Giant 10-sided wave discovered at Saturn's south pole
NASA's Hubble Space Telescope detects unprecedented atmospheric structure on Saturn.
1Unprecedented discovery
NASA's Hubble Space Telescope has detected a massive, 10-sided atmospheric wave structure at Saturn's south pole. This marks the first observation of such a regular jet stream pattern in the planet's southern hemisphere. While showing some similarities to the famous northern hexagon, it contains significant differences. The discovery was published in the journal Science Advances.
2Years of observations
Researchers tracked the development of this extraordinary feature using Hubble observations dating back to 2023. Early images showed faint traces of the structure, which gradually developed into a clearer pattern. The data comes from Hubble's Outer Planet Atmospheres Legacy (OPAL) program, which has been recording annual images of outer planets for over a decade.
3North-south contrast
Amy Simon from NASA's Goddard Space Flight Center stated, "We've never seen anything like this in Saturn's southern hemisphere." While the northern hexagon has remained stable for 40 years, this new structure appears to be strengthening. This provides scientists with a rare opportunity: to observe the formation of a giant atmospheric pattern. Saturn's seasonal cycle also played a key role in the discovery.
4Contribution from amateur astronomers
A team led by Agustín Sánchez-Lavega from Spain's University of the Basque Country noticed a wavy band near the south pole in 2024 images. With contributions from amateur astronomers Trevor Barry and Jean-Paul Oger, they confirmed by 2025 that the feature had developed into a decagon. Hubble's position in space provided clear images without Earth's atmospheric blurring effect.
5Structure extending deep into atmosphere
The newly discovered wave lies within one of Saturn's powerful jet streams. Observations show it extends through several atmospheric layers - meaning it's not just a cloud-top pattern. Small positional variations were observed at different Hubble wavelengths, as each wavelength reveals different atmospheric altitudes.
6Major unanswered questions
As Simon noted, the most intriguing question is: "Why did it form now?" Scientists don't yet know what triggered the decagon or how stable it might be. Answering these questions will require additional observations from Hubble and the James Webb Space Telescope, plus computer modeling. This will help understand how closely it resembles Saturn's long-lived northern hexagon.
7Importance of OPAL program
The OPAL program provides more than isolated snapshots. Years of repeated observations allow scientists to monitor seasonal changes, track temporary storms, and identify gradually developing atmospheric patterns. Mike Wong from the University of California emphasizes that OPAL enables new discoveries through years of accumulated data.
8Contribution to planetary science
This discovery could shed light not just on Saturn, but on atmospheric behaviors of all gas giants. Researchers will continue monitoring whether the southern decagon becomes as stable as its northern counterpart. The findings might even provide new insights into Earth's atmospheric dynamics. Hubble's long operational history gives astronomers the advantage of tracking planetary changes over years.