In a landmark observation by a team of international researchers, NASA's Juno spacecraft has, for the first time, clearly detected the auroras of Jupiter's moon Callisto. This discovery completes the set of auroral signatures we have from all four Galilean moons: Io, Europa, Ganymede and Callisto.
Like Earth, Jupiter experiences brilliant auroras around its poles — but something funky happens with Jupiter's Galilean moons that doesn't happen with our own satellite. "Jupiter exhibits peculiar multiwavelength auroral emissions resulting from the electromagnetic interactions of Io, Europa, and Ganymede with the magnetospheric plasma flow," write the team in a new paper about the discovery. In other words, the moons interact with Jupiter's magnetosphere to create distinct auroral footprints.
