Science

Explanations for hexagon shape

False-color image from the Cassini probe of the central vortex deep inside the hexagon formation

An early hypothesis attributed the hexagon to Rossby waves.[21]

A hypothesis developed at Oxford University is the hexagon forms where there is a steep latitudinal gradient in the speed of the atmospheric winds in Saturn's atmosphere.[22] Similar regular shapes were created in a laboratory when a circular tank of liquid was rotated at different speeds at its centre and periphery. The most common shape was six sided, but shapes with three to eight sides were also produced. The shapes form in an area of turbulent flow between the two different rotating fluid bodies with dissimilar speeds.[22][23] A number of stable vortices of similar size form on the slower (south) side of the fluid boundary, and these interact with each other to space themselves out evenly around the perimeter. The presence of the vortices influences the boundary to move northward where each is present, and this gives rise to the polygon effect.[23] Polygons do not form at wind boundaries unless the speed differential and viscosity parameters are within certain margins and thus absent at other likely places, such as Saturn's south pole or the poles of Jupiter.