How was the earth magnetic field created? Why is it so important?
The magnetic field is thought to be created by the spinning of the Iron and Nickel inner core, The magnetic field protects the earth from the electro magnetic cosmic radiation.
Iron, Nickel and Cobalt have free electrons in their outer shell which can spin creating a magnetic field. Most ordinary magnets are created from Iron because of this property.
The inner core of the earth is thought to be liquid Iron, and Nickel. As the earth rotates around it axis, the core also rotates or spins. The spinning of Iron and Nickel will produce a magnetic field.
There is a relationship between electronic waves and magnetism, which is why they are called electro magnetic waves. Run electricity through wires and it will create a magnetic field. Spin a magnet around electric wires and it will create electric current.
Cosmic radiation is a form of electro magnetic waves. The magnetic field of the earth interacts with the electro magnetic waves preventing most of the harmful radiation from reaching the surface of the earth. Cosmic radiation is harmful to living organisms.
An example of the interaction of the between the earth's magnetic field are the beautiful Northern Lights.