Celebrating a trailblazer
Cecilia Payne-Gaposchkin: 125 years since her birth and 100 years since her revolutionary PhD thesis
This December Newnham College, Cambridge, is honouring one of its most illustrious alumnae, the pioneering astrophysicist Cecilia Payne-Gaposchkin (1900–1979), as it marks both the 125th anniversary of her birth and the centenary of her groundbreaking 1925 doctoral thesis, widely described as: “the most brilliant PhD thesis ever written in astronomy.”
“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. Nothing can compare with that experience.”
Cecilia Payne-Gaposchkin
A Newnham student with a cosmic vision
Born in 1900, Cecilia Payne-Gaposchkin matriculated at Newnham College in 1919 on a scholarship, originally to study Botany, following in the footsteps of her aunt Dora Pertz (NC 1882). However her academic trajectory changed dramatically after she attended a lecture by Arthur Eddington, describing his 1919 solar eclipse expedition. The lecture inspired a transformation of her worldview, and she switched to Physics, developing a keen interest in Astronomy and what was then an emerging field: Astrophysics.
While at Newnham she rediscovered the College’s then-little-used observatory and began observing the stars, laying the groundwork for a lifelong fascination with the cosmos. The historic telescope she used has recently been restored and re-sited in Newnham College’s Porters’ Lodge, a symbol of her scientific legacy.
Writing to Newnham College Principal Myra Curtis in 1949 about the ScD (Doctor of Science, one of the highest degrees awarded by the University for distinguished research in science and literature), later awarded to her by the University of Cambridge (1952), Cecilia remarked:
“Anyone who has been at Cambridge, I think, can hardly feel at home anywhere else. My four years at Newnham have never been matched by anything that has happened since.”
Cecilia Payne-Gaposchkin, credit: Smithsonian Institute
Cecilia Payne-Gaposchkin, credit: Smithsonian Institute
A thesis that changed how we see the universe
In 1925, Payne-Gaposchkin became the first person to earn a doctoral degree (PhD) in astronomy from Harvard University. Her doctoral thesis, ‘Stellar Atmospheres: A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars’ became a turning point in astrophysics.
By analysing stellar spectra, she concluded that stars, including our Sun, are composed primarily of hydrogen and helium, overturning the widely held belief at the time that stars had a composition similar to Earth.
Her conclusions were initially met with scepticism, including from leading astronomers such as Henry Norris Russell, but independent observations in 1929 vindicated her results.
Decades later, astronomer Otto Struve would describe her 1925 dissertation as “undoubtedly the most brilliant Ph.D. thesis ever written in astronomy.” Today, her discovery is regarded as foundational with hydrogen and helium remaining recognised as the dominant elements in stars throughout the universe.
Cecilia Payne-Gaposchkin, credit: Smithsonian Institute
Cecilia Payne-Gaposchkin, credit: Smithsonian Institute
Her career at Harvard continued to mark a series of historic firsts: in 1956 she became the first woman to be promoted to full professor from within the faculty, and shortly after, the first woman to lead a department there.
Throughout her life she conducted extensive research on stellar spectra and variable stars. Her work shaped major developments in our understanding of stellar evolution and the structure of the Milky Way.
"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. 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."
Newnham College grounds, with the white, domed observatory visible.
Newnham College grounds, with the white, domed observatory visible.
The telescope used by Cecilia Payne-Gaposchkin pictured inside the Newnham Observatory.
The telescope used by Cecilia Payne-Gaposchkin pictured inside the Newnham Observatory.
Cecilia Payne Gaposchkin, from Thersites, 1923 (Newnham College Archives, photographer unknown)
Cecilia Payne Gaposchkin, from Thersites, 1923 (Newnham College Archives, photographer unknown)
Celebrations at Newnham - a unique weekend of astronomy, music and talks
From Friday 5 December to Sunday 7 December 2025, Newnham College will host a weekend of events to commemorate these double anniversaries.
Highlights include:
- A keynote talk with Lord Rees of Ludlow OM - Former Astronomer Royal and 60th President of the Royal Society, reflecting on Payne-Gaposchkin’s impact on modern astrophysics.
- A concert inspired by the stars, “The Infinite Shining Heavens” with pianist Anna Tilbrook, soprano Claire Booth and soprano Katherine Gregory (NC 2020).
- Stargazing with the Cambridge Astronomical Association at the Institute of Astronomy.
- A series of talks by notable astrophysicists and astronomers including: Professor Anne Christine Davis, Fellow Professor Maria Ubiali, Professor Hiranya Peiris, former Ruth Holt Research Fellow Dr Ricarda Beckmann and Professor Nikku Madhusudhan.
- Private behind the scenes tours of the Whipple Museum of the History of Science.
- The unveiling of the restored telescope used by Payne-Gaposchkin, now installed in the Porters’ Lodge - pictured below.
Booking is required. For full event listings, timings and how to book, please visit the Newnham College event page.
The text in this work is licensed under a Creative Commons Attribution 4.0 International License.
Story and design by: Jessica Keating
Date: 28 November 2025
