Was the moon magnetized by impact plasmas?
The moon, Mercury and many meteorite parent bodies contain a magnetized crust, which is commonly credited to an ancient core dynamo. A longstanding alternative hypothesis suggests the amplification of the interplanetary magnetic field and induced field of the crust (crustal field) via plasma generated through meteoroid impacts. In a new report now published on Science Advances, Rona Oran and a research team in the Departments of Earth and Planetary Sciences, Geosciences and Space Science in the U.S., Germany and Australia showed that although impact plasmas can transiently enhance the field inside the moon, the resulting fields were at least three orders of magnitude too weak to explain magnetic anomalies of the lunar crust. The team used magnetohydrodynamic and impact simulations alongside analytical relationships in this work to show the core dynamo (and not plasmas generated by asteroid impact) to be the only possible source of magnetization on the moon.
phys.org
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2020-10-07
