New Auroras Found Glowing in the Skies of Jupiter’s Moons
https://www.nytimes.com/2023/02/16/science/auroras-jupiter-moons.html
Excerpt: New research shows auroras can also be seen on the Galilean moons of Jupiter: hypervolcanic Io, icy Europa, quirky Callisto and gigantic Ganymede. ...other than Ganymede, the big moons of Jupiter lack magnetic bubbles. Instead, their auroras owe their existence to Io. Its noxious atmosphere — partly supplied by the moon’s epic volcanic eruptions — regularly sheds into space. The castoffs mingle with sunlight and become electrically excited. Plenty gets captured by Jupiter’s colossal magnetic bubble, but some of it slams back into Io’s atmosphere, or into the other three moons’ gassy sheaths. Those impacts are what ignite the moons’ auroral lights....