The planet known for its numerous moons is Jupiter. As the largest planet in our solar system, Jupiter has an impressive collection of 79 known moons, with the most famous being the four largest, known as the Galilean moons: Io, Europa, Ganymede, and Callisto. These moons vary greatly in size and characteristics, with Ganymede being the largest moon, even larger than the planet Mercury. Jupiter's massive gravitational pull contributes to its ability to capture and retain such a significant number of moons. The study of these moons offers valuable insights into the formation and evolution of our solar system.