Callisto (moon) Callisto (moon) </math>.</ref> Callisto (Jupiter IV) is the second-largest moon of Jupiter, after Ganymede. It is the third-largest moon in the Solar System after Ganymede and Saturn's largest moon Titan, and the largest object in the Solar System not to be properly differentiated. Callisto was discovered in 1610 by Galileo Galilei. At in diameter, 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 . It is not in an orbital resonance like the three other
Solar eclipses on the Moon Earth rotates nearly 24 hours, but its position at the sky is only in one position as it never changes as it does with some other moons (or satellites) in other planets or dwarf planets and a few asteroids even inside the solar system but are very rare in the outer part of the solar system. The last solar eclipse on the Moon was a total eclipse on July 27, 2018, with the whole Nearside and the tiny surroundings of the Farside seeing totality. Unlike the Earth which sees its eclipse for up to 2 1/2 hours the longest in