Europa, Elara, Leda, and Metis are all moons of Jupiter. Europa is the sixth-closest moon to Jupiter and has a diameter of 3, 122 km. Elara is the eighth-closest moon to Jupiter and has a diameter of about 84 km. Leda is the fourteenth-closest moon to Jupiter and has a diameter of about 16 km. Metis is the closest moon to Jupiter and has a diameter of about 129 km. All four of these moons are part of Jupiter's 79 known moons.