1845 in science
The year 1845 in science and technology involved some significant events, listed below.
Astronomy
- April – Lord Rosse discovers that the nebula M51 has a spiral structure.
- September–October – Cornish mathematician John Couch Adams communicates to James Challis and George Biddell Airy his calculations demonstrating that a body is perturbing the orbit of Uranus.
- November 10 – Urbain Le Verrier presents to the Académie des sciences in Paris a memoir showing that existing theories fail to account for the motion of Uranus.
- Construction begins in Ireland of the "Leviathan of Parsonstown", a telescope built by Lord Rosse.
Biology
- August–September – Previously unknown Potato blight strikes the potato crop in Ireland: start of the Great Famine.
Chemistry
- March 17 – Stephen Perry patents the rubber band in England.
- Edmond Frémy discovers the oxidizing agent Frémy's salt.
Exploration
- August – John Franklin's expedition with HMS Erebus and HMS Terror to find the Northwest Passage is last seen entering Baffin Bay prior to its mysterious disappearance.
Medicine
- December 27 – Anesthesia is used in childbirth for the first time, by Dr Crawford Long in Jefferson, Georgia.
Physics
- September 13 – Michael Faraday discovers that an intense magnetic field can rotate the plane of polarized light, the Faraday effect.
- C. H. D. Buys Ballot confirms the Doppler effect for sound waves.
- Kirchhoff's circuit laws are first described by German physicist Gustav Kirchhoff.
Technology
- July 26–August 10 – Isambard Kingdom Brunel’s iron steamship Great Britain makes the Transatlantic Crossing from Liverpool to New York, the first screw propelled vessel to make the passage.
- The saxhorn family of valved brass instruments is patented by Adolphe Sax in France.
Publications
- January 14 – Physikalische Gesellschaft zu Berlin established and begins publishing Fortschritte der Physik and Verhandlungen.
- August 28 – The journal Scientific American begins publication.
- Alexander von Humboldt's Kosmos: Entwurf einer physischen Weltbeschreibung begins publication.
Awards
- Copley Medal: Theodor Schwann
- Wollaston Medal for Geology: John Phillips
Births
- February 17 – Fyodor Pirotsky, Ukrainian-born Russian military and electrical engineer and inventor.
- March 3 – Georg Cantor, Russian-born German mathematician.
- March 27 – Wilhelm Röntgen, German physicist, discoverer of X-rays, Nobel laureate.
- April 21 – William Healey Dall, American malacologist and explorer.
- May 4 – William Kingdon Clifford, English geometer.
- May 16 – Élie Metchnikoff, Russian-born microbiologist, Nobel laureate.
- June 16 – Heinrich Dressel, German archaeologist.
- July 4 – Thomas Barnardo, Irish-born physician and philanthropist.
- September 11 – Émile Baudot, French telegraph engineer.
- November 14 – Ulisse Dini, Italian mathematician.
Deaths
- January 11 - Etheldred Benett, British geologist.
- March 13 – John Frederic Daniell, English chemist and physicist.
- March 18 – 'Johnny Appleseed' , American nurseryman.
- April 10 – Thomas Sewall, American anatomist.
- October 18 – Dominique, comte de Cassini, French astronomer.
- Jean Henri Jaume Saint-Hilaire, French botanist.