The geographic North and South Poles are a human convention, while the magnetic poles are the result of a natural phenomenon. The geographic poles are the places where the Earth’s axis of rotation cuts through the planet’s surface. The magnetic poles are the points on the planet where a magnet points downwards, forming a 90 degree angle with the ground. This happens because the Earth is also a giant magnet, a fact known since antiquity – knowing this, the Chinese invented the compass, around the 4th century. When this knowledge reached Europe, in the 13th century, it boosted the great navigations and mapping from across the globe. The life of navigators became easier with modern cartography, which created the system of meridians and parallels, based on the geographic North Pole. Until the early 19th century, it was believed that the geographic and magnetic poles were in the same place. But in 1831, the English explorer James Clark Ross arrived for the first time in the Arctic where the compass points to the ground – magnetic north – and discovered that the points did not coincide. At that same time, in Denmark, the physicist Hans Oersted was doing his first research on electromagnetism, a science that years later would help to explain this phenomenon.
The Earth’s axis of rotation determines the geographic pole, while Earth’s magma movement creates a magnetic field.
1. Earth rotates around an axis perpendicular to the plane of the Equator. The geographic North and South Poles are the points where the axis passes through the ends of the planet. These points serve as a reference for the Earth’s parallels and meridians.
2. In the center of the planet, there is a large ball of molten iron (magma), a little smaller than the Moon. This ball rotates a little faster than the Earth itself and moves another sea of molten iron around. In these two parts, there are electric charges in constant motion.
3. This back and forth of electrical charges creates a magnetic field. In the case of our planet, physicists believe that the Earth’s magnetism is the product of the movement of the core full of charges. After years of observation, it is known that the “terrestrial magnet”, like all magnets, is stronger at the poles.
4. Everything indicates that the movement of magma – and its electrical charges – is influenced by the rotation of the planet. And, as the axis of a magnetic field is always perpendicular to that of charges, the Earth’s axis would be close to the geographic axis. The current distance between them is 11 degrees