This story starts at Jupiter, with news from the Juno spacecraft team about its November 8, 2020 passage through the magnetic field connecting Jupiter and Ganymede. According to Thomas Greathouse, the mission used its JADE and UVS instruments during this passage, and “JADE measured the electrons traveling along the magnetic field lines, while UVS imaged the related auroral footprint spot.” These measurements allowed the team to see how this massive moon and planet were connected and affecting one another.

This work is published in Geophysical Research Letters with lead author Vincent Hue, who explains: Jupiter’s most massive moons each create their own auroras on Jupiter’s north and south poles. Each auroral footprint, as we call them, is magnetically connected to [its] respective moon, kind of like a magnetic leash connected to the moon glowing on Jupiter itself.

Jupiter’s aurorae glow in colors our eyes can’t see: X-ray and ultraviolet light. These effects and many other details of Jupiter will be studied in detail by the upcoming JUICE mission. For now, it is mathematically daunting and scientifically awesome to understand that the complex aurorae are formed by the ever-changing motions of Jupiter’s moons within the ever-fluctuating solar wind.

More Information

SwRI press release

“A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint,” V. Hue et al., 2022 February 16

VIDEO: SwRI scientists connect the dots between Galilean moon, auroral emissions on Jupiter (YouTube)