{{Short description|Romanian mathematician, astronomer and politician}} {{about||the village in Brăila County|Berteștii de Jos|an institution|Spiru Haret University}} {{Use dmy dates|date=July 2018}} {{Infobox scientist | honorific_prefix = | name = Spiru Haret | honorific_suffix = | native_name = | native_name_lang = | image = Spiru Haret (1).jpg | image_size = | image_upright = | alt = | caption = | birth_name = Spiridon Haret | birth_date = {{Birth date|1851|2|15|df=yes}} | birth_place = [[Iași]], [[Moldavia]] | death_date = {{Death date and age|1912|12|17|1851|2|15|df=yes}} | death_place = [[Bucharest]], [[Kingdom of Romania]] | death_cause = | resting_place = [[Bellu Cemetery]], Bucharest, Romania | resting_place_coordinates = | other_names = | pronounce = | citizenship = | fields = [[Mathematics]], [[Astronomy]] | workplaces = [[University of Bucharest]]<br />[[Politehnica University of Bucharest|School of Bridges and Roads]] | education = [[Saint Sava National College]] | alma_mater = [[University of Bucharest]]<br /> [[University of Paris]] | thesis_title = Sur l’invariabilité des grandes axes des orbites planétaires | thesis_url = https://patrimoine.sorbonne-universite.fr/idurl/1/1853 | thesis_year = 1878 | doctoral_advisor = [[Victor Puiseux]] | academic_advisors = | doctoral_students = | notable_students = | known_for = [[N-body problem]]<br />[[Education in Romania|Romanian education system]] | influences = | influenced = | awards = | spouse = {{marriage |Ana Popescu |22 January 1883|}} | children = | parents = | father = | mother = | relatives = | signature = | signature_alt = | website = | footnotes = | module = {{Infobox officeholder | embed = yes | title1 = [[Ministry of Culture (Romania)|Minister of Religious Affairs and Public Instruction]] | term_start1 = 31 March 1897 | term_end1 = 30 March 1899 | prime_minister1 = [[Dimitrie Sturdza]] | predecessor1 = [[George Mârzescu]] | successor1 = [[Take Ionescu]] | term_start2 = 14 February 1901 | term_end2 = 20 December 1904 | prime_minister2 = [[Dimitrie Sturdza]] | predecessor2 = [[Constantin C. Arion]] | successor2 = [[Mihail Vlădescu]] | term_start3 = 12 March 1907 | term_end3 = 28 December 1910 | prime_minister3 = [[Dimitrie Sturdza]]<br />[[Ion I. C. Brătianu]] | predecessor3 = [[Constantin Istrati]] | successor3 = [[Constantin C. Arion]] | title4 = [[Ministry of Internal Affairs (Romania)|Interior Minister]] | term_start4 = 13 December 1904 | term_end4 = 20 December 1904 | prime_minister4 = [[Dimitrie Sturdza]] | predecessor4 = Vasile Lascăr | successor4 = [[Gheorghe Grigore Cantacuzino]] }} }}
'''Spiru C. Haret''' ({{IPA|ro|ˈspiru haˈret}}; 15 February 1851 – 17 December 1912) was a [[Romania]]n [[mathematician]], [[astronomer]], and [[politician]]. He made a fundamental contribution to the [[N-body problem|''n''-body problem]] in [[celestial mechanics]] by proving that using a [[Orders of approximation|third degree approximation]] for the disturbing forces implies instability of the [[semi-major and semi-minor axes|major axes]] of the orbits, and by introducing the concept of ''secular perturbations'' in relation to this.
As a politician, during his three terms as [[Education minister|Minister of Education]], Haret ran deep reforms, building the modern Romanian education system. He was made a full [[list of members of the Romanian Academy|member of the Romanian Academy]] in 1892.
He also founded the [[Bucharest Astronomical Observatory]], appointing {{ill|Nicolae Coculescu|ro}} as its first director. The crater [[Haret (crater)|Haret]] on the Moon is named after him.
==Life== Haret was born in [[Iași]], [[Moldavia]], to Constantin and Smaranda Haret,<ref name="Ana"/> who were of [[Armenians in Romania|Armenian]] origin.<ref name="ziare">{{cite web|url=https://ziare.com/scoala/invatamant/mari-politicieni-romani-spiru-haret-reformatorul-societatii-romanesti-1217833|title=Mari politicieni români: Spiru Haret, reformatorul societății românești|language=ro|author=Camelia Badea|website=ziare.com| date=February 10, 2013|access-date=February 21, 2022}}</ref> His baptismal record listed his name as Spiridon Haret.<ref name="Ana"/> He started his studies in [[Dorohoi]] Iași, and in 1862 moved to [[Saint Sava National College|Saint Sava High School]] in [[Bucharest]].<ref name="fse">{{cite web|url=https://www.fsespiruharet.ro/despre-spiru-haret/|title=Despre Spiru Haret|language=ro| website=www.fsespiruharet.ro|publisher=Federația Sindicatelor din Educație "Spiru Haret"| access-date=February 21, 2022}}</ref> He showed an early talent for mathematics, publishing two textbooks (one in [[algebra]] and one in [[trigonometry]]) when he was still a high school student. In 1869 he entered the [[University of Bucharest]], where he studied [[physics]] and [[mathematics]]. In 1870, while a student in his second term, he became teacher of mathematics at the [[Nifon Seminary]] in [[Bucharest]], but quit the following year in order to continue his studies. In 1874, at age 23, he graduated with a degree in physics and mathematics.
After graduation, Haret won a scholarship competition organized by [[Titu Maiorescu]] and went to [[Paris]] in order to study mathematics at the [[University of Paris|Sorbonne]]. There he earned a mathematics diploma in 1875 and a physics diploma in 1876. Two years later (on 18 January 1878), he earned his [[Doctor of Philosophy|Ph.D.]] by defending his thesis, ''Sur l’invariabilité des grandes axes des orbites planétaires'' (''On the invariability of the major axis of planetary orbits''),<ref name="Mac">{{MacTutor|id=Haret}}</ref> in front of examiners led by [[Victor Puiseux]], his Ph.D. advisor.<ref>{{MathGenealogy|id=196373}}</ref> In this work he proved a result fundamental for the ''n''-body problem in astronomy, the thesis being published in volume 18 of ''Annales de l'[[Paris Observatory|Observatoire de Paris]]''. Haret was the first Romanian to obtain a Ph.D. degree in Paris.
After his return to Romania in 1878, Haret largely abandoned scientific research and dedicated the rest of his life to improving Romanian education, which was heavily underdeveloped at the time, both as professor and as politician. He was appointed professor of [[Classical mechanics|rational mechanics]] at the Faculty of Science of the University of Bucharest.<ref name="Mac"/> The next year (1879), Haret became a correspondent member of the [[Romanian Academy]], receiving full membership in 1892. He kept the professorship at the Faculty of Science until his retirement in 1910, when he was followed as professor of mechanics by [[Dimitrie Pompeiu]]. From 1882 he was also a professor of [[analytical geometry]] at the [[Politehnica University of Bucharest|School of Bridges and Roads]] in Bucharest. After retirement, Haret occasionally lectured at the informal ''People's University''.
Haret was the [[Education minister|Minister of Public Education]] in three [[Liberalism and radicalism in Romania|liberal]] governments, between 1897 and 1899, 1901–1904, and 1907–1910. As Minister of Education he ran a complete reform, basically building the modern [[Education in Romania|Romanian education system]].
The folk song "[[Cântă cucu-n Bucovina]]" ("Sings the Cuckoo in Bukovina") was composed in 1904 by {{ill|Constantin Mandicevschi|de|Constantin Mandicevschi|ru|Мандычевский, Константин|uk|Мандичевський Костянтин Васильович}} at Haret's request for commemorating the 400th anniversary of the death of [[List of rulers of Moldavia|Prince of Moldavia]] [[Stephen the Great]].<ref>{{cite news|url=https://timpul.md/articol/constantin-mandicevschi-autorul-renumitului-cantec-romanesc-canta-cucu-n-bucovina-113263.html|title=Constantin Mandicevschi – autorul renumitului cântec românesc "Cântă cucu-n Bucovina"|newspaper=Timpul|date=24 July 2017|language=ro}}</ref>
In January 1883, he married in [[Buzău]] a local, Ana Popescu, 15 years his junior. The two had a son, Ion, who died at age 1, and later adopted a child, Mihai. Haret died in Bucharest in 1912 of cancer, and was buried in the city's [[Bellu Cemetery]]; Ana Haret died in 1941, aged 74.<ref name="Ana">{{cite news|url=https://adevarul.ro/locale/buzau/femeia-i-a-sucit-mintile-spiru-haret-roman-doctorat-matematici-sorbona-s-a-indragostit-adolescenta-15-ani-mai-tanara-1_561d0b34f5eaafab2c9e0e99/index.html|title=Femeia care i-a sucit mințile lui Spiru Haret. Primul român cu doctorat în matematici la Sorbona s-a îndrăgostit de o adolescentă cu 15 ani mai tânără|language=ro|author=Iulian Bunila|newspaper=[[Adevărul]]|date=October 14, 2015|access-date=February 21, 2022}}</ref>
==Scientific activity== Haret's major scientific contribution was made in 1878, in his Ph.D. thesis ''Sur l’invariabilité des grandes axes des orbites planétaires''. At the time it was known that planets disturb each other's orbits, thus deviating from the [[Ellipse|elliptic]] motion described by [[Johannes Kepler]]’s [[Kepler's laws of planetary motion|First Law]]. [[Pierre Laplace]] (in 1773) and [[Joseph Louis Lagrange]] (in 1776) had already studied the problem, both of them showing that the major axes of the orbits are stable, by using a first degree approximation of the perturbing forces. In 1808 [[Siméon Denis Poisson]] had proved that the stability also holds when using second degree approximations. In his thesis, Haret proved by using third degree approximations that the axes are not stable as previously believed, but instead feature a time variability, which he called ''secular perturbations''. This result implies that planetary motion is not absolutely stable. [[Henri Poincaré]] considered this result ''a great surprise'' and continued Haret’s research, which eventually led him to the creation of [[chaos theory]]. Haret established the instability of the model of the ''n''-body problem assuming frequencies to be incommensurable; Poincaré also took into account [[Commensurability (astronomy)|commensurabilities]], and using [[generalized Fourier series]] (which generate [[Quasiperiodicity|quasi-periodic]] solutions), he proved the divergence of these series (which means instability), thus confirming Haret’s result.<ref name="obspm">{{citation|url=https://syrte.obspm.fr/journees2004/pdf/ProcJournees04.pdf|author1= Magda Stavinschi|author2= Vasile Mioc|year=2004|contribution=Astronomical Researches in Poincaré's and Romanian Works|title=Journées 2004|editor=Nicole Capitaine|publisher=[[Paris Observatory]]|pages=155–156|isbn=2-901057-51-9}}</ref> [[Félix Tisserand]] recommended the extension of Haret's method to other astronomic problems and, much later, in 1955, [[Jean Meffroy]] restarted Haret’s research using new techniques.<ref>{{cite journal|author=Jean Meffroy| title=Contribution a L'Étude de la Stabilité du Systéme Solaire|language=French|journal=[[Astronomy & Astrophysics|Bulletin Astronomique]]|volume=19 |year=1955|pages=197–221| url=https://adsabs.harvard.edu/full/1955BuAst..19..197M|bibcode=1955BuAst..19..197M}}</ref>
Soon after his return to Romania, Haret abandoned research, focusing for the rest of his life on teaching and, as Minister of Education, on the reform of the education system. He only published an article on the [[Tidal acceleration|secular acceleration]] of the Moon in 1880 and one on [[Jupiter]]’s [[Great Red Spot]] (1912).<ref name="Mac"/>
[[File:Dimitrie Paciurea - Spiru Haret.jpg|thumb|left|Bust of Spiru Haret by [[Dimitrie Paciurea]]]] In 1910 he published ''Social mechanics'', which used mathematics to explain social behaviour (somehow anticipating the fictional "[[Psychohistory (fictional)|psychohistory]]" branch of mathematics developed by [[Hari Seldon]], the fictional character of [[Isaac Asimov]]'s [[The Foundation Series|''Foundation'']], published 40 years later).
==References== {{Reflist}} * {{citation|author=Ion Bulei|year=1990|title=Atunci când veacul se năștea... lumea româneasca 1900–1908|language=ro| trans-title=When the century was born... the Romanian world 1900–1908|publisher= Editura Eminescu|pages=82–96}}
==External links== {{commons category}} * {{citation|author=[[Constantin Schifirneț]]|title=Spiru Haret, reformatorul societății românești|journal=Studiu Introductiv la Operele Lui Spiru Haret, Vol. I, Editura Comunicare.ro, 2009, Pp. 13-42 |language=ro|trans-title=Spiru Haret, the reformer of Romanian society|url=https://www.academia.edu/4394842}} * {{citation|author=[[Constantin Schifirneț]]|title=Spiru Haret, Education and School Legislation Reform| journal=Revista română de sociologie|volume=XXV|issue= 3–4|pages=311–326|year=2014|url=http://www.revistadesociologie.ro/pdf-uri/nr.3-4-2014/07-CSchifirnet.pdf}} *{{citation|author=Sorin-Avram Vîrtop|year=2019|title=Beyond mythology and tradition of an educational reform or about the realism of Spiru Haret's educational reform (1851–1912)|journal=Analele Universității "Constantin Brâncuși" din Târgu Jiu|volume=2|issue=2| url=http://www.utgjiu.ro/revista/dppd/pdf/2019-02/03_VIRTOP.pdf}} *{{cite web|url=http://bsclupan.asm.md/?lng=0&action=show&cat=91&obj=176|title=Spiru Haret|language=ro|publisher={{ill|Andrei Lupan Central Scientific Library|ro|Biblioteca Științifică Centrală „Andrei Lupan” a Academiei de Științe a Moldovei}}|website=bsclupan.asm.md|access-date=February 21, 2022}} *{{cite web|url=http://www.ligaspiruharet.ro/ |archive-url=https://web.archive.org/web/20090411111051/http://www.ligaspiruharet.ro/ |archive-date=2009-04-11 |title=Liga Spiru Haret}}
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{{DEFAULTSORT:Haret, Spiru}} [[Category:1851 births]] [[Category:1912 deaths]] [[Category:Scientists from Iași]] [[Category:Politicians from Iași]] [[Category:Romanian people of Armenian descent]] [[Category:Saint Sava National College alumni]] [[Category:University of Bucharest alumni]] [[Category:University of Paris alumni]] [[Category:Academic staff of the University of Bucharest]] [[Category:Academic staff of the Politehnica University of Bucharest]] [[Category:Romanian mathematicians]] [[Category:Romanian astrophysicists]] [[Category:Romanian schoolteachers]] [[Category:Romanian sociologists]] [[Category:19th-century Romanian writers]] [[Category:20th-century Romanian writers]] [[Category:French-language Romanian writers]] [[Category:Titular members of the Romanian Academy]] [[Category:Ministers of culture of Romania]] [[Category:Ministers of education of Romania]] [[Category:Ministers of interior of Romania]] [[Category:Deaths from cancer in Romania]] [[Category:Burials at Bellu Cemetery]]