Due to the pressure in the water being higher than in the center (the momentum of an individual molecule forces it outwards), a higher column of water is suppor

Due to the pressure in the water being higher than in the center (the momentum of an individual molecule forces it outwards), a higher column of water is supported at the rim. The speeds involved are not relativistic, so this isn't a matter of special or general relativity. Except, of course, one needs to explain the conservation of momentum relative to the universe. Noether said that's because space is isotropic.