The Earth acts as if it is a huge magnet. Whne the solid rocky core moves inside the liquid rock above it, it creates a magnetic field with a north pole and a south pole. This field surrounds the Earth and extends right out into space. The Earth's magnetic field is changing constantly. This means that magnetic North Pole is not always the same as the geographic, or true, North Pole that you find on a amap, although it wanders about in the same region. Millions of years ago, the North Magnetic Pole lay in what is now the Sahara Desert.
Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with one pole near the north pole. and the other near the geographic south pole. An imaginary line joining the magnetic poles would be inclined by approximately 11.3° from the planet's axis of rotation. The cause of the field is probably explained by dynamo theory. Magnetic fields extend infinitely, though they are weaker further from their source. The Earth's magnetic field, which effectively extends several tens of thousands of kilometers into space, is called the magnetosphere.
Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with one pole near the north pole. and the other near the geographic south pole. An imaginary line joining the magnetic poles would be inclined by approximately 11.3° from the planet's axis of rotation. The cause of the field is probably explained by dynamo theory. Magnetic fields extend infinitely, though they are weaker further from their source. The Earth's magnetic field, which effectively extends several tens of thousands of kilometers into space, is called the magnetosphere.
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