Minor-planet moon uncertain. There are 5 Jupiter trojans with a moon. Candidate binaries with an unconfirmed status are displayed on a dark background. There are only 2 centaurs with satellites, both of which are ring systems instead of moons. There are 87 trans-Neptunian objects known to have moons, with a total of 93 moons discovered. Candidate binaries with an unconfirmed status are displayed on a dark background. Minor-planet moon A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. It is thought that many asteroids and Kuiper belt objects may possess moons, in some cases quite
Galilean moons planet Mercury, though only around half as massive. The three inner moons—Io, Europa, and Ganymede—are in a 4:2:1 orbital resonance with each other. Because of their much smaller size, and therefore weaker self-gravitation, all of Jupiter's remaining moons have irregular forms rather than a spherical shape. The Galilean moons were observed in either 1609 or 1610 when Galileo made improvements to his telescope, which enabled him to observe celestial bodies more distinctly than ever. Galileo's observations showed the importance of the telescope as a tool for astronomers by proving that there were objects in space that cannot be seen by