Why does the Earth have a magnetic field ?

[UM-Bot]

http://www.unexplained-mysteries.com/images/newsitems/earthsun.jpg

William B Stoecker: The Earth’s magnetic field makes compasses function and shields us from dangerous solar radiation. Yet we don’t really know what produces it, and there are many, many aspects of it which are a complete mystery. The magnetic poles do not line up exactly with the spin axis and they are not exactly 180 degrees apart. Furthermore, they wander, and the rate of movement has increased markedly in recent decades. Periodically, at intervals of many hundreds of thousands of years apart, the Earth’s magnetic field weakens, dies out, and then reforms... with the magnetic poles reversed. No one knows why, and the field is currently getting weaker and weaker. We are told by establishment scientists that the field is produced by electrical currents in our planet’s nickel-iron core, and that the currents are produced by the planet’s rotation within the field, rather like the alternator in your car. In other words, the current produces the field, and the field produces the current... but how did it all begin?

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[keithisco]

I think you need to seriously read up on Maxwell and Tesla, and even Magnetism 101. Angular Momentum (such as the Coriolis Effect) is little to do with Planetary Magnetic Fileds

[Frank Merton]

What happens if the magnetic field reverses and we go a while, maybe even a few years, without the protection from many forms of solar radiation that the field provides us?

This has happened in the past, and does not seem to have cause any mass extinctions or whatever; still, I would think it would.

[shrooma]

I have to agree with keithisco on this one.

anybody with even a basic understanding of electromagnetism will find the author's 'theory' risible at best.

sadly, yet another case of someone using a string of numbers to try to blind the layman, or the unwary.....

[Goblin-5]

I have to agree with keithisco on this one.

anybody with even a basic understanding of electromagnetism will find the author's 'theory' risible at best.

sadly, yet another case of someone using a string of numbers to try to blind the layman, or the unwary.....

Yet the theory of a dynamo at the core is equally suspect isnt it? Why would the field die off or reverse itself periodically? The earth hasn't stopped spinning (well maybe according to the bible it did) and certainly has not inverted itself (so far as we know anyway) *S*

[shrooma]

i'm sorry goblin, but I don't understand the question??

the geomagnetism at the earth's core is caused by radioactive decay (amongst other things) heating the nickel/iron outer core and causing convection currents in the liquid metal, generating an electric charge, which generates a magnetic field. the process is widely understood and accepted, and as far as I know, isn't under suspicion?

the pole reversal is equally easily explainable ('cept for the maths, which is pretty complicated, and i'm not really a one for boring people with numbers....).

as new magnetic fields are generated, they usually line up with the existing polarities, but random instabilities in the fluctuating fluid occasionally cause fields to generate with slightly different polarities which cause the field to weaken (such as the recently formed one heading toward north america!). usually these instabilities are only temporary, but under the right conditions can become stronger, weakening the original polarity as it does, to the point where the new polarity becomes the strongest, causing the flippage!

(dunno if flippage is a real word, it sounds funny enough that it should be!)

[Abramelin]

Generation of a Magnetic Field by Dynamo Action in a Turbulent Flow of Liquid Sodium

http://prl.aps.org/abstract/PRL/v98/i4/e044502

Molten Metal Magnet

http://prlo.aps.org/story/v19/st3