Vera Rubin, an astronomer whose groundbreaking work on galaxy rotations helped find evidence of dark matter, has died at age 88. Throughout her career, Rubin fiercely advocated for women's equality in the sciences.
The trailblazing American astronomer Vera Rubin passed away at the age of 88, her son said on Monday.
Allan Rubin, a professor of geosciences at Princeton University, told the Associated Press that his mother died on Christmas night of natural causes.
While researching the rotations of spiral galaxies in the 1970s, Rubin found that stars at the edges of the galaxies moved faster than expected.
According to prior predictions, stars located in the outer realms of galaxies should have flown apart due to a lack of dust, stars and gas at the edges. Rubin's research lent support to the theory that an invisible mass or another force must be keeping the galaxy together - namely, dark matter.
Dark matter - which has yet to be directly observed - comprises 27 percent of the universe while only 5 percent of the universe contains normal matter.
"In a spiral galaxy, the ratio of dark-to-light matter is about a factor of ten. That's probably a good number for the ratio of our ignorance-to-knowledge. We're out of kindergarten, but only in about third grade," Rubin once said.
Over the course of her career, Rubin examined over 200 galaxies.
The Carnegie Institute, the non-profit scientific research center where Rubin worked, tweeted that they were "saddened" by her death, adding that she "changed science and scientists with her life and discoveries."
"Vera Rubin was a national treasure as an accomplished astronomer and a wonderful role model for young scientists," said Matthew Scott, president of the Carnegie Institution.
A life with the stars
Born in Philadelphia in 1928, Rubin showed an interest in astronomy from a young age - saying in interviews that she used to watch the stars' rotations from her childhood bed. Her father was an electrical engineer who helped her build a telescope and took her to amateur astronomer meetings.
Rubin graduated from Vassar College in 1948 as the only astronomy major. Following graduation, she tried to enroll in Princeton only to find out that women were entirely barred from the graduate astronomy program.
She went on to earn a master's degree from Cornell University and her doctorate from Georgetown University. She later worked as a faculty member there before working at the Carnegie Institute in Washington D.C.
Rubin's scientific achievements earned her several awards and honors although she never received a Nobel Prize in Physics, despite numerous calls for her Nobel recognition from fellow astronomers.
In 1993, US President Bill Clinton presented her with the national Medal of Science "for her pioneering research programs in observational cosmology."
She also became the second woman astronomer to be elected to the National Academy of Sciences.
Supporting women in science
Due to the struggles she faced as a woman in becoming an astronomer, Rubin actively sought to promote equality for women in STEM (Science, technology, engineering and mathematics) fields.
"It is well known that I am available twenty-four hours a day to women astronomers," Rubin said.
She advocated for more women to be included in the National Academy of Sciences, on review panels and in academic searches. Despite small successes, said she was dissatisfied with the number of women elected each year.
Several female astronomers took to social media to pay tribute to the woman who they say helped inspire them to enter the field.
Dr. Chanda Prescod-Weinstein tweeted that Rubin "treated her like a scientist" and "no one had ever asked what I thought before."
Dr. Lindy Elkins-Tanton, a planetary scientist and the head of the Arizona State University School of Earth and Space Exploration, said it was a "privilege" to work with Rubin.
During a 1989 interview with the American Institute of Physics, Rubin said the problem of women entering the sciences lies "in the way we raise little girls."
"Rather than teaching little girls physics, you have to teach them that they can learn anything they want to," Rubin said.