Formation and evolution of the Solar System have been forged from the remnants in less violent collisions. Moons around some asteroids currently can only be explained as consolidations of material flung away from the parent object without enough energy to entirely escape its gravity. Moons have come to exist around most planets and many other Solar System bodies. These natural satellites originated by one of three possible mechanisms: Jupiter and Saturn have several large moons, such as Io, Europa, Ganymede and Titan, which may have originated from discs around each giant planet in much the same way that the planets formed from the disc around the Sun.
Definition of planet then-accepted planet, Pluto. In its August 2006 response, the International Astronomical Union (IAU), recognised by astronomers as the world body responsible for resolving issues of nomenclature, released its decision on the matter during a meeting in Prague. This definition, which applies only to the Solar System, states that a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has "cleared its neighbourhood" of smaller objects around its orbit. Under this new definition, Pluto and the other trans-Neptunian objects do not qualify as planets. The IAU's decision has not resolved