View source for Biography:Urbain Le Verrier

{{short description|French astronomer and mathematician (1811–1877)}}
{{Infobox scientist
|name              = Urbain Le Verrier
|image             = Le_Verrier_colored.jpg
|image_size        =
|caption           = 
|birth_name        = Urbain Jean Joseph Le Verrier
|birth_date        = {{birth date|1811|3|11|df=y}}
|birth_place       = Saint-Lô, [[Place:First French Empire|France]]
|death_date        = {{Death date and age|1877|9|23|1811|3|11|df=y}}
|death_place       = Paris, [[Place:French Third Republic|France]]
|nationality       = <!-- use only when necessary per WP:INFONAT -->
|field             = Mathematics, astronomy
|work_institutions =
|alma_mater        = École Polytechnique
|doctoral_advisor  =
|doctoral_students =
|known_for         = {{ubl|[[Astronomy:Discovery of Neptune|Discovery of Neptune]]|[[Astronomy:Euler's three-body problem|Euler's three-body problem]]|[[Faddeev–LeVerrier algorithm]]}}
|author_abbrev_bot =
|author_abbrev_zoo =
|influences        =
|influenced        =
|prizes            = {{ubl|[[Physics:Copley Medal|Copley Medal]] (1846)|Gold Medal of the Royal Astronomical Society (1868, 1876)}}
|religion          =
|footnotes         =
|signature         = Signature Urbain Le Verrier.svg
}}
'''Urbain Jean Joseph Le Verrier''' ({{IPA-fr|yʁbɛ̃ ʒɑ̃ ʒɔzɛf lə vɛʁje|lang}}; 11 March 1811 – 23 September 1877) was a French astronomer and mathematician who specialized in [[Physics:Celestial mechanics|celestial mechanics]] and is best known for predicting the existence and position of [[Astronomy:Neptune|Neptune]] using only mathematics.

The calculations were made to explain discrepancies with [[Astronomy:Uranus|Uranus]]'s [[Physics:Orbit|orbit]] and the [[Physical law|laws]] of Kepler and [[Biography:Isaac Newton|Newton]]. Le Verrier sent the coordinates to [[Biography:Johann Gottfried Galle|Johann Gottfried Galle]] in Berlin, asking him to verify. Galle found Neptune the same night he received Le Verrier's letter, within 1° of the predicted position.

The [[Astronomy:Discovery of Neptune|discovery of Neptune]] is widely regarded as a dramatic validation of celestial mechanics, and is one of the most remarkable moments of 19th-century science.

==Life==
[[File:P1010920 Paris XIV Obervatoire de Paris Statue de Le Verrier reductwk.JPG |thumb|Statue of Le Verrier at the Paris Observatory]]

===Early years===
Urbain Le Verrier was born at Saint-Lô, Manche, France, to a modest bourgeois family, his parents being Louis-Baptiste Le Verrier and Marie-Jeanne-Josephine-Pauline de Baudre.<ref name="JL">{{Cite book|language= fr |title= Le Verrier : savant magnifique et détesté |first= James |last= Lequeux |publisher=EDP Sciences |year= 2009 |isbn= 978-2759804221 |url= https://books.google.com/books?id=KmYckRjCug8C}}</ref> 

He studied at the École Polytechnique – briefly chemistry, under Gay-Lussac, writing papers on the combinations of phosphorus and hydrogen, and of phosphorus and oxygen.<ref name="Ball"/> 

He then switched to astronomy, particularly celestial mechanics, and accepted a job at the Paris Observatory. He spent most of his professional life there, eventually becoming director of the institution, 1854–1870 and again 1873–1877.<ref>{{CathEncy|wstitle=Urbain-Jean-Joseph Le Verrier}}</ref>

In 1846 Le Verrier became a member of the French Academy of Sciences, and in 1855 was elected a foreign member of the Royal Swedish Academy of Sciences. His name is one of the 72 names inscribed on the Eiffel Tower.

===Career===
====Early work====
Le Verrier's first work in astronomy was presented to the ''Académie des Sciences'' in September 1839, entitled ''Sur les variations séculaires des orbites des planètes'' (''On the Secular Variations of the Orbits of the Planets''). This work addressed the then most-important question in astronomy: the [[Astronomy:Stability of the Solar System|stability of the Solar System]], first investigated by [[Biography:Pierre-Simon Laplace|Laplace]]. He was able to derive some important limits on the motions of the system, but due to the inaccurately-known masses of the planets, his results were tentative.

From 1844 to 1847, Le Verrier published a series of works on periodic [[Astronomy:Comet|comet]]s, in particular those of [[Astronomy:Lexell's Comet|Lexell]], Faye and DeVico. He was able to show some interesting interactions with the planet [[Astronomy:Jupiter|Jupiter]], proving that certain comets were actually the reappearance of previously-known comets flung into different orbits.<ref name="Tisserand">
{{cite journal
|bibcode=1880AnPar..15...23T
|title=Les Travaux de LeVerrier
|first=M.F.
|last=Tisserand
|language=fr
|journal=Annales de l'Observatoire de Paris |volume=15
|date=1880|page=23
}}</ref>

====Discovery of Neptune====
{{Main|Astronomy:Discovery of Neptune}}
[[File:Leverrier signature.jpg|thumb|LeVerrier's autograph]]

Le Verrier's most famous achievement is his prediction of the existence of the then unknown planet Neptune, using only mathematics and astronomical observations of the known planet Uranus. Encouraged by physicist [[Biography:François Arago|Arago]],<ref>[http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Arago.html Arago summary<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20040807054400/http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Arago.html |date=7 August 2004 }}</ref> Director of the Paris Observatory, Le Verrier was intensely engaged for months in complex calculations to explain small but systematic discrepancies between [[Astronomy:Uranus|Uranus]]'s observed [[Physics:Orbit|orbit]] and the one predicted from the [[Physical law|laws]] of gravity of [[Biography:Isaac Newton|Newton]]. At the same time, but unknown to Le Verrier, similar calculations were made by John Couch Adams in England. Le Verrier announced his final predicted position for Uranus's unseen perturbing [[Astronomy:Planet|planet]] publicly to the French Academy on 31 August 1846, two days before Adams's final solution was privately mailed to the Royal Greenwich Observatory. Le Verrier transmitted his own prediction by 18 September in a letter to [[Biography:Johann Gottfried Galle|Johann Galle]] of the Berlin Observatory. The letter arrived five days later, and the planet was found with the Berlin Fraunhofer refractor that same evening, 23 September 1846, by Galle and Heinrich d'Arrest within 1° of the predicted location near the boundary between Capricorn and [[Astronomy:Aquarius (constellation)|Aquarius]].

There was, and to an extent still is, controversy over the apportionment of credit for the discovery. There is no ambiguity to the discovery claims of Le Verrier, Galle, and d'Arrest. Adams's work was begun earlier than Le Verrier's but was finished later and was unrelated to the actual discovery. Not even the briefest account of Adams's predicted orbital elements was published until more than a month after Berlin's visual confirmation. Adams made full public acknowledgement of Le Verrier's priority and credit (not forgetting to mention the role of Galle) when he gave his paper to the Royal Astronomical Society in November 1846:<ref>{{cite web | author=Adams, J.C., MA, FRAS, Fellow of St John's College, Cambridge | date=1846 | url=https://archive.org/details/appendicestovari00grearich | title=On the Perturbations of Uranus | page=265 | work=Appendices to various nautical almanacs between the years 1834 and 1854 (reprints published 1851) (this is a 50Mb download of the pdf scan of the nineteenth-century printed book) | publisher=UK Nautical Almanac Office, 1851 | access-date=23 January 2008 }}</ref>

{{quote|I mention these dates merely to show that my results were arrived at independently, and previously to the publication of those of M. Le Verrier, and not with the intention of interfering with his just claims to the honours of the discovery; for there is no doubt that his researches were first published to the world, and led to the actual discovery of the planet by Dr. Galle, so that the facts stated above cannot detract, in the slightest degree, from the credit due to M. Le Verrier.|Adams (1846)}}

==== Tables of the planets ====
Early in the 19th century, the methods of predicting the motions of the planets were somewhat scattered, having been developed over decades by many different researchers. In 1847, Le Verrier took on the task to "... embrace in a single work the entire planetary system, put everything in harmony if possible, otherwise, declare with certainty that there are as yet unknown causes of perturbations...",<ref>
{{cite journal
|title=Trois siècles de mécanique céleste à l'Observatoire de Paris
|date=1968
|first=J.
|last=Lévy
|language=fr
|journal=L'Astronomie |volume=82
|page=381|bibcode=1968LAstr..82..381L
}}</ref> 
a work which would occupy him for the rest of his life.

Le Verrier began by re-evaluating, to the 7th order, the technique of calculating the [[Astronomy:Perturbation|planetary perturbations]] known as the perturbing function. This derivation, which resulted in 469 mathematical terms, was complete by 1849. He next collected observations of the positions of the planets as far back as 1750. Examining these and correcting for inconsistencies with the most recent data occupied him until 1852.<ref name="Tisserand"/>

Le Verrier published, in the ''Annales de l'Observatoire de Paris'', tables of the motions of all of the known planets, releasing them as he completed them, starting in 1858.<ref>see, for instance, 
{{cite journal
|url=http://articles.adsabs.harvard.edu/cgi-bin/iarticle_query?journal=AnPar&volume=0004&type=SCREEN_THMB
|title=Théorie et Tables du Mouvement Apparent du Soleil 
|journal=Annales de l'Observatoire Impérial de Paris |volume=4
|language=fr 
|author=LeVerrier 
|date=1858}}</ref> 
The tables formed the [[Fundamental ephemeris|fundamental ephemeris]] of the ''[[Astronomy:Connaissance des Temps|Connaissance des Temps]]'', the astronomical almanac of the ''[[Organization:Bureau des Longitudes|Bureau des Longitudes]]'', until about 1912.<ref>
{{Cite journal 
|bibcode=1910Obs....33..404D
|title=Leverrier's tables of Saturn, Uranus, and Neptune
|journal=The Observatory
|volume=33
|page=404 
|first=A.M.W.
|last=Downing
|date=1910}}</ref> 
About that time, Le Verrier's work on the outer planets was revised and expanded by Gaillot.<ref>see, for instance, 
{{cite journal
|url=http://articles.adsabs.harvard.edu/cgi-bin/iarticle_query?journal=AnPar&volume=0031&type=SCREEN_THMB |title=Tables Rectifiées du Mouvement de Jupiter 
|journal=Annales de l'Observatoire de Paris, Mémoires |volume=31
|language=fr 
|author=Gaillot 
|date=1913}}</ref>

====Precession of Mercury====
{{main|Astronomy:Vulcan (hypothetical planet)}}
[[File:Leverrier grave.jpg|thumb|Le Verrier's grave]]
Le Verrier began studying the motion of [[Astronomy:Mercury (planet)|Mercury]] as early as 1843, with a report entitled ''Détermination nouvelle de l 'orbite de Mercure et de ses perturbations'' (''A New Determination of the Orbit of Mercury and its Perturbations'').<ref name="Tisserand"/>
In 1859, Le Verrier was the first to report that the slow [[Physics:Precession|precession]] of [[Astronomy:Mercury (planet)|Mercury]]'s orbit around the [[Astronomy:Sun|Sun]] could not be completely explained by [[Physics:Newtonian mechanics|Newtonian mechanics]] and perturbations by the known planets. He suggested, among possible explanations, that another planet (or perhaps, instead, a series of smaller 'corpuscules') might exist in an orbit even closer to the Sun than that of Mercury, to account for this perturbation.<ref>U. Le Verrier (1859), (in French), [https://archive.org/stream/comptesrendusheb49acad#page/378/mode/2up "Lettre de M. Le Verrier à M. Faye sur la théorie de Mercure et sur le mouvement du périhélie de cette planète"], Comptes rendus hebdomadaires des séances de l'Académie des sciences (Paris), vol. 49 (1859), pp. 379–383. (At p. 383 in the same volume Le Verrier's report is followed by another, from Faye, enthusiastically recommending to astronomers to search for a previously undetected intra-mercurial object.)</ref> (Other explanations considered included a slight oblateness of the Sun.) The success of the search for [[Astronomy:Neptune|Neptune]] based on its perturbations of the orbit of [[Astronomy:Uranus|Uranus]] led astronomers to place some faith in this possible explanation, and the hypothetical planet was even named [[Astronomy:Vulcan (hypothetical planet)|Vulcan]]. However, no such planet was ever found,<ref>{{cite book | last1=Baum | first1=Richard | last2=Sheehan | first2=William | title=In Search of Planet Vulcan, The Ghost in Newton's Clockwork Machine | date=1997 | isbn=0-306-45567-6 | publisher=Plenum Press | location=New York | url-access=registration | url=https://archive.org/details/insearchofplanet0000baum }}</ref> and the anomalous precession was eventually explained by [[Astronomy:Tests of general relativity#Perihelion precession of Mercury|general relativity theory]].

===Later life===
Le Verrier's methods of management were disliked by the staff of the ''Observatoire'', and the disputes became so great that he was driven out in 1870. He was succeeded by Delaunay, but was reinstated in 1873 after Delaunay accidentally drowned. Le Verrier held the position until his death in 1877.<ref name="Ball">
{{cite book
|url=https://books.google.com/books?id=6Yo-AAAAYAAJ
|title=Great Astronomers
|first=Robert S.
|last=Ball
|date=1907
|publisher=Sir Isaac Pitman and Sons, Ltd., Bath and New York
|pages=335–353}}</ref>

Le Verrier married Lucille Clotilde Choquet in 1837<ref>{{Cite web|url=http://www.annales.org/archives/x/uleverrier.html |title=Biographie de Urbain Jean Joseph Le Verrier (1811–1877)|website=annales.org|access-date=28 October 2012|language=fr}}</ref> and had 3 children.<ref>{{Cite EB1911|wstitle= Leverrier, Urbain Jean Joseph | volume= 16 |last1= Clerke |first1= Agnes Mary | page = 510 |short=1}}</ref><ref>{{Cite web|url=http://www.annales.org/archives/x/leverrier.html|title=Louis Paul Urbain Le Verrier et Jean Charles Léon Le Verrier|website=annales.org|access-date=28 October 2012|language=fr}}</ref> He died in Paris, France and was buried in the Montparnasse Cemetery. A large stone celestial globe sits over his grave. He will be remembered by the phrase attributed to [[Biography:François Arago|Arago]]: "the man who discovered a planet with the point of his pen."

In 1847, he was elected to the American Philosophical Society.<ref>{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1847&year-max=1847&dead=&keyword=&smode=advanced|access-date=14 April 2021|website=search.amphilsoc.org}}</ref>

==Honours==
* Gold Medal of the Royal Astronomical Society – 1868 and 1876
* Namesake of [[Astronomy:Impact crater|crater]]s on the [[Astronomy:Le Verrier (lunar crater)|Moon]] and [[Astronomy:Mars|Mars]], a [[Astronomy:Rings of Neptune|ring of Neptune]], and the [[Astronomy:Asteroid|asteroid]] [[Astronomy:1997 Leverrier|1997 Leverrier]]
* One of the 72 names engraved on the Eiffel Tower

==See also==
* [[Astronomy:Discovery of Neptune|Discovery of Neptune]]
* List of works by Henri Chapu Statue of Le Verrier
* Lyttleton, Raymond Arthur, (1968) ''Mysteries of the Solar System'', Clarendon, Oxford, UK (1968), Chapter 7: The discovery of Neptune<ref>{{cite book
		| last = Lyttleton
		| first = Raymond Arthur
		| title = Mysteries of the Solar System
		| date = 1968 | publisher = Clarendon Press| place =Oxford|pages=215-250}}</ref>

==References==
{{reflist}}

==Further reading==
* {{Citation | first = David | last = Aubin | title = The Fading Star of the Paris Observatory in the Nineteenth Century: Astronomers' Urban Culture of Circulation and Observation | url = http://www.institut.math.jussieu.fr/~daubin/publis/2003c.pdf | journal = Osiris | volume = 18 | year = 2003 | pages = 79–100 | bibcode = 2003Osir...18...79A | doi = 10.1086/649378 | s2cid = 143773138 | url-status=dead | archive-url = https://web.archive.org/web/20071129105436/http://www.institut.math.jussieu.fr/~daubin/publis/2003c.pdf | archive-date = 29 November 2007 }}.
* {{cite book | author=Grosser, M. | title=The Discovery of Neptune | date=1962 | publisher=Harvard University Press | isbn=0-674-21225-8 }}
* {{Citation | last = Le Verrier | first = Urbain | year = 1835 | journal = Annales de Chimie et de Physique | place = Paris | volume = 60 | page = 174 | title = Chemical research of Le Verrier}}.
* {{Citation | first = Fabien | last = Locher | title = L'empire de l'astronome : Urbain Le Verrier, l'Ordre et le Pouvoir | url = http://chrhc.revues.org/index248.html | journal = Cahiers d'histoire. Revue d'histoire critique | volume = 102 | year = 2007 | issue = 102 | language = fr |trans-title=The empire of Astronomy: Urbain le Verrier, the order and the power | pages = 33–48| doi = 10.4000/chrhc.248 | doi-access = free }}.
* {{Citation | first = Fabien | last = Locher | title = Le Savant et la Tempête. Étudier l'atmosphère et prévoir le temps au XIXe siècle | place = Rennes | language = fr |trans-title=The Sage and the Tempest. Studying the Atmosphere and Forecasting the Weather in the Nineteenth Century | publisher = Presses Universitaires de Rennes | series = Carnot | year = 2008}}.
*{{Citation|last1=Lequeux|first1=James|title=Le Verrier – Magnificent and Detestable Astronomer|date=2013|publisher=Springer|location=New York|bibcode=2013lvda.book.....L |isbn=9781461455646|edition=English Trans by Bernard Sheehan}}
* {{Citation | last = Rawlins | first = Dennis |  year = 1999 | title = Recovery of the RGO Neptune Papers. Adams' Final Prediction Missed by Over Ten Degrees | url = http://www.dioi.org/vols/w91.pdf | journal = DIO | volume = 9 | number = 1 | pages = 3–25| bibcode = 1999DIO.....9....3R }}.
* {{cite journal | last = See | first = T. J. J. |  title = Leverrier's Letter to Galle and the Discovery of Neptune | journal = Popular Astronomy | year = 1910 | volume = 18 | pages = 475–76 | bibcode = 1910PA.....18..475S}}.

==External links==
{{Commons}}
{{NSRW Poster|Leverrier, Urbain Jean J.|Urbain Le Verrier}}
* [http://www-personal.umich.edu/~jbourj/money4.htm Le Verrier on the French 50 Franc banknote]
* {{Cite journal |bibcode=1859AnPar...5....1L|title=Theorie du mouvement de Mercure|journal=Annales de l'Observatoire Impérial de Paris |volume=5|last1=Le Verrier|first1=Urbain J|year=1859|pages=1–195}}
* [https://books.google.com/books?id=fC4CAAAAYAAJ&dq=leverrier&pg=RA4-PA453 Obituary] – ''Nature'', 1877, vol. 16, p. 453
* [http://fultonhistory.com/Newspaper%2014/New%20York%20NY%20Herald/New%20York%20NY%20Herald%201877/New%20York%20NY%20Herald%201877%20-%201201.pdf Interesting interview with M. LeVerrier, director of the Paris Observatory] – ''New York Herald'', 14 April 1877, p.&nbsp;7
* Archived at [https://ghostarchive.org/varchive/youtube/20211211/cypN_4NUD3w Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20200425051207/https://www.youtube.com/watch?v=cypN_4NUD3w&gl=US&hl=en Wayback Machine]{{cbignore}}: {{cite web|title=Episode 5 – Urbain Le Verrier|date=6 February 2019|publisher=École polytechnique|website=YouTube|url=https://www.youtube.com/watch?v=cypN_4NUD3w}}{{cbignore}}
* [https://bibnum.obspm.fr/exhibits/show/le_verrier Virtual exhibition on Paris Observatory digital library]
* [https://bibnum.obspm.fr/ark:/11287/1wk9Q Le Verrier's works digitalized] on Paris Observatory digital library

{{Copley Medallists 1801-1850}}
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{{DEFAULTSORT:Le Verrier, Urbain}}
[[Category:Neptune]]

{{Sourceattribution|Urbain Le Verrier}}