At present, of all the stone bodies of the solar system, only Earth, Mercury and Ganymede have their own magnetic field. But as the data collected by interplanetary missions show, in the past, much more satellites and planets had their own magnetosphere. Among them is the Moon. Analysis of the samples of lunar rocks delivered to Earth showed that they were formed in a magnetic field, the power of which even exceeded the current magnetic field of the Earth.
For a long time there was no consensus among researchers about the question of how the Moon could have its own magnetic field. According to one theory, it was temporary. Magnetic fields were generated on the lunar surface during the strongest asteroid collisions, imprinted in molten rock. However, modern research does not support this version. The lunar magnetic field was constant and existed for at least the first billion of her life.
In a recent issue of the journal Earth and Planetary Science Letters, the results of new research on this topic were published. According to its results, the magnetic field of the moon arose due to the effect of a planetary dynamo.
A group of planetary scientists from the Lyndon Johnson Space Center conducted a series of experiments with matter, trying to determine the composition of the lunar core. According to their conclusion, it mainly consists of iron and nickel, with minor impurities of carbon and sulfur. Immediately after the formation of the moon, the core was expanded. Then it began to crystallize, which led to the appearance of streams of heated matter in the bowels of the satellite and the formation of a global magnetic field. About 3.1 billion years ago, this process stopped and the moon lost its magnetosphere.