If you REALLY want to aim for realism, gravity should depend on all quads on the planet. So, if you were to build a huge floating island, the gravity between it and the planet would be less than the usual
If you really truly wanted to aim for realism, digging to the core would require a huge budget and an international coalition that would get bogged down in politics and mismanagement and it would never happen.
If you really truly wanted to aim for realism, digging to the core would require a huge budget and an international coalition that would get bogged down in politics and mismanagement and it would never happen.