Discovery of Neptune

1846 discovery of Neptune through mathematically-predicted observation

The planet Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence of a major planet were made on the night of September 23–24, Autumnal Equinox of 1846, at the Berlin Observatory, by astronomer Johann Gottfried Galle, working from Le Verrier's calculations. It was a sensational moment of 19th-century science, and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet "with the point of his pen".

This keyword could refer to multiple things. Here are some suggestions: