Simplified example thumb| Earth's gravitational field is not uniform. An oblate spheroid is typically used as the idealized Earth, but even if the Earth were spherical and did not rotate, the strength of gravity would not be the same everywhere because density varies throughout the planet. This is due to magma distributions, the density and weight of different geological compositions in the Earth's crust, mountain ranges, deep sea trenches, crust compaction due to glaciers, and so on.
simplified example thumb| earth's gravitational field is not uniform an oblate spheroid is typically used as the idealized earth but even if the earth were spherical and did not rotate the strength of gravity would not be the same everywhere because density varies throughout the planet this is due to magma distributions the density and weight of different geological compositions in the earth's crust mountain ranges deep sea trenches crust compaction due to glaciers and so on