Mystery of Moon's Magnetic Field Deepens

By Hum
in Science News & Discussion

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Grand Master

Hum

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The moon generated a surprisingly intense magnetic field until at least 3.56 billion years ago, 160 million years longer than previously thought, a new study reports.

These findings could shed light not just on the magnetic field of the moon, which is now extremely weak, but on that of asteroids and other distant worlds, investigators added.

Earth's magnetic field is created by its internal dynamo, which itself is generated by the planet's churning molten metal core. Research increasingly suggests that the moon once had a dynamo as well, with evidence of magnetism found in lunar rocks returned by Apollo astronauts.

Models of the moon's core suggest its dynamo should have lasted only until about 4.1 billion years ago. However, last year, scientists revealed that the moon possessed a magnetic field for much longer than previously thought, with a powerful dynamo in its core from 4.2 billion years ago to at least 3.72 billion years ago.

Researchers have proposed two possibilities to explain why the moon's dynamo lasted so long. One possible explanation is that giant cosmic impacts set the moon lurching enough to drive its dynamo. Another explanation has to do with how the moon's core spins around a slightly different axis than its surrounding mantle layer, generating wobbles ? known as precession ? that could dramatically stir its core.

The cosmic-impact idea is supported by the fact that the moon experienced massive collisions until around 3.7 billion years ago, such as the one that created the 715-mile-wide (1,150 kilometers) Mare Imbrium, among other craters.

However, the dynamo generated by each impact would have lasted for a mere 10,000 years or so, scientists say. In contrast, if precession drove a lunar dynamo, the moon could have continuously possessed a magnetic field until as late as 1.8 billion years ago.

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Grand Master

DocM

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is there any theory to revitalize the moon's magnetosphere?

and of course if possible to revitalize mars's magnetic too ...

Magnetospheres are generated by the liquid part of the (mostly iron) core spinning, and yhe moon's doesn't because it cooled and solidified. To start it back up you'd need to re-melt it - no small task. Don't hold your breath.

Earth's core is still molten because it's 1) much larger, so it cools slower, and 2) there are trace radioactive isotopes (potassium, uranium etc.) whose decay heats it, further slowing its cooling.

Experienced

Zlain

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Where in the Bible does it mention all this?

If I could dislike this post, I would.

Quite interesting information. If the magnetic field was restarted, would it actually give us more shielding or less, because that is bound to influence the magnetic field of the Earth, but its the alignments of those fields which are important (which is why satellites are more prone to SPE damage at the polar horns than low inclined orbits).

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