Our Moon Phases application uses JavaScript. If your browser is not JavaScript capable, then you will not be able to see the moon under the words "Current Moon" More information about our moon Formation of Earth-Moon system in the course of solar system formation: The probability of the moon formation and dynamical effects of moon on obliquity of terrestrial spin are great. Earth is formed by coagulation between portoplanets that are formed through runaway growth. Kokubo and Ida (1998,2000, Icarus) showed that portoplanets have masses of Mars (0.1 Earth mass). The protoplanets become isolated when they acquire such masses. They, however, start orbital crossing and mutual collisions when nebula gas is depleted to some extent (Kominami and Ida 2002, Icarus). As a result, Earth is formed. Moon formation is a by-product of a collision between protoplanets (giant impact hypothesis). Giant impacts do occur, but they do not necessarily produce a large satellite like the moon. The probability of forming a large satellite like the moon exists. The moon's gravity precess terrestrial spin axis. The precession may control evolution of obliquity of Earth (Laskar et al.1993, Nature). The obliquity should affect the global climate of Earth. Obliquity change of Earth according to tidal orbital evolution of Moon is apparent.