◀ ▲ ▶History / 19th-century / Person: Verrier, Urbain Jean Joseph Le

Person: Verrier, Urbain Jean Joseph Le

Urbain Le Verrier is best known for the calculations which led to the discovery of Neptune.

Mathematical Profile (Excerpt):

• Urbain attended the College in Saint-Lô for eight years, completing his studies there at the age of sixteen in 1827.
• He had showed himself to be a very talented pupil and, after the College in Saint-Lô, he studied mathematics at the College Royal de Caen for three years, from 1827 to 1830.
• Despite being an outstanding pupil at the College in Caen, coming top of his class, he failed the competitive entrance examination to the École Polytechnique in 1830.
• There he studied for a year under the mathematician Choquet, the director of the Mayer Institute, and in 1831 he was placed second in the nation-wide Concours général and admitted to the École Polytechnique.
• He had been taught by the chemist Louis Joseph Gay-Lussac (1778-1850) while he was an undergraduate and Gay-Lussac directed the experiments that Le Verrier was undertaking.
• His research soon came to the notice of other leading scientists such as the physicist and chemist Pierre Louis Dulong (1785-1838) and the chemist Antoine Jérôme Balard (1802-1876).
• He published two papers on his chemistry research in the Annales de Chimie et de Physique, namely Sur les combinaisons du phosphore avec l'hydrogène Ⓣ(On the combinations of phosphorus with hydrogen) (1835) and Sur les combinaisons du phosphore avec l'oxygène Ⓣ(On the combinations of phosphorus with oxygen) (1837).
• Le Verrier was offered a position as a teacher of chemistry in the provinces in 1836 but chose to remain in Paris undertaking research with Gay-Lussac.
• In 1836 two positions as répétiteur had become vacant at the École Polytechnique.
• One position, as répétiteur to Gay-Lussac, was a chemistry appointment and Le Verrier applied for this position.
• Regnault was appointed as répétiteur to Gay-Lussac at the École Polytechnique.
• Le Verrier then decided to apply for the second position of répétiteur to Felix Savary, which was an astronomy appointment.
• Although it might seem strange for someone who was undertaking research in chemistry to apply for an astronomy position, Le Verrier's mathematical expertise meant that he was qualified.
• Le Verrier was appointed to teach astronomy as Felix Savary's répétiteur at the École Polytechnique in 1837.
• In addition to Le Verrier, Eugène Catalan and Charles Delaunay were appointed as répétiteurs to Savary in 1838.
• Also in 1837 Le Verrier was appointed as an admissions examiner for the École Polytechnique.
• When Savary became seriously ill in 1840, Le Verrier took over all Savary's teaching.
• Savary died in July 1841 and Le Verrier might have expected to be appointed to succeed him.
• However, Michel Chasles was appointed as Savary's successor and Le Verrier remained as a répétiteur to Chasles (as did Catalan and Delaunay).
• Le Verrier's first contribution to astronomy was the paper Sur les variations séculaires des orbites des planètes Ⓣ(On the secular variations of the orbits of the planets) which he presented to the Academy of Sciences in September 1839.
• This paper considered the problem of the stability of the solar system.
• Le Verrier then worked on a study of periodic comets and was able to show that certain comets, previously thought to be distinct objects, were in fact the same object perturbed into a very different orbit by the gravitational attraction of Jupiter.
• His work gained him considerable recognition and, on 19 January 1846, he was elected to the Academy of Sciences.
• Receive, Monsieur le Ministre, the homage of my respectful regards.
• U J Le Verrier, Member of the Institute.
• His main work was in celestial mechanics and his most famous achievement was his calculation of the position of an unknown planet, later named Neptune, from irregularities in Uranus's orbit.
• François Arago had asked him to work on the irregularities in Uranus's orbit in 1845 and Le Verrier had published his first memoir on the subject in December 1845.
• His perturbation analysis showed remarkable computational skills for he had taken his approximations to the seventh order, involving 469 distinct terms.
• On 18 September 1846, Le Verrier wrote to Johann Galle at the Berlin Observatory asking him to look for the planet at the position he predicted.
• so novel a thing to undertake observations in reliance upon merely theoretical deductions; and that, while much labour was certain, success appeared very doubtful.
• However, on receiving Le Verrier's letter, five days after it was sent, Galle saw the confidence that Le Verrier had in his work and so searched for the new planet on the same evening he received the letter.
• John Couch Adams has been recognised as having made similar calculations of a perturbing planet independently of Le Verrier.
• This is not the place to discuss the validity of the claims for Adams, but we should note that recent research has suggested that his results were considerably less accurate than those of Le Verrier.
• Le Verrier received many honours and widespread recognition for his achievement.
• He was awarded the Copley Medal of the Royal Society of London and, in France, became an officer in the Legion of Honour.
• In 1847 a chair of celestial mechanics was specially created for Le Verrier at the Sorbonne.
• He embarked on an ambitions research programme, namely to produce a single work for the whole of the planetary system.
• put everything in harmony if possible and, if it is not, declare with certainty that there exist still unknown causes of perturbations, the sources of which would then and only then be recognisable.
• Le Verrier had now achieved an important status and he used his influence to radically change the mathematics teaching at the École Polytechnique.
• Its members included General Jean-Victor Poncelet (1788-1867) who had just retired after two rather ineffective years as Commandant (the first academic to hold this post since the reforms of 1804), and Jean-Marie Duhamel as Directeur des Études.
• In six months of 1850 Le Verrier wrote a large and remarkable report on the school, including many aspects of its history drawn from the archives.
• He also published a substantial supplement with the Assemblée Nationale.
• Irritated by the long and recent dominance of the policies of Laplace and Cauchy, Le Verrier argued in effect for a return to Monge's aspirations.
• When the recommendations were approved, some reactions at the school were stark: Liouville and Chasles resigned immediately in protest at this rejection of the emphasis on teaching purish mathematics that they had inherited and continued from predecessors such as Cauchy.
• It is not only for his theoretical contributions to astronomy that Le Verrier deserves praise.
• His systematic inquiry in Europe and Asia enabled him to determine the path of the cyclone.
• Occupied during this period with the reorganization of the meteorological observation service of the Paris observatory, Le Verrier conceived "the project of a vast meteorological network designed to warn sailors of approaching storms." The greatest difficulty lay in securing the cooperation of the various telegraphic services.
• By 1857 the project was sufficiently advanced for distribution of a daily bulletin giving the atmospheric conditions at fourteen French and five foreign stations.
• Also in 1854 Le Verrier became director of the Paris Observatory which, under Arago's leadership, had not performed to standards that Le Verrier expected.
• Eventually, his unpopularity led to him being removed from the post in 1870.
• Charles Delaunay was appointed as his successor but Delaunay died in a tragic accident in August 1872.
• Following this, in 1873 Le Verrier again was given the post but his authority was severely restricted as he was supervised by a council.
• Le Verrier's major piece of work looking at the whole planetary system began with a look at the inner planets and immediately he discovered a discrepancy in the motion in the perihelion of Mercury in 1855.
• This leaves 43 seconds of arc per century unaccounted for.
• Le Verrier, because the masses of the planets was not known very accurately in his day, found an advance of the perihelion of Mercury of 38 seconds of arc per century unaccounted for.
• Now the advance of the perihelion of Mercury by more than Newtonian theory predicted was to become important evidence for Einstein's general theory of relativity, but of course none of this could be known to Le Verrier who, in a paper presented to the Academy of Sciences on 12 September 1859, attributed it to an undiscovered planet, which he called Vulcan, closer to the Sun than Mercury or to a second asteroid belt so close to the Sun as to be invisible.
• Only three months after presenting his paper he received a letter from Edmond Lescarbault who lived in Orgères near Rennes saying he had observed the transit of Vulcan nine months earlier.
• Le Verrier rushed to Orgères to meet with Monsieur Lescarbault.
• Over the following years many tried to find Vulcan, either by looking for transits or during a total eclipse when a planet close to the sun would become visible.
• For example, Le Verrier himself led an expedition to Spain in July 1860 to observe a total eclipse.
• Many false reports encouraged Le Verrier, but none proved correct.
• It was long after Le Verrier's death, in 1915, that Einstein's general theory of relativity explained the orbit of Mercury without the need for perturbing bodies.
• Vulcan was, in many ways, an unfortunate side-show in Le Verrier's important work on the orbits of all the planetary bodies.
• He constructed tables for the planets and theories for their orbits.
• He published Théorie du mouvement apparent du Soleil Ⓣ(Theory of the apparent movement of the Sun)(1858), and Tables du Soleil Ⓣ(Tables of the Sun) (1858); Théorie de Mercure Ⓣ(Mercury Theory) (1859), and Tables de Mercure Ⓣ(Mercury Tables) (1859); Théorie de Vénus Ⓣ(Venus Theory) (1861), and Tables de Vénus Ⓣ(Venus tables) (1861); Théorie de Mars Ⓣ(Mars Theory) (1861), and Tables de Mars Ⓣ(Mars Tables) (1861); Théorie de Jupiter Ⓣ(Jupiter Theory) (1876), and Tables de Jupiter Ⓣ(Jupiter tables) (1876); Théorie de Saturne Ⓣ(Saturn Theory) (1876), and Tables de Saturne Ⓣ(Saturn tables) (1876); Théorie d'Uranus Ⓣ(Uranus Theory) (1876); Théorie de Neptune Ⓣ(Neptune Theory) (1876); and Tables d'Uranus Ⓣ(Uranus Tables) (1877).
• He received the Gold Medal of the Royal Astronomical Society in 1868 for his work on the theories and tables of Mercury, Venus, Earth and Mars, and he received a second Gold Medal from the Royal Astronomical Society in 1876 for his work on the remaining planets.
• Charles Pritchard (1808-1893) presented him with the Gold Medal in 1868 and John Couch Adams presented Le Verrier with the second Gold Medal in 1876 but by this time he was too ill to receive it in person.
• Le Verrier began to suffer from a liver disease in 1873.
• It became progressively worse and he died in Paris, being buried in the Montparnasse Cemetery in a grave which has a large stone celestial globe over it.
• He was elected to almost every Academy in Europe.
• An asteroid, a ring of Neptune, and a lunar crater have been named after Le Verrier.
• Streets in Besançon, Brive-la-Gaillarde, Caen, Joué-lès-Tours, Lille, Nantes, Paris, Saint-Lô, Toulouse, and Tourcoing have been named after him.
• There has been an Air France plane and a French weather ship named 'Le Verrier'.

Born 11 March 1811, Saint-Lô, France. Died 23 September 1877, Paris, France.

View full biography at MacTutor

Tags relevant for this person:

Astronomy, Physics

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@J-J-O'Connor

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References

Adapted from other CC BY-SA 4.0 Sources:

1. O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive