<p>It seems your question assumes that Earth magnetic field is caused by natural magnets inside the Earth. Instead, the magnetic field comes from the movement of charged particles.<br>
Any electrical charged particle in movement generates a magnetic field (see <a href="https://en.wikipedia.org/wiki/Biot%E2%80%93Savart_law" rel="nofollow noreferrer">Biot-Savart law</a> and <a href="https://en.wikipedia.org/wiki/Amp%C3%A8re%27s_circuital_law" rel="nofollow noreferrer">Ampere law</a>), hence, thanks to the movement of particles in a liquid mantle we have a magnetic field. Obviously, particles must have electrical charge, which is more common in metals.<br>
If mantle turns solid, movement is gone, and the magnetic field reduces its strengh.</p>

CC BY-SA 4.0
2018-12-17T19:13:12.220Z
2018-12-17T19:13:12.220Z
Santiago
<p>I'm pretty sure metal loses more of its structure as it heats up, so...how does the difference in rotation of Earth's liquid inner and outer core generate any kind of magnetic field? Why wouldn't the magnetic field be even stronger if those two layers weren't rotating?</p>

CC BY-SA 4.0
2018-12-17T03:14:15.337Z
you may have a better time asking this on the physics stack, since it is less about the earth and more about how electromagnetics work.
John
CC BY-SA 4.0
2018-12-17T13:51:56.603Z
Also the inner core is not liquid.
John
<geomagnetism>
How does liquid iron create a magnetic field?
user14554
# How does liquid iron create a magnetic field?

(Asked by: username_0 on 2018-12-17)

I'm pretty sure metal loses more of its structure as it heats up, so...how does the difference in rotation of Earth's liquid inner and outer core generate any kind of magnetic field? Why wouldn't the magnetic field be even stronger if those two layers weren't rotating?

**Tags:** geomagnetism

> **Comments:**
> **username_1**: you may have a better time asking this on the physics stack, since it is less about the earth and more about how electromagnetics work.  
> **username_1**: Also the inner core is not liquid.  

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## 1 answers

### Answer by username_2 on 2018-12-17. Score: 3

It seems your question assumes that Earth magnetic field is caused by natural magnets inside the Earth. Instead, the magnetic field comes from the movement of charged particles.  
Any electrical charged particle in movement generates a magnetic field (see [Biot-Savart law](https://en.wikipedia.org/wiki/Biot%E2%80%93Savart_law) and [Ampere law](https://en.wikipedia.org/wiki/Amp%C3%A8re%27s_circuital_law)), hence, thanks to the movement of particles in a liquid mantle we have a magnetic field. Obviously, particles must have electrical charge, which is more common in metals.  
If mantle turns solid, movement is gone, and the magnetic field reduces its strengh.


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