Cecilia Payne: An Astronomer With a Breakthrough Discovery
Understanding the configuration of stars enables astronomers to interpret more of the galaxy, but who initially discovered this?
Written by Sara Pereira
Large clusters of hot hydrogen and helium cloaked in the brilliance of the universe, the celestial enigmas you admire when you look up at the night sky would not be as appreciated today if it weren’t for Cecilia Payne-Gaposchkin. Introducing them in her doctoral thesis at Harvard University in 1925, Cecilia was able to make a revolutionary discovery despite the impediments most women trying to excel in science faced. Her work is recognized today for affirming that hydrogen is a fundamental and ubiquitous element in our universe.
Born in Wendover, England, Payne had her heart set on science, though unaware of the exact kind at the time, and later attended Cambridge University in 1919, knowing that due to her status as a woman, there would be no opportunity for her to receive an advanced degree. Listening to a lecture by astronomer Arthur Eddington, it became clear her interests lay in that field. In her classes, Payne was typically the only woman and was required to sit in the front row. Occasionally, her instructors would make remarks that embarrassed her in front of all her classmates.
In 1923, Payne moved to the United States and lived in Massachusetts to begin a fellowship at Harvard University. Numerous scientists at Harvard had already been looking at star’s spectrums, otherwise known as stellar spectra; this meant that elements within stars could be researched through absorption lines, occurring when an electron jumps from a lower energy state to a higher energy state. Many researchers, like Henry Russell, believed that the Earth’s elements were very similar to that of a star’s. However, she was able to refute this theory by leveraging her expertise, discovering that heat made atoms ionize and caused differences in absorption lines on stellar spectra. Over the course of approximately two years, her thesis asserted that most of a star’s mass is hydrogen and helium, while heavier elements in the Earth barely contributed to its mass.
Edge of a nearby stellar nursery called NGC 3324, found at the northwest corner of the Carina Nebula, and forms the mountains and valleys spanning this image; captured by the James Webb Space Telescope
Initially met with skepticism regarding her thesis, Payne transformed her groundbreaking ideas into a book titled Stellar Atmospheres in 1925. Upon the completion of her thesis, it was submitted to Henry Russell. He dismissed her findings as impossible, undermining her extensive research and effort in determining the composition of stars. Nevertheless, astronomers agreed with her and her book, acknowledging that her thesis was entirely accurate. Adopting the title of a technical assistant to an instructor at Harvard and later, becoming the first female astronomy teacher and the chair of the astronomy department there, her book and her research has changed the understanding of stellar spectra and astronomy forever.
Works Cited
“Cecilia Payne: Discoverer of the Chemical Makeup of Stars: AMNH.” American Museum of Natural History, www.amnh.org/learn-teach/curriculum-collections/cosmic-horizons-book/cecilia-payne-profile.
“Cecilia Payne-Gaposchkin: The Woman Who Found Hydrogen in the Stars.” Physics World, 2 June 2023, physicsworld.com/a/cecilia-payne-gaposchkin-the-woman-who-found-hydrogen-in-the-stars/.
Women in Science: 50 Fearless Pioneers Who Changed the World. Clarkson Potter/Ten Speed, 2016.
