
Henri Becquerel Accidentally Discovered Radioactivity in 1896
On March 1, 1896, French physicist Henri Becquerel accidentally discovered radioactivity while studying phosphorescence. He found that uranium salts emitted rays capable of exposing photographic plates without any light source — entirely on their own. This discovery overturned established views of matter and energy, and later earned him a share of the 1903 Nobel Prize in Physics alongside Marie and Pierre Curie.