The expected coincidence was established.

It was proved that the moon is retained in her orbit and made to revolve round the earth by the force of terrestrial gravity.

The genii of Kepler had given place to the vortices of Descartes, and these in their turn to the central force of Newton.
In like manner the earth, and each of the planets, are made to move in an elliptic orbit round the sun by his attractive force, and perturbations arise by reason of the disturbing action of the planetary masses on one another.

Knowing the masses and the distances, these disturbances may be computed.

Later astronomers have even succeeded with the inverse problem, that is, knowing the perturbations or disturbances, to find the place and the mass of the disturbing body.