Urbain Jean Joseph Leverrier
1811-1877
French Mathematician and Astronomer
Urbain Jean Joseph Leverrier was born in St. Lô France in 1811. Little is known about his early life, but he studied briefly in the lab of famous chemist Joseph Gay-Lussac (1778-1850) prior to settling on celestial mechanics as a field of study. By the age of 25 he had been appointed as an astronomer and professor at the Polytechnique and, in 1846, was admitted to the French Academy.
Leverrier is best known for his work leading to the discovery of Neptune in 1846, a discovery he shares with John Couch Adams (1819-1892) and Johann Gottfried Galle (1812-1910). Like Adams and others, Leverrier was intrigued by the fact that Uranus's orbit did not match predictions based on accepted laws of physics. Solving the problem some time after Adams did, Leverrier published his results first. He approached a number of French astronomers, requesting that they look at the calculated position for the new planet, but met with no success. Part of the reason for this was that he was known as a rather unpleasant person.
Leverrier eventually convinced Galle to search for the new planet. Galle and his assistant found it in their first observing session at precisely the calculated position, beating a group of English astronomers who searched slightly less diligently. This led to a dispute between the English andFrench over priority, eventually being resolved as a joint discovery shared by both Adams and Leverrier. Of this discovery, one of Leverrier's colleagues said, ". . . he discovered a star with the tip of his pen, without any instruments other than the strength of his calculations alone."
Immediately following the announcement of Neptune's discovery, the London Times announced "Leverrier's planet found" in large headlines. And, in recognition of his role in Neptune's discovery, Leverrier was awarded the Copley Medal of the Royal Society of London and other honors.
Because of the acclaim that resulted from this discovery, Leverrier was made a Senator by Louis Napoleon in 1852 and then Director-General of the Paris Observatory in 1854. However, these honors did not stop his research. Following his success with Neptune, Leverrier became interested in similar problems in predicting the orbit of Mercury. Taking a similar approach, in 1859 Leverrier predicted the existence of a planet, which he called Vulcan, closer to the sun than Mercury. Although several astronomers later reported unconfirmed sightings of Vulcan and Leverrier believed in its existence until his death, it has been determined that no such planet exists. In fact, Albert Einstein (1879-1955) showed the anomalous motions of Mercury to be due instead to an application of relativity theory, removing the physical and mathematical necessity for a new innermost planet altogether.
Leverrier was an unpopular director because of his continuing quest for greater and greater levels of efficiency. Because of this, Leverrier was removed from his position at the Paris Observatory in 1870. However, when his appointed successor died only three years later, Leverrier was re-appointed to the post, but with severe restrictions on his authority. He continued there, still searching for Vulcan, until his death in 1877 at the age of 66. He is remembered as not only the co-discoverer of Neptune, but as one of France's greatest astronomers.
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