Gravity Map
Earth, lumpy? Hey!! This is our planet you're talking about here!!! Have some respect!
"Sir Isaac Newton formulated the basic law of gravity in the 17th century. All objects, he said, attract one another with a force that is proportional to their masses and that is dependent upon the distances between them. Although the force of gravity is relatively constant everywhere on earth, small variations exist because the planet is not a homogeneous structure with equally distributed mass. The planet is lumpy, with materials of different densities scattered above and below the surfaces of land and water."
The New York Times