Does Earth Have a Magnetic Field and How Does It Work?

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Discussion Overview

The discussion revolves around the existence and mechanisms of Earth's magnetic field, exploring various theories, effects, and implications. Participants delve into the nature of the magnetic field, its causes, and its relationship with Earth's core and rotation, as well as its effects on navigation and radiation shielding.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that Earth has a magnetic field, speculating that it is generated by the motion of liquid metals in the core, such as iron.
  • There are claims about the magnetic field's fluctuations and shifts over time, with some participants expressing concern about potential upheavals.
  • Questions arise regarding how moving liquid metals can create a magnetic field, with discussions about the role of moving charges in matter.
  • Participants speculate on the effects of Earth's rotation on the magnetic field, including the possibility of electric fields being generated due to spin.
  • Some suggest that the magnetic field is poorly understood, with references to the 'dynamo effect' and second-order effects of conductive fluids.
  • There are discussions about the non-uniformity of the magnetic field and its implications for navigation and other effects.
  • One participant mentions a hypothesis linking ocean movements and saltwater conductivity to Earth's magnetism.
  • Concerns are raised about the self-referential nature of defining the magnetic field using compasses, referencing Gödel's incompleteness theorem.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the mechanisms behind Earth's magnetic field, with multiple competing views and ongoing questions about its nature and effects. The discussion remains unresolved with various hypotheses presented.

Contextual Notes

The discussion highlights limitations in understanding the magnetic field, including missing assumptions and the complexity of interactions between different materials and movements within the Earth's core.

  • #31
water is fairly paramagnetic
 
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  • #32
shouldn't magnetic fields be stronger closer to water then?
 
  • #33
ya , you can push a grape with a bar magnet hanging from a torsion setup.
Isn't the Earth's B field pretty weak . I'm not necessarily saying our oceans are the major contributor to our field , but i just want to discuss it .
 
  • #34
has the strength of this megnatic field benn calculated?
 
  • #35
yes , about 30 micro teslas at the surface . about 60 microteslas at the poles
 
  • #36
i doubt that such weak megnatic field will be prominent (but obviosly it is)
but since it is not uniform are we talking about average value ?
?
 
  • #37
Something tells me that it is not the water in the ocean. Wouldn't there be extremely stronger fields over water than there would be over land? wouldn't someone have noticed that by now.

It makes more sense to me that it is something in the Earth's core because that allows for the field to be distributed across the entire Earth more plausibly.
 
  • #38
I'd go for the argument which uses the Earth's metallic core to explain the majority of the B field. After all, there is such a small mass of surface water compared with the vast volume available in the region of the core.
 
  • #39
yeah the oceans do not seem to present an satisfying explanation
 
  • #40
its a nice idea though. I would like them to be right. I wonder what kind of energy you could create by cycling salt saturated water in a whirlpool and running current through it. I speculate it would be an overall loss in energy, but who knows.
 

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