How did a Mysterious 10-Sided Decagon Wave Form on Saturn’s South Pole?

NASA’s Hubble Space Telescope has tracked a giant 10 sided atmospheric wave around Saturn’s south pole. It marks the first time a regular multi sided jet pattern has been observed in the planet's southern hemisphere. 

The Saturn South Pole decagon discovery was published in Science Advances. These findings from the Outer Planet Atmospheres Legacy (OPAL) program reveal that the structure began taking shape in 2023. 

Researchers are eager to study this feature as seasonal shifts bring the region into clearer view. Co-author Dr. Amy Simon noted, "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."

How Astronomers Discovered 10-Sided Saturn South Pole Wave

Amateur observers and researchers first spotted a faint wavy line around Saturn's south pole in 2024 using pictures submitted to the Planetary Virtual Observatory Laboratory. 

To verify what they were seeing scientists turned to sharp images captured by the Hubble Space Telescope. Hubble's space based view confirmed that the 10-sided shape was already starting to form in 2023.

Because Hubble snapped photos using different filters, light from various depths showed that the wave cuts through multiple layers of Saturn's atmosphere rather than sitting on top as a simple cloud layer.

You: What could be stranger than a giant, evolving, 10-sided atmospheric wave encircling Saturn's south pole?

Saturn: Have you seen the north pole? https://t.co/7uuFA3dvMG https://t.co/ZBcxrAXzhg pic.twitter.com/m5NO3eERu7

— NASA Solar System (@NASASolarSystem) September 3, 2026

Why This Southern Pattern of Saturn Ring Surprises Scientists

For decades scientists only knew about the 6-sided hexagon at Saturn's north pole. When the Cassini spacecraft orbited Saturn between 2004 and 2017 its cameras saw no geometric shapes near the south pole at all.

Watching this new feature build up gives researchers a live look at how gas giant atmospheres move:

• Jet streams are fast winds that dictate the way these wave-like patterns take shape and maintain themselves.

• It takes Saturn 29 years to orbit around the Sun. Thus, the poles receive sunlight in different ways over prolonged periods of time.

• Being able to observe a formation process of something from scratch allows researchers to test whether the models of giant planets work properly.

Teams using both Hubble and the James Webb Space Telescope will keep tracking the south pole to see if the 10-sided wave stays put or fades away. The discovery of this 10-sided wave gives space researchers a direct view of a giant planet's weather as it changes. 

Unlike the steady northern hexagon this developing southern wave shows how dynamic gas planets can be over just a few years. Future pictures from space telescopes will tell us if the decagon is here to stay or just a short-lived phase in Saturn's long seasonal cycle.