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Bizarre Decagon Spotted Over Saturn’s South Pole
Developing
In Short: Scientists have discovered a 10-sided atmospheric wave at Saturn's south pole, a feature that has puzzled researchers given the planet's symmetrical jet stream system.
For decades, Saturn's north pole has been home to a distinctive six-sided jet stream known as the hexagon, first observed by NASA's Voyager spacecraft in the 1980s. Now, a similar but different feature has been spotted at the south pole: a decagon, or 10-sided atmospheric wave, which was first identified in Hubble images from 2023.
Dr. Amy Simon, an astronomer at NASA's Goddard Space Flight Center, noted, 'We've never seen anything quite like this in Saturn's southern hemisphere.' The decagon stands out due to its angular shape, suggesting it may offer insights into the planet's deeper atmospheric processes.
Saturn's southern hemisphere was not observable from Earth from 2012 to 2023 due to the planet's axial tilt. The decagon first became apparent in Hubble images last autumn and has been confirmed to have been visible since 2023, though it was less defined then. Scientists are unsure when the decagon first formed, as no spacecraft have been at Saturn since 2017.
Planetary scientist Agustín Sánchez-Lavega of the University of the Basque Country commented, 'This discovery suggests that the hexagon at the north pole is not as extraordinary as previously thought.' The decagon's variability contrasts with the more stable hexagon, indicating that Saturn's atmospheric dynamics may be more complex than previously understood.
Background
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is the point in the Southern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True South Pole to distinguish from the south magnetic pole.
What's confirmed
What's still developing
- The weird weather pattern didn’t show up in years of observations by NASA’s Cassini mission An image captured by the Hubble Space Telescope shows a 10-sided atmospheric wave surrounding Saturn’s south pole, as seen on August 29, 2025.
- Now, scientists using the Hubble Space Telescope and the help of a network of amateur astronomers have identified a similar 10-sided jet moving independently of the rest of the atmosphere circling Saturn’s south pole, researchers report September 2 in Science Advances.
- But the decagon’s angular shape rather than a smooth circle is striking and suggests there’s something intriguing to learn, perhaps about the planet’s deeper atmosphere, she says.
- The planet’s north pole has been marked by a distinctive cloud-darkening hexagonal jet of gas for at least 45 years — scientists first spotted it when NASA’s Voyager probes zipped past the ringed giant in 1980 and 1981.
- Atmospheric features like the hexagon “can last for decades, but on the other hand [things] can change very fast.” In and of itself, seeing a jet on Saturn is perfectly normal, says MIT planetary scientist Wanying Kang, who wasn’t involved in the new research.