<p>Well, firstly it's important to recognise that the poles are merely the extremities of the shape of a magnetic field - the earth's magnetic field.  All magnetic fields have polarities as such.</p>

<p>However, you're asking why the field itself even exists, I gather.  In this case it's generated by electric currents in the conductive molten iron (and other metals) in the core of the earth, as a result of convection currents generated by escaping heat.   This is known as a geodynamo, and is one way of generating a magnetic field.  However, exactly why this occurs is still under investigation.</p>

<p>More is available in this <a href="http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Physical_origin">Wiki piece - specifically on the physical origins of the earth's magnetic field</a>.</p>

CC BY-SA 3.0
2014-04-16T06:20:21.927Z
2014-04-16T14:10:32.443Z
2014-04-16T14:10:32.443Z
Mark Mayo
<p>A compass can tell me the directions of the Earth's North and South poles?  What is it about the Earth that produces this "polarity" such that a compass can pick it up?</p>

<p>The first thing that jumped into my head was the Earth's rotation, but if that is the explanation, why have I heard from people that the Earth's polarity can switch every million years or so?</p>

<p><img src="https://i.sstatic.net/8VhZa.jpg" alt="enter image description here"></p>

CC BY-SA 3.0
2014-04-16T10:45:03.813Z
A better question would be: why are the Earth's magnetic poles near its axis of rotation? If you consider the two questions similar enough, edit your question to this format, or ask it as a new question, or let me know and I will ask myself.
Pavel V.
CC BY-SA 3.0
2014-04-16T10:56:37.817Z
The alignment of geographic and magnetic axis varies inside the solar system. See sketches in http://saturn.jpl.nasa.gov/files/Planetary_Magnetics.pdf
tobias47n9e
CC BY-SA 3.0
2014-04-16T10:57:47.733Z
@PavelV., I believe your question is separate to the one I asked.  Feel free to ask this question yourself.
Kenshin
<geophysics><geomagnetism><paleomagnetism>
What causes the Earth to have magnetic poles?
Kenshin
# What causes the Earth to have magnetic poles?

(Asked by: username_0 on 2014-04-16)

A compass can tell me the directions of the Earth's North and South poles? What is it about the Earth that produces this "polarity" such that a compass can pick it up?

The first thing that jumped into my head was the Earth's rotation, but if that is the explanation, why have I heard from people that the Earth's polarity can switch every million years or so?

![enter image description here](https://i.sstatic.net/8VhZa.jpg)

**Tags:** geophysics, geomagnetism, paleomagnetism

> **Comments:**
> **username_1**: A better question would be: why are the Earth's magnetic poles near its axis of rotation? If you consider the two questions similar enough, edit your question to this format, or ask it as a new question, or let me know and I will ask myself.  
> **username_2**: The alignment of geographic and magnetic axis varies inside the solar system. See sketches in http://saturn.jpl.nasa.gov/files/Planetary_Magnetics.pdf  
> **username_0**: @PavelV., I believe your question is separate to the one I asked.  Feel free to ask this question yourself.  

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## 1 answers

### Answer by username_3 on 2014-04-16. Score: 23 | Accepted answer

Well, firstly it's important to recognise that the poles are merely the extremities of the shape of a magnetic field - the earth's magnetic field. All magnetic fields have polarities as such.

However, you're asking why the field itself even exists, I gather. In this case it's generated by electric currents in the conductive molten iron (and other metals) in the core of the earth, as a result of convection currents generated by escaping heat. This is known as a geodynamo, and is one way of generating a magnetic field. However, exactly why this occurs is still under investigation.

More is available in this [Wiki piece - specifically on the physical origins of the earth's magnetic field](http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Physical_origin).


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