Juno Detects Callisto’s “Footprints” in Jupiter’s Aurorae

Jupiter hosts the brightest and most spectacular auroras in the Solar System, and its largest moons (the Galileans) create their own auroral signatures known as “satellite footprints” in the planet’s atmosphere. Until now, astronomers had detected the auroral signatures of three Galileans (Io, Europa, and Ganymede), but not Callisto. Thanks to an international team, close-up images of Callisto’s footprints have been seen at last.