- Spiru Haret
Spiru C. Haret (
February 15 1851, Iaşi– 17 December 1912) was a Romanian mathematician, astronomerand politicianof Armenian descent. He made a fundamental contribution to the "n"-body problem in celestial mechanicsby proving that using a third degree approximation for the disturbing forces implies instability of the 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 Minister of Education, Spiru Haret ran deep reforms, building the modern Romanian education system. He was made a full member of the Romanian Academyin 1892.
Spiru Haret also founded the
Astronomical observatoryin Bucharest, appointing Nicolae Coculescuas its first director. A crater on the Moon was named after him: "Haret".
Spiru Haret showed an early talent for mathematics, publishing two textbooks (one in
algebraand one in trigonometry) when he was still a high schoolstudent. In 1869 he entered the University of Bucharest, where he studied physicsand mathematics. In 1870, while a student in his second term, he became teacher of mathematics at Nifon Seminaryin 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
scholarshipcompetition organized by Titu Maiorescuand went to Parisin order to study mathematics at the Sorbonne. There he earned a mathematics diploma in 1875 and a physics diploma in 1876. Two years later (on January 18, 1878) he earned his 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"), in front of examiners led by Victor Puiseux. In this work he proved a result fundamental for the "n"-body problem in astronomy, the thesis being published in Vol. XVIII of the "Annales de l'Observatoire de Paris". Spiru Haret was the first Romanian to obtain a Ph.D. degree in Paris.
After his return to Romania in 1878, Haret 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
rational mechanicsat the Science Faculty in Bucharest. The next year (1879), Spiru Haret became a correspondent member of the Romanian Academy, receiving full membership in 1892. He kept the professorship at the Science Faculty 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 geometryat the "Bridges and Roads' School in Bucharest". After retirement Haret occasionally lectured at the informal "People's University".
Haret was the Minister of Public Education in three liberal governments, between 1897-1899, 1901-1904 and 1907-1910. As Minister of Education he ran a complete reform, basically building the modern Romanian education system.
Spiru 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 disturbe each other’s orbits, thus deviating from the elliptic motion described by
Johannes Kepler’s 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 Poissonhad 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 Poincaréconsidered this result "a great surprise" and continued Haret’s research, which eventually led him to the creation of chaos theory. Félix Tisserandrecommended the extension of Haret's method to other astronomic problems and, much later, in 1955, Jean Meffroyrestarted Haret’s research using new techniques.
Soon after his return to Romania, Spiru 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 secular acceleration of the Moon in 1880 and one on
Jupiter’s Great Red Spot(1912).
In 1910 he published "Social mechanics", which used mathematics to explain social behavior.
* [http://syrte.obspm.fr/journees2004/PDF/Stavinschi.pdf M. Stavinschi and V. Mioc (2004), "Astronomical Researches in Poincaré's and Romanian Works", Astronomical Institute of the Romanian Academy]
* Ion Bulei (1990), "Atunci când veacul se năştea... lumea româneasca 1900-1908" ("When the century was born... the Romanian world 1900-1908"), Editura Eminescu, p. 82 – 96
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