Scientists behind NASA’s Juno mission, which is currently in orbit around Jupiter, have revealed a brand new three-dimensional infrared movie that shows off the densely-packed cyclones and anticyclones that pepper the gas giant’s polar regions. The film is the very first detailed view of a dynamo, or engine, powering the magnetic field of a planet beyond the Earth. It will assist in the understanding of the forces at work powering the storm systems that range between 4,000 to 4,600 kilometres (2,500 to 2,900 miles) in diameter.
In order to stitch a movie together, the Juno team took data that has recently been acquired by the spacecraft’s Jovian InfraRed Auroral Mapper (JIRAM) instrument before blowing it up into a three-dimensional flyby of the planetary king’s north pole. Being able to image in the infrared part of the spectrum means that JIRAM is able to uncover light emerging from deep inside Jupiter with ease, whether it’s during the night or day. The instrument effortlessly peers some 50 to 70 kilometres (30 to 45 miles) beneath the Jovian cloud tops.
“Before Juno, we could only guess what Jupiter’s poles would look like,” admits Juno co-investigator Alberto Adriani, who is based at the Institute for Space Astrophysics and Planetology in Rome. “Now, with Juno flying over the poles at a close distance it permits the collection of infrared imagery on Jupiter’s polar weather patterns and its massive cyclones in unprecedented spatial resolution.”
The teams interrogating the data are also keen to uncover more about the interior composition of the gas giant – in particular, how the planet’s deep interior rotates. “We could not distinguish between extreme models of Jupiter’s interior rotation, which fitted the data collected by Earth-based observations and other deep space missions before Juno’s arrival at Jupiter,” explains Tristan Guillot, a Juno co-investigator from the Université Côte d’Azur, Nice, France. “[In comparison to telescopes on Earth] Juno is different – it orbits the planet from pole to pole and gets closer to Jupiter than any spacecraft ever before. Thanks to the amazing increase in accuracy brought by Juno’s gravity data, we have essentially solved the issue of how Jupiter’s interior rotates: the zones and belts that we see in the atmosphere rotating at different speeds extend to about 3,000 kilometres (1,900 miles).”
He adds: “At this point, hydrogen becomes conductive enough to be dragged into the near-uniform rotation by the planet’s powerful magnetic field.”
Helpfully, the data used to analyse Jupiter’s rotation contains information about the planet’s interior and makeup. In fact, not knowing much about the gas giant’s spin was impacting the ability to delve deeper through the thick cloud layer. “Our work can really begin in earnest,” says Guillot. “And that’s determining the interior composition of the Solar System’s largest planet.”
Juno’s deputy-principal investigator Jack Connerney of the Space Research Corporation in Annapolis, Maryland, has also presented the very first view of the dynamo that’s powering Jupiter’s magnetic field. He and his colleagues revealed the measurements made during Juno’s eight orbits of the planet and, from these, were able to derive maps of the magnetic field at the surface and beneath it – the place where the dynamo is suspected to originate. They discovered irregularities, regions of surprising magnetic field intensity, and that Jupiter’s magnetic field is much more complex in the northern hemisphere compared to its southern hemisphere.
“We’re finding that Jupiter’s magnetic field is unlike anything previously imagined,” says Connerney. “Juno’s investigations of the magnetic environment at Jupiter represent the beginning of a new era in the studies of planetary dynamos.”
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