Hubble tracks new decagon encircling Saturn's south pole

• NASA’s Hubble Space Telescope has captured images showing a 10-sided atmospheric wave, or decagon, encircling Saturn’s south pole. The feature, first observed in 2024 by amateur astronomers, appears to be evolving and strengthening. The decagon is distinct from Saturn’s well-known hexagon at its north pole, suggesting a new atmospheric phenomenon.
• The decagon is visible in Hubble images taken over several years, with the structure becoming more defined in 2025. The wave spans multiple layers of Saturn’s atmosphere, indicating it is not just a cloud-level feature but a vertically extended atmospheric structure. Observers note that the decagon’s position shifts slightly due to Hubble’s varying wavelengths.
• The discovery is part of NASA’s Outer Planet Atmospheres Legacy (OPAL) program, which has been observing outer planets annually for over a decade. The results are published in *Science Advances*, and the study highlights the importance of long-term observations in detecting atmospheric changes.
• The decagon’s sudden appearance and its similarity to the hexagon at Saturn’s north pole raise questions about its formation and potential significance for understanding atmospheric dynamics on gas giants. Further study with Hubble and the James Webb Space Telescope is needed to determine its longevity and underlying mechanisms.
• The OPAL program has allowed scientists to track seasonal changes and identify slow-evolving atmospheric features. The team plans to continue observing Saturn to see if the decagon stabilizes or continues to evolve. The findings underscore the value of long-term data collection in planetary science.

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