Jupiter, the largest planet in our solar system, has more than 70 known moons, each with unique characteristics. The four largest moons—Io, Europa, Ganymede, and Callisto—are known as the Galilean moons, discovered by Galileo in 1610. Io is the most volcanically active body in the solar system, with hundreds of erupting volcanoes that reshape its surface continuously. Europa’s icy crust hides a subsurface ocean that might harbor life, making it a prime candidate for astrobiology studies. Ganymede, the largest moon in the solar system, even has its own magnetic field. Callisto, heavily cratered and ancient, offers clues about the early solar system. Exploring these moons is a priority for planetary scientists, as they provide insights into planetary formation, geology, and potentially, the conditions for life beyond Earth. Missions like Europa Clipper and JUICE will help unlock these mysteries in the coming years.