 Enlightenment scientist Isaac Newton, working from Jean Richer's pendulum experiments and Christiaan Huygens's theories for their interpretation, reasoned that Jupiter and Earth are oblate spheroids owing to their centrifugal force.Earth's diverse cartographic and geodetic systems are based on reference ellipsoids, all of which are oblate.A science-fiction example of an extremely oblate planet is Mesklin from Hal Clement's novel "Mission of Gravity".