The Failure of Newton's Theory
As time went on, detailed
calculations accounted more and more precisely for the orbits of the planets.
Any deviations from the expected behavior soon became viewed as evidence for
unseen masses in the Solar System. However, later
observations of anomalies in the orbit of Mercury could not be accounted for by
the gravitational perturbation of a new planet
(the hypothetical new planet, which turned out not to exist, was called
Vulcan).
As we shall discuss shortly,
early in the twentieth century the anomalies in Mercury's orbit forced the replacement of
Newton's law of gravitation with Einstein's theory of
general relativity.