Earth has a terrestrial magnetic field thanks to which we are still alive. This magnetic field extends from the inside of the planet to the outside and into space where it meets the solar wind. It is also known by the name of geomagnetic field and is given by the amount of metals found in the nucleus, the last of the layers of the Earth.
In this article we are going to see the importance of the Earth's magnetic field, its origin, function and what is currently happening with it.
What is
It is as if it is a type of magnet that we have inside our planet. The magnetic field is generated by a kind of electrical currents that result from the so-called convection currents that exist in the core of the Earth. These electric currents occur because in the nucleus there are a large amount of metals such as iron and nickel. The process by which convection currents take place is called a geodynamic.
Science has been studying this Earth's magnetic field for a long time. The Earth's core is about two-thirds the size of the moon. It is about 5.700 degrees Celsius, so the iron is almost as hot as the surface of the Sun itself. Given Since there is a pressure exerted by the other layers of the Earth, we can see that the iron is not liquid. The outer core is another 2.000 km thick layer that is made up of iron, nickel and other metals that are in a liquid state. This is because the pressure in the outer core is lower, so that the high temperatures cause the metals to be molten.
Differences in temperature, pressure, and composition within the outer core are what cause the so-called convection currents of the molten metal. When colder, denser matter sinks, warmer, less dense matter begins to rise. It is the same that happens with air masses in the atmosphere. We also have to count that, coriolis effect because of the rotational movement of the earth it also acts. As a result, eddies are created that mix the molten metals.
How it is formed
The continuous movement of the liquid composed of iron in its majority is what generates electrical currents that, in turn, produce magnetic fields. Electrically charged metals pass through these magnetic fields and continue to create electric currents of their own. In this way, the cycle is perpetuated. The complete and self-sufficient cycle is called a geodynamic.
The Coriolis force causes a spiral that causes many magnetic fields to line up in the same direction. The combined effect of all these lines of magnetic force create the magnetic field that envelops the Earth.
When we speak of the layer of the Earth or the atmosphere that has to do with the Earth's magnetic field, we speak of the magnetosphere. It is the area of the atmosphere that is outside, surrounding the planet, and that is totally controlled by this Earth's magnetic field. The shape of the magnetosphere is given by the solar wind that hits the surface. This solar wind compresses a part of the magnetosphere and, therefore, expands the opposite side. This large expansion is known as the "magnetic tail."
The solar wind is the activity of our major star, the Sun. This solar wind is loaded with radiation that, if it enters our atmosphere, could cause serious damage to telecommunications systems globally. It would be a disaster for the technological age in which we live. The GPS would fail, there was no telephone coverage, radio waves or television, etc. Therefore, thanks to the existence of the magnetosphere we are protected.
Characteristics of the Earth's magnetic field
We are going to analyze the characteristics of this magnetic field that science has discovered over the years and with thousands of studies about it.
- The intensity of the magnetic field is lowest near the equator and highest at the poles.
- The outer limit is the magnetopause.
- The magnetosphere acts in a dynamic way under the action of the solar wind. Depending on its activity, it can be compressed on one side more and expanded on another, which is called the magnetic tail.
- The north and south magnetic poles are not the same as the geographic poles. For example, between the magnetic and geographic north poles there is about 11 degrees of deviation.
- The direction of the field is slowly changing and scientists have been studying its change of direction. The movement has accelerated 40 miles per year.
- There are various geological records that have been studied thanks to certain minerals from the seabed, which say that the magnetic field has been completely reversed hundreds of times in the last 500 million years. In this inversion, the poles would be at opposite ends such that if we used a conventional compass, it would not point north, but would point south.
Importance of the magnetic field
So that you can see the importance of the magnetic field, we are going to explain what functions it exercises and what it is for having it around our planet. It is what protects us from the damage that the solar wind can cause, as we have mentioned before. Thanks to this magnetosphere, we can perceive the solar wind through some very attractive phenomena such as the Aurora borealis.
This magnetic field is also responsible for our having an atmosphere. The atmosphere is the one that protects us from the solar rays of the Sun and the one that maintains the habitable temperature. If not, the temperatures would range between 123 degrees and -153 degrees. It must also be said that thousands of animals, including species such as birds and turtles, use the magnetic field to navigate and orient themselves during their migration period.
I hope that with this information you can learn more about the Earth's magnetic field and its importance.