Preliminaries to the Neptune Discovery: Newtonian Gravitational Theory

The discovery of Neptune stunned the 19th century world. It involved the mathematical prediction of the existence of a major planet never yet seen through a telescope, because of the way it seemed to be pulling on a known planet, Uranus, away from its predicted orbit. When an actual planet was discovered near the predicted position, it was famously hailed as the greatest triumph of Isaac Newton’s theory of gravitation.