Why does the earth behave like a magnet?
There are still arguments about the mechanisms through which planetary magnetic fields are produced. It is believed that some conditions must be fulfilled. 1. There must be a conducting core in the planet. Earth has it because it is believed to have an iron core. 2. There should also be a heat source inside to produce convection currents in the conducting material. 3. The planet should be rotating reasonably fast. These conditions are satisfied for the earth, not for the moon, mars and mercury. Mercury does have a weak magnetic field whose origin is still under discussion. It should have cooled inside and would not have any conducting material swirling around. Venus would be a candidate but is cancelled out because it rotates very slowly once every 243 earth days. The required conditions are well satisfied for Jupiter. It is large, very hot inside with lot of convection and fast rate of rotation once every 10 hours. It is believed that the conducting material is provided by hot metalli
