The cosmic importance of hydrogen was first grasped by a young PhD student, Cecilia Payne (Payne-Gaposchkin after she married), who in 1925 discovered hydrogen in the stars. Indeed, she earned a PhD at a time when it was still extremely difficult for women to do so, and did breakthrough research for her thesis. For all the success of her science, her story also demonstrates the barriers and sexism that made it difficult for women to fulfil their scientific aspirations and affected their careers throughout.
Cecilia Payne was born in Wendover, England, in 1900. Her father died when she was four, but her mother Emma saw that she had a gifted child who wanted to be a scientist. Emma enrolled her daughter in St Paul’s School for Girls in London, which was well equipped to teach science. The 17 year old thrived there and, as Payne-Gaposchkin later wrote in her autobiography The Dyer’s Hand (republished under the title Cecilia Payne-Gaposchkin: An Autobiography and Other Recollections), she would steal up to the science lab for “a little worship service of my own, adoring the chemical elements”.
Her advanced science education began in 1919 when she entered Newnham College at the University of Cambridge on a scholarship. There, she studied botany, her first love, as well as physics and chemistry – despite the fact that at the time, the university did not offer degrees to women.
At Cambridge, the likes of Ernest Rutherford were exploring the atomic and subatomic worlds, and Arthur Eddington was studying the structure and development of stars. Indeed, Payne-Gaposchkin’s physics instructor was Rutherford himself, but as the only woman in his class, she found herself being humiliated. University regulations at the time required that she sit in the front row. As she relates in her autobiography, “At every lecture [Rutherford] would gaze at me pointedly…and would begin in his stentorian voice: ‘Ladies and gentlemen.’ All the boys regularly greeted this witticism with thunderous applause [and] stamping with their feet…at every lecture I wished I could sink into the earth. To this day I instinctively take my place as far back as possible in a lecture room.”
Instead, Payne-Gaposchkin found inspiration in Eddington. Almost by chance, she attended his lecture about his 1919 expedition to West Africa that confirmed Einstein’s theory of general relativity. This so impressed her that she decided to choose physics and astronomy over botany. When later she happened to meet Eddington, as she writes in her autobiography, “I blurted out that I should like to be an astronomer…he made the reply that was to sustain me through many rebuffs: ‘I can see no insuperable objection.” He engaged her in his work on stellar structures, but he also cautioned her that after Cambridge, there would likely be no opportunities for a female astronomer in England.
Fortunately, a new possibility arose when Payne-Gaposchkin met Harlow Shapley, director of the Harvard College Observatory in Cambridge, Massachusetts, during his visit to the UK. He encouraged her efforts and she learned that he was instituting a graduate programme in astronomy. With a glowing recommendation from Eddington, Shapley offered her a modest stipend as a research fellow. In 1923, she sailed to the U.S. to begin work on a Ph.D under Shapley’s direction.
In her Ph.D work, Payne-Gaposchkin drew on the physics she had learned at Cambridge to analyse this unique cache of data with the latest theories. The origin of spectral lines had been established only a decade earlier in 1913 by Niels Bohr’s early quantum theory of the hydrogen atom, later extended by others. These theories applied to neutral atoms. Payne-Gaposchkin’s great insight was to appreciate that spectra from excited or ionized atoms – such as would occur in the hot outer atmosphere of a star – differed from those of neutral atoms of the same species.
Her analysis also showed that hydrogen was a million times more abundant than the other elements. Helium, meanwhile, was a thousand times more abundant. The conclusion that the Sun was made almost entirely of hydrogen immediately ran into trouble with a respected outside examiner of her dissertation.
Even without proper credit, the power of Payne-Gaposchkin’s thesis speaks for itself. Her lucid writing style, command of the subject and pioneering science shine through. The work was printed as a monograph, and it sold 600 copies – virtually bestseller status for a dissertation. The highest praise came almost 40 years later, when the distinguished astronomer Otto Struve called Stellar Atmospheres “the most brilliant PhD thesis ever written in astronomy”.
In some sense, one might say she “had it all” in combining science with family and children, but getting there was unnecessarily difficult and gruelling because of bias against women. She became a full professor only at age 56, much later than a man with similar achievements would have reached that status, and after being passed over for advancement, which must have taken a psychological toll. Only a person with exceptional drive and persistence, along with scientific ability, could have endured until final recognition.
Ultimately, Cecilia Payne-Gaposchkin, who died in 1979, was a pioneering scientist who did amazing work throughout her career, but was not treated professionally for most of it. She advanced the position of women in astronomy, but she still encountered barriers that kept her from being the complete scientist she wanted to be. Her stellar work was often overlooked, and her legacy forgotten, as she became one of the many “hidden” women in science who actually laid the foundation in their fields. It is only more recently that the significant contributions of the likes of Payne-Gaposchkin are being post-scripted into the history of science, and she should be remembered as a key transitional figure between older and newer possibilities for women in science.
I thought this was a story worth telling….and re-telling.
