Pop science
Jupiter’s weather report is pretty complex...
NASA’s Juno probe discovered a giant new storm swirling near Jupiter’s south pole in November 2019, a few weeks after pulling off a dramatic death-dodging manoeuvre.
Juno spied the newfound maelstrom, which is about as wide as Texas, during its 22nd science pass of Jupiter. The storm joins a family of six other cyclones in Jupiter’s south polar region, which Juno had spotted on previous passes by the gas giant. Those encounters also revealed nine cyclones near Jupiter’s north pole.
The southern tempests are arrayed in a strikingly regular fashion. Previously five of them had formed a pentagon around a central storm, which is as wide as the continental United States. With the new addition, that girdling structure is now a hexagon.
“These cyclones are new weather phenomena that have not been seen or predicted before,”
Cheng Li, a Juno scientist from the University of California, Berkeley, said in a statement.
“Nature is revealing new physics regarding fluid motions and how giant planet atmospheres work,” he added. “We are beginning to grasp it through observations and computer simulations. Future Juno flybys will help us further refine our understanding by revealing how the cyclones evolve over time.”
Juno orbits Jupiter on a highly elliptical path every 53 Earth days, gathering most of its data when it comes closest to the giant planet. But it took some fancy flying to make sure Juno survived the experience. The mission team determined that the probe’s trajectory would take Juno into Jupiter’s shadow for 12 hours on 3 November, and that likely would’ve been a death sentence for the solar-powered probe.
“We would’ve gotten cold.
Really, really cold,” Juno project scientist Steve Levin of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, said during a press conference at the annual autumn meeting of the American Geophysical Union (AGU), where the team announced the new results.
But the navigation team at JPL came up with a solution: ‘jumping Jupiter’s shadow’. On 30 September, Juno’s handlers directed the solar-powered probe to fire its small reaction-control engines in pulses for 10.5 hours. This pushed the probe’s path steadily outward and ultimately out of the shadow path altogether, Levin explained.
“Without that manoeuvre, without the creative genius of the folks at JPL on the navigation team, we wouldn’t have the beautiful data that we have to show you today,” he said.