Io and Jupiter: The volcano-magnetosphere connection

In the interlude between spacecraft encounters with Jupiter, Earth-bound observers using clever and powerful techniques have made substantial headway in monitoring two major phenomena: volcanos on Jupiter's moon Io (most active in the solar system) and Jupiter's magnetosphere (largest and densest of all the planets). While these two may seem unrelated, planetary scientists believe they are quite closely tied. Astronomers are working together to probe the fundamental and enigmatic connection between volcanos and magnetospheres. Volcanic activity on Io is powered not by radioactive heating, as it is on Earth, but by the continual flexing of Io by Jupiter's intense gravitational field, which generates heat as in a rapidly flexed tennis ball. Most of this heat is eventually radiated into space from a series of hot volcanic centers, or “hot spots,” where the surface is up to several hundred degrees hotter than its surroundings. The heat radiation is so intense that Io literally “glows in the dark” at infrared wavelengths, allowing astronomers with infrared telescopes to follow the frequent changes in the level of volcanic activity.