<p>The age of the <a href="http://en.wikipedia.org/wiki/Earth%27s_magnetic_field">Earth's magnetic field</a> could be as old as the existence of the physical conditions capable of generating a magnetic field. Because we believe the geomagnetic field originates from the liquid outer core, your question could be restated as: When did the Earth form a liquid core?</p>

<p>How the Earth's core formed is still not well understood and the area of research is referred to as <a href="http://www.google.com/url?sa=t&amp;rct=j&amp;q=&amp;esrc=s&amp;source=web&amp;cd=14&amp;cad=rja&amp;uact=8&amp;sqi=2&amp;ved=0CGUQFjAN&amp;url=http%3A%2F%2Fastro.berkeley.edu%2F~gmarcy%2Fastro160%2Fpapers%2FFormation_of_rocky_planets.pdf&amp;ei=gXnhU6uNM4PooAS0zIC4Dg&amp;usg=AFQjCNGVJ2yeuS7ejUCfKbOY4-mqRIWFnw">planetary differentiation</a>.</p>

CC BY-SA 3.0
2014-08-06T00:46:09.953Z
2014-08-06T00:46:09.953Z
Mark Rovetta
<p>Merely what the title states. My knowledge of geography/geology/*logy is limited to high-school, and some snippets, and snatches of conversation.</p>

<p>As I understand Earth's magnetic field is attributed to the bi-layered nature of it's core. Proto-Earth probably did not have a magnetic field. Apparently much later Earth's core cooled enough to separate into two layers - causing the field to appear</p>

<p>How long did it take for Earth's magnetic field to first appear? 
As a corollary, did water appear first on Earth, OR did the magnetic field appear first?</p>

<geophysics><earth-history><geomagnetism>
How long did it take for Earth's magnetic field to first appear?
Everyone
# How long did it take for Earth's magnetic field to first appear?

(Asked by: username_0 on 2014-08-05)

Merely what the title states. My knowledge of geography/geology/\*logy is limited to high-school, and some snippets, and snatches of conversation.

As I understand Earth's magnetic field is attributed to the bi-layered nature of it's core. Proto-Earth probably did not have a magnetic field. Apparently much later Earth's core cooled enough to separate into two layers - causing the field to appear

How long did it take for Earth's magnetic field to first appear?
As a corollary, did water appear first on Earth, OR did the magnetic field appear first?

**Tags:** geophysics, earth-history, geomagnetism


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## 1 answers

### Answer by username_1 on 2014-08-06. Score: 10

The age of the [Earth's magnetic field](http://en.wikipedia.org/wiki/Earth%27s_magnetic_field) could be as old as the existence of the physical conditions capable of generating a magnetic field. Because we believe the geomagnetic field originates from the liquid outer core, your question could be restated as: When did the Earth form a liquid core?

How the Earth's core formed is still not well understood and the area of research is referred to as [planetary differentiation](http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=14&cad=rja&uact=8&sqi=2&ved=0CGUQFjAN&url=http%3A%2F%2Fastro.berkeley.edu%2F~gmarcy%2Fastro160%2Fpapers%2FFormation_of_rocky_planets.pdf&ei=gXnhU6uNM4PooAS0zIC4Dg&usg=AFQjCNGVJ2yeuS7ejUCfKbOY4-mqRIWFnw).


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