Scientists Identify Decagonal Wave Pattern in Saturn's Southern Clouds
A team of researchers has detected a ten-sided jet stream formation in Saturn's southern polar clouds, a larger and more dynamic counterpart to the planet's known hexagonal feature.
Researchers observing Saturn with the Hubble Space Telescope have identified a decagonal wave pattern in the icy ammonia clouds above the planet's south pole. The structure, which spans more than 10,000 miles on a single side, appears larger and less stable than the hexagonal jet stream at Saturn's north pole that was first seen by NASA's Voyager probes in the 1980s.
The decagon was first captured in 2023 after earlier observations missed it, suggesting it may have formed between 2017 and 2023 when the southern pole was tilted away from Earth. Measurements using the European Southern Observatory's Very Large Telescope indicate the pattern drifts eastward at about 6 mph (10 kph), whereas the northern hexagon remains nearly stationary.
"Saturn still has the ability to surprise us," said Leigh Fletcher of the University of Leicester, who participated in the wind-speed analysis.
"The ‘unique’ hexagon is not as extraordinary as we thought," lead author Agustín Sánchez-Lavega of the University of the Basque Country wrote in an email accompanying the study published in Science Advances.
The discovery provides a new comparative basis for studying atmospheric dynamics on gas giants. Sánchez-Lavega noted that examining both polar formations could improve understanding of planetary weather patterns and may reveal connections to polygonal cyclone arrangements observed on Jupiter. Ongoing observations over the coming years are expected to clarify whether the decagonal feature will persist as long as the hexagon, which has been visible for more than four decades.