Jupiter’s cyclones imaged by Juno
Jupiter’s cyclones were first discovered thanks to NASA’s Juno spacecraft, which has been orbiting the gas giant since 2016. At Jupiter’s north pole, one cyclone near the pole is surrounded by eight others in an octagonal pattern. At the south pole, a similar cluster of five cyclones forms the shape of a pentagon. Each of the cyclones is roughly the size of the United States.
A group of scientists led by Andrew Ingersoll, Earle C. Anthony Professor of Planetary Sciences at the California Institute of Technology, set out to uncover the mysterious force guiding these geometric storms.
In a new paper, published in the journal Nature Astronomy, the researchers detail their results, showing that an “anticyclonic ring” of winds blowing in opposite direction to the cyclones “is needed for the stability of the polygonal pattern”. Some key questions do remain unanswered, however, according to the scientists.
“Since 2017 the Juno spacecraft has observed a cyclone at the north pole of Jupiter surrounded by eight smaller cyclones arranged in a polygonal pattern,” the researchers wrote in their paper. “It is not clear why this configuration is so stable or how it is maintained.”
“The polygons and the individual vortices that comprise them have been stable for the four years since Juno discovered them,” the team explained. “The polygonal patterns rotate slowly, or not at all… In contrast, Saturn has only one vortex, a cyclone, at each pole.”
The team used Juno’s Jovian InfraRed Auroral Mapper (JIRAM) instrument to measure the winds and dynamics of the cyclones raging on Jupiter’s surface. JIRAM is able to image the surface of Jupiter at scales of 180 kilometers (110 miles). Using the imager, they detected strong wind currents that keep the cyclones in place, explaining their stability.