Researchers from the University of the Basque Country and collaborators announced the detection of an enormous decagonal wave pattern swirling in the icy ammonia clouds above Saturn’s south pole. The feature, observed with the Hubble Space Telescope in 2023, appears larger and more dynamic than the iconic hexagonal cloud formation at the planet’s north pole that was first photographed by NASA’s Voyager probes in the 1980s.
How the decagon was found
The team first spotted the ten‑sided structure when Saturn’s southern hemisphere rotated back into view between 2017 and 2023, after being hidden from Earth’s line of sight. Measurements from the European Southern Observatory’s Very Large Telescope in Chile confirmed the pattern’s size, with one side already extending more than 10,000 miles (16,700 kilometers). Unlike the relatively stationary hexagon, the decagon drifts eastward at about six miles per hour (ten kilometers per hour).
Why it matters
Lead author Agustín Sánchez‑Lavega said the discovery challenges the notion that Saturn’s hexagon is a unique atmospheric oddity. By comparing the two polygonal jet streams on opposite poles, scientists hope to deepen their understanding of weather dynamics on giant gas planets, and perhaps draw parallels to the polygonal cyclones observed on Jupiter.
“Saturn still has the ability to surprise us,” said Leigh Fletcher of the University of Leicester, who helped measure the wind speeds within the decagon. The researchers plan to continue monitoring the southern hemisphere over the coming years, hoping to capture more detail and determine whether the decagon will endure as long as the hexagon, which has persisted for more than four decades.
Future observations
Improved viewing opportunities as Saturn’s tilt changes will allow astronomers to track the evolution of the decagonal jet stream. Continued study of these rare, polygonal cloud formations could provide valuable clues about the atmospheric physics of not only Saturn but also other gas giants throughout the solar system.
Original reporting: Alexandria, VA News – WTOP News — read the source article.
