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Astronomers discover mysterious 10-sided cloud structure at Saturn's south pole
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Astronomers have made a surprising discovery at Saturn's south pole: a gigantic, ten-sided cloud formation. This new structure, termed a "decagon," represents the first polygonal pattern found in Saturn's southern hemisphere. It joins the famous, decades-old hexagon at the planet's north pole, fundamentally challenging previous assumptions about Saturn's unique atmospheric phenomena.
The discovery stems from recent observations using NASA's Hubble Space Telescope. Saturn's axial tilt had rendered its southern hemisphere invisible from Earth between 2012 and 2023. When Hubble finally captured clear images in 2023, scientists spotted the unexpected decagon for the first time.
The sheer scale of the new feature is immense. It spans approximately 104,250 miles (167,820 kilometers) wide, making it significantly larger than the northern hexagon. Each of its ten sides measures roughly 10,425 miles (16,782 kilometers) in length. The entire structure rotates slowly around the pole, completing one full turn every 800 days.
This finding alters our understanding of giant planet meteorology. "This is a very unusual atmospheric phenomenon... It tells us that the hexagon is not a unique, singular feature, as was previously thought," explained study lead author Agustin Sanchez-Lavega of the University of the Basque Country. The research suggests both polygons form through similar mechanisms involving meandering atmospheric jets.
The decagon is not a static structure. Unlike the relatively uniform northern hexagon, the southern decagon shows varying darkness across its features. This variation indicates it may be actively evolving, raising questions about its long-term stability.
Scientists are now focused on the decagon's future. A key uncertainty is how it will respond to increasing solar radiation, which will peak at its latitude around 60 degrees south in 2032. Researchers will monitor whether the pattern stabilizes or disintegrates. They also aim to model its three-dimensional structure, winds, and temperatures to refine their understanding of its formation. The findings were published on September 2 in the journal Science Advances.
