Jupiter and Saturn host strikingly different polar storms, despite being similar giant planets, and scientists have long wondered why. New simulations suggest the answer may lie deep below the clouds.
Spacecraft flybys have given scientists a front row seat to some of the strangest weather in the solar system, especially over the poles of Jupiter and Saturn. Saturn’s north pole is dominated by one giant storm that traces out a surprising hexagon, while Jupiter’s polar region looks more like a tightly packed cluster: a central vortex ringed by eight smaller ones.
That contrast is hard to dismiss as a surface-level quirk. Jupiter and Saturn are similar in size and built largely from the same gases, yet their polar storms settle into very different long-lived arrangements.
A team at MIT argues the answer may be hidden below the cloud tops. In work published in the Proceedings of the National Academy of Sciences, the researchers used computer simulations to watch orderly vortex patterns emerge from random churning on a gas giant. Depending on the conditions, the simulated winds either merged into a single dominant polar vortex like Saturn’s, or stabilized into multiple large circulations resembling Jupiter’s.
The key divider was a trait the team calls the “softness” of a vortex’s base, which reflects a planet’s interior composition. They describe each vortex as a spinning cylinder extending through many atmospheric layers. If the lower portion sits in softer, lighter material, the vortex hits a growth limit, leaving room for several smaller storms to coexist. If the base is harder and denser, the vortex can expand far more, swallowing nearby vortices until one massive system remains.
