Ganymede (moon)

Ganymede (gan'-ə-meed, IPA: ; Greek Γανυμήδης) is Jupiter's largest moon, and the largest moon in the Solar System; it is larger in diameter than Mercury but has only about half its mass. Ganymede is one of four planetary satellites of Jupiter that could be seen with the naked eye under favorable conditions, if not for the brighter light of nearby Jupiter. Other than possibly the Galilean Satellites, the only planetary satellite visible with the naked eye is our own Moon.

Ganymede's discovery is generally credited to Galileo Galilei who documented its existence in 1610. The name Ganymede was suggested soon after by Simon Marius, for the cup-bearer of the Greek gods, beloved of Zeus (see Ganymede). This name and the names of the other Galilean satellites fell into disfavor for a considerable time, and were not revived in common use until the mid-20th century. In much of the earlier astronomical literature, it is simply referred to by its Roman numeral designation (a system introduced by Galileo) as Jupiter III or as the "third satellite of Jupiter". Ganymede is the only Galilean moon of Jupiter named after a male figure.