Saturn's famous hexagon now has a ten-sided counterpart: a decagon wave circling Saturn's south pole, spotted in amateur telescope images and traced in NASA/ESA Hubble images.
How the Saturn decagon was found, how it compares with the Cassini hexagon at the north pole, what Earth's jet stream shares with it, and what scientists still don't know: why it has ten sides, and why it became visible now.
0:00 Six sides north, ten south, and Earth's jet stream
0:34 What the decagon is
1:24 Saturn's hexagon
3:07 How it was found
4:24 How a backyard telescope sees Saturn
5:20 Saturn's south pole before
6:10 How wind draws a polygon
8:27 Why now?
9:13 The question
What is known: the decagon is a wave along a jet stream near 60°S; each side is about 16,800 km, so the widely quoted ~168,000 km is the distance AROUND it, not across. It was visible in Hubble images from 2023 and clear by 2025, and appeared to be strengthening in observations through 2025. What is not known: why it formed now, and whether it will last.
Sources
- Sánchez-Lavega et al., "A decagon wave around Saturn's south pole", Science Advances (2026)
- NASA / STScI release, 2 Sep 2026; ABC News (Trevor Barry interview), 7 Sep 2026
- NASA/JPL Photojournal: PIA21611, PIA09186, PIA11682, PIA14944 (The Rose), PIA08332
- NASA Juno results (2018, 2019); NASA SVS "The Big Chill" (2014); Barbosa Aguiar & Read (2010)
Visuals: Hubble images NASA, ESA, STScI, A. Sánchez-Lavega (UPV), A. Simon (NASA-GSFC), M. Wong (UC Berkeley), processing A. Pagan (CC BY 4.0, credited on screen). Cassini images NASA/JPL-Caltech/Space Science Institute (PIA21611 also Hampton University; PIA09186 University of Arizona). Juno JIRAM: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM. Video: NASA Goddard Scientific Visualization Studio. Diagrams are labelled schematics; the decagon crop is contrast-enhanced and labelled so.
Narration is a synthetic voice. Independent production, not affiliated with or endorsed by NASA, ESA or STScI.
Will Saturn keep its decagon, the way it has kept the hexagon, or lose it? Tell us in the comments.
