Although some would argue that the hexagon is the bestagon, astronomers have discovered that Saturn appears to favor the ten-sided decagon on its south pole. This comes as its south pole has recently been confirmed to show a pattern that’s oddly ten-sided, per a recent research article by [Agustín Sánchez-Lavega] et al. in Science Advances.

Because Saturn is a gas giant, this naturally isn’t some gigantic planet-sized rock formation, but rather an interesting wave phenomenon in this massive gas bubble. The hexagon shape on its north pole had been known about for a while already, so it is perhaps not too surprising to find something similar on its south pole.

These shapes are generally the result of standing waves within a polar vortex, through the interaction of waves in Saturn’s atmosphere. For the north pole hexagon, the formation is driven by an intense eastward jet, but no similar wave had been reported for the planet’s south pole.

While in this paper a decagon shape is identified based on multiple observations, they postulate that it’s due to a meandering wave in the area rather than a jet as at the other pole. This clearly doesn’t make this wave pattern as obvious as the one at the north pole, but it provides another fascinating insight into fluid dynamics scaled up to a planetary gas giant.