NASA’s Hubble Space Telescope has glimpsed a strange ten-sided atmospheric wave at Saturn’s south pole, the first regular-sided jet pattern ever observed there.
In a recent paper published in Science Advances, researchers examined Saturn’s peculiar decahedron, detecting signs of an entirely new atmospheric phenomenon for the gas giant. A similar hexagon-shaped wave resides at Saturn’s north pole but differs in noticeable ways.
Years of Hubble observations from 2023 to 2025 allowed the team to trace subtle hints that they eventually resolved into the decagonal wave at Saturn’s south pole.
Observing the Solar System
“We’ve never seen anything quite like this in Saturn’s southern hemisphere,” said co-author Amy Simon, OPAL principal investigator, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “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.”
Since its 1990 launch into low Earth orbit, the Hubble Space Telescope has been observing our solar system, uncovering new details about our planetary neighbors. One such project is the Outer Planet Atmospheres Legacy (OPAL) program, which began collecting data with observations of Uranus in 2014 and now provides the crucial evidence for this discovery, with high-resolution images that resolve murky hints from ground-based observations.
As Saturn’s seasons changed, its south pole came into alignment with ground-based observatories. In images from those telescopes submitted to the Planetary Virtual Observatory Laboratory, amateur astronomers Trevor Barry and Jean-Paul Oger, along with Agustín Sánchez-Lavega of the University of the Basque Country in Spain, noticed something interesting happening on the gas giant.
A Strange Band on Saturn
The researchers spotted an undulating band along Saturn’s south pole, which, in further 2025 ground-based telescope images, began to suggest a decagonal (ten-sided) structure. With its incredible image clarity and spatial resolution, Hubble’s imagery finally allowed researchers to resolve the decagonal shape with certainty.
“Given Saturn’s symmetry in its north-south jet stream system, we have been searching for a counterpart to Saturn’s northern hexagon on the south pole in Hubble images since 1990,” said lead author Agustín Sánchez-Lavega of the University of the Basque Country in Spain. “Images from NASA’s Cassini spacecraft, which orbited Saturn between 2004 and 2017, showed no inkling of a long-lived formation, either. The Hubble data confirmed the feature’s presence back to 2023.”
The wave is an interesting three-dimensional feature that extends through multiple layers of the atmosphere within one of the planet’s jet streams. Because Hubble can image the planet in multiple wavelengths, the decagon’s location appears to shift between observations, as each wavelength penetrates the atmosphere to a different degree.
Questions About Saturn
“The most intriguing part to me is that this seems to have just formed recently,” said Simon. “The question is, why did it suddenly form now when we haven’t seen one before?”
Recognizing Saturn’s decagonal wave is only a first step. Follow-up observations to collect more data and computer models to piece together what is occurring on the planet will be required to firmly grasp the phenomenon. Questions remain about how it formed, how long it may last, and how similar it is compared to the northern hexagonal wave.
One thing the team will be sure to watch for in their continued observations is whether the shape evolves or maintains its decagonal structure. Their continued work could provide important new insights into how atmospheric dynamics operate on gas giants and what they can reveal about our own planet’s atmospheric phenomena.
The paper, “A Decagon Wave Around Saturn’s South Pole,” appeared in Science Advances on September 2, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.