NASA's Hubble Telescope Spots Giant 10-Sided Atmospheric Wave Around Saturn's South Pole

NASA's Hubble Space Telescope has detected a giant, evolving 10-sided atmospheric wave around Saturn's south pole. The feature is the first large, regular-sided jet pattern seen in Saturn's southern hemisphere. It looks similar to Saturn's famous hexagon at the north pole, but is also different, suggesting that scientists are seeing a new atmospheric phenomenon develop, according to NASA.

The results were published in the journal Science Advances. Researchers studied this structure by combining years of observations made by Hubble since 2023. Early signs of it were visible even before distinct patterns emerged in the images. These observations were conducted under Hubble's Outer Planet Atmospheres Legacy (OPAL) program, which has been capturing annual images of the outer planets for over a decade.

Study co-author Amy Simon noted that scientists had never before observed such a feature in Saturn's southern hemisphere. She explained that while the northern hexagon has been visible for over 40 years, the southern structure appears to be intensifying, offering scientists a chance to witness the evolution of a massive atmospheric pattern.

This discovery was made possible by Saturn's changing seasons, which gradually brought its south pole back into view from Earth. Astronomers studying ground-based images of Saturn were the first to identify this feature.

In 2024, Agustin Sanchez-Lavega, a researcher at the University of the Basque Country in Spain and the study's lead author-along with amateur astronomers Trevor Barry and Jean-Paul Oger, spotted a faint, wavy band near Saturn's south pole in ground-based images.

The University of the Basque Country operates the Planetary Virtual Observatory Laboratory website, where observers from around the world submit ground-based images of solar system planets.

Additional ground-based images captured in 2025 revealed clearer indications of a 10-sided structure.

Subsequently, Hubble's observations provided a much clearer picture of the feature. From space, Hubble captures exceptionally sharp images with high spatial resolution throughout Saturn's entire rotation. These images are free from the blurring caused by Earth's atmosphere.

Sanchez-Lavega noted that researchers had been searching for a structure similar to the northern hexagon at the south pole in Hubble images since 1990, given the similarities in Saturn's north-south jet stream systems. He explained that images from NASA's Cassini spacecraft, which orbited Saturn from 2004 to 2017, showed no signs of such a long-lasting structure. However, Hubble data confirmed the feature's presence as of 2023.

This wave exists within Saturn's powerful jet stream and extends across several atmospheric layers. This indicates that it is not merely a feature visible at the cloud level, but a structure that extends vertically through the atmosphere.

The apparent position of the decagon shifts slightly because Hubble captures images at different wavelengths. These various wavelengths probe different altitudes within Saturn's atmosphere.

Simon remarked that the most intriguing aspect is that this feature appears to have formed recently. She also raised the question of why it has suddenly appeared now, given that scientists had not observed it previously.

According to researchers, further study using Hubble and NASA's James Webb Space Telescope is required to understand the decagon's formation, its longevity, and how it compares to the long-standing hexagon at the north pole.

Hubble's long-term operations have enabled astronomers to observe changes occurring over time in the planets of our solar system and other celestial objects.

The OPAL program does not limit scientists to just a single snapshot. Through this, they can study weather changes, monitor short-lived storms, and identify atmospheric features that evolve gradually.