Beyond Dark Matter: The extraordinary life of Vera Rubin

At the close of 2016, while America marked the passing of actresses Carrie Fisher and Debbie Reynolds, astrophysicists and astronomers remembered and honored another woman: Dr. Vera Rubin, an astronomer who drastically changed her field for the foreseeable future. Her meticulous observations and innovative thinking led to new theories about the universe’s makeup. Scientists at Yale and all over the world are still working on those theories today.

Rubin’s most significant work involved her observation of the behavior of spiral galaxies during the 1960s and early 70s. Her initial data surprised her because it indicated that stars on the edges of those galaxies were spinning much faster than she expected. Her expectations were based on Newtonian laws of gravitation, which allow physicists to approximate orbital motion based on the objects’ observable masses.

Reina Maruyama, a dark matter researcher at Yale’s Wright Lab, has praised Rubin for the unusual rigor of her investigations. After observing something unexpected, Rubin continued her methodical data collection to confirm her observations rather than jumping to early conclusions. She confirmed that her initial results were accurate; these findings in turn gave weight to a hitherto-ignored theory developed by a Swiss astrophysicist in the early 1930s involving the existence of some shadowy, mysterious “dark matter.” The matter is “dark” because, unlike all previously identified matter, it does not emit or interact with electromagnetic radiation such as visible light. The existence of dark matter would help explain Rubin’s unexpected results, since extra matter would make the galaxy spin faster.

Although mainstream media hails her as the astrophysicist who “confirmed the existence of dark matter,” other sources point out that Rubin herself was not so certain about dark matter’s existence. Steve Lamoreaux, a colleague of Maruyama’s at the Yale Wright Lab, notes that “Rubin wasn’t necessarily a proponent of dark matter.” In a relatively recent article from New Scientist, Rubin remarked, “If I could have my pick, I would like to learn that Newton’s laws must be modified in order to correctly describe gravitational interactions at large distances. That’s more appealing than a universe filled with a new kind of sub-nuclear particle.”

Both Lamoreaux and Maruyama describe Rubin as “thoughtful” and “independently minded,” and they acknowledge that her caution sets a good scientific example. “We are still at the stage where open minds are needed, until the preponderance of evidence together with cross checks of different phenomena provide a solid and irrefutable case for dark matter” Lamoreaux said.

Many astrophysicists initially criticized Rubin for her radical claims, but most eventually came to realize the value and groundbreaking implications of her data and analyses. This recognition led to Rubin’s election as only the third female astronomer member of the National Academy of Sciences. She also received the National Medal of Science, America’s most prestigious scientific award.

Rubin faced many challenges caused by prejudice against women in science, particularly in astrophysics. Discrimination came in many forms, both overt and subtle. When Rubin was a young girl, many adults steered her away from science and scoffed at her dreams of becoming an astronomer. Education was often a lonely pursuit for her; she was the only astronomer in her class at Vassar College. Princeton’s astrophysics graduate program, which Rubin had hoped to attend, refused to admit women, so she earned a master’s degree from Cornell and a Ph.D. from Georgetown while raising her children. She continued to face opposition after raising her children. She faced frequent ridicule from older male scientists, and she had to fight for important resources like observation privileges at Caltech’s Palomar Observatory. She was the first woman to be allowed such privileges. Reflecting on being a working mother as well as a pioneering astronomer, she concluded, “Having a family and a career was very hard, but it’s do-able.” All four of her children eventually went on to earn doctorate degrees themselves.

Rubin’s legacy also includes her efforts to bridge the gap between scientists and the public. At a commencement address in 1996, she said, “We need senators who have studied physics and representatives who understand ecology.” In order to facilitate efforts at improved science literacy, she encouraged her fellow scientists to practice communicating in ways that people outside their isolated scientific communities could understand. In 1997, she published a collection of essays entitled Bright Galaxies, Dark Matters. While some material in the book contains more math than the average person wants to read, the majority of the book conveys fascinating facts in an engaging and accessible manner.

Rubin was not only an advocate for increased science literacy and improved communication, but also a vocal champion of women in science. Her advocacy and strong sense of the value of diversity and equality stemmed from her own experiences. She once wrote that “We all need permission to do science, but, for reasons that are deeply ingrained in history, this permission is more often given to men than to women.” Today, the difficulties Rubin faced have morphed into other types of challenges. “We all have stories,” says Maruyama, “but women like Rubin have really opened the path for the rest of us.”

Image courtesy of Wikimedia Commons