“Hydrostatic
equilibrium” governs the structure of all gaseous bodies
(planets or
stars). The inside has higher temperature and density because of the
weight of the overlying material.
Temperature at
center is ~20000K. Note relation between temperature and pressure – pressure
needed to prevent collapse (and more upper weight requires more pressure).
Note odd state of metallic hydrogen (conducting – semi-free electrons). Core
is uncertain (current limit about 5 earth masses – that’s odd).
