Terrestrial origin of the Moon

Abstract

Abundance patterns of siderophile elements in the Earth's mantle have been determined by complex processes connected with internal segregation of a metallic core amounting to 32% of the Earth's mass. Although the lunar core may be only 2% of the lunar mass and formed in very different conditions to the Earth's core, the lunar siderophile pattern is closely related to that of the Earth's mantle, implying that the material in the Moon derived mainly from the Earth's mantle after core formation. New models for the accretion of the Earth which require impacts by large planetesimals in the presence of a corotating primitive terrestrial atmosphere provide a mechanism for transferring material from the Earth's mantle into geocentric orbit as a ring of proto-lunarplanetesimals, from which the Moon later accreted.