James Challis

James Challis FRS (12 December 1803 – 3 December 1882) was an English clergyman, physicist and astronomer. Plumian Professor of Astronomy and Experimental Philosophy and the director of the Cambridge Observatory, he investigated a wide range of physical phenomena though made few lasting contributions outside astronomy. He is best remembered for his missed opportunity to discover the planet Neptune in 1846.

Early life

Challis was born in Braintree, Essex where his father, John Challis, was a stonemason. After attending various local schools, he graduated from Trinity College, Cambridge in 1825 as Senior Wrangler and first Smith's prizeman. He was elected a fellow of Trinity in 1826 and was ordained in 1830. He held the benefice of Papworth Everard, Cambridgeshire from the college until 1852. In 1831 Challis married Sarah Copsey, née Chandler, a widow, and consequently resigned his Trinity fellowship. The couple had a son and a daughter.

Plumian professor

In 1836, he became director of the Cambridge Observatory and Plumian Professor, holding the latter post until his death. He lectured in all areas of physics. As examiner for the Smith's prize, he appraised the early work of G. G. Stokes, Arthur Cayley, John Couch Adams, William Thomson (later Lord Kelvin), Peter Guthrie Tait and James Clerk Maxwell. For over a decade, in correspondence and publications, Challis repeatedly disagreed with Stokes's conclusions from his research.

Challis was referee for Thomson and for Stokes in their respective applications for chairs at the University of Glasgow, and for Maxwell at Aberdeen. He and Thomson together set and examined the Adams prize topic on Saturn's rings, won by Maxwell in 1857.