Astronomy Question: When did the Earth become a polar magnet?
 

I was looking at the lunar eclipse last night -- cool shit... but then I started wondering about the Earth's magnetic field... Sure the icecaps are probably based on exposure to light... and the Earth has an iron core? And the magnetic polarity of Earth changes every 100,000 years or some shit -- but I still don't know how the fucking Earth got magnetized...

I remember in 1st grade I made an electromagnet -- a big nail with a coil of wire and a big ass battery... Did somebody wrap a big wire around the earth -- magnetized it -- and then vanished into space? :1orglaugh :helpme

from rotating around the sun at a high rate of speed

http://www.astronomers.net/web/images/u000-aliens.jpg

Move along.. nothing to see here.

So we are in the Sun's magnetic field right now?

I'm not, I live on Kapac.

looks like the "Sun's magnetic field" theory is right:

http://www.phy6.org/earthmag/NSTA1C.htm

oook....earth got magnetic field, from all the meltod iron beneath earth crust, which is rotating, and creating magnetic field

doesnt answer the question but i found this interesting tidbit...

While the core of the earth is made of iron, it cannot be magnetic because it is so hot. What Gilbert didn't know is that when iron is heated up hot enough it loses all of its magnetism, the temperature of a material where it loses its ferromagnetism is known as its curie point. For iron the curie point is 770 °C. The iron inside the earth is much hotter than 770 °C and so cannot be an iron magnet.


hmm so what IS magnetised? =[

but the molten iron keeps rotating and moving all the time, it is al about the friction!!

no friction - no satisfaction

hmm.... this is also interestin

. Lava includes hot, iron-containing minerals such as basalt, which can be magnetized. As the lava cools it locks in the direction of the magnetic field of the earth. This locks in the latitude at which the lava cooled. On Aneroid peak in eastern Oregon there are lava layers which preserve horizontal magnetic fields. This means that those lavas cooled near the equator. Continental drift has moved them far north to where they are today in Oregon.

oo and..

Light is Electromagnetic Radiation

Faraday's discoveries provided the basis from which James Clerk Maxwell created the theory of electromagnetism and discovered that light was electromagnetic radiation