Heroes of Space: Vera Rubin
Rubin became the first person to provide evidence for the existence of dark matter
Rubin, who is most famous for her inferring the existence of dark matter, is seen here measuring spectra
Vera Rubin was born in Philadelphia, United States in 1928. Her father worked as an electrical engineer, her mother for the Bell Telephone Company and her sister pursued a career as an administrative judge. Rubin was different, however, and was always fascinated by physics and astronomy.
After earning her undergraduate degree at Vassar College, Rubin attempted to enroll at Princeton University where she hoped to continue her dreams of becoming an astronomer. But despite her obvious talent, she was told that “Princeton does not accept women”. This extremely unfair policy was not lifted until 1975.
Rubin wasn’t put off and applied to Cornell University where she was accepted onto a Master’s degree. She studied under highly respected physicists Philip Morrison, Richard Feynman and Hans Bethe. During this time, and unknown to her, she would make one of the first observations of the motions of galaxies. At the time it was suggested that galaxies moved outwards in accordance with the Big Bang theory, but Rubin figured that these structures swirled around some unknown centre. Unfortunately, her suggestion was not well received by the scientific community. Undeterred, she went on to earn her PhD in 1954 from Georgetown University in Washington DC. Her advisor was George Gamow, a theoretical physicist and cosmologist who was an early supporter of the Big Bang theory. Under his supervision, the young Rubin concluded that galaxies were clumped together in clusters, rather than randomly distributed throughout the universe. The idea of galaxy clusters was ludicrous according to the majority of scientists and it wasn’t for another two decades that they would be persuaded otherwise.
In 1965, she successfully became the first woman to be granted permission to use the instruments at Palomar Observatory, California. In the same year, Rubin successfully secured a position at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, where she began work on galaxy clusters – what she found was even more extraordinary than her previous work and would have consequences for our understanding of today’s cosmos. When Rubin observed her galaxies, she found that their rotation curves didn’t match up to theory. What could the explanation be?
Dark matter cannot be seen directly with telescopes
Little did she know, she had found the first indicator for dark matter, an elusive material believed to make up around 25 per cent of the “missing” mass of the universe. Rubin knew that her new findings would be criticised and so, in a bid to avoid it, she decided to slant her research more towards the study of the rotation curves of singular galaxies, rather than the wildly debated galaxy clusters. She began her research with our closest spiral, the Andromeda galaxy.
Luckily, her theory was greeted with open minds as well as prestigious awards. Rubin believed that since galaxies are rotating so fast, the gravity that holds the stars together alone wouldn’t be enough to stop the structure from flying apart. There must be something – an unseen mass – holding them together. This binding material would be dark matter.
However, Rubin admitted that she prefers the alternate theory to dark matter, known as MoND (Modified Newtonian Dynamics), a theory that has very little support. “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,” she has said. “That’s more appealing than a universe filled with a new kind of sub- nuclear particle.”
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