A 13,000 kilometre ten-sided wave over Saturn's south pole is confirmed in Hubble images
A ten-sided wave, its edges drawn by strong winds, sits over Saturn's south pole; the pattern is about 13,000 kilometres across, slightly wider than Earth. Amy Simon and colleagues examined images taken with Hubble between 2023 and 2025, and the results appeared in Science Advances. Older Hubble and Cassini imaging shows no such structure: the wave began to take shape in 2023 and looks fully developed in the frames from August and September 2025.
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A 13,000 kilometre pattern confirmed in Hubble images
A ten-sided weather pattern, its sharp edges drawn by powerful winds, sits near Saturn's south pole. Amateur astronomers noticed it in 2024, and Amy Simon of NASA's Goddard Space Flight Center and colleagues then examined images taken with Hubble between 2023 and 2025. The results appeared in the journal Science Advances. The pattern is about 13,000 kilometres across, slightly wider than Earth. Agustín Sánchez-Lavega of the University of the Basque Country says the team confirmed the existence of the decagon with absolute clarity. Sánchez-Lavega, who works at Spain's Bilbao School of Engineering, is lead author of the study and says nothing in Earth's atmosphere compares with this wave.[1], [2]
Absent from Cassini imaging, the pattern took shape after 2023
Older Hubble images and the frames taken by NASA's Cassini probe show no such structure over the south pole. The wave first appears in Hubble photographs from 2023, grows steadily sharper and looks fully developed in images taken in August and September 2025. The polar projections published with the study come from Hubble observations on 29 August 2025: a red wavelength at 763 nanometres and a methane absorption filter at 889 nanometres. The hexagon at the north pole has been known for more than 40 years; Simon says the northern pattern is a little smaller and the southern one drifts a little more with the planet's rotation.[1], [2]
There is no single model for the shape
Sánchez-Lavega says there is no single model for the shape: the structure may have arisen from an instability in the jet stream where it sits, or from a wave forced from deeper levels of the atmosphere. It may also be linked to a nearby storm with a high pressure centre resembling Jupiter's Great Red Spot. Some of the edges look fuzzy, and Sánchez-Lavega reads that as a sign that the wave is unstable or still evolving; the structure may become more pronounced when sunlight over the southern polar region peaks at that latitude around 2032. Why the north carries six sides and the south ten, and why Jupiter, known for its storms, shows nothing similar, is unclear. No spacecraft has orbited Saturn since 2017.[1], [2]
