Solar wind origin of terrestrial water

TL;DR

This paper explores the hypothesis that solar wind hydrogen significantly contributed to Earth's water reserves during early planetary history, potentially accounting for up to 10% or more of Earth's water.

Contribution

It proposes a novel mechanism for Earth's water origin involving solar wind hydrogen capture, especially during the planet's first billion years.

Findings

Solar wind hydrogen could contribute up to 10% of Earth's water.

Early solar wind was 1000 times stronger, increasing water contribution.

Solar wind hydrogen might have been the main source of Earth's water.

Abstract

The origin of the Earth water reserves during the evolution of the planet is one of the big miracles in geophysics. Common explanations are storage of water in the Earth mantle at a time when the crust had not yet formed and depositing of water by comets during the time of late heavy bombardement. Both explanations have different problems - especially when comparing with the evolution of Mars and Venus. Here we discuss the possible role of hydrogen collected from the solar wind by the early Earth magnetosphere. While the water production by solar wind capture is very small today it may have been significant during the first billion years after planetary formation because solar wind was much stronger at that time and Earth magnetospheric configuration may have been different. We estimate that the contribution of solar wind hydrogen to the Earth water reserves can be up to 10% when we assume a that the Earth dipole acted as a collector and early solar wind was 1000 times stronger than today. We can not even exclude that solar wind hydrogen was the main contributor to Earth water reserves.