Cecilia Payne discovered that stars are made largely of the two lightest chemical elements – hydrogen and helium. She made her discovery while in graduate school. At first nobody believed it – scientists were convinced that the sun’s composition was similar to the earth’s.
Within a few years a major paradigm shift took place and Payne’s discovery became mainstream science – it was soon widely recognized that hydrogen is by far the commonest chemical element in stars and hence the universe.
Payne-Gaposchkin (her name after marriage) was the most eminent female astronomer of her time, the first to be appointed full professor at Harvard University, and the first to chair a department.
Beginnings
Cecilia Helena Payne was born on May 10, 1900 into an upper-class family in the market town of Wendover, England, UK.
Her father was the multi-faceted Edward John Payne – talented musician, fellow of Oxford University, author of major histories, and latterly a barrister and judge. He drowned in a canal when Cecilia was four. Before this, he gave his daughter a love of music, playing scales to her from age two so she developed perfect pitch. Cecilia remembered him filling their home with music and fun.
Her mother was Emma Leonora Helena née Pertz, a skilled artist, who came from an academically accomplished German family. A rather stern woman, Cecilia’s mother raised her three children alone. All were very young when her husband died – Cecilia was the eldest.
Cecilia’s mother made sure her children were well-educated: her son grew up to become an archeologist and her other daughter an architect.
At age eight, Cecilia decided to become a scientist. This happened after she recognized a plant she had previously known only from her mother’s description of it – the bee orchid.
The bee orchid. Image courtesy of Bernard Dupont.
Later she recalled her excitement at finding for herself the plant that resembles a bumblebee:
“For the first time I knew the leaping of the heart, the sudden enlightenment, that were to become my passion… These moments are rare, and they come without warning, on ‘days to be marked with a white stone’.”
Fabulous First School
At age six, Cecilia began attending a small girls’ school across the street from her home in Wendover. It was run by Miss Elizabeth Edwards, who told her classes that women were the stronger sex. Miss Edwards ran the school with military-style discipline. Rather than walk anywhere, the girls marched. Every day began with a hymn or a patriotic song.
Cecilia learned to read and became an avid reader. There were frequent exercises in mental arithmetic. Miss Edwards required her girls to learn lengthy poems by heart – Cecilia said this helped her later scientific work because it developed her memory to a very high level.
By the time she left this small school, Cecilia had learned basic Latin and could speak French and German. She had studied geometry, could do algebra up to the level of quadratic equations, and had been taught how to use a chemical balance. At home she became a skilled pianist.
It had all been wonderful.
Horrible High School
At age 12, Cecilia moved reluctantly with her family to London. Previously accustomed to the freedom of living in a small town with plenty of space and nearby fields and hills, she hated the big, smoky city.
In London she attended St. Mary’s College, but found it inferior to the little school in Wendover. She felt there were far too many church services, leaving less time for other subjects: there was no science for a year; German was not taught; and her favorite subject – mathematics – was a whole year behind. The school believed there was a conflict between science and religion and preferred religion. Cecilia compensated by working through the only two scientific books in her home: a botany text in French and German, which she translated into English; and Isaac Newton’s masterpiece: Principia. Later she found Swedenborg’s Chemistry, Physics, Philosophy and Thomas Huxley’s Collected Essays. She believed Huxley gifted his scientific spirit to her.
At age 13, she burst into tears when she went to the doctor complaining she was growing hair on her face. The doctor said nothing could be done, but told her, “At least you’ve got brains. Make something of them.” She became even more determined to become a scientist.
Cecilia studied calculus and coordinate geometry on her own. Just before her seventeenth birthday her school told her it could do no more for her and asked her to leave.
Superb St. Paul’s
Gustav Holst taught Cecilia music shortly after composing The Planets. Recognizing her as a brilliant musician, he encouraged her to make music her life’s work.
She was positively encouraged to love science and was taught music by the famous composer Gustav Holst – the first man she had said more than just a few words to since her father’s death over a decade earlier.
She played in the school’s orchestra and Holst taught her to conduct. He urged Cecilia to become a musician, but her heart was set on becoming a scientist.
Cambridge
Celia Payne’s ambition was to study science at the University of Cambridge. With no money for this, she needed to win a full scholarship. Fortunately she achieved this formidable objective, winning the only scholarship generous enough to cover all her costs.
At age 19, in September 1919, she began studying for a botany degree at Cambridge’s Newnham College. She insisted on studying the physics course – an unusual choice for a would-be botanist, but Ernest Rutherford was in charge of the Cavendish Laboratory and Payne wanted to attend the great man’s lectures.
The renowned Agnes Arber tutored her in botany, but it began to dawn on Payne that she was more interested in the physical sciences.
Working in the Cavendish Laboratory, she came into contact with several Nobel Prize winners, including the discoverer of the electron, J. J. Thomson, and Rutherford himself. The lectures she attended on the quantized Bohr atom were given by Niels Bohr in person.
She could not sleep for three nights after attending a lecture by Arthur Eddington on the General Theory of Relativity. She almost drove herself to a nervous breakdown thinking excitedly about its meaning, ramifications, and how it had changed her perception of the world.
She decided to major in physics and also started attending astronomy lectures. She pored over astronomy books avidly and after making some astronomical observations she approached Eddington, who was happy to give her research work to carry out on an informal basis. This led to her writing a paper on the proper motion of stars, published by the Royal Astronomical Society. While carrying out this work, she learned never to be ashamed of admitting to not understanding something.
“An admission of ignorance may well be a step to a new discovery.”
She spent many days and nights working on astronomy projects when she really ought to have been studying physics. She left Cambridge with a second class honors degree rather than a first. The degree was not awarded officially – it was only in 1947 that the University of Cambridge began awarding degrees to women.
After learning that the only career option open to her in her own country was teaching in girls’ schools, she decided to go to America to study for a doctorate and become an astronomer.
From Cambridge to Cambridge
In the fall of 1923, age 23, Cecilia Payne arrived in Cambridge, Massachusetts.
Financed by a Harvard Observatory fellowship for women, she affiliated with Radcliffe College, a women’s college that is now part of Harvard University. She lived in a shared room in Radcliffe’s graduate dormitory.
Harold Shapley, Harvard Observatory’s director was her doctoral supervisor. Payne had first met him in London where he had made a great impression on her with his lecture on ‘The Universe.’
Shapley soon introduced Payne to her external Ph.D. advisor, the renowned astronomer Henry Norris Russell of Princeton University. Russell had been Shapley’s doctoral supervisor and the two remained close to one another scientifically.
Payne soon realized that Russell’s influence on American astronomy was so powerful that to get on the wrong side of him would be professional suicide. If Russell did not approve of a paper, it would not be published.
“His word could make or break a young scientist. It was my good fortune to receive the stamp of approval in the beginning, though he vetoed some of my cherished ideas.”
In the Footsteps of Henrietta Leavitt
Shapley assigned Payne to work at the desk once occupied by the great Henrietta Leavitt.
“I heard tell that Miss Leavitt’s lamp was still to be seen burning in the night, that her spirit still haunted the plate stacks. I suspect that some credulous soul (and there were such in those days) had seen me from afar, burning the midnight oil.”
Payne-Gaposchkin’s Lifetime in Context
Cecilia Payne-Gaposchkin’s lifetime and the lifetimes of related scientists.
What are Stars made of?
A Remarkable Doctoral Thesis
It took only two years for Payne to be awarded a Ph.D. for one of the most remarkable theses ever written by an astronomy student.
“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 understand something.”
Before she started her research, scientists knew that our sun and other stars contained hydrogen, helium, and many other chemical elements.
A Brief History
of Hydrogen and Helium in the Stars
Seeing the Elements in Stars
In 1859, Robert Bunsen and Gustav Kirchhoff discovered that the frequencies of light emitted (and absorbed) by an element at high temperatures are unique to the element. This new science of spectroscopy offered a way to identify elements by the ‘fingerprints’ of the light they emitted or absorbed. Kirchhoff quickly turned his spectroscope to the sun and found evidence for magnesium, calcium, nickel, barium, copper and zinc.
For the first time in history scientists now knew for certain that the sun and stars were not made of some exotic, alien material. Chemical elements found on Earth were also present in the sun. But nobody could tell how much of each element there was.
Gustav Kirchhoff and Robert Bunsen invented spectroscopy, allowing elements to be fingerprinted using light, paving the way for the sun’s composition to be discovered.
Other scientists quickly followed in Kirchhoff’s footsteps.
Discovering Hydrogen and Helium in Stars
In 1864, William Huggins obtained spectra showing that hydrogen is present in the sun and other stars.
In 1868, Norman Lockyer saw a spectral line in the sun’s atmosphere matching no element seen on Earth. He proposed the existence of a new chemical element and named it helium for the Greek sun god Helios. In 1895, William Ramsay released a gas from rock and found its spectrum to be the same as Lockyer’s helium. This established helium’s place in both the stars and the periodic table.
The abundances of hydrogen and helium in the sun were unknown, but scientists guessed they would be similar to the small abundances on the earth.
William Huggins and Norman Lockyer detected hydrogen and helium in the sun.
Hydrogen Powers the Sun
In 1919, Jean Perrin proposed that the sun obtains its energy when light atoms merge to form heavier atoms. This process would result in a tiny loss of mass, producing prodigious amounts of energy in line with Albert Einstein’s famous equation: E = mc2.
In August 1920, Arthur Eddington, remembered fondly by Payne from her time at the University of Cambridge, made the specific suggestion that if the sun’s mass was five percent hydrogen, then it could generate its energy by converting hydrogen to helium.
Eddington’s only mistake, as we’ll see, was to underestimate the abundance of hydrogen on the sun.
Jean Perrin and Arthur Eddington proposed stars produce energy from mass.
Element Abundances in Stars
The spectrum of any star is determined by the elements and conditions in its atmosphere.
In 1920 and 1921, Meghnad Saha published groundbreaking papers relating the ionization states of the elements and the fine details in star spectra to the temperature and pressure of their atmospheres.
In 1923 and 1924, Ralph Fowler and Edward Milne saw that Saha had not accounted for the thermal dependence of atomic excitation. They refined Saha’s theory making it easier to calculate temperatures and pressures in the atmospheres of stars. They found that the intensity of an absorption line in a star’s spectrum is in proportion to the concentration of atoms in the absorbing layer of the star’s atmosphere. See the image below:
The sun’s visible absorption spectrum: the greater the dip in the red line, the greater the intensity of absorption. Absorption takes place when light generated in the sun’s core is absorbed by atoms in its atmosphere. Absorption frequencies are unique to the atoms or ions that are absorbing light energy. Image courtesy of Rolf A. F. Witzsche.
The work of Meghnad Saha, Edward Milne, and Ralph Fowler provided a way of calculating abundances of elements in stars.
Payne:
Stars are Mainly Hydrogen and Helium
Soon after she landed in America, Payne began her work at the Harvard Observatory aiming to calculate the abundances of elements in stars. Shapley made Harvard’s enormous library of spectra available to her.
First she developed a way to quantify the intensity of absorption lines. Then she spent a year working all day and much of the night analyzing the spectra of hundreds of stars, trying to develop general principles from her observations.
Silicon became one of her favorite chemical elements when she discovered how the absorption intensities of silicon and its ions: Si, Si+, Si2+, and Si3+ varied with a star’s spectral class. A star’s spectral class is defined by the degree of ionization of elements in its atmosphere, which is closely related to its temperature.
Spectral Classes of Stars
The more negative the magnitude, the brighter the star. Image by Rursus.
After two years of unremitting effort, Payne built a temperature scale for stars versus their absorption intensities allowing her to calculate the abundances of chemical elements. She was amazed when she discovered:
- regardless of spectral type, stars all had similar compositions
- the abundances of hydrogen and helium in all stars were enormous, much greater than all the other elements combined
“The fact that so many stars have identical spectra is in itself a fact suggesting uniformity of composition; and the success of the theory of thermal ionization in predicting the spectral changes that occur from class to class is a further indication in the same direction.”
Unfortunately, her supervisor Shapley and the highly influential Russell said it was impossible that hydrogen and helium could dwarf the presence of all the other elements and advised her not to claim this in her Ph.D. thesis. Since Russell’s word was law, she followed his advice. Her thesis showed the sun was almost entirely hydrogen and helium, but she spent her time explaining why this could not be right rather than exploring the implications. Nevertheless, Shapley had her thesis printed as a book, Stellar Atmospheres, and it was widely-praised. Russell recommended Payne be awarded a National Research Fellowship.
In the Physical Review, John Quincy Stewart, one of Russell’s colleagues, described Stellar Atmospheres as:
“…worthy of a place in every physical, as in every astronomical library.”
To be fair to Russell, the idea that stars are made of hydrogen, helium, and very little else seemed bizarre. Payne’s result had been obtained using a method nobody had used before. For astronomers to come to terms with such an idea required a major paradigm shift, a complete change in the way they thought of stars and the universe itself.
By 1929, Russell’s own work had validated Payne’s results.
“The most important previous determination of the abundance of the elements by astrophysical means is that by Miss Payne, who determined… the relative abundance of eighteen of the most important elements. [Comparing our results gives] a very gratifying agreement, especially when it is considered Miss Payne’s results were determined by a different theoretical method, with instruments of a quite different type… and even on different bodies.”
This was the turning point. Astronomers began building their theories around the fact that stars are mainly hydrogen. Today we know that 91.00% of the atoms in the sun are hydrogen and 8.87% are helium. The atoms of other elements make up only 0.13%.
Otto Struve, Director of the National Radio Astronomy Observatories said of Payne’s work in Astronomy of the 20th Century:
It is undoubtedly the most brilliant Ph.D. thesis ever written in astronomy.
Professional Astronomer and Professor
After graduating with a doctorate, Payne continued working at the Harvard Observatory studying stars of high luminosity and variable stars: she and her assistants made over three million observations. She wrote about this work in her 1930 book Stars of High Luminosity and her 1954 book Variable Stars and Galactic Structure.
She spent her entire career at Harvard, where in 1956 she was the first woman to be appointed full professor and the first to chair a department. She retired officially in 1966, but continued to carry out research work.
Honors
1924: Elected to American Astronomical Society
1934: Annie J. Cannon Award in Astronomy
1936: Elected to American Philosophical Society
1952: Radcliffe College Award of Merit
1961: Rittenhouse Medal of the Franklin Institute
1976: Henry Norris Russell Prize
Personal Details and The End
Payne became an American citizen in 1931.
In 1933, she met the Russian astrophysicist Sergei Gaposchkin in Germany. They married in 1934 and set up home in Lexington, Massachusetts. At first they communicated entirely in German because it was the only language they were both fluent in. Following their marriage most of their research work was carried out jointly.
They had three children: Katherine and Peter became astronomers; Edward became a neurosurgeon.
Cecilia taught Sunday school at the First Unitarian Church, of which all the family were members.
Cecilia Payne-Gaposchkin died in her sleep, age 79, of lung cancer in Cambridge, Massachusetts, on December 7, 1979. Her daughter Katherine noted that cigarettes had been her mother’s only vice. Cecilia left her body to science, after which she was buried in Tewksbury, Massachusetts in the Tufts Medical School graveyard. She was survived by her husband and children.
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Further Reading
Cecilia H. Payne
Stellar Atmospheres
The Observatory Cambridge, Massachusetts, 1925
Henry Norris Russell
On the Composition of the Sun’s Atmosphere
Astrophysical Journal, Vol. 70, pp. 11-60, July 1929
Cecilia Payne-Gaposchkin, edited by Katherine Haramundanis
An Autobiography and Other Recollections
Cambridge University Press, 1984
Creative Commons
Image of bee orchid by Bernard Dupont under the Creative Commons Attribution-Share Alike 2.0 Generic license.
Image of spectral classes of stars by Rursus under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Did she ever have a son? My farther was born Clifford Edward Payne in London around the right time but we have never been able to trace his heratage. He was fostered by a woman with surname Roberts and I was the first born Payne-Roberts. Just a thought!?
Extremely informative. I am about to read her bio. This gave me an excellent heads up.
this is so good 11/10 ign
well this article was helpful soooo….. theres that?