posted 09-23-2017 06:18 PM               

The discovery of the planet Neptune on September 23, 1846, is justly famed as a triumph of reason, hard work, and the brilliant application of celestial mechanics. The French astronomer Urbain Jean Joseph Le Verrier recognized that slight perturbations in the observed motion of Uranus indicated that a new, unknown planet was exerting a gravitational influence. Le Verrier calculated where the planet should be — an extraordinary feat when computing was done with pencil and paper; Johann Galle at Berlin Observatory pointed a telescope at the right spot, and there was Neptune.

The tale also goes that John Couch Adams, a young English mathematician at Cambridge, had tackled the same problem independently and predicted the planet's position to within half a degree of Le Verrier's position as early as September 1845. But, according to the story, the English astronomy establishment ignored the young Adams, letting the discovery slip away to the French. After the discovery, a consensus seemed to emerge that both Adams and Le Verrier deserved equal credit for the roles they had played.

That story, however, conceals a fierce priority dispute that for a while threatened to become a major international incident. Few realized that the consensus story was actually a carefully crafted compromise based on selective use of documents. Only now are hidden papers coming to light that reveal the truth behind the politically expedient version.