Main Question or Discussion Point
Earth’s interior is much hotter than the surrounding environment (i.e., empty space) so there must be a tendency of the Earth to expand - yet the Earth’s volume remains essential constant. This is so because an equilibrium has been achieved in which the heat-driven expansion is balanced by a gravity-driven contraction. My question: How is this described mathematically? How do we numerically describe the equilibrium between the amount of HEAT inside the Earth and GRAVITY?