8 Responses. > 1  the Moon takes an elliptical path around the Earth. The planets make nearly elliptical orbits around the Sun, close enough for reasonable approximations, but the Moonâs Orbit around the Earth is sufficiently influenced by the Sun that it follows a path detectably different from an ellipse.
Quick Answer. In 1896, French scientist Antoine Henri Becquerel discovered radioactivity which was an early contribution to atomic theory. He discovered this phenomenon while experimenting with uranium and a photographic plate. Continue Reading.
strate the existence of the elements discovered through their radioactive emissions. She was awarded two Nobel Prizes, one in 1903 together with Pierre Curie and. Henri Becquerel for the discovery of radioactivity, and other in 1911 for the dis-. covery of polonium and radium (Fig.