Chapter 1: The Pioneering Mind of Cecilia Payne-Gaposchkin

The knowledge that stars, including our Sun, are predominantly composed of hydrogen and helium is widely accepted in the field of astronomy. However, few are aware of the individual who first proposed this groundbreaking hypothesis. This trailblazer was Cecilia Helena Payne-Gaposchkin, born on May 10, 1900, in Britain.

On May 29, 1919, a century ago, Arthur Eddington and Frank Dyson undertook the ambitious task of organizing an expedition to Africa and Brazil to observe stars during a solar eclipse, aiming to validate Einstein's general theory of relativity. Upon his return, Eddington delivered a lecture about his journey.

At that time, Cecilia was immersed in her studies of botany, physics, and chemistry at Cambridge, and this lecture had a profound impact on her. She recounted, "The result was a complete transformation of my world picture. [...] My world had been so shaken that I experienced something very like a nervous breakdown."

Despite completing her studies, she was denied a degree— a common practice at Cambridge in the early 1900s, which did not confer degrees to women. Subsequently, she relocated to the United States after securing a fellowship at the Harvard College Observatory. It was here that she penned her thesis, concluding that helium and, particularly, hydrogen were significantly more prevalent in stars, including the Sun.

Her dissertation was scrutinized by astronomer Henry Norris Russell, who supported the views of American physicist Henry Rowland and the prevailing belief that the elemental makeup of the Sun and Earth were akin. Russell discouraged her from maintaining her conclusions, leading her to label her findings as "spurious." It wasn't until years later that Otto Struve, another astronomer, reached similar conclusions through different methods and deemed her work "the most brilliant PhD thesis ever written in astronomy." Although he acknowledged her discovery in his 1929 publication, he, like many men of his era, often overshadowed her contributions.

Cecilia continued her research at Harvard, focusing on high-luminosity and variable stars, with her data pivotal in understanding stellar evolution. Despite her brilliance, she faced barriers, as women were initially excluded from professorships at Harvard, relegating her to lower-paid research positions.

Thanks to the advocacy of Harlow Shapley, the Director of the Harvard College Observatory who supported her fellowship and encouraged her thesis work, she eventually earned the title of Astronomer. In 1956, she made history as the first woman to lead a department at Harvard, taking the helm of the Department of Astronomy. She passed away on December 7, 1979.

Cecilia Payne-Gaposchkin was an extraordinary woman who unveiled the fundamental composition of the universe, yet her remarkable contributions remain underappreciated.

The first video titled "The Story of: Cecilia Payne-Gaposchkin | Stories in STEAM | Storytime!" offers an engaging overview of her life and achievements, highlighting her role in the field of astronomy.

Section 1.1: The Impact of Eddington’s Lecture

Cecilia's transformation began with Eddington's lecture, igniting her passion for astronomy and reshaping her academic trajectory.

Subsection 1.1.1: Historical Context

Chapter 2: Cecilia’s Lasting Legacy

The second video, "What Stars Are Made Of: The Life of Cecilia Payne-Gaposchkin," delves deeper into her findings and their significance in understanding stellar composition.