Apparently, Saturn has been hiding his talents. For decades, humanity has been baffled by the gas giant’s enormous hexagon swirling around its north pole, a six-sided atmospheric structure unlike anything known in the Solar System. Now, it seems that strange feature is not an isolated incident, and Saturn may have a propensity for polygons, rather than a passing whim. Lurking around the planet’s south pole, astronomers led by Agustín Sánchez-Lavega of the Basque University in Spain have discovered another giant polygon, and this one has ten sides. “This discovery suggests that the hexagon is not as extraordinary as previously thought and that, in fact, the conditions in Saturn’s atmosphere are such that polygonal waves can form in both hemispheres surrounding the polar regions,” Sánchez-Lavega told ScienceAlert. frameborder=”0″ enable=”accelerometer; autoplay; writing on clipboard; encrypted media; gyroscope; picture in picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” enablefullscreen> Saturn’s most prominent and well-known feature is its magnificent icy ring system, but the hexagon at its north pole would have to be a pretty close second. It was first discovered in images from the Voyager probes in 1980 and 1981: a vast, six-sided atmospheric wave that rotates around the pole at about 78.5 degrees latitude. For decades, both the Hubble Space Telescope and the Cassini-Huygens probe on Saturn also captured the strange feature, suggesting that it has remained stable for at least 44 years. It is a climate phenomenon, but why it has such a nearly perfect polygonal shape remains a mystery. And although scientists also thought that Saturn’s southern subpolar jets could produce a similar feature, none were revealed in multiple searches. polygonal fell for the second time. Astronomers, a dark, wavy line was visible around the planet’s south pole. Work in 2025 confirmed it. While creating polar projections from images of Saturn taken by astronomers Trevor Barry of Broken Hill Observatory in Australia and Jean-Paul Oger of the French Astronomy Association, the team finally saw it: Ten sides, forming an unmistakable polygon around the pole. appearance of Saturn’s south polar decagon between 2023 and 2025. (Sánchez-Lavega et al., Sci. Adv., 2026) High-quality images from the Hubble Space Telescope confirmed this and allowed the team to track it until 2023. “The discovery of the wave really came as a surprise, as neither previous images of Saturn taken by the Hubble Space Telescope nor those captured by the Cassini spacecraft while orbiting the planet between 2004 and 2017 had shown this.” Sánchez-Lavega said. Centered about 60 degrees south, the decagon appears to be a large atmospheric wave traveling on one of Saturn’s powerful eastward jet streams. The jet itself races around the planet at about 420 kilometers (260 miles) per hour, while the decagon moves at a comparatively leisurely pace of around 10 kilometers. per hour at different wavelengths revealed traces of its shape at different altitudes and latitudes, suggesting a vast vertical layered structure embedded in Saturn’s atmosphere. Basically, it is the same type of phenomenon as the hexagon, but, despite the difference in the number of sides, the two polygons are not mirror images of each other. from the north pole. (NASA/JPL-Caltech/Space Science Institute) “In addition to the difference in the number of sides,” Sánchez-Lavega explained, “the decagon is located at a less polar latitude than the hexagon in the southern hemisphere, and may not be as robust as we have seen it form.” southern polygon has ten sides, compared to the six in the north, preferred by nature? High-pressure vortex that researchers call Red Spot: smaller temporal analogues of Jupiter’s famous storm. Interestingly, the decagon appears more pronounced near the vortex and less distinctive on the opposite side of the planet. Simulations of three decagon formation scenarios (Sánchez-Lavega et al., Sci. Adv., 2026) “The hypothesis that a nearby anticyclone at that latitude is driving the oscillation is attractive,” Sánchez-Lavega said. “The same thing happened with the hexagon when it was discovered in 1980, but then the nearby vortex disappeared and the hexagon remained tantalizingly out of reach.” and years could reveal a lot more about how it formed. Saturn is tilted on its axis as it orbits the Sun every 29.5 years, giving the planet long seasons that last about 7.5 years each. Its southern hemisphere now moves from spring into summer, tilting ever more toward the Sun. view, astronomers will increasingly have a better vantage point from which to observe its development. “We need to understand how the decagon evolves; In other words, whether in the coming years it will become unstable and fragment or, on the contrary, become more stable and robust as solar radiation increases,” said Sánchez-Lavega. It lasted at least 44 years; we only learned of its existence long after its establishment. With the decagon, scientists now have a front-row seat to watch Saturn build its polygons in real time, and whatever happens, it will be a great spectacle. The research was published in Science Advances. This article was fact checked by Fiona MacDonald and edited by Fiona MacDonald. error, please let us know.
