who discovered the sun is made of hydrogen
Cecilia Payne-Gaposchkin Cecilia Helena Payne-Gaposchkin (May 10, 1900 – December 7, 1979) was a British–American astronomer and astrophysicist who, in 1925, proposed in her Ph.D. thesis an explanation for the composition of stars in terms of the relative abundances of hydrogen and helium.[1]