HOW THE EARTH AS A MAGNET?

The observation that magnets align themselves along a North South Axis impiles that the Earth itself must causes a magnetic field in did the earth behaves as if it has a bar magnet at its Centre magnet and compass needles Allign  themselves  with the earth's line of magnetic force this lines are not exactly along geographical meridians show the North and South magnetic poles do not coincide with the Geographic once their position are slowly changing all the times so the declination( the angle between magnetic and Geographic meridians) is variable. 

If a compass is free to rotate in vertical pain as well as horizontal one it deeds towards the surface of the earth at the very angles depending on the latitude at the North and South magnetic balls a deep needle point vertically while at the magnetic equator it lies horizontally.

 physicist have deduced from a study of earthquake waves that the earth has a liquid core they are are therefore confident that there is no real bar magnet under the Earth surface one possible explanation of the Earth's magnetic behaviour is that the liquid core as circulating electric current inside it which make it behave like a gigantic dynamo. 

The earth magnetic field extend some 80000 km into space and this causes many strange effects such as electric winds and Aurorae  when the field track charge particle from the sun and outer space.