An unusual 10-sided atmospheric wave has emerged above Saturn's south pole, revealing a phenomenon that scientists have yet to fully understand. Captured by the Hubble Space Telescope, this distinctive feature appears unprecedented compared to atmospheric waves observed on Earth.
Saturn, already known for its intense storms and unique atmospheric formations, now presents researchers with another intriguing mystery. The decagonal wave challenges existing knowledge about how large, complex structures can develop and persist in the gas giant’s atmosphere.
The findings were detailed in a recent paper published in Science Advances. Observations from Hubble show the wave began appearing in 2023, becoming more evident by mid to late 2025.
An interesting aspect of this discovery is its difference from the northern polar wave on Saturn, which features a well-documented six-sided pattern known since the 1980s. While the northern hexagon is a long-standing feature, the southern decagon has only recently formed, and scientists are still exploring why the two poles display such contrasting shapes.
New Discovery of a Decagonal Wave at Saturn's South Pole
Scientists studying Saturn’s south pole have detected a wave with ten distinct sides, forming a shape resembling a decagon. This pattern exists within the planet’s atmospheric jet streams, but the exact forces shaping its geometric form remain unknown.
As Agustín Sánchez-Lavega, the lead author and physicist from Spain’s Bilbao School of Engineering, noted, nothing like this has ever been seen in Earth's atmosphere.
“We do not yet know for certain,” Sánchez-Lavega said. “There is no single model to explain it. It may be the result of an instability in the jet stream in which it is situated or a wave forced from deeper levels of the atmosphere.”
The team is investigating whether disturbances in Saturn’s atmospheric flows could generate this shape. A nearby high-pressure storm, somewhat akin to Jupiter’s Great Red Spot, might influence the wave, though its precise origin remains unknown.
Tracking the Evolution of Saturn’s South Pole Decagon Using Hubble
By analyzing images taken at different times, researchers tracked the wave’s gradual development. Earlier data from the Hubble Space Telescope and NASA’s Cassini mission showed no evidence of the decagonal wave, indicating this is a recent phenomenon.
An ESA/Hubble press release confirms the first subtle signs were recorded in 2023. By August and September 2025, the pattern was fully visible. Observations from August 29, 2025, included views at 763 nanometers (red wavelength) and through a methane absorption filter at 889 nanometers, revealing the decagon encircling the southern polar region.
Despite improved clarity in recent images, some edges of the decagon remain blurred. This suggests to Sánchez-Lavega that the wave could be unstable or still in formation rather than a stable, permanent feature.
A remaining question is why such distinct polygonal waves appear on Saturn but not on Jupiter, which also has a turbulent gaseous atmosphere but lacks analogous geometric atmospheric phenomena.
Investigating the Origins of Saturn’s Polar Polygonal Waves
Saturn exhibits two very different polygonal patterns at opposite poles: the well-known northern hexagon and the newly found southern decagon. Sánchez-Lavega proposed that differences in latitude may influence these formations, and that seasonal variations in sunlight might also be a contributing factor, although this hypothesis has yet to be confirmed.
“If the seasonal insolation cycle over the southern polar region plays a role in the formation of this structure, it may well become more pronounced in the coming years, when insolation reaches its peak at the latitude of the decagon around the year 2032,” he said.
As it stands, the cause behind the disparity in side count between the two hemispheres remains a mystery. Scientists are still trying to determine why Saturn produces such polygonal waves and why similar patterns have not been detected on Jupiter.
“What causes one hemisphere to have six sides and the other 10—perhaps this is related to the difference in latitude between the two cases,” Sánchez-Lavega said. “There are many unanswered questions, which we hope future observations and models will help to clarify.”
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