Hubble tracks a new 10-sided atmospheric wave at Saturn’s south pole

NASA Science, Hubble Mission Team at Goddard: “Recent observations with NASA’s Hubble Space Telescope have revealed a giant, evolving, 10-sided atmospheric wave encircling Saturn's south pole. This discovery marks the first time a large, regular-sided jet pattern has been observed in the planet's southern hemisphere.” “The feature appears remarkably similar to Saturn's famous hexagon at its northern pole, but is also distinctly different.” “The results published Wednesday in the journal Science Advances.”

Amy Simon, study co-author and OPAL principal investigator at NASA Goddard, is quoted: “We've never seen anything quite like this in Saturn's southern hemisphere.” “The northern hexagon has been there every time we've looked for more than 40 years. This feature is different — it appears to be strengthening, giving us the rare opportunity to watch a giant atmospheric pattern develop.”

Lead author Agustín Sánchez-Lavega is identified as a researcher at the University of the Basque Country. NASA says ground-based observers, including amateur astronomers Trevor Barry and Jean-Paul Oger, first noticed a subtle undulating band along the southern pole, with additional 2025 ground imagery, after which Hubble OPAL data confirmed the feature’s presence back to 2023. Co-author Michael Wong is identified at the University of California, Berkeley.

The authors, NASA writes, say further study is needed from Hubble and NASA’s James Webb Space Telescope, as well as computer models, “to understand how the decagon formed, how long it may last, and how it compares to the long-lived hexagon in the north.” Whether the decagon will stabilize like the northern hexagon is explicitly open on that page.