Spiru Haret
Encyclopedia
Spiru C. Haret (ˈspiru haˈret; 15 February 1851 – 17 December 1912) was a Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

n mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

, astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...

 and politician
Politician
A politician, political leader, or political figure is an individual who is involved in influencing public policy and decision making...

. He made a fundamental contribution to the n-body problem
N-body problem
The n-body problem is the problem of predicting the motion of a group of celestial objects that interact with each other gravitationally. Solving this problem has been motivated by the need to understand the motion of the Sun, planets and the visible stars...

 in celestial mechanics
Celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...

 by proving that using a third degree approximation
Orders of approximation
In science, engineering, and other quantitative disciplines, orders of approximation refer to formal or informal terms for how precise an approximation is, and to indicate progressively more refined approximations: in increasing order of precision, a zeroth order approximation, a first order...

 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, Haret ran deep reforms, building the modern Romanian education system. He was made a full member of the Romanian Academy
Romanian Academy
The Romanian Academy is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 acting members who are elected for life....

 in 1892.

He also founded the Astronomical observatory in Bucharest
Bucharest
Bucharest is the capital municipality, cultural, industrial, and financial centre of Romania. It is the largest city in Romania, located in the southeast of the country, at , and lies on the banks of the Dâmbovița River....

, appointing Nicolae Coculescu as its first director. The crater Haret
Haret (crater)
Haret is a small lunar crater that is located in the southern region on the far side of the Moon. It lies in midst of the triangle of craters formed by Bose to the northeast, Cabannes to the southeast, and Abbe to the west...

 on the Moon is named after him.

Life

Haret was born in Iaşi
Iasi
Iași is the second most populous city and a municipality in Romania. Located in the historical Moldavia region, Iași has traditionally been one of the leading centres of Romanian social, cultural, academic and artistic life...

, Moldavia
Moldavia
Moldavia is a geographic and historical region and former principality in Eastern Europe, corresponding to the territory between the Eastern Carpathians and the Dniester river...

, to an old Armenian
Armenians in Romania
Armenians have been present in what is now Romania and Moldova for over a millennium, and have been an important presence as traders since the 14th century...

 family, and showed an early talent for mathematics, publishing two textbooks (one in algebra
Algebra
Algebra is the branch of mathematics concerning the study of the rules of operations and relations, and the constructions and concepts arising from them, including terms, polynomials, equations and algebraic structures...

 and one in trigonometry
Trigonometry
Trigonometry is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides. Trigonometry defines the trigonometric functions, which describe those relationships and have applicability to cyclical phenomena, such as waves...

) when he was still a high school
High school
High school is a term used in parts of the English speaking world to describe institutions which provide all or part of secondary education. The term is often incorporated into the name of such institutions....

 student. In 1869 he entered the University of Bucharest
University of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...

, where he studied physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 and mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

. In 1870, while a student in his second term, he became teacher of mathematics at 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
Scholarship
A scholarship is an award of financial aid for a student to further education. Scholarships are awarded on various criteria usually reflecting the values and purposes of the donor or founder of the award.-Types:...

 competition organized by Titu Maiorescu
Titu Maiorescu
Titu Liviu Maiorescu was a Romanian literary critic and politician, founder of the Junimea Society. As a literary critic, he was instrumental in the development of Romanian culture in the second half of the 19th century....

 and went to Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 in order to study mathematics at the Sorbonne
University of Paris
The University of Paris was a university located in Paris, France and one of the earliest to be established in Europe. It was founded in the mid 12th century, and officially recognized as a university probably between 1160 and 1250...

. 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.
Ph.D.
A Ph.D. is a Doctor of Philosophy, an academic degree.Ph.D. may also refer to:* Ph.D. , a 1980s British group*Piled Higher and Deeper, a web comic strip*PhD: Phantasy Degree, a Korean comic series* PhD Docbook renderer, an XML renderer...

 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
Victor Puiseux
Victor Alexandre Puiseux was a French mathematician and astronomer. Puiseux series are named after him, as is in part the Bertrand–Diquet–Puiseux theorem.-Life:...

. 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
Paris Observatory
The Paris Observatory is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world...

. 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 mechanics at the Science Faculty in Bucharest. The next year (1879), Haret became a correspondent member of the Romanian Academy
Romanian Academy
The Romanian Academy is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 acting members who are elected for life....

, 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
Dimitrie Pompeiu
-Biography:After studying in Dorohoi and Bucharest, he went to France, where he studied mathematics at the University of Paris . He obtained a Ph.D. degree in mathematics in 1905 with a thesis, On the continuity of complex variable functions, written under the direction of Henri Poincaré...

. From 1882 he was also a professor of analytical geometry at 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.

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 elliptic
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...

 motion described by Johannes Kepler
Johannes Kepler
Johannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...

’s First Law
Kepler's laws of planetary motion
In astronomy, Kepler's laws give a description of the motion of planets around the Sun.Kepler's laws are:#The orbit of every planet is an ellipse with the Sun at one of the two foci....

. Pierre Laplace (in 1773) and Joseph Louis Lagrange
Joseph Louis Lagrange
Joseph-Louis Lagrange , born Giuseppe Lodovico Lagrangia, was a mathematician and astronomer, who was born in Turin, Piedmont, lived part of his life in Prussia and part in France, making significant contributions to all fields of analysis, to number theory, and to classical and celestial mechanics...

 (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
Siméon Denis Poisson
Siméon Denis Poisson , was a French mathematician, geometer, and physicist. He however, was the final leading opponent of the wave theory of light as a member of the elite l'Académie française, but was proven wrong by Augustin-Jean Fresnel.-Biography:...

 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
Henri Poincaré
Jules Henri Poincaré was a French mathematician, theoretical physicist, engineer, and a philosopher of science...

 considered this result a great surprise and continued Haret’s research, which eventually led him to the creation of chaos theory
Chaos theory
Chaos theory is a field of study in mathematics, with applications in several disciplines including physics, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions, an effect which is popularly referred to as the...

. Félix Tisserand
Félix Tisserand
François Félix Tisserand was a French astronomer.Tisserand was born at Nuits-Saint-Georges, Côte-d'Or. In 1863 he entered the École Normale Supérieure, and on leaving he went for a month as professor at the lycée at Metz. Urbain Le Verrier offered him a post in the Paris Observatory, which he...

 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.

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 secular acceleration of the Moon in 1880 and one on Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

’s Great Red Spot (1912).

In 1910 he published Social mechanics, which used mathematics to explain social behaviour (somehow anticipating the fictional "psychohistory
Psychohistory (fictional)
Psychohistory is a fictional science in Isaac Asimov's Foundation universe which combines history, sociology, and mathematical statistics to make general predictions about the future behavior of very large groups of people, such as the Galactic Empire...

" branch of mathematics developed by Hari Seldon
Hari Seldon
Hari Seldon, a fictional character, is the intellectual hero of Isaac Asimov's Foundation Series. In his capacity as mathematics professor at Streeling University on Trantor, he developed psychohistory, allowing him to predict the future in probabilistic terms...

, the fictional character of Isaac Asimov
Isaac Asimov
Isaac Asimov was an American author and professor of biochemistry at Boston University, best known for his works of science fiction and for his popular science books. Asimov was one of the most prolific writers of all time, having written or edited more than 500 books and an estimated 90,000...

's Foundation
The Foundation Series
The Foundation Series is a science fiction series by Isaac Asimov. There are seven volumes in the Foundation Series proper, which in its in-universe chronological order are: Prelude to Foundation, Forward the Foundation, Foundation, Foundation and Empire, Second Foundation, Foundation's Edge, and...

, published 40 years later).

External links

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