In an early solar system, the Earth, like the rest of the planets, was formed from the disk of dust and gas that surrounded our Sun. The denser material sank inward into the forming planet, creating the layers that exist today in day: core, mantle and crust. Although the core is predominantly iron, seismic data indicate that some lighter elements, such as oxygen, silicon, sulfur, carbon, and hydrogen, dissolved in it during the differentiation process.
The movement of liquid iron creates the electrical currents that power the magnetic field, which not only helps guide navigation systems, but also protects us from harmful extraterrestrial radiation and keeps our atmosphere in place. Here are four curiosities that you may not know about the magnetic field.
1. Changes orientation ‘suddenly’
The internal magnetic field of the Earth has not always been oriented as it is today. The direction of the bipolar component (north pole / south pole) reverses approximately every 300,000 to 1,000,000 years. Although it may seem like a long time, this reversal is very sudden on a geological time scale. The time between reversals is highly variable, and regularities or periodicities in the reversal pattern have not yet been discovered.
We know this from the geological clues that we observe on our planet, such as the oppositely magnetized ocean floor strips that appear symmetrically, for example, in the Mid-Atlantic Cordillera.
A study conducted by the University of Leeds and the University of California, San Diego recently revealed that changes in the direction of the Earth’s magnetic field can take place 10 times faster than previously thought. The study offered a new insight into the spiral flow of iron 2,800 kilometers below the planet’s surface and how it has influenced the movement of the magnetic field over the past 100,000 years.
2. Life could not exist without the magnetic field
Life as we know it could not exist without the Earth’s magnetic field and its ability to deflect dangerous ionizing particles from the solar wind and further cosmic rays.
The absence of a magnetic field would imply that the solar wind is much closer to Earth. Cosmic ray particles that are normally deflected by the Earth’s field or trapped in its outer portions would reach the planet’s surface. These particles can cause genetic damage in communities of plants and animals , leading to the disappearance of species and, on a primitive Earth, would probably have prevented the appearance of any species, at least, outside the oceans.
3. Its origin has been widely discussed
In the 1830s, the German mathematician and astronomer Carl Friedrich Gauss studied the Earth’s magnetic field and concluded that the main bipolar component originated within the Earth rather than outside it, showing that it was an inversely proportional decreasing function. to the square of the radius of the Earth. This conclusion led scientists to speculate about the origin of the Earth’s magnetic field in terms of ferromagnetism (like a giant magnet), various theories of rotation, and dynamo. But the theories of ferromagnetism and rotation are already discredited : ferromagnetism, because the Curie point (the temperature at which ferromagnetism is destroyed) is reached only 20 kilometers below the surface; and the theories of rotation, because apparently there is no fundamental relationship between moving mass and a magnetic field.
Most geomagnetic scientists today lean towards various dynamo theories, whereby an energy source in the Earth’s core causes a self-sustaining magnetic field.
4. Not all planets have a magnetic field.
And at the same time, not all planets that have a magnetic field are rocky and have a metallic core. Today we know that planets in our solar system such as Mercury, Mars, Jupiter, Saturn, Uranus and Neptune have a magnetic field or magnetosphere. However, the rocky planet Venus does not have a magnetic field.
