See also: 1844 in science, other events of 1845, 1846 in science and the list of years in science.
Astronomy April – William Parsons, third Earl of Rosse, discovers that the nebula M51 has a spiral structure Physics September 13 – Michael Faraday discovers that an intense magnetic field can rotate the plane of polarized light Awards Copley Medal: Theodor Schwann Wollaston Medal for Geology: John Phillips Births September 11 - Emile Baudot, telegraph engineer († 1903) Deaths March 13 - John Frederic Daniell, chemist and physicist (born 1790) October 18 - Dominique, comte de Cassini, French astronomer (born 1748)