Io

AKA:  I Jupiter
Class:   Moon
Discovered:  1610  by Galileo Galilei
Named after:  The Greek mythological priestess of Hera who became one of the lovers of Zeus.

Facts:

5th Moon from Jupiter.
4th largest moon in the Solar System.
The most most geologically active object in the Solar System (over 400 active volcanoes).

Details: