Does it just exist?

 

Any precise reason?

 

Why is there a magnetic field on earth?

Yes, the Earth's magnetic field exists, I think we can observe this in several ways. A compass come to mind.

 

The precise reason? This confuses me, do you mean what makes the magnetic field? If so then it's electrical currents caused by the rotating inner and outer cores of the Earth. That seems to describe it pretty well but there are still questions.

 

Why is there a magnetic field? The above reason of rotating inner and outer cores is how it's produced but there is no reason why beyond that I can think of.

Oh,

 

how do rotating inner and outer cores create a magnetic field?

the inner and outer cores are conductive(being made primarily out of metal). if you take a nice big conductor(like the core) and spin it(also like the core) you get a magnetic field.

http://en.wikipedia.org/wiki/Dynamo_theory

the inner and outer cores are conductive(being made primarily out of metal). if you take a nice big conductor(like the core) and spin it(also like the core) you get a magnetic field.

 

 

Don't you first need an electric current?

Don't you first need an electric current?

 

Yeah, and the Earth provides one as well. According to Dynamo Theory, all "astrophysical bodies" (stars, planets, ect) which contain seemingly-unfounded-long-lived magnetic fields also contain highly conducting fluids (e.g., the Earth's molten core, which is like the stuff that makes up the sun). When these fluids move, and they are always moving, they create electric currents, which maintain the magnetic fields.

 

hope i helped...and i hope i remembered my dynamo theory well enough.

Edited April 20, 200916 yr by Lan(r)12