British astronomer and astrophysicist Cecilia Payne-Gaposchkin was born #OTD in 1900.
In 1925 she proposed that stars were composed primarily of hydrogen and helium. Her groundbreaking conclusion was initially rejected, because it contradicted the science of the time, which held that no significant elemental differences distinguished the Sun and Earth. Independent observations eventually proved that she was correct.
Books by Cecilia Payne-Gaposchkin are coming soon at PG.
