Jupiter’s poles are home to astonishingly large cyclones that have swirled in perfect geometric formation for years.
Forming a polygon at the planet’s north pole is a large cyclone surrounded by eight smaller ones. Similarly, at its south pole there are five smaller cyclones that dance around a big one at its center.
In contrast, Saturn has only one vortex, or cyclone, at each pole.
These geometrical storms have baffled scientists who have been trying to find an explanation for the phenomenon since 2017 when the spacecraft Juno first observed the cyclones at the poles.
These swirling winds are astonishingly stable. They maintain their tight octagonal formation without drifting away or merging into each other, said a previous study.
In a new study published by Nature Astronomy, a team of scientists, led by Andrew Ingersoll of California Institute of Technology, may have found the secret behind the stability of these cyclones.
The results of the study suggest that an “anticyclonic ring” of winds that blow in the opposite direction is needed between the big cyclone at the center and the smaller cyclones that surround it to maintain the stability of the polygonal pattern.
Scientists previously tried to replicate the polygonal storm in order to understand how the formation remains stable. Previous theoretical study showed that “the stable ones have shielding (a ring of anticyclonic vorticity surrounding each of the cyclones) and the unstable ones do not,” said the researchers in the paper.
JIRAM, Juno’s Jovian InfraRed Auroral Mapper, provided a sequence of photos that allowed researchers to see features of the pole at scales as small as 180 kilometers.
While flying by the gas giant, the instrument took a series of 12 images that covered the same region of the north pole of Jupiter every 8 minutes.
The high-resolution pictures of Jupiter’s poles captured by JIRAM showed a stream of strong winds blowing in the opposite direction which functioned as a brace for the cyclones and helped them stabilise.
Though the images have shed light on certain things, other questions remains unanswered. For instance, scientists expected to find signs of convection (a method of heat transfer within fluids) within the cyclones. However, this was not the case.
With uncertain implications for convection, the scientists suggested further study in the field was required.
“A parallel study of Jupiter’s south pole vortices, focusing on vorticity and stability, represents a step in the right direction,” the study said.