Compasses are a very useful tool if you are trying to orient yourself when the world insists on not giving you any clue that allows you to deduce your position. One of these situations could be, for example, that of a sailor who is in the middle of the rough ocean , at night and with the cloudy sky.
The first rudimentary compasses were invented in China during the reign of the Han dynasty (221 BC-206 BC) and were imported to Europe back in the 11th century. As is normal, that needle that moved without apparent cause aroused the curiosity of those who used it: there were those who believed that the compasses pointed towards a magnetic island located in the north and others said that it was attracted directly by the pole star. But the first to propose that the origin of the magnetic field was in the interior of our own planet was the natural philosopher and physician William Gilbert who, after doing experiments with spheres of magnetite, suggested that the compasses pointed towards the points of the planet in the that a magnetized needle would stay vertical.
But it turns out that orienting yourself with a compass is not a completely reliable method because the magnetic poles are not aligned with the axis of rotation of the Earth, but deviated about 10º . Therefore, a compass will only point directly to geographic north where the magnetic north pole, geographic north, and the compass are aligned. Also, to finish the matter off, the position of the magnetic poles changes slightly every year.
Currently the magnetic north pole is located in the middle of the Arctic Ocean, about 420 kilometers from the geographic north pole, and moves in the direction of the Russian coast at a rate of between 50 and 65 kilometers per year . On the other hand, separated by about 2,800 kilometers, the magnetic south pole is even further from the geographic south pole, moving between 10 and 15 kilometers per year in a northwesterly direction. These variations in the position of the magnetic poles are due to the fact that their origin is in the movement of the mass of molten iron and nickel that make up the outer core of the planet: the arrangement of all this liquid material is constantly changing and, therefore, the magnetic field to which it gives rise is affected.
