earthorigin

earthorigin is a term used in geology and planetary science to refer to the study of the origin and early history of Earth. It encompasses cosmological processes that formed the planet, the differentiation of its interior into core, mantle, and crust, and the subsequent development of oceans, atmosphere, and biosphere. The concept intersects cosmochemistry, geochemistry, paleontology, and astrobiology, and is often discussed as part of broader inquiries into planetary formation and planetary habitability.

Current consensus places Earth's formation in the first tens of millions of years of the solar system, about 4.54 ± 0.05 billion years ago, through the accretion of dust and planetesimals within a protoplanetary disk around the early Sun. The growing body heated and differentiated, yielding a metallic core and a silicate mantle and crust. A widely accepted scenario for the Moon's origin involves a giant impact with a Mars-sized body, Theia, which contributed material to Earth and set its angular momentum.

Volatile delivery and volcanic outgassing produced early atmospheres and, over time, water accumulated in oceans. The precise timing of oceans' appearance remains debated, but by 4.0 billion years ago they were likely present on a partially molten Earth.

Origin of life is a major component of earthorigin studies, with evidence for biological activity dating to around 3.5–4.0 billion years ago and ongoing research into abiogenesis. Methods include radiometric dating, isotopic analyses of rocks and meteorites, geochemical modeling, and space-borne observations.

See also: planetary formation, geochronology, abiogenesis.