The planet is a basic sphere collider with all objects casting a single ray downwards and on collision with the sphere a y+ force is applied so they also stay buoyant. Over the sphere is an area that overrides the gravity to the center of the sphere and everything is pulled towards the center.
Tested some other shapes also such as cube, torus, but the objects didn't stay well adrift or had troubles getting the gravity to work.
Thanks for playing and reviewing!