Why Does the Earth Have Two Magnetic Poles?

[suryakanta06]

why Earth behaves as a magnet

 

[Astronuc]

Is one referring to gravitation, a property of matter, or is one referring to the Earth's magnetic field, which is due to the liquid ferro-nickel core (mostly iron with some nickel)?

 

[suryakanta06]

Is one referring to gravitation, a property of matter, or is one referring to the Earth's magnetic field, which is due to the liquid ferro-nickel core (mostly iron with some nickel)?

sir i m talking about the existence of two magnetic poles.what is the reason behind it and what property of the make it happen.please explain

 

[Astronuc]

sir i m talking about the existence of two magnetic poles.what is the reason behind it and what property of the make it happen.please explain

One explanation:

Origin of the Magnetic Field

Magnetic fields are produced by the motion of electrical charges. For example, the magnetic field of a bar magnet results from the motion of negatively charged electrons in the magnet. The origin of the Earth's magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel. This mechanism is termed the dynamo effect.

Rocks that are formed from the molten state contain indicators of the magnetic field at the time of their solidification. The study of such "magnetic fossils" indicates that the Earth's magnetic field reverses itself every million years or so (the north and south magnetic poles switch). This is but one detail of the magnetic field that is not well understood.

http://csep10.phys.utk.edu/astr161/lect/earth/magnetic.html

New Insights Into Origin Of Earth's Magnetic Field
http://www.sciencedaily.com/releases/2007/03/070309103129.htm

The Dynamo Effect
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html#c2

See also
http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/

 

[Studiot]

We believe the outer layers of the planet are solid but the core is liquid because the outer layers can transmit both types of seismological waves - S waves and P waves, but the core can only transmit P waves.
Solids can transmit both types of wave but liquids cannot.
P waves stands for pressure wave and S waves stands for shear waves. Liquids cannot support shear, only pressure.

 

[billiards]

sir i m talking about the existence of two magnetic poles.what is the reason behind it and what property of the make it happen.please explain

Okay, so why did you title this thread "gravitation"? That's completely different from magnetics!

The Earth's magnetic field is due to the swirling around of liquid iron in the outer core.

We believe the outer layers of the planet are solid but the core is liquid because the outer layers can transmit both types of seismological waves - S waves and P waves, but the core can only transmit P waves.
Solids can transmit both types of wave but liquids cannot.
P waves stands for pressure wave and S waves stands for shear waves. Liquids cannot support shear, only pressure.

Yes, but only the outer core is liquid, the inner core is solid.