Hi, Ive been and got myself involved in a discusion on the earths magnetic field lol. the usual explanation is "its simple primary school elecromagnetism" lol, and the moving conductive iron fluid suposedly cuases both a current and magnetic field. but we all know a moving cunductor in a magnetic field produces a current that produces an opposing magnetic field.
some interesting discusion comes from the disaster movie
from some simple googling :-
the earths core is molten iron/nickel but where the presusre in the inner part is so high it is solid despite the temperature. the curie point is affected by pressure but seems not enough to allow the solid center to have magnetic properties. so the core can not become magnetises as such, although the outer crust does, it has many rocks porlarized in oposite directions. the earths core spins much the same speed as the earth, doing maybe one more revolution per 1000 years.
the possibilites as I see them are
1) there are charged particles wich are unevenly distrubuted in the inner and outer core and so cuase a net rotation of current with the earths rotation. I have no idea what could cuase such charge seperation, unles centrifgal force, or maybe nuclear proceses? but this wouldnt explain pole reversal. or maybe hall effect ?
2) the convection currents cuase movement of a conductive fluid in a already existing magnetic field wich create a potential diference, this cuases a current to flow that would opose the magnetic field, but by the time the current builds up the convection curent has changed direction and so reinforces the field, although im not sure if the delay could be long enough to fit with the speed of convection current.
maybe its a combination of both ? any thoughts ?
there has been I think attempts at an experiment with a spining mass of molten sodium.
Colin =^.^=