Who Was Cecilia Payne and How Did She Change Astronomy?

In 1919, a student at the University of Cambridge had an extra ticket to a lecture being given by an astronomer who had just returned from a trip off the west coast of Africa where he observed the stars and a solar eclipse.

Cecilia Payne-Gaposchkin, then 19 years old and an undergraduate student, took the extra ticket. The lecture changed her life and inspired her to become an astronomer.  

“For three nights, I think, I did not sleep,” she later wrote.

In turn, Payne-Gaposchkin changed astronomy when she proposed what the stars were made of. Although scientists would later come to accept her ideas — and even try to take credit for them — Payne-Gaposchkin faced discrimination and rejection throughout her distinguished career.

By the mid-1800s, astronomers thought the same elements that made up life on Earth also made up the stars, comets, and other planets. Advancements in telescopes allowed scientists to see the sky in a new way, but many scientists kept with the same thinking.

In 1924, Payne-Gaposchkin was a doctoral student in physics at Harvard University. She had finished her undergraduate studies at the University of Cambridge in England, but the school didn’t grant graduate degrees to women, and she had to come to the U.S. for advanced study.

Using the telescope in Harvard’s observatory, Payne-Gaposchkin saw the universe in a new way.  

“She calculated that stars were mostly made of hydrogen, as in a million times more hydrogen, than the scientific community had assumed,” says Donovan Moore, author of What Stars Are Made of: The Life of Cecilia Payne-Gaposchkin.

Read More: Who Was Anna Mani, and How Was She a Pioneer for Women in STEM?

At the time, atomic fusion was not yet a thing, and scientists thought the sun had a similar elemental makeup as Earth. Payne-Gaposchkin conducted a spectral analysis, which found that the stars were made up almost entirely of hydrogen and helium.

Even Payne-Gaposchkin was initially surprised by her results. But she trusted her math and presented her findings in her doctoral dissertation. Although she was correct, leading scientists in the field of astrophysics weren’t ready to accept a new idea, particularly one that was coming from a graduate student, let alone a woman.

“When she showed her findings to [Henry] Norris Russell, the Director of the Princeton Observatory, the Dean of American astronomers at the time, he flatly told her she was wrong,” Moore says. “But Cecilia believed in her findings, and she was clever. She re-wrote her thesis to state that hydrogen was almost certainly not as preeminent as she had found.”

The almost certainly, Moore says, was Payne-Gaposchkin’s way of leaving “the door open to someday being found to be correct.”

Payne-Gaposchkin was indeed found to be correct, and scientists now accept that the stars (including the sun) are made up of 73 percent hydrogen and 25 percent helium.

As the scientific community adjusted to the idea that the stars and sun were not the same as the Earth, Payne-Gaposchkin’s detractors rushed forward to claim credit for themselves. 

“Years later, she was, in fac,t proven to be right — by the very man who told her she was wrong: Norris Russell. He got the credit,” Moore says.

History would later correct itself, and Payne-Gaposchkin would become known as the scientist who truly identified what the stars were made of. But, Payne-Gaposchkin would not be remembered as prominently as other scientists who also made critical discoveries.  

After Payne-Gaposchkin had corrected her dissertation by hedging that hydrogen was “almost certainly not as prominent,” she could graduate with her Ph.D. in 1925.  Although she received “near universal skepticism” for her ideas, Moore says she believed in herself and did not bend to the criticism. She also remained determined to have a career in astronomy, even though the field was almost entirely male and extremely unwelcoming of women.

“It ultimately paid off,” Moore says. “She was finally recognized for her discovery, married, brought up a family, and was named the first female professor at Harvard to be promoted through the ranks of tenure. She later became chairman of the Harvard Department of Astronomy.”

Scientists would later remember Payne-Gaposchkin for her accomplishments and how her determination to be part of the scientific community would one day open doors for other women who wished to do the same. Vera Rubin — who discovered that dark matter was dominant in the universe and initially received pushback — has cited Payne-Gaposchkin as an inspiration.

In the end, Payne-Gaposchkin prevailed. Three years before her death in 1979, she received a lifetime achievement award from the American Astronomical Society. Ironically, the award was named in honor of Henry Norris Russell, one of her early detractors and one of the scientists who tried to claim credit for her work.

“It was extremely difficult for a woman to be taken seriously in the 1920s. She, unfortunately, found herself in that position. It’s also unfortunate that not a lot has changed,” Moore says.

Read More: How Vera C. Rubin Revolutionized Dark Matter

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• The American Scholar. SCIENCE: The Ladies of Observatory Hill: Annie Jump Cannon and Cecilia Payne-Gaposchkin

• Donovan Moore. What Stars Are Made Of: The Life of Cecilia Payne-Gaposchkin

• Women in their Element. Cecilia Payne-Gaposchkin and the Elemental Composition of Stars

• The American Astronomical Society. Henry Norris Russell Lectureship

Emilie Lucchesi has written for some of the country's largest newspapers, including The New York Times, Chicago Tribune and Los Angeles Times. She holds a bachelor's degree in journalism from the University of Missouri and an MA from DePaul University. She also holds a Ph.D. in communication from the University of Illinois-Chicago with an emphasis on media framing, message construction and stigma communication. Emilie has authored three nonfiction books. Her third, A Light in the Dark: Surviving More Than Ted Bundy, releases October 3, 2023, from Chicago Review Press and is co-authored with survivor Kathy Kleiner Rubin.