As the 40th anniversary of her death approaches, there is an international push to remember the achievements of Celia Payne-Gaposchkin, a British-American astronomer and astrophysicist who has not been fully celebrated for being the first person to explain what stars are made of, including the Sun.
She was never given proper credit for the discovery, as another astronomer Henry Norris Russell persuaded her not to present her conclusion in her celebrated 1925 PhD thesis when she was 25.
The thesis was considered by many astronomers as one of the best and most influential in the field of astronomy.
Russell later published the discovery on his own. He did mention Celia Payne-Gaposchkin in the paper, but it was Russell who got all the credit for her PhD thesis
Celia Payne-Gaposchkin is the reason we know basically anything about variable stars (stars whose brightness as seen from earth fluctuates). Literally every other study on variable stars is based on her work.
Her thesis was called “Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars” and led to astronomers Otto Struve and Velta Zeberg calling it undoubtedly the most brilliant PhD thesis ever written in astronomy”.
In her PhD she managed to accurately relate the spectral classes of stars to their actual temperatures.
She did so by applying the ionization theory. In the PhD, she argued that the variation of the stellar absorption lines was more due to different amounts of ionization.
The main discovery was that the Sun was made out of silicon, carbon and other metals, many of which can also be found in the Earth spectrum. What was an important discovery was that Celia Payne-Gaposchkin, found out that helium and hydrogen were vastly more present in the Sun and in stars in general and argued that hydrogen is actually the most abundant element in the Universe.
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.