Moons of Jupiter around Ganymede. In 2016, the "Juno" spacecraft imaged the Galilean moons from above their orbital plane as it approached Jupiter orbit insertion, creating a time-lapse movie of their motion. Moons of Jupiter There are 79 known moons of Jupiter. This gives Jupiter the largest number of moons with reasonably stable orbits of any planet in the Solar System. The most massive of the moons are the four Galilean moons, which were independently discovered in 1610 by Galileo Galilei and Simon Marius and were the first objects found to orbit a body that was neither Earth nor the Sun. From the
Discovery and exploration of the Solar System announced the discovery of Eris in 2005, a scattered disc object initially thought to be larger than Pluto, which would make it the largest object discovered in orbit around the Sun since Neptune. "New Horizons"' fly-by of Pluto in July 2015 resulted in more-accurate measurements of Pluto, which is slightly larger, though less massive, than Eris. Since the start of the Space Age, a great deal of exploration has been performed by robotic spacecraft missions that have been organized and executed by various space agencies. All planets in the Solar System have now been visited to varying degrees by spacecraft