Moon Lost its Magnetic Field 1B Years Ago After its 'Internal Dynamo' Ended, Study Finds
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Moon lost its magnetic field 1B years ago after its 'internal dynamo' ended, study finds:
The Moon likely lost its magnetic field after an internal dynamo stopped firing 1 billion years ago, according to a new study.
The research, published in Science Advances, looks at rocks from Earth's lunar satellite that were melted by an impact and found that measurements taken from these rocks show a significantly weak magnetic field, just 0.1 microteslas, approximately 1 billion years ago.
"Combined with previous paleointensity estimates, this indicates that the lunar dynamo likely ceased sometime between ~1.92 and ~0.80 Ga ago," the researchers wrote in the study's abstract. "The protracted lifetime of the lunar magnetic field indicates that the late dynamo was likely powered by crystallization of the lunar core."
Previous research found that the magnetic field on the Moon was 100 microteslas approximately 4 billion years ago, roughly double that of present-day Earth.
The Moon is thought to be 4.5 billion years old, but a separate study published in August 2018 suggests that the satellite could be 100 million years older than previously thought.
Speaking with Newsweek, one of the study's authors, Benjamin Weiss, said the magnetic field likely helped protect the Moon from the Sun's solar wind.
"This may have prevented the surface from being space weathered and the soil becoming rich in solar gases like it is today," Weiss told the news outlet. Furthermore, the Moon was likely about twice as close to the Earth during the time the Moon was inferred to have a strong magnetic field compared today."
It's unclear why the internal dynamo stopped or what caused the magnetic shield to erode.
Journal Reference:
Saied Mighani, Huapei Wang, David L. Shuster, CauE S. Borlina, et. al. The end of the lunar dynamo [open], Science Advances (DOI: 10.1126/sciadv.aax0883)
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