Hubble tracks new decagon encircling Saturn’s south pole

A mysterious giant 10-sided pattern of clouds has recently formed around Saturn's south pole, a new. This newfound "decagon" joins the bizarre colossal hexagon seen for decades at Saturn's north pole. Saturn's hexagon — a cloud pattern about 20,000 miles (32,000 kilometers) wide — was first discovered in 1988 by scientists reviewing data from NASA's Voyager flybys of Saturn in 1980 and 1981.

Despite decades of observations, no similar structure was seen anywhere else on Saturn — until now, as scientists have discovered an even larger structure on Saturn. The newfound decagon is about 104,250 miles (167,820 kilometers) wide, with each of its 10 sides measuring about 10,425… Astronomers discover mysterious 10-sided cloud structure at Saturn's south pole.

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 north pole but is also distinctly different, suggesting scientists may be witnessing a new atmospheric phenomenon developing on the iconic gas giant. Hubble tracks new decagon encircling Saturn's south pole.

September 2, 2026 Hubble tracks new decagon encircling Saturn's south pole by NASA edited by Robert Egan, reviewed by Andrew Zinin Robert Egan Senior Editor Meet our editorial team Behind our editorial process Andrew Zinin Chief Editor Meet our editorial team Behind our editorial process Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread The GIST Add as preferred source Recent NASA Hubble Space Telescope images show the gas giant Saturn and its southern pole, where astronomers have discovered a 10-sided atmospheric wave.

Observations show the decagon extends through multiple layers of Saturn’s atmosphere. The results are published today in the journal Science Advances.

By piecing together several years of Hubble observations dating to 2023, researchers found subtle hints of the structure beginning to emerge before it became a clearly defined pattern. Those observations were taken as part of Hubble's Outer Planet Atmospheres Legacy (OPAL) program, which has photographed the outer planets annually for more than a decade.

"We've never seen anything quite like this in Saturn's southern hemisphere," said Amy Simon, study co-author and 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." A single filter from NASA’s Hubble Space Telescope distinctly shows a 10-sided wave encircling Saturn’s south pole, labeled “decagon”. An “X” denotes where data was not captured.

Agustín Sánchez-Lavega, lead author of the new study, is a researcher at the University of the Basque Country in Spain. The university manages a website called Planetary Virtual Observatory Laboratory that accepts ground-based images of solar system planets contributed by observers around the world.

It was in those images, first in 2024, that Sánchez-Lavega and amateur astronomers Trevor Barry and Jean-Paul Oger noticed a subtle undulating band along the south pole. Additional 2025 imagery taken from the ground hinted more strongly at this decagon structure.