Hubble Confirms New 10-Sided Wave at Saturn’s South Pole

Saturn’s south pole has acquired a shape astronomers spent decades looking for: a 10-sided atmospheric wave circling the planet. NASA’s Hubble Space Telescope has confirmed the feature in observations dating back to 2023, and researchers say it appears to be strengthening.

The discovery began closer to Earth. In 2024, Agustín Sánchez-Lavega of the University of the Basque Country and amateur astronomers Trevor Barry and Jean-Paul Oger noticed a faint, undulating band in ground-based images. More images taken in 2025 made the pattern clearer. Hubble then supplied the sharper view needed to establish that the band formed a decagon. Saturn’s changing seasons had gradually brought its southern pole back into view.

The wave is more than a mark on the visible clouds. It sits within one of Saturn’s powerful jet streams and reaches multiple layers of the atmosphere. Hubble images taken at different wavelengths show slight shifts in the feature’s apparent position because each wavelength probes a different altitude. From space, Hubble can also observe complete rotations of Saturn without the blurring caused by Earth’s atmosphere.

For planetary scientists, the practical gain is a time series of a giant atmospheric pattern in the act of developing. The images give researchers a target for new observations with Hubble and NASA’s James Webb Space Telescope, as well as for computer models that can test how the decagon formed and how it compares with Saturn’s northern hexagon.

The limits are clear. Researchers do not yet know why the southern pattern formed, how long it will last, or whether it will become as enduring as the northern feature. NASA says the results, published in Science Advances, mark the first observation of a large, regular-sided jet pattern in Saturn’s southern hemisphere.