4 of the largest Moons of Jupiter
Io is the innermost of the four Galilean moons of the planet Jupiter and, with a diameter of 3,642 kilometres the fourth-largest moon in the Solar System. Io played a significant role in the development of astronomy in the 17th and 18th centuries. It was discovered in 1610 by Galileo Galilei, along with the other Galilean satellites. It was named after the mythological character Io, a priestess of Hera who became one of Zeus’s lovers. With over 400 active volcanoes, Io is the most geologically active object in the Solar System.
Ganymede is a satellite of Jupiter and the largest moon in the Solar System. It is the seventh moon and third Galilean satellite outward from Jupiter. Ganymede’s discovery is credited to Galileo Galilei, who was the first to observe it on January 7, 1610.The satellite’s name was soon suggested by astronomer Simon Marius, for the mythological Ganymede, cupbearer of the Greek gods and Zeus’s lover
Europa is the sixth-closest moon of the planet Jupiter, and the smallest of its four Galilean satellites, but still the sixth-largest moon in the Solar System. Europa was discovered in 1610 by Galileo Galilei and possibly independently by Simon Marius around the same time. It is named after a Phoenician noblewoman in Greek mythology, Europa, who was courted by Zeus and became the queen of Crete
Callisto is a moon of the planet Jupiter. It was discovered in 1610 by Galileo Galilei. It is the third-largest moon in the Solar System and the second largest in the Jovian system, after Ganymede. Callisto has about 99% the diameter of the planet Mercury but only about a third of its mass. It is the fourth Galilean moon of Jupiter by distance, with an orbital radius of about 1,880,000 km.Callisto is named after one of Zeus's many lovers in Greek mythology.