Making the Moon from a fast-spinning Earth: a giant impact followed by resonant despinning.

Late Impacts and the Origins of the Atmospheres on Venus, Earth, and Mars

Introduction. Diverse origins of terrestrial planet atmospheres are inferred from differences in the noble gas abundances and isotope ratios observed on Venus, Earth, and Mars [e.g., 1, 2]. Models for the origin of terrestrial atmospheres typically require an intricate sequence of events, including substantial loss and isotopic fractionation of solar nebula gases, outgassed mantle volatiles, an...

Fast accretion of the earth with a late moon-forming giant impact.

Constraints on the formation history of the Earth are critical for understanding of planet formation processes. (182)Hf-(182)W chronometry of terrestrial rocks points to accretion of Earth in approximately 30 Myr after the formation of the solar system, immediately followed by the Moon-forming giant impact (MGI). Nevertheless, some N-body simulations and (182)Hf-(182)W and (87)Rb-(87)Sr chronol...

Tidal Evolution of the Moon from a Fast-spinning High-obliquity Earth

A young Moon-forming giant impact at 70-110 million years accompanied by late-stage mixing, core formation and degassing of the Earth.

New W isotope data for lunar metals demonstrate that the Moon formed late in isotopic equilibrium with the bulk silicate Earth (BSE). On this basis, lunar Sr isotope data are used to define the former composition of the Earth and hence the Rb-Sr age of the Moon, which is 4.48+/-0.02Ga, or 70-110Ma (million years) after the start of the Solar System. This age is significantly later than had been...

Atmospheric Loss during High Angular Momentum Giant

Introduction. During the end stage of planet formation , terrestrial planets are expected to experience a number of giant impacts. Understanding how much of the planet's atmosphere is lost to space during such collisions is vital to be able to determine the origin and evolution of planetary atmospheres. Recently, geo-chemical observations [1, 2] and high angular momentum models for the Moon-for...