[raattgift]

> Nothing about our current theories of gravity requires the gravitational body to not be flat

On the contrary the bulk behaviour of the source matter demands an ellipsoidal Earth: <https://en.wikipedia.org/wiki/Hydrostatic_equilibrium#Deriva...>.

One might attempt to banish magma, lava, and other indicators of fluid flow (the oceans, the atmosphere, planetary differentiation generally) and imagine an infinitely rigid lipped/walled plate underneath. However, then:

An eternally-accelerating flat plate does not generate the Weyl curvature tensor which a set of plumb bobs or zero-length springs can measure.

Even before General Relativity, such measurements were undertaken and characterized as smooth functions of distance from the Equator less than sixty years after Newton e.g. <https://en.wikipedia.org/wiki/Clairaut%27s_theorem_(gravity)>.