Henri Becquerel's discovery of radioactivity - 125 years later

This year it is 125 years since Henri Becquerel accidentally discovered radioactivity. It has been argued that this was the result after Becquerel's long, systematic research into the phenomenon of luminescence. Becquerel's discovery, together with Marie and Pierre Curie's discovery of radium, became the breakthrough for the 20th century research in medical radiation physics and the use of radioactivity in medicine. In this paper, we draw attention to Becquerel's discovery and the impact it had on medicine and society.