Jupiter's moon Callisto joins other moons in auroral footprint fun
NASA's Juno spacecraft has finally detected auroral "footprints" from Callisto, marking the first time all four of Jupiter's big moons—Io, Europa, Ganymede, and now Callisto—have been seen lighting up Jupiter's atmosphere.
These glowing footprints happen when each moon interacts with Jupiter's powerful magnetic field.
Callisto's aurora is usually hidden by Jupiter's much brighter auroral oval
Callisto's aurora is usually hidden by Jupiter's much brighter auroral oval. But in September 2019, a blast of solar wind shifted things just enough for Juno to catch the signature.
Using ultraviolet and radio sensors, the spacecraft confirmed Callisto was leaving its own subtle mark.
NASA's Europa Clipper and ESA's JUICE mission will follow up
This discovery helps scientists piece together how Jupiter's magnetosphere works and shows every major moon leaves a trace.
The findings were published September 1, 2025.
And there's more ahead: NASA's Europa Clipper arrives in 2030 and ESA's JUICE mission follows in 2031 to keep exploring these cosmic connections.