Solar wind weakens Mercury's magnetic field

More proof of an electromagnetic universe

Mercury - Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

The Messenger space probe of Mercury has confirmed that the innermost planet – the smallest of the eight planets and the closest to the Sun – has a magnetic field 150 times weaker than that of the Earth.

Mercury looks more like the Moon than the Earth, says this article on It’s the only rocky planet that has a global magnetic field like Earth.

But why is its magnetic field so much weaker than Earth’s?

It’s because the solar wind – the electric current constantly flowing from the Sun – counteracts Mercury’s internal dynamo and thus weakens its magnetic field, say scientists at the Technische Universität Braunschweig and the Max Planck Institute for Solar System Research.

“Mercury strongly interacts with the surrounding solar wind,” says Daniel Heyner, lead author of a new article published in Science magazine and doctoral student at the Max Planck Institute. This interaction drives strong electrical currents in the magnetosphere of the planet, whose magnetic fields counteract the internal dynamo effect.

“The dynamo process in Mercury’s interior is almost nipped in the bud by the interaction,” explains Karl-Heinz Glassmeier at the Technische Universität Braunschweig, head of the research group.

At an average distance from the Sun of only 58 million kilometres – around one third of the distance of the Earth – Mercury is much more exposed to the solar wind than is Earth.

So let me ask you. If the solar wind can affect Mercury’s magnetic field so drastically, then why, given the right circumstances, couldn’t it affect the earth’s magnetic field? And why, given the right alignment, couldn’t it lead to a magnetic reversal?

See entire article, originally titled “Mercury’s magnetic  field — nipped in the bud”:

Thanks to Wanda for this link

The solar wind is a stream of energized, charged particles, primarily electrons and protons, flowing outward from the Sun in all directions at very high speeds — an average of almost a million mph.

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