The Life and Times of Dr. Vera Cooper Rubin: Astronomy Pioneer

vera rubin
Dr. Vera Cooper Rubin in 1970, working on measuring galaxy rotation rates. Vera Rubin

 We've all heard of dark matter — that weird, "invisible" stuff that makes up about a quarter of the mass in the universe. Astronomers don't know what it is, exactly, but they have measured its effects on regular matter and on light as it passes through a dark matter "conglomeration". That we know about it at all is due largely to the efforts of a woman who dedicated much of her career to finding an answer to a puzzling question: why don't galaxies rotate the velocity we expect them to? That woman was Dr. Vera Cooper Rubin.

Early Life

Dr. Vera Cooper Rubin was born July 23, 1928, to Philip and Rose Appelbaum Cooper. She spent her early childhood in Philadelphia, PA and moved to Washington, D.C. when she was ten. As a child, she was inspired by astronomer Maria Mitchell and resolved to study astronomy as well. She came into the subject at a time when women just weren't expected to "do" astronomy. She did study it at Vassar College and then applied to attend Princeton to further her education. At the time, women were not allowed in the Princeton graduate program. (That changed in 1975 when women were admitted for the first time). That setback didn't stop her; she applied to and was accepted at Cornell University for her master's degree. She did her Ph.D. studies at Georgetown University, working on galaxy motions mentored by physicist George Gamow, and graduated in 1954. Her thesis suggested that galaxies clumped together in clusters. It was not a well-accepted idea at the time, but she was well ahead of her time. Today we know that clusters of galaxies most certainly do exist

Tracking the Motions of Galaxies Leads to Dark Matter

After finishing her graduate work, Dr. Rubin raised a family and continued to study the motions of galaxies. Sexism hindered some of her work, as did the "controversial" topic that she pursued: galaxy motions. She continued to fight some very obvious barriers to her work. For example, through much of her early career, she was kept from using the Palomar Observatory (one of the world's leading astronomy observing facilities) because of her gender. One of the arguments made to keep her out was that the observatory didn't have the right bathroom for women. Such a problem was easily solved, but it took time. And, the "lack of bathrooms" excuse was symbolic of a deeper prejudice against women in science.

Dr. Rubin forged ahead anyway and finally got permission to observe at Palomar in 1965, the first woman allowed to do so. She began working at the Carnegie Institution of Washington's Department of Terrestrial Magnetism, focusing on galactic and extragalactic dynamics. Those focus on the motions of galaxies both singularly and in clusters. In particular, Dr. Rubin studied the rotation rates of galaxies and the material in them.

She discovered a puzzling problem right away: that the predicted motion of galaxy rotation didn't always match the observed rotation. The problem is fairly simple to understand. Galaxies rotate fast enough that they would fly apart if the combined gravitational effect of all their stars was the only thing holding them together. So, why didn't they come apart?  Rubin and others decided that there was some kind of unseen mass in or around the galaxy helping to hold it together. 

The difference between the predicted and observed galaxy rotation rates was dubbed the "galaxy rotation problem". Based on the observations that Dr. Rubin and her colleague Kent Ford made (and they made hundreds of them), it turned out that galaxies have to have at least ten times as much "invisible" mass as they do visible mass in their stars and nebulae. Her calculations led to the development of a theory of something called "dark matter". It turns out that this dark matter has an affect on galaxy motions that can be measured. 

Dark Matter: An Idea Whose Time Finally Came

The idea of dark matter was not strictly Vera Rubin's invention. In 1933, Swiss astronomer Fritz Zwicky proposed the existence of something that affected galaxy motions. Just as some scientists scoffed at Dr. Rubin's early studies of galaxy dynamics, Zwicky's peers generally ignored his predictions and observations. When Dr. Rubin began her studies of galaxy rotation rates in the early 1970s, she knew she had to provide conclusive evidence for the rotation rate differences. That is why she went on to do so many observations. It was important to have conclusive data. Eventually, she found strong evidence for that "stuff" that Zwicky had suspected but never proved. Her extensive work over the following decades eventually led to the confirmation that dark matter exists.

An Honored Life

Dr. Vera Rubin spent much of her life working on the dark matter problem, but she was also well-known for her work to make astronomy more accessible to women. She worked tirelessly to bring more women into the sciences, and for recognition of their important work. In particular, she urged the National Academy of Sciences to elect more deserving women to membership. She mentored many women in the sciences and was an advocate of strong STEM education.

For her work, Rubin was awarded a number of prestigious honors and awards, including the Gold Medal of the Royal Astronomical Society (the previous female recipient was Caroline Herschel in 1828). Minor planet 5726 Rubin is named in her honor. Many feel that she deserved the Nobel Prize in Physics for her accomplishments, but the committee eventually snubbed her and her accomplishments. 

Personal Life

Dr. Rubin married Robert Rubin, also a scientist, in 1948. They had four children, all of whom eventually became scientists as well. Robert Rubin died in 2008. Vera Cooper Rubin stayed active in research until her death on December 25, 2016. 

In Memoriam

In the days after Dr. Rubin's death, many who knew her, or who worked with her or were mentored by her, made public comments that her work succeeded in illuminating a part of the universe. It is a piece of the cosmos that, until she made her observations and followed her hunches, was totally unknown. Today, astronomers continue to study dark matter in an effort to understand its distribution throughout the universe, as well as its makeup and the role it has played in the early universe. All thanks to the work of Dr. Vera Rubin.

Fast Facts about Vera Rubin

  • Born: July 23, 1928,
  • Died: December 25, 2016
  • Married: Robert Rubin in 1948; four children. 
  • Education: astrophysics Ph.D. Georgetown University
  • Famous for: measurements of galaxy rotation that led to the discovery and verification of dark matter. 
  • Member of the National Academy of Sciences, winner of multiple awards for her research, and recipient of honorary doctorates from Harvard, Yale, Smith College, and Grinnell College, as well as Princeton.