Our celestial companion now does not have a global magnetic field. There are separate magnetized areas, according to the "weather" they do not. But it seems that this was not always the case.
Lunar "curls" (swirls) - mysterious structures on the visible surface of the moon. They resemble bright cloud-like structures that appear to be painted against a dark background. The most famous structure is the Reiner Gamma, which is considered one of the most famous anomalies in the solar system in amateur astronomer circles.
It is known that zones of anomalies have local magnetization, but no one has yet tried to understand how it arose.
Past experiments have shown that many lunar rocks become magnetic at temperatures over 600 degrees Celsius in an oxygen-free environment. This is because some minerals break down at high temperatures to form metallic iron. If this happens in a sufficiently strong magnetic field, the newly formed iron will be magnetized accordingly.
Rainer Gamma. On the moon.
On Earth, this phenomenon (paleomagnetism) is and is the basis of serious scientific theories. But, here iron is oxidized by oxygen or reacts with acids dissolved in water. After that, the results of the reactions are accumulated in sedimentary rocks and are oriented by the magnetic field. On the Moon, all this is not - there diamagnets can orient themselves along the field only in the melt.
A team of researchers from the Universities of Rutgers and California at Berkeley tried to mathematically simulate the processes that once took place on the moon.
According to the results of their work, the source of local magnetism can be extended structures such as iron veins, formed in the era when volcanism was still on the Moon.
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And the source of their magnetization was a magnetic field external to them. The field of the moon. This was very recently - from 1 to 2.5 billion years ago.
Details can be found in an article published in the Journal of Geophysical Research.
Sergey Sysoev