Sample 15498 lunar soil helped to uncover the secret of the magnetic field of the moon

During the mission of Apollo 15 in August 1971 from the area of the canyon, Hedley on the Earth’s satellite has produced over 70 kg of soil, among which was the sample 15498. Glassy mass, which has preserved its magnetic properties since its formation. Now she helped scientists understand that the magnetic field of the moon disappeared for a billion years later than we previously thought.

Value of sample 15498 is that he’s younger than the other – this rock was formed from molten from the impact of an asteroid moon rocks are approximately 2.5 billion years ago. Other samples at the disposal of scientists account for 3.2 billion years, the Moon formed about 4 billion years ago. Then she was hot, had a rotating liquid core and had its magnetic field.

The strength of this field for “newborn” of the moon is estimated at 100 micro-Tesla, but as it cools down a large space of stone it was failing until 2 billion years ago has not disappeared at all. But how did it happen? Having carefully studied with the help of ultra-sensitive magnetometers sample 15498, the researchers found that at the time of its appearance, the strength of the magnetic field of the moon was only 5 microtesla, is ten times weaker than the earth. But it still kept!

Knowing that the Moon lost its magnetic field on a billion years later than previously thought, scientists have pondered why? The most plausible hypothesis of the influence of tidal forces from the gravity of the moon to the Earth, which have forced already rather cold – the first to fluctuate, thereby maintaining its magnetic field. But the farther the satellite is gone from the planet, the weaker became their mutual influence, the faster inhibited this Dynamo.

A theory remains a theory – and scientists are using these assumptions to understand how to actually work the process of generation of the magnetic field of the Earth. The moon is long dead, she doesn’t care, but for life on our planet magnetic field is very important not to interested in the issue at all.
Source — MIT

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