Saturn south pole decagon atmospheric discovery

Astronomers have identified a massive, ten-sided atmospheric structure, referred to as a ‘decagon’, encircling Saturn’s south pole. Published in the journal Science Advances, the discovery was made through the Outer Planet Atmospheres Legacy (OPAL) program using observations from the Hubble Space Telescope.

This decagon is estimated to be approximately 167,820 kilometers wide, significantly larger than the stable six-sided hexagon found at Saturn’s north pole. Unlike the northern hexagon, which has remained stable for over 40 years, the southern decagon appears to be a recent and dynamic phenomenon. It was not detected by the Cassini probe during its mission between 2004 and 2017, leading researchers to suggest it may have formed between 2017 and 2023 due to seasonal changes or atmospheric instabilities.

The structure is described as an atmospheric wave embedded within a powerful jet stream where high-latitude winds can exceed 400 km/h. While the winds are fast, the decagonal pattern itself moves eastward at approximately 9 to 10 km/h, with its ten vertices exhibiting a back-and-forth movement in a cycle of roughly 32 days. Scientists intend to use both the Hubble and James Webb telescopes to monitor the evolution of this pattern.