She was the first woman to receive tenure and the first to chair a department in the faculty of arts and sciences at Harvard. Her dissertation was hailed as “the most brilliant Ph.D. thesis ever written in astronomy.” Yet few have heard of Cecilia Payne-Gaposchkin (1900–1979), an English-American astronomer — and Unitarian — who discovered the true physical constitution of the universe.
“There is no joy more intense than that of coming upon a fact that cannot be understood in terms of currently accepted ideas.”
“Payne-Gaposchkin’s most dramatic scientific contribution was the discovery that hydrogen is millions of times more abundant than any other element in the universe,” said Jeremy Knowles, dean of the faculty of arts and sciences, as Harvard celebrated her accomplishments in February 2002 by adding her portrait to the Faculty Room in University Hall, where only one other woman is depicted. He quoted an undergraduate’s wry assessment: “Every high school student knows that Newton discovered gravity, that Darwin discovered evolution, even that Einstein discovered relativity. But when it comes to the composition of our universe, the textbooks simply say that the most prevalent element in the universe is hydrogen. And no one ever wonders how we know.”
In her 1925 dissertation Cecilia Payne showed that stars are “all essentially of the same composition,” according to astronomer Owen Gingerich. At the time, however, she distrusted her discovery that stars are made almost entirely of hydrogen and helium. Princeton astronomer Henry Norris Russell wrote to her that “it is clearly impossible that hydrogen should be a million times more abundant than the metals,” but he later discovered that she was right — and took credit for explaining the phenomenon.
Born and educated in England, she came to the United States to study in 1923 at the encouragement of the director of the Harvard Observatory. At the time, the chair of Harvard’s physics department would not accept a female graduate student, so the faculty committee that awarded her Ph.D. effectively created a department of astronomy. After receiving her degree, “she lectured in the astronomy department, but her lectures were not listed in the course catalogue,” Knowles said. “She directed graduate research without status; she had no research leaves; and her small salary was categorized by the department under ‘equipment.’ And yet she survived and flourished. ‘It was a case,’ she said, ‘not of survival of the fittest, but of the most doggedly persistent.'”
In 1933 she visited Germany and met the Russian astronomer and political exile Sergei Gaposchkin. She arranged a place for him at the Harvard Observatory. They married two years later. In 1938, Harvard officially appointed her to the faculty of astronomy, and in 1956, she was the first woman promoted to a full professorship.
She and her husband were members of the First Parish in Lexington, where she taught nine- to twelve-year-olds in the Sunday school. Her daughter Katherine Haramundanis tells a story about her mother donning heavy woolen slacks and walking more than three miles to teach Sunday school one bitterly cold winter morning when the family car would not start. The story reveals a great deal about her character. In her autobiography she described her attitude in the face of slow promotions and low pay: “I simply went on plodding, rewarded by the beauty of the scenery, towards an unexpected goal.”
What are the stars made of? The answer to this fundamental question of astrophysics was discovered in 1925 by Cecilia Payne and explained in her Ph.D. thesis. Payne showed how to decode the complicated spectra of starlight in order to learn the relative amounts of the chemical elements in the stars. In 1960 the distinguished astronomer Otto Struve referred to this work as “the most brilliant Ph.D. thesis ever written in astronomy.”
Cecilia Payne was born in Wendover, England in 1900. In 1919 while at Newham college at Cambridge, she became interested in astronomy after hearing a lecture by Professor Eddington about his eclipse expedition to Brazil. Because astronomy continued to be seen as a branch of mathematics she was unable to change her major field of study to astronomy from physics. She continued however to attend Eddington’s lectures. When she finally confessed her wish to become an astronomer to Eddington his response was, “I can see no insuperable objections.” After graduating from Cambridge she became concerned about the future for women in astonomy careers in England. She chose to head toward the United States where she thought a woman might be more accepted. She received a fellowship to study at Harvard Observatory and so she headed across the seas to continue her career.
Payne quickly settled in among the women at the Harvard Observatory, working there under the director Harlow Shapley. She quickly began an investigation of the stellar spectra being compiled for the Henry Draper catalog. In 1925 Cecilia Payne became the first person, woman or man, to receive an Ph.D. in astronomy from Harvard. Shapley had attempted to get her a Ph.D. in the already existing physics department, but the chair refused. To get around this roadblock she received her Ph.D. in astronomy instead. Her thesis, later published as the observatory’s first monograph, Stellar Atmospheres, A contribution to the Observational Study of High Temperature in the Reversing Layer of Stars was labeled at the time and for many years afterwards as “the most brilliant Ph.D. thesis ever written in astronomy.” In this thesis Payne calculated a temperature scale to match the classification system which Annie Cannon had developed. She also theorized about the composition of the stars. She suggested that the stars were mostly hydrogen. However, when Eddington heard this theory he told her that she was wrong because astronomers at the time felt that all celestial bodies had very similar compostions. As a result, Payne wrote in her thesis that her results were improbable and probably wrong. Today, of course, we know her results were actually fairly accurate.
After her fellowship was finished, Payne was hired by Harvard and worked with the various other women then employed at the Harvard Observatory. In 1932 Payne began a tour of Europe visiting various observatories around the continent. Her final destination was Berlin for the meeting of the Astronomische Gesellschaft. She documents in her autobiography the conditions both in Russia and in Nazi Germany at the time. While in Berlin she met a young Russian Astronomer Sergei Gaposchkin and heard his plight as a Russian Astronomer in Nazi Germany. She resolved to help him get out of Europe. She found him a position at Harvard and he arrived in November 1932. Less than two years later in March 1934 Sergei and Cecilia were married.
Cecilia Payne (1900–1979) was born in Wendover, England. After entering Cambridge University she soon knew she wanted to study a science, but was not sure which one. She then chanced to hear the astronomer Arthur Eddington give a public lecture on his recent expedition to observe the 1919 solar eclipse, an observation that proved Einstein’s Theory of General Relativity. She later recalled her exhilaration: “The result was a complete transformation of my world picture. When I returned to my room I found that I could write down the lecture word for word.” She realized that physics was for her.
Later, when the Cambridge Observatory held an open night for the public, she went and asked the staff so many questions that they fetched “The Professor.” She seized the opportunity and told Professor Eddington that she wanted to be an astronomer. He suggested a number of books for her to read, but she had already read them. Eddington then invited her to use the Observatory’s library, with access to all the latest astronomical journals. This simple gesture opened the world of astronomical research to her.
England, though, was not in Payne’s professional future. She realized early during her Cambridge years that a woman had little chance of advancing beyond a teaching role, and no chance at all of getting an advanced degree. In 1923 she left England for the United States, where she lived the rest of her life. She met Harlow Shapley, the new director of the Harvard College Observatory, who offered her a graduate fellowship.
Harvard had the world’s largest archive of stellar spectra on photographic plates. Astronomers obtain such spectra by attaching a spectroscope to a telescope. This instrument spreads starlight out into its “rainbow” of colors, spanning all the wavelengths of visible light. The wavelength increases from the violet to the red end of the spectrum, as the energy of the light decreases. A typical stellar spectrum has many narrow dark gaps where the light at particular wavelengths (or energies) is missing. These gaps are called absorption “lines,” and are due to various chemical elements in the star’s atmosphere that absorb the light coming from hotter regions below.
The study of spectra had in fact given rise to the science of astrophysics. In 1859, Gustav Kirchoff and Robert Bunsen in Germany heated various chemical elements and observed the spectra of the light given off by the incandescent gas. They found that each element has its own characteristic set of spectral lines—its uniquely identifying “fingerprint.” In 1863, William Huggins in England observed many of these same lines in the spectra of the stars. The visible universe, it turned out, is made of the same chemical elements as those found on Earth.
In principle, it seemed that one might obtain the composition of the stars by comparing their spectral lines to those of known chemical elements observed in laboratory spectra. Astronomers had identified elements like calcium and iron as responsible for some of the most prominent lines, so they naturally assumed that such heavy elements were among the major constituents of the stars. In fact, Henry Norris Russell at Princeton had concluded that if the Earth’s crust were heated to the temperature of the Sun, its spectrum would look nearly the same.
When Payne arrived at Harvard, a comprehensive study of stellar spectra had long been underway. Annie Jump Cannon had sorted the spectra of several hundred thousand stars into seven distinct classes. She had devised and ordered the classification scheme, based on differences in the spectral features. Astronomers assumed that the spectral classes represented a sequence of decreasing surface temperatures of the stars, but no one was able to demonstrate this quantitatively.
Cecilia Payne, who studied the new science of quantum physics, knew that the pattern of features in the spectrum of any atom was determined by the configuration of its electrons. She also knew that at high temperatures, one or more electrons are stripped from the atoms, which are then called ions. The Indian physicist M. N. Saha had recently shown how the temperature and pressure in the atmosphere of a star determine the extent to which various atoms are ionized.
Payne began a long project to measure the absorption lines in stellar spectra, and within two years produced a thesis for her doctoral degree, the first awarded for work at Harvard College Observatory. In it, she showed that the wide variation in stellar spectra is due mainly to the different ionization states of the atoms and hence different surface temperatures of the stars, not to different amounts of the elements. She calculated the relative amounts of eighteen elements and showed that the compositions were nearly the same among the different kinds of stars. She discovered, surprisingly, that the Sun and the other stars are composed almost entirely of hydrogen and helium, the two lightest elements. All the heavier elements, like those making up the bulk of the Earth, account for less than two percent of the mass of the stars.
Most of the mass of the visible universe is hydrogen, the lightest element, and not the heavier elements that are more prominent in the spectra of the stars! This was indeed a revolutionary discovery. Shapley sent Payne’s thesis to Professor Russell at Princeton, who informed her that the result was “clearly impossible.” To protect her career, Payne inserted a statement in her thesis that the calculated abundances of hydrogen and helium were “almost certainly not real.”
She then converted her thesis into the book Stellar Atmospheres, which was well-received by astronomers. Within a few years it was clear to everyone that her results were both fundamental and correct. Cecilia Payne had showed for the first time how to “read” the surface temperature of any star from its spectrum. She showed that Cannon’s ordering of the stellar spectral classes was indeed a sequence of decreasing temperatures and she was able to calculate the temperatures. The so-called Hertzsprung-Russell diagram, a plot of luminosity versus spectral class of the stars, could now be properly interpreted, and it became by far the most powerful analytical tool in stellar astrophysics.
Payne also contributed widely to the physical understanding of variable stars. Much of this work was done in association with the Russian astronomer Sergei Gaposchkin, whom she married in 1934.
From the time she finished her Ph.D. through the 1930s, Payne advised students, conducted research, and lectured—all the usual duties of a professor. Yet, because she was a woman, her only title at Harvard was “technical assistant” to Professor Shapley. Despite being indisputably one of the most brilliant and creative astronomers of the twentieth century, Cecilia Payne was never elected to the elite National Academy of Sciences. But times were beginning to change. In 1956, she was finally made a full professor (the first woman so recognized at Harvard) and chair of the Astronomy Department.
Her fellow astronomers certainly came to appreciate her genius. In 1976, the American Astronomical Society awarded her the prestigious Henry Norris Russell Prize. In her acceptance lecture, she said, “The reward of the young scientist is the emotional thrill of being the first person in the history of the world to see something or to understand something.” As much as any astronomer, she had fully experienced that most important of all scientific rewards.
Cecilia was an English-American astronomer and one of three children. She won a scholarship to read botany, physics and chemistry at Newnham College, Cambridge University in 1919, where her interest in astronomy was sparked by a lecture given by Eddington, on his eclipse expedition to Africa as a test of Einstein’s general theory of relativity. Although she completed her studies, Cambridge did not grant degrees to women at this time, although she was elected a member of the Royal Astronomical Society while still a student at Cambridge.
Having met Harlow Shapely of Harvard College observatory, she left England for the US to persue a graduate program in astronomy. Payne was the second student, after Adelaide Ames, to join a fellowship program at the Observatory to encourage women to study there. She became the first person to earn a PhD in astronomy from Radcliffe for her thesis “Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars”. Astronomer Otto Struve characterized it as “undoubtedly the most brilliant Ph.D. thesis ever written in astronomy”. Her work allowed her to relate the spectal classes of stars into actual temperatures. She also showed that the variation in stellar absorption lines was due to differing amounts of ionization that occurred at different temperatures, and not due to the different abundances of elements. She also correctly suggested that silicon, carbon, and other common metals seen in the Sun were found in about the same relative amounts as on Earth but the helium and particularly hydrogen were vastly more abundant, by about a factor of one million in the case of hydrogen, concluding that hydrogen was the main constituent of stars. However, she is not fully credited with the discovery because her male superiors convinced her to retract her findings on stellar hydrogen and publish a far less definitive statement. By the time she was awarded her PhD she had also already published six papers on stellar atmospheres, all by age 25. By the time of her death she had published over 150 papers and monographs.
Payne married in 1934 and had three children, but remained scientifically active throughout her life, spending her entire academic career at Harvard. However, she received little pay, and despite her work, had a low status and held no official position, serving only as a technical assistant to Shapely from 1927-1938. In 1938 she was given the title of astronomer, and once Donald Menzel took over as Director in 1954 she became the first female to be promoted to full-professor from within the faculty at Harvard’s Faculty of Arts and Sciences. Later, with her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard.
After her thesis Payne contined to study stars of high luminosity in order to understand the structure of the Milky Way. Later with her husband, she surveyed all the stars brighter than the tenth magnitude. She then studied variable stars, making, with her assistants over 1,250,000 observations. This was later extended to the Magellanic Clouds, adding a further 2,000,000 observations of variable stars. This data was used to determine the paths of stellar evolution.
Payne-Gaposchkin’s PhD is considered by many as the turning point of the Harvard College Observatory, and of women in astronomy, allowing women to enter the mainstream world of astronomy. She received the Annie Cannon Award in astronomy in 1934 for her work.
Cecilia continued to publish and wrote several other books, some of them coauthored by her husband. Payne, with Annie Cannon, eventually received the title of Astronomer from Harvard . Despite the fact that she lectured at the University, it was not until the 1950s that Payne received the title of Professor and eventually Chair of the Astronomy Department at Harvard. Cecilia Payne-Gaposchkin is one of the great women astronomers of this century.
The asteroid 2039 Payne-Gaposchkin is named after her.
Much of the information for this page as well as the photos come from Cecilia Payne’s autobiography edited by her daughter.
- Payne-Gaposchkin, Cecilia. Cecilia Payne-Gaposchkin: An Autobiography and Other Recollections. Katherine Haramundanis Ed. Cambridge: Cambridge University Press, 1984.
Other interesting books include:
- Rossiter, Margaret W. Women Scientists in America: Struggles and Strategies to 1940. Baltimore: Johns Hopkins University Press, 1983.
- Jones, Bessie and Lyle boyd. The Harvard College Observatory: The First Four Directorships, 1839-1919. Cambridge, Mass.: Belknap Press of Harvard University Press, 1971.