NASA's Astronomy Picture of the Day for September 8, 2026 featured a Hubble Space Telescope composite showing Saturn's south pole marked by an X and surrounded by bands of circulating clouds, with a decagon — a 10-sided shape — most prominent in the dark inner regions. The image was taken the previous year, according to the entry.

Saturn's north pole has been known to be surrounded by a hexagonal cloud since its discovery in 1987 in data from NASA's Voyager spacecraft, which flew past the planet in the early 1980s. The entry says the geometric boundaries are possibly caused by waves arising when fast-moving gas away from the poles interacts with slower-moving gas closer to the poles. It notes the northern hexagon has proven stable for over 40 years, while the stability of the southern decagon is expected to remain a research topic.

The composite is credited to NASA, ESA, STScI and HST, with A. Sánchez-Lavega (UPV), A. Simon (NASA-GSFC) and M. Wong (UC Berkeley), and processing by A. Pagan (STScI).