Strong, Sporadic Magnetic Fields Could Explain One of The Moon's Enduring Mysteries - ScienceAlert

Some of these rocks are more than 3 billion years old and appear to have been formed in the presence of a strong geomagnetic field, like the one on Earth.

But even if the field was sustained for a surprisingly long time, the strength of this field – given the Moon's size – is unlikely to match what the surface rocks are telling us.

 "[I]nstead of thinking about how to power a strong magnetic field continuously over billions of years, maybe there's a way to get a high-intensity field intermittently," explains planetary scientist Alexander Evans. .

In the first billion years or so of the Moon's existence, its core was not much hotter than the mantle above.

The new models could help explain why different lunar rocks show different magnetic signatures.