These two outer planets have among other unique features, areas that are at times at an apparent standstill with their surroundings, by virtue of their matched Orbital and Rotational Velocities. An analogy would be A harvesting machine that has grabbing means mounted on a rotating wheel, or band. This horisontal wheel or operating band, at the harvesting point, moves at the same speed, but in opposite direction as the harvesting vehicle, so that at the moment of gathering, the harvesting can always be done at an apparent standstill. The doubling of ground speed at the opposite side to the harvesting point, could help to eject the gathered material,. This efficient pickup of all the goodies from the field (solar energy) on that zero-velocity ring or band makes it the area providing the most energy, the crop, the "raison d'etre" of the exercise. . This localized energy potential being the driving force for the unique features, rings, bands on those planets. (motor driving the contraption using most energy, actually) Machines coincidentally developed not in the sense of Newton's Creator nudging the solar system once in awhile, but by virtue of the conditions already present at the Big Beginning. Details of the idea in the Science, Astronomy section, currently under "Jupiter--". Nebel.