Marie Curie and the Discovery of Radioactivity

In December 1897, Marie Curie needed a subject for her doctoral thesis. While others chased the newly discovered X-rays, she chose a fainter mystery: the strange rays emitted by uranium, found by Henri Becquerel a year before. As a young mother to her infant daughter Irène, she began work in a damp, unheated storeroom at the School of Industrial Physics and Chemistry in Paris. It was a miserable space, previously used as a medical school dissecting room. While her husband, Pierre, a professor at the school, continued his own research on crystals, Marie set out to precisely measure the energy that seemed to radiate from uranium salts, an energy no one yet understood.