Earth, Ellipsoidal era

The period from Eratosthenes to Picard can be called the spherical era of geodesy. A new ellipsoidal era was begun by Newton and the Dutch mathematician and scientist Christiaan Huygens. In Ptolemaic astronomy it had seemed natural to assume that the Earth was an exact sphere with a centre that, in turn, all too easily became regarded as the centre of the entire universe.