# Dynamic flattening

With celestial bodies - especially the earth - dynamic flattening is understood to mean that flattening of a homogeneous ellipsoid of revolution which would show the same period of precession under the influence of the known tidal forces of other celestial bodies . Because the denser core is subject to lower centrifugal acceleration, the dynamic flattening is usually less than the geometric flattening: ${\ displaystyle f_ {d}}$

${\ displaystyle f_ {d}

at the earth:

${\ displaystyle f_ {d} = {\ frac {1} {305}} .

Immanuel Kant was credited with being the first to calculate its dynamic flattening from the earth's precession period.

## Individual evidence

1. ^ Hermann Wagner: Textbook of Geography . Volume 1, Hahn, Hanover 1900, limited preview in the Google book search.