Education and Doctoral Thesis

Cecilia Payne was born into a moderately wealthy family that lived in the English countryside. The only girl with two brothers, Cecilia often found herself either exploring with them or alone in nature. In both cases, she was equally curious about her surroundings. She was tutored alongside her brothers, at an early age, in poetry, music, math, but not much science. Even when Cecilia went away to a girl’s boarding school, she was unsatisfied both with the available science labs and antiquated equipment, and also the inadequate staff to teach her about it all.

So she applied to enter Newnham College, Cambridge in 1919, and found herself in a dream world. She was now working in the same laboratories as, and sometimes under the tutelage of great names in physics and atomic science: Ernest Rutherford, J.J. Thompson, Niels Bohr, and Arthur Eddington, whom she considered “the greatest intellect [she] ever had the privilege to meet” (The Dyer’s Hand, 236). She also found a certain degree of acceptance among the students active in politics: “we women, of course, had no votes, but that did not prevent us from conducting spirited debates…We declared almost unanimously for labor” (The Dyer’s Hand, 112). The student body was less welcoming in other ways. As one of the few women in the sciences at the college, she repeatedly faced discredit and harassment from her peers, which was never admonished by her professors. The school failed to provide a supportive structure: in one class, an advanced physics course taught by Rutherford, she was required to sit in the front row, alone. Rutherford would often single her out, much to the chagrin of the boys in class.

In search of better opportunities to study astronomy at high university levels, she looked towards Cambridge, MA, and a graduate research position at the Harvard College Observatory. At the end of her degree at Newnham, she met the current Observatory director Harlow Shapley, visiting England as a lecturer. Ready to move forward on her career path, she asked Shapley if he should like a new and eager research assistant in America. Shapley responded that he would be delighted: “When Miss Cannon retires, you can succeed her!”

This answer presages the types of gender discrimination Cecilia would continue to face. While it was rarely as direct or obstructionary as in England, the climate in America still resisted her entry into the professional sciences. Shapely gave her an office in the same building as the Glass Plate collection and the Computer offices, but where no other (male) research astronomers worked. She found difficulty advancing in her professional life: Shapely provided insufficient wages (for projects which he measured in “girl hours”), and, after almost 30 years of dedicated work, Harvard still expressed reticence to recognize Cecilia’s work with a dignified title and position. In her autobiography, Cecilia laments that, in her youthful vigor, she had been “over optimistic” about America’s freedoms and equalities. But even in the face of this resistance, she remained adamant that no quality could prevent her from working with what she loved. On a questionnaire for the Radcliffe Alumni Association, in response to the questions “Can a woman successfully carry on a career and marriage simultaneously? Can she if she has children? What is the most important forward movement in which women can be of service?,” she answers: “??? Same as for men.”

Perhaps the most frustrating moment in Cecilia’s career came at the end of her graduate research at Harvard, when she was finishing her thesis. Written in a “six week ecstasy,” and later hailed as “the greatest PhD thesis even written in astronomy,” Stellar Atmospheres was published as the first in the series Harvard Observatory Monographs in 1925 (such grand praise comes from the eminent Otto Struve of Yerkes Observatory). It made an observation that hydrogen and helium are much more massively abundant in the universe than previously assumed. This ran contrary to the current paradigm: that all stellar objects were primarily iron at core, like Earth, the Moon, and the other nearby rocky bodies. The lead thinker in this school, Henry Norris Russell, a senior astronomer at Princeton and close colleague of Shapley, resisted her conclusions, encouraging her to be more conservative and cautious about the implications of her observations. In the end, Cecilia published in her thesis that “the outstanding discrepancies between the astrophysical and terrestrial abundances are displayed for hydrogen and helium. The enormous abundance derived for these elements in the stellar atmosphere is almost certainly not real.” (Stellar Atmospheres, 188).

Of course, we know now that it is actually very real, and that her observations pointed towards a truth about the physical universe, that the stars are made of hydrogen and helium gases. In fact, Russell published a paper four years later (Russell 1929) in which he endorsed Cecilia’s observations, and extended the conclusion to the physical principles of the universe. What caused such an about-face? Some attribute it to misogyny and an initial distrust of Cecilia’s work until he could verify it himself; but others consider the dynamics of professional astronomy research at the time. David Devorkin argues that Russell was simply cautioning a young student from making brash jumps, about being skeptical of their methods, data, and about trusting the authorities above. Even after he had confirmed it through his own observation, it was Russell’s long-earned professional clout and central status in North American astronomy that gave him the voice to challenge the current paradigm.

CPG Thesis Summary

The most salient elements of Payne's thesis are reproduced in the above image (Figs. 2-5). The first table (Fig. 3) shows the stellar temperature scale, derived using stellar spectra and their line intensities, combined with the most recent developments in quantum theory and physical chemistry (Meghnad Saha's thermal ionization equation, and Edward Milne's and Ralph Fowler's equations of spectral intensities). In this list of elements, which maps their maximum representation in the classification scheme, as well as the temperature at which they emit this spectra, Payne moved closer to realizing a new pattern of abundances in the stars. Figure 4 shows that, after applying these equations and reducing the results in accordance with instrumental and human error, both Hydrogen and Helium (and ionized Helium) appear in "enormous abundance." As mentioned, she reluctantly backed away from this shocking claim in the face of institutional resistance, first from a notorious professor and then an advisor who invested heavily in the accepted paradigm. Four years later, however, the very man who discouraged her proved her correct -- with only minimum fanfare for the origins of the idea.

Confused at the detail and rigor with which Payne approach this topic? We were too, so we unpacked her subject and work processes to better understand the gravity of her discoveries!

** Much of this page was adapted from Wolbach Library's exhibit "Cecilia and Sergei: American Astronomers," with permission from the author. 

Image Sources

  1. Payne, C. (1925). Stellar atmospheres; A contribution to the observational study of high temperature in the reversing layers of stars. (Doctoral dissertation), p. 1. Retrieved from SAO/NASA Astrophysics Data System. (1925PhDT.........1P)
  2. Payne, C. (1925). Stellar atmospheres; A contribution to the observational study of high temperature in the reversing layers of stars. (Doctoral dissertation), p. 132. Retrieved from SAO/NASA Astrophysics Data System. (1925PhDT.........1P)
  3. Adapted from Table XXVIII from Stellar atmospheres; A contribution to the observational study of high temperature in the reversing layers of stars. (Doctoral dissertation) by C. Payne, 1925, p. 184. Retrieved from SAO/NASA Astrophysics Data System. (1925PhDT.........1P)
  4. Payne, C. (1925). Stellar atmospheres; A contribution to the observational study of high temperature in the reversing layers of stars. (Doctoral dissertation), p. 188. Retrieved from SAO/NASA Astrophysics Data System. (1925PhDT.........1P)