysterious invisible stuff exists than all the particles of ordinary matter in stars and gas clouds put together. Rubin was a meticulous observer and processed her data with the utmost attention to detail, so eventually the truth dawned. Even the most skeptical of critics could not deny the credibility of the observational results she and Ford published, and what these facts implied, especially in the face of developments in theoretical astrophysics and radio astronomy happening at about the same time.