In
cosmogony,
planetary differentiation is a process by which the
denser portions of a
molten planet will sink to the center; while less dense materials rise to the surface. Such a process tends to create a
core,
crust, and
mantle. On
Terra, this process created a surface density of 3000kg/m
3; while the average density, of the planet, is 5515kg/m
3.