Saturn’s Southern Decagon
The Voyager flybys in the early 1980s revealed a mysterious hexagon at Saturn‘s northern pole. For decades, researchers searched for a similar polygon at the southern pole, with no luck. But that appears to be changing.
Saturn’s axial tilt hid its southern pole from Earth-based observation in mid-2012 and the region remained out of view until 2023. Since late 2023, though, repeated observations have shown a 10-sided polygon circling the southern pole. Unlike the northern hexagon, which has been stable for 40+ years, the decagon appears to be actively evolving.
Researchers haven’t settled on the mechanism underlying the decagon yet. One suggestion is that it’s a meandering atmospheric wave trapped vertically and confined by the polar jet. Another possibility is that the decagon comes from perturbations to the polar jet, perhaps from nearby anticyclones. We can expect plenty of analyses and simulations to come! (Image and research credit: A. Sánchez-Lavega et al.; via Gizmodo)
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