A persisting hexagonal wave pattern around the north polar vortex in the atmosphere at about 78N was first noted in the Voyager images.
The sides of the hex are each about 13,800 km (8,600 mi) long, which is longer than the diameter of the Earth. The entire structure rotates with a period of 10h 39m 24s (the same period as that of the planet's radio emissions) which is assumed to be equal to the period of rotation of Saturn's interior. The hexagonal feature does not shift in longitude like the other clouds in the visible atmosphere.
The pattern's origin is a matter of much speculation. Most astronomers believe it was caused by some standing-wave pattern in the atmosphere. Polygonal shapes have been replicated in the laboratory through differential rotation of fluids.

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