Cecilia Payne, Astronomer & Astrophysicist

Cecilia Helena Payne-Gaposchkin was a remarkable woman. Not only was her work hailed as “undoubtedly the most brilliant Ph.D. thesis ever written in astronomy” by renowned astronomers Otto Struve and Velta Zebergs, but she also made breakthroughs in the cyclic domination of science by men. Her story is one of great triumphs in the sphere of scientific breakthrough, made all the more impressive due to her disadvantaged position as a young woman in the male-dominated scientific domain. There were innumerable odds stacked against her, yet she prevailed, championing the creation of the most powerful analytical tool used in astrophysics. Cecilia H. Payne discovered the chemical composition of stars and quantitatively demonstrated what no one had before: the classification of stars according to their temperature.

Science was Payne’s passion stemming from her early years. However, her early education proved largely disappointing with regards to mathematics and science. This was largely due to the gender stigma around the idea of women in science, as the general consensus at the time was that it was a man’s field, and a man’s field only. However, Payne was resourceful and driven, and she worked her way around this through individual study. Her school, St. Mary’s College, proved wholly unsatisfying with regards to furthering her education in the fields. Eventually, she was asked to leave and go study elsewhere, which, in her own words, was the greatest service they ever did for her. When she attended St Paul’s Girls’ School, Brook Green, Hammersmith in 1918, she flourished, and despite only having one year to prepare for the Cambridge scholarship examination, she was awarded the only scholarship valuable enough to cover all her expenses — the Mary Edward scholarship for natural sciences. This was especially impressive, considering her status as a woman, largely self-taught and from a relatively poor background.

The turning point in her education was an astronomy lecture by Arthur Eddington, after he had returned from an exhibition to witness a solar eclipse in 1919 that proved Einstein’s theory of general relativity. Sufficiently inspired, Payne switched her focus solely to physics and, despite not being able to study astronomy as part of her natural sciences degree, she attended all the lectures on the subject she could. In 1923, she received a bachelor’s degree in natural sciences from Newman College, Cambridge, however, she realised then that if she wanted to continue pursuing her studies, she would have to look beyond Cambridge. Due to the patriarchal nature of science, unless she only wanted a teaching job, she would have no future in the United Kingdom.

Her path to revolutionizing astrophysics gained momentum when she was offered a graduate fellowship at Harvard University by Harlow Shapely. Harvard had the world’s largest collection of stellar spectra, which provide for each sample of starlight, a series of dark bands on a continuous spectrum of visible light corresponding to specific transitions between electron levels in atoms. It was through painstaking analysis of these spectra that led Payne to discover the composition of stars. Each element has its own specific set of spectral lines, which act as a ”fingerprint” to help identify each element. The number of absorptions correspond to all possible transitions of electrons between atomic energy levels. The leading theory at the time was championed by male astronomer Henry Norris Russel, who proposed that stars were made of heavy elements, such as calcium and iron, and were similar to earth in that regard. He proposed that if it were possible to heat the earth’s crust to temperatures achieved in stars, then the absorption spectra produced would be near identical. This conclusion was based on the principle that these elements were responsible for some of the most prominent lines on the spectra. Payne, having studied the emerging science of quantum physics, understood that the spectral lines from atoms were determined by electronic configuration. Additionally, she understood that the high temperatures caused varying degrees of ionization, where the valence (outer) electrons were stripped from the atoms. Using this information, she undertook a long and arduous investigation to measure absorption lines in spectra and produced her first thesis for her doctoral degree in just two years. Her findings concluded that the variation in surface temperature of stars was mainly due to the different ionization states of the stars, not due to the differences in elements like Russel theorised. Furthermore, she discovered that, surprisingly, all stars shared similar compositions and that their primary elements were hydrogen and helium, not the heavier elements like iron and calcium. In fact, she proposed that heavier elements account for only as much as 2% of a star’s composition. This was a revolutionary discovery.

However, despite her incredible and insightful work, the patriarchy in the scientific domain became a force, which largely dismissed her findings and barred her from the recognition she deserved. When Shapely sent her work to Professor Russel, the mastermind behind the opposing theory, he regarded it as “clearly impossible.” Through this blatant dismissal, she bowed to the pressure from Russel and included a line at the end of her thesis chalking her (correct) results up to abnormalities in the behavior of hydrogen. This encapsulates the attitude towards women in science, highlighting the fact that even though the scientific method is universal, work by women can still be marginalized and flat out refuted due to the patriarchy. To take matters further, despite undertaking all the typical duties of a professor, she was officially delegated the role of ‘technical assistant’ to Harlow Shapely, once again showing how women were sidelined. Despite the trials and tribulations she was subjected to by the patriarchy she emerged triumphant and serves as a role model for all aspiring women in science. In 1956 she was elected chair of the astronomy department in Harvard and made a full time professor, this being the first ever occasion where a woman was recognized in this position. Despite the initial rejection of her thesis, by 1929, even Russel conceded that she was correct, and her published works gained universal recognition. This led her to winning many awards for her work, including the Henry Norris Russel prize for her contributions to modern astrophysics. Undoubtedly, Cecilia H. Payne is an inspiration, proving that even the patriarchy cannot stand against irrefutable science if you have the commitment and passion to pursue it.

by Laura Jewsbury

References

Gregersen, E. (2021, May 6). Cecilia Payne-Gaposchkin. Encyclopedia Britannica. https://www.britannica.com/biography/Cecilia-Payne-Gaposchkin

Cecilia Payne: Discoverer of the Chemical Makeup of Stars | AMNH. (n.d.). American Museum of Natural History. https://www.amnh.org/learn-teach/curriculum-collections/cosmic-horizons-book/cecilia-payne-profile

O’Connor, J., & Robertson, E. (2017, November). Cecilia Payne-Gaposchkin. Maths History. https://mathshistory.st-andrews.ac.uk/Biographies/Payne-Gaposchkin