The Earth’s magnetic North and South poles are located near the geographic North and South poles.
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The magnetic north direction indicated by the compass does not coincide with the true north or geodetic north. The magneticaxis and the rotationalaxis of the Earth differ from each other by an angle of 11.5°, which is called the magnetic declination or local declination.
Due to the high temperature, the outer core of the Earth is liquid. Since the planet rotates, the outer core is in constant flow. The flowing liquid is rich in metals, therefore it generates a magnetic field.
The Earth’s magnetic field is like a dynamo, in which the current flowing in the coil induces a magnetic field that magnetizes the iron core. The coil symbolizes the Earth’s outer core, the iron core stands for the inner core. The outer core contains electric charges which induce current due to the rotation; the current magnetizes the inner core.
The magnetic field changes with time, its strength and direction has changed frequently over the history of the Earth. The magnetic poles have shifted several times, they constantly move, up to 15 km (9.3 mi) per year.
The magnetic field is distorted by external influences. On the day side of the Earth (the side facing the Sun) it is compressed by Solar Wind, while on the opposite side (the night side) it is expanded. The magnetic field diverts a portion of the harmful radiation of the Sun, thereby protecting the Earth. When particles of the Solar Wind enter the atmosphere, they can be seen as Aurora Borealis (in the northern hemisphere) and Aurora Australis (in the Southern hemisphere).