A six-sided weather system
Processed image. A published still from Cassini’s eight-frame sequence spanning 10 hours on 10 December 2012. Each frame combines 16 map-projected filter images; colours assigned to ultraviolet, visible and near-infrared light distinguish atmospheric particles. The viewpoint follows Saturn’s rotation, isolating cloud motion in the original sequence. This photographic composite is not a natural-colour view or a numerical weather simulation.
NASA/JPL image-use policy · credited mission imagery; resized to WebP
· Original image source · Image licenceAn angular outline in an atmosphere made of moving gas.
- World
- Saturn
- Case date or period
- Observations · 2006–2017
Look closer
Saturn’s northern hexagon is a persistent atmospheric pattern surrounding the polar region. Cassini recorded it under changing seasonal illumination and with different instruments.
Follow the evidence
Compare the visible-light observations with the infrared product. The images make its geometry tangible, while the colours and resolution depend on the observing method.
A polygon is a constraint on the physics
Masoud Rostami, Vladimir Zeitlin and Aymeric Spiga tested a rotating shallow-water model using observed polar winds. Including the central polar vortex produced a persistent hexagon-like jet; their jet-only configuration did not. The model averages away the atmosphere’s poorly known vertical structure. Its success shows that a natural fluid instability can produce this shape under selected conditions, rather than proving that Saturn follows that exact mechanism. Laboratory polygons and simulated jets therefore test explanations; Cassini’s cloud sequences supply the observations they must match.
Let the filters change what you notice
The December 2012 still distinguishes particles through assigned colours, while the June 2013 VIMS view reveals reflected sunlight against thermal emission. Compare those views with the later natural-colour pair. A persistent outline and changing small clouds offer separate clues; a polygon alone cannot identify the mechanism that maintains it.
Sources & further reading
- Saturn Strange Hexagon — NASA / JPL; original instrument/observation metadata
- Saturn's Hexagon as Summer Solstice Approaches — NASA / JPL; original instrument/observation metadata
- Looking Down on the Hexagon in Infrared — NASA / JPL; original instrument/observation metadata
- On the dynamical nature of Saturn’s North Polar hexagon — Rostami, Zeitlin and Spiga (2017) — Icarus / original author-hosted paper
- In Full View: Saturn’s Streaming Hexagon — 10 December 2012 photographic sequence — NASA / JPL; original observation product metadata