Concept in Definition ABC
Miscellanea / / July 04, 2021
By Florencia Ucha, in May. 2011
We call geoid to theoretical almost spherical shape assumed by planet Earth, in which the average level of the seas that run through it will be taken as the surface. It is spoken in an almost spherical way because there is a slight flattening at both poles, given by the equipotential surface of the Earth's gravitational field that coincides with the mean level of the seas. So, if we consider the crust, the earth will not be one hundred percent a geoid, although it will be if it is represented with the mean level of the tides.
The idea of the earth as a geoid was anticipated by the scientist Isaac Newton in his work, The Beginning of Him in 1687. Newton would demonstrate it through a homemade exercise: if you spin a viscous body rapidly in a liquid fluid, the shape of Balance which will present the mass under the plan of the law of gravity and rotating around its own axis will be a spheroid flattened at their respective poles.
Meanwhile, the proposal Newton's would be studied and verified in situ time later by
The shape of the geoid can be determined by: gravimetric measurements (measuring the magnitude of the intensity of gravity at various points on the earth's surface. As a consequence, it is a sphere flattened at its poles, the acceleration of gravity will go in crescendo from the Equator to the Poles), astronomical measurements (They measure the vertical of the place in question and wait for its variants. The variation will be related to the shape) and measurement of the deformations produced in the orbit of the satellites caused by the fact that the earth is not homogeneous.
Topics in Geoid