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Urbain Le Verrier, born in Saint-Lô on March 11, 1811, died in Paris on September 23, 1877, is a French astronomer, mathematician specializing in celestial mechanics and founder of modern French meteorology. He is known worldwide for having discovered the planet Neptune by calculation on September 23, 1846.
His studies

Urbain Jean Joseph Le Verrier was born into a modest bourgeois family, to Louis-Baptiste Le Verrier, “supernumerary in the administration of estates” and Marie-Jeanne-Joséphine-Pauline de Baudre[1]. After eight years of study at the municipal college of his hometown Saint-Lô, he entered the royal college of Caen where he studied mathematics from 1827 to 1830. His father, who believed in his future in the sciences, enrolled him at the Mayer Institution directed by the mathematician Choquet and sold his house to cover the costs of this preparatory school. He continued his studies at the Louis-le-Grand college in Paris and was admitted in 1831 to the École Polytechnique, from which he left two years later, being ranked eighth[2] as an engineer in the tobacco administration. He resigned in 1835 to devote himself to a scientific career[3]. He first worked in the Gay-Lussac chemistry laboratory and became a mathematics tutor and teacher at the Stanislas college[1].

In 1837 he requested the position of chemistry tutor at the École Polytechnique but this was awarded to Victor Regnault. On the other hand, he was offered a position as tutor in “geodesy, astronomy and machines”, which he accepted and where he specialized in positional astronomy and celestial mechanics. The same year, he married Lucile Marie Clotilde Choquet (daughter of his former teacher), with whom he had three children[1],[note 1]. In 1839, he presented to the Academy of Sciences his first dissertation on the secular variations in the orbits of the planets (notably of Uranus, Alexis Bouvard not being able to resolve the problem of the anomalies of this planet). It is also in this dissertation that we find the first description of the Faddeev-Le Verrier algorithm[4].

After 11 months of calculations, Le Verrier presented one of his memoirs to the Academy of Sciences in 1846. The latter is called On the planet which produces the anomalies observed in the movement of Uranus; determination of its mass, its orbit and its current position[5].

Urbain Le Verrier became a member of the astronomy section of the Academy of Sciences on January 19, 1846 and on October 14 of the same year, deputy member of the Bureau of Longitudes[6].
The discovery of Neptune
Main article: discovery of Neptune.

Urbain Le Verrier became famous when the planet whose characteristics he had calculated as a hypothetical cause of the anomalies in the movements of Uranus was actually observed by the German astronomer Johann Galle at the Berlin observatory, on the night of September 23 to 24, 1846. This new planet will be baptized Neptune, despite the proposal by François Arago, under the blackmail of Le Verrier (a rumor claims that Arago has an affair with Madame Le Verrier[1]), who was made to baptize it Le Verrier at the Academy of Sciences, while the English proposed Janus or Oceanus.

The planet Uranus, discovered by William Herschel in 1781, indeed presented irregularities in relation to the orbit it should have had according to Isaac Newton's law of universal gravitation. Le Verrier postulates that these irregularities may be caused by another planet, never before observed. Encouraged by François Arago, Le Verrier began in 1844 to calculate the characteristics of this new planet (mass, orbit, current position), the results of which he communicated to the Academy of Sciences on August 31, 1846.

These calculations will be confirmed (more or less) by Johann Galle, who observed the new star the same day when he received its position to within 5 degrees by a letter from Le Verrier[7]. In front of the Academy of Sciences, Arago uttered the famous sentence: “Mr. Le Verrier saw the new star at the end of his pen[8]”. The Royal Society awarded him the Copley Medal the same year, praising it as “…one of the greatest triumphs of modern analysis applied to the theory of gravitation…”.

This discovery will be the subject of numerous controversies at the time, since these calculations were carried out at the same time by John Couch Adams, but without either of them knowing the work of the other. The planet's characteristics had been determined by Adams a year earlier but had not been published.

After the discovery of Neptune, Le Verrier was promoted to officer of the Legion of Honor by Louis-Philippe[7]. And in 1846, a chair of celestial mechanics was created for Le Verrier at the Faculty of Sciences in Paris. Pierre-Ossian Bonnet succeeded him in 1878.

Later, Le Verrier attempted to repeat the same feat to explain the disturbances of Mercury. After several observations by other astronomers of round spots passing in front of the Sun (including the famous one of Doctor Lescarbault in 1860), Le Verrier deduced the presence of another planet, Vulcan, whose passage in front of the Sun he predicted in 1877. These predictions turned out to be inaccurate, and these anomalies were explained half a century later by Albert Einstein with the theory of general relativity.
Director of the Paris Observatory

On January 30, 1854, Le Verrier was appointed director of the Paris Observatory, succeeding François Arago and taking the opposite approach to the policy of his predecessor. In particular, he had the amphitheater built by the latter demolished to fit out his apartments[9], and undertook a total reorganization which he was unable to complete due to lack of funds: highly hierarchical division of labor (observers were paid 15 centimes per star observed, surveillance of workers[1]), applying the English model of the industrial revolution to the field of astronomy[10]. There he will establish a catalog of 306 fundamental stars.

But he appeared so angry and odious that, following several petitions and the resignation of around sixty astronomers from the Paris Observatory, and despite his political affiliation, he was relieved of his functions in 1870 by imperial decree[note 2]. He resigned at the same time from the general council of La Manche, then from the Bureau des Longitudes. He subsequently led a career as a scientific journalist, then resumed the position of director of the Observatory in 1873 after the accidental death of his successor, Charles-Eugène Delaunay, until his death.

Urbain Le Verrier died on the site of the Observatory on September 23, 1877.
Meteorologist

By becoming director of the Paris Observatory, he also inherited a small meteorological service. Meteorology, still little developed, depended on the Paris Observatory.

On November 14, 1854, a terrible storm, occurring without the slightest warning during the Crimean War, crossed Europe from west to east, causing the loss of 41 ships in the Black Sea. Le Verrier and Emmanuel Liais, his deputy director, then undertook, at the request of Napoleon III, to set up a network of meteorological observatories on French territory, intended primarily for sailors in order to warn them of the arrival of storms. This network brings together 24 stations, 13 of which are connected by telegraph, then will extend to 59 observatories spread across the whole of Europe in 1865. Le Verrier had discovered that a meteorological event in a place is the result of a movement, on an Earth scale, of physical phenomena. On September 17, 1863, the first weather forecast (24-hour forecast using maps and daily weather reports) for the port of Hamburg was carried out[11]. This is the birth of modern meteorology[12]. This initiative by Le Verrier is at the origin of the creation of modern French meteorology.

At the head of a commission which bore his name, he reformed the teaching of the École Polytechnique[13] by introducing more applied science.
Politician

At the same time, he also leads a political life. In 1848, during the June Days, while serving in the Ga