5 January 1819: John Couch Adams, Cornish discoverer of the planet Neptune, born.

As below, so above. Lately, while dimpled chads littered the Florida beaches, the tally of planets in our solar system has also been subject to a controversial recount. After the search for a reputed tenth “Planet X” was abandoned, a number of astronomers have argued that the ninth planet Pluto does not deserve the designation of planet at all, being after all smaller than our own moon. While nobody tried to drag the Supreme Court into this, a recent scientific conference was convened to discuss the matter. While the conference voted to leave Pluto alone, the designers of the new Rose Planetarium at the American Museum of Natural History in New York nevertheless opted to expunge Pluto from its scale-model display, causing no small amount of dismay and annoyance.

But whatever Pluto’s merits may be, we wouldn’t have gotten this far if it weren’t for the work of an unassuming Cornishman named John Couch Adams.

As a child John Couch Adams showed a self-taught aptitude for astronomy, learning the layout of the heavens first-hand by laying out late at night stargazing on the Cornish moorlands. He did more than stargaze: while in his teens he published an account of a solar eclipse he observed at Devonport. Later, using only a small spyglass, he became one of the first to gain a glimpse of Halley’s Comet as it hove into earth’s view on 16 October 1834.

At the age of 22 he took his interests a step further. He became interested in the perturbations he observed in the orbit of the seventh planet Uranus. Using mathematics to analyse the orbit of Uranus, he determined that the irregularities of the planet’s orbit could only be explained by the presence of another, as yet unseen planet farther out in space. While Adams wasn’t the first astronomer to suspect something was amiss out there, he continued with his mathematical analysis and determined the precise position and orbit where this planet would be found.

The publication of Adams’ calculations in 1846 stirred some doubts among those who wondered how such a relatively obscure 27 year old Cornishman could have come to make such a momentous discovery. But the eminent astronomer John Herschel supported Adams’ claim to the discovery, even though the delay in submitting the claim led to another controversy when a French astronomer named Leverier claimed prior discovery. It was eventually proven that Leverier had discovered the planet now called Neptune only several months after Adams did.

International renown did not give John Couch Adams a swollen head. In 1847 he quietly refused an English knighthood offered to him for his discovery, and years later he would decline an appointment to the office of Astronomer Royal to England’s Queen Victoria, preferring to go on teaching astronomy at Cambridge University instead.

A modern-day link with the astronomical sophistication of the ancient Celts, John Couch Adams was the first observer since Copernicus to fundamentally revise our view of the solar system, breaking out of the classical seven-planet concept and pioneering the way to the ongoing search for other planets in the universe.

The events and people of the six Celtic nations of Ireland, Scotland, Wales, Brittany, Cornwall, and the Isle of Mann covered in This Month in Celtic History are drawn from the Celtic League American Branch’s annual Celtic Calendar, now available.