Editing 1845 in science (section)

==Astronomy==
* April – [[William Parsons, 3rd Earl of Rosse|Lord Rosse]] discovers that the nebula [[Whirlpool Galaxy|M51]] has a spiral structure.
* September–October – [[Cornish people|Cornish]] mathematician [[John Couch Adams]] communicates to [[James Challis]] and [[George Biddell Airy]] his calculations demonstrating that a body ([[Neptune]]) is perturbing the orbit of [[Uranus]].<ref>{{cite journal|first1=William|last1=Sheehan|first2=Nicholas|last2=Kollerstrom|first3=Craig B.|last3=Waff|url=http://www.sciam.com/article.cfm?articleID=000CA850-8EA4-119B-8EA483414B7FFE9F|title=The Case of the Pilfered Planet - Did the British steal Neptune?|journal=[[Scientific American]]|date=2004-11-22|volume=291|issue=6|pages=92–99|doi=10.1038/scientificamerican1204-92|pmid=15597985|url-access=subscription}}</ref>
* 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.<ref>{{Cite EB1911|wstitle=Adams, John Couch}}</ref>
* Construction begins in [[Ireland]] of the "[[Leviathan of Parsonstown]]", a [[telescope]] built by Lord Rosse.