The polar night/midnight sun is explained by the axial tilt of the earth in relation to the sunlight that hits it. At the moment this tilt is about 23,4° and does not have a tidal locking with the sun. That why we have seasons and polar night and a midnight sun. If on the north pole is midnight sun, at the south pole there is polar night and vice versa.
If the globe model was wrong, what would be the right explanation for this phenomenon?