When we talk about magnetic declination At any point on Earth we are talking about the angle between a local magnetic north and geographic north. The geographic north is also known by the name of true north. This magnetic declination marks the difference between the geographic north and the one indicated by a compass, which is the magnetic north.
In this article we are going to tell you all the characteristics and what function the magnetic declination has.
Key features
Magnetic declination is not always stable on our planet. Depending on where we are, the value of this can vary. Furthermore, due to the rotational and translational movement of the earth and the nutation effect, this value of the magnetic declination also changes with the passage of time. We can say that this term helps us to remit the entire disagreement that exists between the models of ideal causes and reality. It can help us to get an idea about the margins of error and calculation errors that exist in supposedly rational measurement systems.
The term magnetic declination does not suggest that there may be unexpected variations in the coordinate axes. We can also find different perspectives, geographies that are dislocated and rearranged and some opportunities to be able to investigate.
There is a research and production group that has been recently built and that is made up of visual artists, curators and theorists whose work is part of the awareness of various postcolonial and decolonial studies with a closer immediate context. This research group is called magnetic declination.
How Magnetic Declination Works
If we want to know how this phenomenon of our planet works, we have to know what the terrestrial magnetism. Planet Earth has a magnetic field due to the composition of the Earth's core. The other terrestrial is composed mainly of iron and nickel. These heavy metals are in a semi-liquid state in the outer core of the Earth. This is due to the increase in temperatures at depth and the high pressure at which these molten metals and rocks are found.
Thanks to the movement that exists between densities of materials within the earth's core there are so-called convection currents. These convection currents in the mantle are those that cause the movement of tectonic plates and those that promote continental drift. In addition, they are the cause of this Earth's magnetic field.
As the masses of heavy metals are in continuous movement, various electric currents are generated that are produced at the same time as the movement and produce the electric field. This makes the Earth act like a gigantic magnet and it has two magnetic poles: the north pole and the south pole. If we speak from the magnetic point of view, the north pole is in the south and is closer to the geographic south pole. On the other hand, the magnetic south pole is close to the geographic north pole. This situation of the different magnetic poles of our planet is what justifies the north pole of the magnetized compass needle pointing to the geographic north. The position of the magnetic poles does not exactly coincide with that of the geographic poles. If it is true that they are very close to them although they do not maintain a fixed position. This position varies over the years given the different movements of the Earth.
Geographic and magnetic north
The geographic north is what is known by the name of true north. It coincides with the axis of rotation of the earth and is the one that defines in: the intersection with the earth's surface. On the one hand we have the geographic north pole and on the other hand the geographic south pole.
When we speak in magnetic terms we can say that the magnetic north pole is defined by that magnetic field where the compasses point. The position of this magnetic north pole does not coincide with that of geographic north and has been moving for years. Since there are studies and reports on the position of this magnetic field, it is known that the position has varied about 1100 kilometers away since the XNUMXth century. More or less it is known that each year the magnetic north pole changes its position by about 60 kilometers.
Currently the magnetic north pole is at a distance of 1600 kilometers from the geographic north pole. It is located in northeastern Canada and is moving towards Russia. We must not forget that strictly magnetic north is a south pole.
Importance of magnetic declination
It is an angle in a horizontal plane formed by magnetic north and geographic north. This angle, there moving the magnetic north every year would also give its values. It not only varies with the years but also with the place where we are. One of the reasons why nautical charts have a certain value is because there is an annual increase or decrease in the value of the magnetic declination depending on the position where we are.
To know the value of the magnetic declination we must know that, if the magnetic north is located to the right of the true north, the magnetic declination is positive. On the other hand, if magnetic north is located to the left of true north, the magnetic declination will have a negative value. This is how when we analyze the nautical charts we can find values of a graduated circle between 0 and 360 degrees and that indicates the value of the magnetic declination for the year of the edition of said chart. In addition, it usually indicates the value of the annual variation of this magnetic declination depending on the movement of the magnetic north pole.
If we multiply the annual variation of the magnetic declination by the years that elapse from the edition of the chart until today, we can have the exact value of the updated magnetic declination. In this way, it is not necessary that every year we have to buy a new nautical chart.
I hope that with this information you can learn more about magnetic declination.