Since her death in 1979, the woman who discovered what the universe is made of has not so much as received a memorial plaque. Her newspaper obituaries do not mention her greatest discovery. […] Every high school student knows that Isaac Newton discovered gravity, that Charles Darwin discovered evolution, and that Albert Einstein discovered the relativity of time. But when it comes to the composition of our universe, the textbooks simply say that the most abundant atom in the universe is hydrogen. And no one ever wonders how we know.
—— Jeremy Knowles, discussing the complete lack of recognition Cecilia Payne gets, even today, for her revolutionary discovery.
Cecilia Payne-Gaposchkin (May 10, 1900 – December 7, 1979) was anEnglish-American astronomer who in 1925 was first to show that the Sun is mainly composed of hydrogen, contradicting accepted wisdom at the time.
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. Astronomy was considered as a branch of mathematics and she was unable to change her major field of study to astronomy from physics. When she finally confessed her wish to become an astronomer to Eddington his response was, “I can see no insuperable objections.” She completed her studies, but was not awarded a degree as Cambridge did not grant degrees to women at that time. After meeting Harlow Shapley, the Director of the Harvard College Observatory, who had just begun a graduate program in astronomy, Cecilia Payne left England for the United States in 1923. This was made possible by a fellowship to encourage women to study at the Observatory. The first student was Adelaide Ames (1922) and the second student was Payne.
She was an Elected member of Royal Astronomical Society while still a student at Cambridge 1923.
Shapley persuaded Cecilia Payne to write a doctoral dissertation, and so in 1925 she became the first person to earn a Ph.D. in astronomy from Radcliffe (now part of Harvard) 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”.
By applying the ionization theory developed by Indian physicist Megh Nad Saha she was able to accurately relate the spectral classes of stars to their actual temperatures. She showed that the great 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 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 that helium and particularly hydrogen were vastly more abundant (by about a factor of one million in the case of hydrogen). Her thesis thus established that hydrogen was the overwhelming constituent of the stars. When her dissertation was reviewed, she was dissuaded by Henry Norris Russell from concluding that the composition of the Sun is different from the Earth, which was the accepted wisdom at the time. However, Russell changed his mind four years later when other evidence emerged. After Payne-Gaposchkin was proven correct Russell was often given the credit.
She served as a technical assistant to Shapley from 1927 to 1938. At one point she considered leaving Harvard because of her low status and poor salary as she held no official position there. Shapley, however, made efforts to improve her position, and in 1938 she was given the title of “Astronomer”. On becoming director in 1954, Donald Menzel tried to improve her appointment, and in 1956 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.
Payne’s career marked a sort of turning point at Harvard College Observatory. Under the direction of Harlow Shapley, the observatory had already offered more opportunities in astronomy to women than other institutions. However, with Payne-Gaposchkin’s Ph.D., women entered the ‘mainstream’. The trail she blazed into the largely male-dominated scientific community was an inspiration to many.
The Asteroid 2039 Payne-Gaposchkin is named after her.
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. Nothing can compare with that experience… The reward of the old scientist is the sense of having seen a vague sketch grow into a masterly landscape.
- —Cecilia Payne-Gaposchkin (accepting the Henry Norris Russell Prize from the American Astronomical Society)
[More on this wonderful woman here http://www.harvardsquarelibrary.org/unitarians/payne2.html]
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