In 1896, Henri Becquerel encouraged her to study the radiation emitted by uranium salts, which he had discovered. Together with her husband, Marie then began studying the materials that produced such radiation, searching for new elements that, according to the hypothesis they both supported, should exist in certain minerals such as pitchblende (which had the curious characteristic of emitting even more radiation than the uranium extracted from it). Indeed, in 1898, they deduced that there must be some component in pitchblende releasing more energy than uranium; on December 26 of that same year, Maria Skłodowska Curie announced the discovery of this new substance to the Paris Academy of Sciences.