Spiru C. Haret (; 15 February 1851 – 17 December 1912) was a
Romania
Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...
n
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
,
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
, and
politician
A politician is a person active in party politics, or a person holding or seeking an elected office in government. Politicians propose, support, reject and create laws that govern the land and by an extension of its people. Broadly speaking, a ...
. He made a fundamental contribution to the
''n''-body problem in
celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to ...
by 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, Haret ran deep reforms, building the modern Romanian education system. He was made a full
member of the Romanian Academy in 1892.
He also founded the
Bucharest Observatory
The Bucharest Observatory is an astronomical observatory located at no. 21 Lascăr Catargiu Boulevard, Bucharest, Romania.
The observatory was built between 1908 and 1910, for Admiral Vasile Urseanu. It was equipped with a 150 mm diameter Z ...
, appointing as its first director. The crater
Haret on the Moon is named after him.
Life
![Statuia lui Spiru Haret](https://upload.wikimedia.org/wikipedia/commons/c/cd/Statuia_lui_Spiru_Haret.JPG)
Haret was born in
Iași
Iași ( , , ; also known by other alternative names), also referred to mostly historically as Jassy ( , ), is the second largest city in Romania and the seat of Iași County. Located in the historical region of Moldavia, it has traditionally ...
,
Moldavia
Moldavia ( ro, Moldova, or , literally "The Country of Moldavia"; in Romanian Cyrillic: or ; chu, Землѧ Молдавскаѧ; el, Ἡγεμονία τῆς Μολδαβίας) is a historical region and former principality in Centr ...
, to Constantin and Smaranda Haret,
who were of
Armenian
Armenian may refer to:
* Something of, from, or related to Armenia, a country in the South Caucasus region of Eurasia
* Armenians, the national people of Armenia, or people of Armenian descent
** Armenian Diaspora, Armenian communities across the ...
origin.
His baptismal record listed his name as Spiridon Haret.
He started his studies in
Dorohoi
Dorohoi () is a municipiu, city in Botoșani County, Romania, on the right bank of the river Jijia, which broadens into a lake on the north.
History
Dorohoi used to be a market for the timber and farm produce of the north Moldavian highlands; m ...
Iași, and in 1862 moved to
Saint Sava High School in
Bucharest
Bucharest ( , ; ro, București ) is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, on the banks of the Dâmbovița River, less than north of ...
.
He showed an early talent for mathematics, publishing two textbooks (one in
algebra
Algebra () is one of the broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathematics.
Elementary a ...
and one in
trigonometry
Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. T ...
) when he was still a high school student. In 1869 he entered the
University of Bucharest
The University of Bucharest ( ro, Universitatea din București), commonly known after its abbreviation UB in Romania, is a public university founded in its current form on by a decree of Prince Alexandru Ioan Cuza to convert the former Princel ...
, where he studied
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
and
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
. In 1870, while a student in his second term, he became teacher of mathematics at the
Nifon Seminary in
Bucharest
Bucharest ( , ; ro, București ) is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, on the banks of the Dâmbovița River, less than north of ...
, 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
Titu Liviu Maiorescu (; 15 February 1840 – 18 June 1917) 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 ...
and went to
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
in order to study mathematics at the
Sorbonne
Sorbonne may refer to:
* Sorbonne (building), historic building in Paris, which housed the University of Paris and is now shared among multiple universities.
*the University of Paris (c. 1150 – 1970)
*one of its components or linked institution, ...
. There he earned a mathematics diploma in 1875 and a physics diploma in 1876. Two years later (on 18 January 1878), he earned his
Ph.D.
A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...
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 Alexandre Puiseux (; 16 April 1820 – 9 September 1883) was a French mathematician and astronomer. Puiseux series are named after him, as is in part the Bertrand–Diquet–Puiseux theorem. His work on algebraic functions and uniform ...
, his Ph.D. advisor. 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'
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
rational mechanics at the Faculty of Science of the University of Bucharest.
The next year (1879), Haret became a correspondent member of the
Romanian Academy
The Romanian Academy ( ro, Academia Română ) is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 active members who are elected for life.
According to its byl ...
, 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
Dimitrie D. Pompeiu (; – 8 October 1954) was a Romanian mathematician, professor at the University of Bucharest, titular member of the Romanian Academy, and President of the Chamber of Deputies.
Biography
He was born in 1873 in Broscăuți, ...
. From 1882 he was also a professor of
analytical geometry
In classical mathematics, analytic geometry, also known as coordinate geometry or Cartesian geometry, is the study of geometry using a coordinate system. This contrasts with synthetic geometry.
Analytic geometry is used in physics and engineer ...
at the
School of Bridges and Roads in Bucharest. After retirement, Haret occasionally lectured at the informal ''People's University''.
Haret was the
Minister of Public Education in three
liberal
Liberal or liberalism may refer to:
Politics
* a supporter of liberalism
** Liberalism by country
* an adherent of a Liberal Party
* Liberalism (international relations)
* Sexually liberal feminism
* Social liberalism
Arts, entertainment and m ...
governments, between 1897 and 1899, 1901–1904, and 1907–1910. As Minister of Education he ran a complete reform, basically building the modern
Romanian education system.
In January 1883, he married in
Buzău
The city of Buzău (formerly spelled ''Buzeu'' or ''Buzĕu''; ) is the county seat of Buzău County, Romania, in the historical region of Muntenia. It lies near the right bank of the Buzău River, between the south-eastern curvature of the Car ...
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
Șerban Vodă Cemetery (commonly known as Bellu Cemetery) is the largest and most famous cemetery in Bucharest, Romania.
It is located on a plot of land donated to the local administration by Baron Barbu Bellu. It has been in use since 1858. T ...
; Ana Haret died in 1941, aged 74.
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
In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in ...
motion described by
Johannes Kepler
Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws ...
’s
First Law.
Pierre Laplace
Pierre-Simon, marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French scholar and polymath whose work was important to the development of engineering, mathematics, statistics, physics, astronomy, and philosophy. He summarized ...
(in 1773) and
Joseph Louis Lagrange
Joseph-Louis Lagrange (born Giuseppe Luigi Lagrangia[Siméon Denis Poisson
Baron Siméon Denis Poisson FRS FRSE (; 21 June 1781 – 25 April 1840) was a French mathematician and physicist who worked on statistics, complex analysis, partial differential equations, the calculus of variations, analytical mechanics, electri ...](_blank)
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
Jules Henri Poincaré ( S: stress final syllable ; 29 April 1854 – 17 July 1912) was a French mathematician, theoretical physicist, engineer, and philosopher of science. He is often described as a polymath, and in mathematics as "The ...
considered this result ''a great surprise'' and continued Haret’s research, which eventually led him to the creation of
chaos theory
Chaos theory is an interdisciplinary area of scientific study and branch of mathematics focused on underlying patterns and deterministic laws of dynamical systems that are highly sensitive to initial conditions, and were once thought to have co ...
. Haret established the instability of the model of the ''n''-body problem assuming frequencies to be incommensurable; Poincaré also into account
commensurabilities, and using
generalized Fourier series
In mathematical analysis, many generalizations of Fourier series have proved to be useful. They are all special cases of decompositions over an orthonormal basis of an inner product space. Here we consider that of square-integrable functions de ...
(which generate
quasi-periodic
Quasiperiodicity is the property of a system that displays irregular periodicity. Periodic behavior is defined as recurring at regular intervals, such as "every 24 hours". Quasiperiodic behavior is a pattern of recurrence with a component of unpr ...
solutions), he proved the divergence of these series (which means instability), thus confirming Haret’s result.
Félix Tisserand
François Félix Tisserand (13 January 1845 – 20 October 1896) was a French astronomer.
Life
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 profes ...
recommended the extension of Haret's method to other astronomic problems and, much later, in 1955,
Jean Meffroy
Jean may refer to:
People
* Jean (female given name)
* Jean (male given name)
* Jean (surname)
Fictional characters
* Jean Grey, a Marvel Comics character
* Jean Valjean, fictional character in novel ''Les Misérables'' and its adaptations
* Jean ...
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 is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...
’s
Great Red Spot (1912).
![Dimitrie Paciurea - Spiru Haret](https://upload.wikimedia.org/wikipedia/commons/d/d7/Dimitrie_Paciurea_-_Spiru_Haret.jpg)
In 1910 he published ''Social mechanics'', which used mathematics to explain social behaviour (somehow anticipating the fictional "
psychohistory
Psychohistory is an amalgam of psychology, history, and related social sciences and the humanities. Its proponents claim to examine the "why" of history, especially the difference between stated intention and actual behavior. Psychobiography, chil ...
" branch of mathematics developed by
Hari Seldon
Hari Seldon is a fictional character in Isaac Asimov's ''Foundation'' series. In his capacity as mathematics professor at Streeling University on the planet Trantor, Seldon develops psychohistory, an algorithmic science that allows him to predic ...
, the fictional character of
Isaac Asimov
yi, יצחק אזימאװ
, birth_date =
, birth_place = Petrovichi, Russian SFSR
, spouse =
, relatives =
, children = 2
, death_date =
, death_place = Manhattan, New York City, U.S.
, nationality = Russian (1920–1922)Soviet (192 ...
's
''Foundation'', published 40 years later).
References
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External links
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{{DEFAULTSORT:Haret, Spiru
1851 births
1912 deaths
Scientists from Iași
Politicians from Iași
Romanian people of Armenian descent
Saint Sava National College alumni
University of Bucharest alumni
University of Paris alumni
University of Bucharest faculty
Politehnica University of Bucharest faculty
Romanian mathematicians
Romanian physicists
Romanian astrophysicists
Romanian schoolteachers
Romanian sociologists
19th-century Romanian writers
20th-century Romanian writers
Romanian writers in French
Titular members of the Romanian Academy
Romanian Ministers of Culture
Romanian Ministers of Education
Romanian Ministers of Interior
Deaths from cancer in Romania
Burials at Bellu Cemetery