ABSTRACT
Physical geodesy is the branch of science that relates the internal distribution of mass within the Earth to its corresponding gravity field. Physical geodesy is also of concern to the geophysicist who studies gravity anomalies in search of patterns that indicate the presence of substrata oil deposits and to the geodesist who computes the trajectory of missiles and satellites flying above the Earth. Historically, physical geodesy and geometrical geodesy have shared the challenge of finding the elusive geoid and using it as a reference for elevation. One way to understand physical geodesy and the geoid better is to look at some of the physical quantities that can be measured and to describe the quantities that might be derived from those observations. From a geometrical geodesy perspective, it appears that the combination of precise ellipsoid heights and high-order orthometric heights is the best way to determine geoid heights.
