See also: 1842 in science, other events of 1843, 1844 in science and the list of years in science.

Table of contents

1 Astronomy 2 Chemistry 3 Mathematics 4 Physics 5 Technology 6 Awards 7 Births 8 Deaths

Astronomy

• John Couch Adams predicts the existence and location of Neptune from irregularities in the orbit of Uranus
• Heinrich Schwabe reports a periodic change in the number of sunspots: they wax and wan in number according to a ten-year cycle

• Carl Mosander discovers Terbium and Erbium

• Pierre-Alphonse Laurent discovers and presents the Laurent expansion theorem
• William Rowan Hamilton discovers the calculus of quaternions and deduces that they are non-commutative
• Arthur Cayley and James Joseph Sylvester found the algebraic invariant theory

• James Joule experimentally finds the mechanical equivalent of heat

• Launch of SS Great Britain, the first iron-hulled, propeller-driven ship to cross the Atlantic Ocean
• Robert Stirling and his brother James convert a steam engine at a Dundee factory to operate as a Stirling engine
• The first public telegraph line in the United Kingdom is laid between Paddington and Slough
• Completion of the Thames Tunnel, the first underwater tunnel in the world

• Copley Medal: Jean-Baptiste Dumas
• Wollaston Medal for Geology: Jean-Baptiste Elie de Beaumont; Pierre Armand Dufrenoy

• June 12 - David Gill, astronomer († 1914)
• December 11 - Robert Koch, physician, famous for the discovery of the tubercle bacillus (1882) and the cholera bacillus (1883) and for his development of Koch's postulates. He was awarded the Nobel Prize in Physiology or Medicine in 1905 († 1910)