Adams , John Couch

(1819–1892) British astronomer

Adams was born in the small Cornish town of Launceston, where his father was a tenant farmer. He developed an early interest in astronomy, constructing his own sundial and observing solar altitudes, and pursuing his astronomical studies in the local Mechanics Institute. He graduated brilliantly from Cambridge University in 1843, and became Lowndean Professor of Astronomy and Geometry there in 1858; in 1860 he was appointed director of the Cambridge Observatory.

His fame rests largely on the dramatic events surrounding the discovery of the planet Neptune in 1846. Astronomers had detected a discrepancy between the observed and predicted positions of Uranus and thus it appeared that either Newton's theory of gravitation was not as universal as had been supposed, or there was an as yet undetected body exerting a significant gravitational influence over the orbit of Uranus. There is evidence that Adams had decided to work on this problem as early as 1841. He had a general solution to the problem by 1843 and a complete solution by September, 1845. It was then that he payed a visit to George Airy, the Astronomer Royal, with the exact position of the new planet.

Airy payed little attention to it and was moved to action only when, in June 1846, the French astronomer, Urbain Leverrier, also announced the position of a new planet. It was within one degree of the position predicted by Adams the previous year. Airy asked James Challis, director of the Cambridge Observatory, to start looking for the new planet with his large 25-inch (63.5-cm) refractor. Unfortunately Challis decided to cover a much wider area of the sky than was necessary and also lacked up-to-date and complete charts of the area. His start was soon lost and Johann Galle in Berlin had no difficulty in discovering the planet on his first night of observation. All the fame, prizes, and honors initially went to Leverrier.

When it was publicly pointed out, by Challis and John Herschel, that Adams's work had priority over Leverrier's, the shy Adams wanted no part of the controversy that followed. In fact he seemed genuinely uninterested in honors. He declined both a knighthood and the post of Astronomer Royal, which was offered him after Airy's retirement in 1881. He later worked on the perturbations of the planets (1866), and on the secular variation of the mean motion of the Moon (1852), both difficult questions of mathematical astronomy. His scientific papers were published by his brother in two volumes, in 1876 and 1901.