1. A Six-Sided Ring of Wind Circles Saturn's North Pole
The six-sided shape first showed up in pictures from the two Voyager spacecraft in the early 1980s. It is a jet stream: a fast river of wind that flows around the pole along a six-sided path, at about 77 degrees north latitude. NASA describes it as wider than two Earths side by side, with wind believed to blow at around 100 meters per second (220 miles per hour)[1].
Then the north pole moved into winter. For about 15 years it sat in winter darkness, and Cassini, a NASA spacecraft that reached Saturn in 2004, could not photograph the pole well at first. When spring light returned, Cassini took the first full pictures of the hexagon in about 30 years, and it was still there[1][2]. That is far longer than an Earth hurricane, which lasts about a week[2].
So the hexagon is a puzzle on two counts: why corners, and why so long-lived? The first has an answer that starts with a river.
2. A Jet Stream That Wiggles Six Times Forms a Hexagon
Earth has jet streams too. NOAA describes them as narrow bands of strong wind high in the atmosphere that meander around the globe, dipping and rising, and sometimes splitting[3]. They can top 275 miles per hour (442 kilometers per hour)[3], so strong wind alone is not what makes the hexagon unusual. The odd part is the shape: a jet whose wiggles are so regular that it closes into a polygon.
A simple way to picture it is a river with bends. The water keeps moving, but the bends stay where they are. At Saturn's pole the river is a ring around the pole, and it has six bends. In scientists' terms, six waves travel around the pole along with the jet, so the pattern looks stuck in place compared with the atmosphere around it[4].
Researchers who studied Cassini and ground-based pictures from 2008 to 2014 interpret the hexagon as a vertically trapped Rossby wave on the polar jet. A Rossby wave is a very large, slow ripple in a spinning atmosphere. They found the corners turning with a steady period of 10 hours 39 minutes 23.01 seconds[5].
3. A Spinning Tank of Water in Oxford Also Made a Six-Sided Shape
An idea like this needs a test. At Oxford University in England, researchers filled a tank with water and glycerol, added white tracer particles so the flow would show up, and set the tank on a turntable. A disc or ring turned at a different speed from the rest of the tank, which crudely copies the speed difference on the edges of Saturn's jet[6].
The flow was unstable. It developed meanders and small swirls, and these eventually settled into a six-sided pattern[6]. Other settings gave other polygons, so six was one possible result, not the only one[7]. The Oxford team was careful about what this proves: the experiment does not show that Saturn's hexagon forms in the same way, only that it could[6].
4. How Can a Wind Pattern Stay the Same for Decades?
The 2014 study offers a proposal: the hexagon and the jet may reach deep into the atmosphere, anchored in layers that the seasons barely touch[5][8]. The jet's shape stayed essentially unchanged through the long polar night[5]. A proposal is not an answer, and NASA scientists say plainly that they do not know what controls the path the stream takes[2].
There is a bonus clue in the steady turning. If the hexagon is rooted deep, its rotation could reveal how fast Saturn itself spins, which has been hard to pin down by other methods such as radio emissions or the planet's gravity[5][8].
5. The Hexagon's Color Changed but Its Shape Did Not
Between 2012 and 2016, Cassini pictures show the area inside the hexagon changing from bluish to golden. NASA's leading explanation is that more sunlight on the pole produced more photochemical haze as the north pole approached its summer solstice in 2017. NASA also notes that other effects, such as changes in air circulation, could play a part[9].
Saturn's seasons last around seven Earth years[4], so this was a slow change. The jet seems to act as a barrier: Cassini images show fewer large haze particles inside the hexagon and more outside[10]. The color shifted with the seasons, while the six-sided outline stayed put.
6. A Ten-Sided Shape Is Now Growing at Saturn's South Pole
In September 2026, a team led by Agustín Sánchez-Lavega of the University of the Basque Country in Spain published a paper in Science Advances about a 10-sided atmospheric wave around Saturn's south pole. Ground-based observers noticed it in 2024 and 2025 images, and Hubble Space Telescope data showed it was already there in 2023[11]. It is the first large, regular-sided jet pattern seen in Saturn's southern hemisphere[12].
It also behaves differently from the north. NASA's Amy Simon said the hexagon has been there every time anyone has looked, for more than 40 years, but the new feature "appears to be strengthening"[11]. The researchers are only starting to piece together its history, so nobody can yet say why the north has six sides and the south has ten[12].
How to Follow the Hexagon Story Yourself
- Spin some water. Pour water into a wide, shallow dish on a table and sprinkle on a little pepper. Stir gently once and watch the specks. Wipe up any spilled water afterward, and keep the pepper away from your eyes and mouth. Do the ones at the edge and the middle move at different speeds? This will not make a hexagon. It only shows that one body of water can flow differently in different places, which is the starting point of the Oxford experiment.
- Look at Earth's jet stream. Many national weather services publish maps of high-altitude winds. Find one and look for wiggles in the fast band. Can you spot bends like the "river with bends" picture in section 2?
- Compare two pictures. NASA's image pages for Cassini show the 2012 and 2016 views of the pole. Put them side by side. What changed, and what did not?
- Find Saturn in the sky. Saturn is easy to spot on many nights, and a small telescope shows its rings. The hexagon is not something to expect from a basic backyard setup.