sorry I forgot the answer. dummy!
The Earth's magnetic field changes over time because that is the way that God makes it.
There is no reason to believe that the Earth's magnetic field will change any time soon... or, for that matter, that anything extraordinary is going to happen in 2012.
It is Earths' "Magnetosphere".
A compass is an instrument containing a freely suspended magnetic element which displays the direction of the horizontal component of the Earth's magnetic field at the point of observation.
Yes.
It is made by the movement of the earths core and magma field
The earths magnetic field results from deep in the earths core. Magnetic conduction from within the earths core is believed to be the cause of this.
because it has the hydro electric power to control the earths magnetic field
It changes over time through direction and strength. So therefore Magnetic North becomes Magnetic South.
the earths magnetic signature is a negative polarity signature
earths magnetic field is generated by the circulation of liquid metal.
magnetosphere