Saturn's Southern Skies Reveal a Surprising Ten-Sided Atmospheric Feature
Saturn is already famous for the striking hexagon at its northern pole, and now astronomers have confirmed a second geometric marvel in its atmosphere. This newly verified structure is a giant decagon located around the planet's south pole. It was first captured in images taken during 2023, with subsequent Hubble Space Telescope observations proving that the formation is real. The feature lies at about 60 degrees southern latitude and is connected to a powerful eastward jet stream moving through the atmosphere at close to 420 kilometers per hour. The decagon itself, by contrast, creeps along at just roughly 10 km/h.
The southern decagon is reminiscent of Saturn's well-known northern hexagon, which Voyager spacecraft first documented in 1980 and 1981. Data gathered later by Hubble and the Cassini mission showed that the northern hexagon has persisted for at least 44 years. The newly found southern feature, however, is classified as an atmospheric wave and appears to be far less stable. Observations also indicate that the decagon lies farther away from the pole than the hexagon does.
Chasing the Decagon and Why It Matters
In 2024, amateur skywatchers recorded a dark, undulating line encircling Saturn's south pole. When scientists analyzed the data in 2025, they found that the line traced a clear ten-sided outline. Hubble images then allowed researchers to follow the structure all the way back to at least 2023. Several computer simulations have been tested to explain how the decagon might have formed, but so far none has matched the observed shape. One potential culprit is an anticyclone, a high-pressure vortex sitting slightly north of the structure and spanning nearly 4,000 kilometers across.
Finding a ten-sided pattern at Saturn underscores just how complex the planet's weather systems are and creates new opportunities for scientific exploration.
— Source: Astronomical observations
Astronomers plan to monitor the decagon over the next several years as Saturn's southern hemisphere moves from spring into summer. Understanding this unusual feature may provide broader insight into how atmospheric patterns develop on Saturn and on other giant worlds, including Jupiter. Watching how the shape shifts with the changing seasons will be essential to learning more about its long-term behavior and evolution.
As researchers continue to unravel the mysteries of Saturn's atmosphere, understanding the dynamics of its magnetic shield becomes increasingly crucial. This recent discovery of a shift in Saturn's magnetic field sheds light on how such atmospheric phenomena, like the newly identified decagon, may be influenced by broader planetary forces.