You might have learnt about the two poles of the Earth – North and South, one pole in each direction – North and South of the Earth.
Did you know that there are many North and South poles of our planet. Can you guess how many north poles are there. If we limit ourselves to the most common ones, we can find at least five of them – Magnetic Pole, Pole of Inaccessibility, Geographic Pole, Geomagnetic Pole and Celestial Pole.
Following are the most common five North Poles:
1. The Geographic North Pole
The first and best known is the Geographic North Pole, also known as True North. It is the point at which the axis around which the earth rotates passes. Alternatively, it can be said to be the point with latitude 90° north. It is curious to note that at the North Pole, as well as at the South Pole, there is no latitude. Here the meridians meet and so if from the geographic North Pole we move in a straight line, we go any way towards the geographic South Pole, and vice versa.
2. The Magnetic North Pole
The magnetic north pole is the boreal point of the Earth’s surface where the flow lines of the geomagnetic field are perpendicular to the ground and directed towards the ground. At this point on Earth a compass working with a horizontal axis of rotation would point towards the ground.
In essence, the definition is still valid today. Although it is based on a basic contradiction. It would actually be the magnetic south pole. The Magnetic North Pole of the Earth in fact attracts the magnetic north pole of magnets, i.e. it is actually a magnetic south pole. Given, however, its proximity to the True North was called the Magnetic North Pole.
And it moves!
The Magnetic North Pole is currently located at 86.50°N and 164.04°E. It is off the coast of Canada and is moving (at a speed that has varied from 11 km per year at the beginning of the century to about 60 in recent years) towards Siberia where it could arrive around 2050. In 2019 the magnetic North Pole crossed the Greenwich Meridian twice in one year. This forced the update of the World Magnetic Model (VMM), a tool developed by the US National Oceanic and Atmospheric Administration and the British Geological Survey that provides data to satellites of modern navigation systems.
3. The North Pole of Inaccessibility
Unlike the others it is not characterized by physical peculiarities, but it has the characteristic of being complex to reach for some reason. In this case, it indicates the point of the Arctic Ocean furthest from any coastline. It is located about 1100 km from the nearest coast at the geographical coordinates: 84°03′N – 174°51′W.
4. The North Geomagnetic Pole
The North Geomagnetic pole, defined as the point to the north where the axis of the Earth’s magnetosphere ends. As for the Magnetic North Pole, it is magnetically a South Pole. It is not a real point, but a convention based on the physical model of the dipole (a bar magnet), which in 90% of cases explains the real behavior of the Earth’s magnetic field.
According to this theory, a magnetic field acting as it is measured experimentally could be generated by a huge magnetic bar that crosses the Earth from side to side at an angle of about 11.5° to the Earth’s axis of rotation. The point at which it intersects the Earth’s surface is called the geomagnetic north pole. Geomagnetic north pole and magnetic north pole do not coincide, currently there is an average distance of about 30° longitude. Also this pole moves in time, but with a lower speed and distances than its magnetic relative.
5. The North Celestial Pole
The North Celestial Pole is the point in the sky about which all the stars seen from the Northern Hemisphere rotate. The North Star, also called Polaris, is located almost exactly at this point in the sky. If you go out at night and find the north star you will notice that it does not move during the course of the night, while all the other stars do move, they rotate from east to west around the north star.
Following are the most common five South Poles:
1. The Geographic South Pole
The Geographic South Pole is the southernmost point on the Earth. It is the precise point of the southern intersection of the Earth’s axis and the Earth’s surface. From here, all directions are north. Its latitude is 90 degrees south, and all lines of longitude meet there (as well as at the North Pole, on the opposite end of the Earth).
The Geographic South Pole is located on Antarctica, one of the Earth’s seven continents. Although land at the South Pole is only about a hundred meters above sea level, the ice sheet above it is roughly 2,700 meters (9,000 feet) thick. This elevation makes the South Pole much colder than the North Pole.
2. The Magnetic South Pole
Earth’s magnetic south pole is where the magnetic field lines are oriented vertically and come out of the surface of the Earth. The magnetic inclination is thus defined as -90 degrees. The magnetic pole varies in position on a yearly basis due to secular variation (drift in Earth’s magnetic field). The most likely location of the pole is 71°36’S 152°0’E.
Yes, the magnetic south pole also moves!
The south magnetic pole is constantly shifting due to changes in Earth’s magnetic field. As of 2005 it was calculated to lie at 64°31′48″S 137°51′36″E, placing it off the coast of Antarctica, between Adélie Land and Wilkes Land. In 2015 it lay at 64.28°S 136.59°E (east). That point lies outside the Antarctic Circle. Due to polar drift, the pole is moving northwest by about 10 to 15 kilometers (6 to 9 mi) per year. Its current distance from the actual Geographic South Pole is approximately 2,860 km (1,780 mi).
3. The South Pole of Inaccessibility
The South Pole of Inaccessibility is the point on the Antarctic continent most distant from the Southern Ocean. A variety of coordinate locations have been given for this pole. The discrepancies are due to the question of whether the “coast” is measured to the grounding line or to the edges of ice shelves, the difficulty of determining the location of the “solid” coastline, the movement of ice sheets and improvements in the accuracy of survey data over the years, as well as possible topographical errors.
4. The Geomagnetic South Pole
The Geomagnetic South Pole is the point where the axis of this best-fitting tilted dipole intersects the Earth’s surface in the southern hemisphere. As of 2020, it is located at 80.65°S 107.32°E, whereas in 2005, it was calculated to be located at79.74°S 108.22°E, near Vostok Station.
5. The Celestial South Pole
The South Celestial Pole is the point in the sky about which all the stars seen from the Southern Hemisphere rotate. No matter where you live in the Southern Hemisphere there is an easy way to find the South Celestial Pole. The South Celestial Pole is up from the horizon exactly an angle equal to your latitude. So if you live at 50 degrees latitude, the South Celestial Pole will be due south, up 50 degrees.
The arrow you see pointing toward the South Celestial Pole in the diagram above is in fact the axis about which the Sun, and all other stars rotate.
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Image Credit: Earth space vector created by macrovector – www.freepik.com