When the Moon had a magnetosphere

James Green; David Draper; Scott Boardsen; Chuanfei Dong

doi:10.1126/sciadv.abc0865

When the Moon had a magnetosphere

Sci Adv. 2020 Oct 14;6(42):eabc0865. doi: 10.1126/sciadv.abc0865. Print 2020 Oct.

Authors

James Green¹, David Draper², Scott Boardsen³, Chuanfei Dong⁴

Affiliations

¹ NASA Headquarters, Washington, DC, USA. [email protected].
² NASA Headquarters, Washington, DC, USA.
³ University of Maryland Baltimore County, Baltimore, MD, USA.
⁴ Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ, USA.

Abstract

Apollo lunar samples reveal that the Moon generated its own global magnetosphere, lasting from ~4.25 to ~2.5 billion years (Ga) ago. At peak lunar magnetic intensity (4 Ga ago), the Moon was volcanically active, likely generating a very tenuous atmosphere, and, it is believed, was at a geocentric distance of ~18 Earth radii (R _E). Solar storms strip a planet's atmosphere over time, and only a strong magnetosphere would be able to provide maximum protection. We present simplified magnetic dipole field modeling confined within a paraboloidal-shaped magnetopause to show how the expected Earth-Moon coupled magnetospheres provide a substantial buffer from the expected intense solar wind, reducing Earth's atmospheric loss to space.

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).