What is the geoid?
Q: What is the geoid?
A: The geoid is a 3-D geometrical shape like an orange, which is a specific kind of oblate spheroid.
Q: How is the geoid defined?
A: The geoid is defined as the shape that the surface of the oceans would take under the influence of Earth's gravitation and rotation alone, in the absence of other influences such as winds and tides.
Q: Who defined the geoid and when?
A: The geoid was defined by Gauss, in 1828.
Q: What is the geodesy?
A: The study of Earth's measurements and shapes is called geodesy.
Q: Why use a reference ellipsoid instead of the geoid?
A: For many practical purposes, a simpler shape is used because that makes calculations easier. That shape is called a reference ellipsoid.
Q: How is the shape of the Earth described in basic education?
A: In basic education, the shape of the Earth is described as being like an orange, a sphere but wider round the equator.
Q: Are similar shapes to the geoid found in other celestial spinning spheres?
A: Yes, this shape is produced by all celestial spinning spheres, such as stars and planets. The details differ somewhat in each individual case.
