how does earth produces its magnetic field?

Question

anonymous · Answer

if you know that earths crust is mostly made up of metals and also earth has excessive electrons.

these things make a giant electro-magnet in the middle of the earth

anonymous · Answer

it is due to the flow of the charges in core or the inner mantle of earth..the metals ,there, are flowing in liquid state and ionic (charged) form so they create a magnetic field in similar manner as the flow of electrons cause magnetic field around a current carrying wire..
it has nothing to do with crust :)

anonymous · Answer

because the inside of the earth has much iron in the form of molten state and iron is a ferromagnetic substance which has permanent magnetism property even in the absence of any external field. So naturally earth acts as a giant magnet

anonymous · Answer

@krishnakumar123: if u see into ferromagnetism carefully,u will realise that ferromagnetic substances just cant go around dancing "i m a magnet"...u need extenal magnetic field H to make them work and as long as i know there is no magnet hanging around earth to make these ferromagnetic substance a magnet... Earth's field changes over time because it is really generated by the motion of molten iron alloys in the Earth's outer core http://en.wikipedia.org/wiki/Earth%27s_magnetic_field please verify....