Magnetism:

The study of magnetism is a science in itself. The electrical and magnetic phenomenon act together; a full study of magnetism and electromagnetism could without difficulty fill a book. The magnetism exists when electric charges move associative to other objects or associative to a frame of reference.

Geomagnetism:

The Earth has a core made up mainly of iron heated to the point that some of it is liquid. Since the Earth rotates, the iron flows in complicated ways. This flow gives rise to a vast magnetic field, known as the geomagnetic fields, which backgrounds the Earth.