Known for

In 1845, the Cornishman John Couch Adams calculated the position of a new planet. John was a modest man and did not publish his calculations. A year later, a Frenchman made the same calculations as John and proved the existence of the planet Neptune.

Yn 1845 Kernow John Couch Adams a galkyas desedhans planet nowydh. Den klor o John ha ny dhellos y galkyansow. Bledhen a-wosa, Frynk a wrug an keth kalkyansow ha John ha previ bosva planet Neptun.

Photograph of John Couch Adams, the Cornishman who calculated the position of Neptune
John Couch Adams
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Farmer’s son

John Couch Adams was born on 5th June 1819 at Laneast, near Launceston. His parents were poor sheep farmers. As a boy, John looked after his parents’ sheep. He was a very clever child and became very good at maths. At home, John read his mother’s books about astronomy (the study of space). His parents saved enough money to send him to school in Saltash, and then to university at Cambridge, but he had to work to pay for his university tuition.

A new planet?

John did very well at university. In 1843, he was awarded the highest graded degree of his whole year group. John was now one of the most intelligent people in the country. He stayed at university to become a lecturer (teacher) and continued his interest in astronomy. 

In September 1845, John tried to work out what force was affecting the orbit (movement) of the planet Uranus. Using maths, John calculated that there must be another planet affecting Uranus. If he was right, John had discovered a new planet.

Proving his theory

John’s idea was only a theory. He needed to prove it by looking for the new planet with a telescope. He told Britain’s chief astronomer, Sir George Airy, about his calculations, but no attempt was made by the British to look for the planet that year.

The next year, a Frenchman called Urbain Le Verrier made the same calculations as John and published them. Le Verrier was able to find someone to look for the new planet with a telescope. On 23rd September 1846, the planet was found – Le Verrier had been right, and so had John a year before. The planet was given the name Neptune.

A modest man

John was a very modest man. He had not published his calculations and had not persuaded Sir George Airy to look for the planet. John did not seem to mind that Le Verrier shared the credit for discovering Neptune. John later became President of the Royal Astronomical Society, a Fellow of the Royal Society and Professor of Astronomy at the University of Cambridge. This modest Cornishman from a small farm near Launceston is remembered as one of world’s most brilliant mathematicians.

Did you know?

John taught his house cleaner to read and sent money home to pay for his brothers to go to school.

He also met with Caroline Fox, who recorded the meeting in her diary.



Oxford Dictionary of National Biography

Hutchins, R, ‘Adams, John Couch (1819–1892)’, Oxford Dictionary of National Biography (2004)

100 Cornish Lives

Smelt, M, 100 Cornish Lives (2006)

Famous Men and Women of Cornish Birth

Spreadbury, ID, Famous Men and Women of Cornish Birth, 100 Lives (1972)

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