The term "Jovian moons" refers to the natural satellites that orbit the planet Jupiter. Jupiter, the largest planet in our solar system, has over 79 known moons, with the four largest being called the Galilean moons. These are Io, Europa, Ganymede, and Callisto, discovered by Galileo Galilei in 1610. Each of the Galilean moons has unique characteristics. Io is known for its volcanic activity, while Europa is believed to have a subsurface ocean that may harbor life. Ganymede is the largest moon in the solar system, and Callisto has a heavily cratered surface, indicating a long history of impacts.