Creating an Isotopically Similar Earth-Moon System with Correct Angular Momentum from a Giant Impact

TL;DR

This paper presents a straightforward impact model that successfully produces an Earth-Moon system with correct angular momentum and isotopic similarity, addressing longstanding challenges in the giant impact hypothesis.

Contribution

It introduces initial impact conditions that naturally yield the desired Earth-Moon system properties without complex multi-stage processes.

Findings

Achieved correct angular momentum in the Earth-Moon system

Produced isotopically similar Earth and Moon

Model is simple and directly linked to impact conditions

Abstract

The giant impact hypothesis is the dominant theory explaining the formation of our Moon. However, its inability to produce an isotopically similar Earth-Moon system with correct angular momentum has cast a shadow on its validity. Computer-generated impacts have been successful in producing virtual systems that possess many of the physical properties we observe. Yet, addressing the isotopic similarities between the Earth and Moon coupled with correct angular momentum has proven to be challenging. Equilibration and evection resonance have been put forth as a means of reconciling the models. However, both were rejected in a meeting at The Royal Society in London. The main concern was that models were multi-staged and too complex. Here, we present initial impact conditions that produce an Earth-Moon system whose angular momentum and isotopic properties are correct. The model is straightforward and the results are a natural consequence of the impact.