The Mass of the Earth

The mass of the Earth has never been directly measured. It's calculated using the radius of the Earth, the value of g we get from a ball drop experiment (acceleration due to gravity), and the gravitational constant, G.

Sheol

Cutaway of planet Earth showing the crust, mantle, great gulf and hell.

Sheol refers to life beyond the grave, quite literally an underworld realm of the dead. It's also modified in a variety of ways which can be grouped to correspond to the main regions of the interior of the Earth.