A team of researchers led from Spain has announced the discovery of an enormous ten-sided wave structure in the icy ammonia clouds above Saturn's south pole. The formation, which rotates and meanders through the atmosphere, appears to be even larger and more unstable than the well-known hexagonal cloud pattern surrounding the planet's north pole, first observed by NASA's twin Voyager probes in the 1980s.

This new jet-stream feature emerged in observations from the Hubble Space Telescope in 2023, following earlier surveys that had detected nothing at that location. Investigators suspect that the strange atmospheric phenomenon may have taken shape between 2017 and 2023, a period when Saturn's south pole was tilted away from Earth and thus remained out of our line of sight.

The structure could continue to evolve. Each side of the decagon already exceeds 10,000 miles, or approximately 16,700 kilometers.

The findings carry significant scientific weight because they demonstrate that "the singular hexagon is not as extraordinary as we thought," lead author Agustín Sánchez-Lavega of the University of the Basque Country explained via email to the Associated Press. The results appear in the journal Science Advances.

While every planet in the solar system with an atmosphere exhibits disturbances capable of generating waves, only Saturn produces these polygon-shaped configurations—geometric figures bounded by straight lines.