Hubble reveals mysterious 10-sided pattern swirling at Saturn's south pole

Using the Hubble Space Telescope, astronomers have identified a giant, evolving 10-sided decagon in Saturn’s southern polar region, marking the first large regular-sided jet pattern observed there. The decagon appears larger and more unstable than Saturn’s northern hexagon, and researchers suggest it may have formed sometime between 2017 and 2023 as Saturn’s south pole became more visible. Jet-stream dynamics, possibly linked to nearby storms, appear to drive the feature, which exceeds 10,000 miles in one side and is migrating eastward at a slow pace. The finding, published in Science Advances, shows polygonal weather patterns can occur in both hemispheres and informs understanding of giant-planet atmospheres. Ongoing observations in coming years aim to determine whether the decagon will persist as long as the north hexagon or evolve differently.