The Earth’s magnetic field, also known as the geomagnetic field, extends from the Earth’s interior to outer space, where it interacts with the solar wind, a set of charged particles emanating from the Sun. This magnetic field serves as a protective shield against solar radiation, without which the solar wind would sweep most of the atmosphere into space. The Earth’s magnetic field actually extends tens of thousands of kilometers into space – this region is called the magnetosphere.
In the 16th century, English physicist William Gilbert claimed that the Earth is a big magnet, but Johannes Kepler was the first to suggest that the motion of the planets can be traced back to magnetic forces. Newton refined the proposal, explaining the phenomenon with the force of gravity.
The Earth’s magnetic field is primarily external core It originates from a region called the shale, which is a layer of molten iron and nickel about 2,890 kilometers below the Earth’s surface. The space is created by the boiling, flowing magnetizable liquid in the depths. The constant flow also causes the magnetic pole to wander, this is the phenomenon of the geodynamo. A combination of Earth’s rotation and convection currents driven by heat radiating from the deeper inner core creates the magnetic field of the moving, electrically conductive fluid.
The electric circuit of the forces acting on the outer core generates and maintains the magnetic field, which has a dipolar structure with both a north and a south pole. It is characterized by lines of force that leave one pole, the south, and enter the other, the north. But there are small differences in the field, the field lines are distorted by the solar wind.
In a dipolar magnetic field, the strength of the field decreases with increasing distance from the source.
The internal fluid motions are not perfectly balanced, fluctuating, and this leads to an imperfect, non-static magnetic field. Its strength and direction slowly change over time, due to changing conditions and flow patterns within the outer core. Navigation systems must account for this shift for accurate data. But changes in solar activity can also affect the Earth’s magnetic field, when waves of particles are pushed towards the Earth, distorting the magnetic field and causing temporary disturbances, geomagnetic storms.
It is not static
The fact that the Earth’s magnetic field is not fixed was recognized at the beginning of the 19th century, when it was noticed that the magnetic needle of a compass slowly shifts over time. These changes are happening all over the world. In different regions of the Earth and at different times, magnetism can be very different, it can increase in some places and decrease in others. The field is stronger near the poles and weaker at the equator. However, there are also regional differences, where the basalt concentration is high, the rock is rich in magnets, the magnetic field can be stronger, but it can also be affected by volcanic activity or tectonic features.
The Earth’s magnetic field can be reversed, this is a geomagnetic reversal, when the north and south poles switch places. The last such reversal occurred about 780,000 years ago as a result of complex dynamical processes. The weakened magnetic field can cause more solar radiation on Earth and can have a strong effect on the atmosphere.
Question, are we affected by the magnetic field? It is from a previous investigation revealed, we perceive magnetic waves unconsciously: the brain waves of voluntary participants were measured with EEG under the influence of a magnetic field, and in some of them the alpha waves changed in response to the stimulus. Then they explained the matter by saying that there are small magnetic crystals in special sensor cells, and these react to magnetism.
Another is the University of Tokyo study, which analyzed how humans perceive the Earth’s magnetic field. It turned out that the cryptochrome photoreceptor in our cells is responsible for magnetic sensing. This also explains how animals, such as birds, orientate themselves by aligning themselves with the magnetic field.
5 books
More than 600 amazing, interesting and educational stories!
Again 150 brand new, exciting topics with surprising answers
Follow Index on Facebook too!
I’m following you!
