Caption: 
(below right) About 1 ton of volcanic gases are spewed out by Jupiter’s Moon Io every second. When ionized these gases become trapped in Jupiter’s strong magnetic field (shown in blue) and form a vast ring (shown in red) around the planet with Jupiter’s 10-hour spin period. Jupiter’s strong magnetic, rapid rotation and Io’s prodigious source of material result in a giant magnetosphere (middle) that dwarfs the magnetosphere of the Earth. The entire magnetosphere of Earth would fit within the planet Jupiter. The contrast in size, spin and internal sources makes the dynamics of the Jovian magnetosphere very different from the situation at Earth.

Credit: 
Image courtesy Fran Bagenal