John Couch Adams ( KOOTCH; 5 June 1819 – 21 January 1892) was a British mathematician and astronomer. He was born in Laneast, near Launceston, Cornwall, and died in Cambridge. His most famous achievement was predicting the existence and position of Neptune, using only mathematics. The calculations were made to explain discrepancies with Uranus's orbit and the laws of Kepler and Newton. At the same time, but unknown to each other, the same calculations were made by Urbain Le Verrier. Le Verrier sent his co-ordinates to Berlin Observatory astronomer Johann Gottfried Galle, who confirmed the existence of the planet on 23 September 1846, finding it within 1° of Le Verrier's predicted location. (There was, and to some extent still is, some controversy over the apportionment of credit for the discovery; see Discovery of Neptune.) Later, Adams explained the origin of meteor showers, which holds to the present day. Adams was Lowndean Professor in the University of Cambridge from 1859 until his death. He won the Gold Medal of the Royal Astronomical Society in 1866. In 1884, he attended the International Meridian Conference as a delegate for Britain. A crater on the Moon is jointly named after him, Walter Sydney Adams and Charles Hitchcock Adams. Neptune's outermost known ring and the asteroid 1996 Adams are also named after him. The Adams Prize, presented by the University of Cambridge, commemorates his prediction of the position of Neptune. His personal library is held at Cambridge University Library.
Early life
Adams was born at Lidcot, a farm at Laneast, near Launceston, Cornwall, the eldest of seven children. His parents were Thomas Adams (1788–1859), a poor tenant farmer, and his wife, Tabitha Knill Grylls (1796–1866). The family were devout Wesleyans who enjoyed music and among John's brothers, Thomas became a missionary, George a farmer, and William Grylls Adams, professor of natural philosophy and astronomy at King's College London. Tabitha was a farmer's daughter but had received a rudimentary education from John Couch, her uncle, whose small library she had inherited. John was intrigued by the astronomy books from an early age. John attended the Laneast village school where he acquired some Greek and algebra. From there, he went, at the age of twelve, to Devonport, where his mother's cousin, the Rev. John Couch Grylls, kept a private school. There he learned classics but was largely self-taught in mathematics, studying in the Library of Devonport Mechanics' Institute and reading Rees's Cyclopædia and Samuel Vince's Fluxions. He observed Halley's Comet in 1835 from Landulph and the following year started to make his own astronomical calculations, predictions and observations, engaging in private tutoring to finance his activities. In 1836, his mother inherited a small estate at Badharlick and his promise as a mathematician induced his parents to send him to the University of Cambridge. In October 1839 he entered as a sizar at St John's College, graduating B.A. in 1843 as senior wrangler and first Smith's prizewinner of his year.
Discovery of Neptune
In 1821, Alexis Bouvard had published astronomical tables of the orbit of Uranus, making predictions of future positions based on Newton's laws of motion and gravitation. Subsequent observations revealed substantial deviations from the tables, leading Bouvard to hypothesise some perturbing body. Adams learnt of the irregularities while still an undergraduate and became convinced of the "perturbation" theory. Adams believed, in the face of anything that had been attempted before, that he could use the observed data on Uranus, and utilising nothing more than Newton's law of gravitation, deduce the mass, position and orbit of the perturbing body. On 3 July 1841, he noted his intention to work on the problem.
After his final examinations in 1843, Adams was elected fellow of his college and spent the summer vacation in Cornwall calculating the first of six iterations. While he worked on the problem back in Cambridge, he tutored undergraduates, sending money home to educate his brothers, and even taught his bed maker to read. Apparently, Adams communicated his work to James Challis, director of the Cambridge Observatory, in mid-September 1845, but there is some controversy as to how. On 21 October 1845, Adams, returning from a Cornwall vacation, without appointment, twice called on Astronomer Royal George Biddell Airy in Greenwich. Failing to find him at home, Adams reputedly left a manuscript of his solution, again without the detailed calculations. Airy responded with a letter to Adams asking for some clarification. It appears that Adams did not regard the question as "trivial", as is often alleged, but he failed to complete a response. Various theories have been discussed as to Adams's failure to reply, such as his general nervousness, procrastination and disorganisation. Meanwhile, Urbain Le Verrier, on 10 November 1845, presented to the Académie des sciences in Paris a memoir on Uranus, showing that the preexisting theory failed to account for its motion. On reading Le Verrier's memoir, Airy was struck by the coincidence and initiated a desperate race for English priority in discovery of the planet. The search was begun by a laborious method on 29 July. Only after the discovery of Neptune on 23 September 1846 had been announced in Paris did it become apparent that Neptune had been observed on 8 and 12 August but because Challis lacked an up-to-date star-map it was not recognized as a planet. A keen controversy arose in France and England as to the merits of the two astronomers. As the facts became known, there was wide recognition that the two astronomers had independently solved the problem of Uranus, and each was ascribed equal importance. However, there have been subsequent assertions that "The Brits Stole Neptune" and that Adams's British contemporaries retrospectively ascribed him more credit than he was due. But it is also notable (and not included in some of the foregoing discussion references) that Adams himself publicly acknowledged Le Verrier's priority and credit (not forgetting to mention the role of Galle) in the paper that he gave 'On the Perturbations of Uranus' to the Royal Astronomical Society in November 1846:
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