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.
Henri Becquerel. February 26, 1896, was an overcast day in Paris â and that presented a problem for French physicist Antoine Henri Becquerel.Becquerel was hoping to demonstrate a link between minerals that glow when exposed to strong light and a new type of electromagnetic radiation called X-rays.enchmarks: Henri Becquerel discovers radioactivity on February 26, 1896. Credit: A photographic plate made by Henri Becquerel shows the effects of exposure to radioactivity. A metal Maltese cross, placed between the plate and radioactive uranium salt, left a clearly visible shadow on the plate.