John Couch Adams, Astronomer who discovered planet Neptune

John Couch Adams. Born: 5 June 1819 in Lidcott, near Launceston, Cornwall, England. Died: 21 Jan 1892 in Cambridge, Cambridgeshire, England. John Couch Adams will be best remembered, however, for his role as the co-discoverer of Neptune.

A great scientist born in Laneast parish on Bodmin Moor in 1819. from an early age he showed a bent for mathematics and astronomy in particular. He went to Cambridge University. Solely by the application of mathematics, he proved that there must be another planet circling the sun. A french astronomer came to the same conclusion, and they published their conclusions at the same time. The planet was called Neptune.

He became Professor of Astronomy in Cambridge in 1858. He turned down a knighthood and also the post of Astronomer Royal

Born to poor parents, with his father Thomas being a tenant farmer. His parents farmed near Launceston, Cornwall, and it was on Lidcott farm that John, the eldest of his parents seven children, was born.

John Couch Adams went the village school at Laneast, where he studied Greek and algebra, until he was 12 years old. This was followed by a private school at Devonport run by his cousin the Rev. John Couch Grylls. At the Devonport school he showed great mathematical ability and became interested in astronomy. In 1835 he observed Halley's comet. He calculated an annular eclipse of the Sun would be visible in Lidcott in 1836, and he was able to watch it.

He won a scholarship to St John's College, Cambridge, entering the university in October 1839 to study mathematics. He graduated as Senior Wrangler (ranked top of the First Class) four years later having. Also in 1843, following his final exams, he became a Fellow of St John's College.

He had in 1841, while still an undergraduate, noted the irregularities of the orbit of Uranus, and had determined to ascertain if there was a planet beyond it. In September 1845 Adams gave information on the position of the new planet to James Challis, director of the Cambridge Observatory. But problems with communicating with the Cambridge Observatory seemed to mean that this was never followed through by them.

In November 1845 Adams was elected a Fellow of the Royal Astronomical Society for his paper "Elements of the comet Faye", rather than for finding a new planet.

Urbain Le Verrier, a French astronomer, published a paper in June 1846 predicting a new planet. At this time Adams prediction had not been published. It was Le Verrier's prediction which led to the discovery of Neptune on 23 September 1846 by Galle at the Berlin Observatory.

His paper was eventually published in January 1847. The Royal Astronomical Society pondered who should receive their Gold Medal for the discovery of Neptune. Their rules only allowed one medal to be awarded so after many arguments neither received a Gold Medal for the discovery of Neptune.

Adams became Regius Professor of Mathematics at St Andrews in October 1857. And in March 1859 Lowndean Professor of Astronomy and Geometry at Cambridge and held the post for over 32 years. He became director of the Cambridge Observatory in 1861.

Adams's made many other contributions to astronomy, notably his studies of the Leonid meteor shower. He predicted correctly in 1864 that the meteor shower would occur in November 1866. Adams also studied terrestrial magnetism, determined the Gaussian magnetic constants at every point on the Earth and produced maps with contour lines of equal magnetic variation which were published after his death.

In October 1889 Adams became seriously ill with a stomach hemorrhage. He recovered but the illness recurred and he died in the Cambridge Observatory in 1892.


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