How Strong is the Earth's Magnetic Field?
The earth magnetic field refers to the magnetic field distributed in the space around the earth.
- The earth magnetic field is the spatial distribution around the earth
- In history, the first to put forward the concept of the geomagnetic field theory was the British
- The Earth's magnetic field consists of the basic magnetic field, the external magnetic field, and
- The earth magnetic field is not isolated. It is affected by external disturbances.
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| Geography near Antarctica |
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| Geography near North Pole |
- Scientists have found in the study of the geomagnetic field that the geomagnetic field is changing, not only the intensity is not constant, but also the magnetic poles are changing, which will happen every once in a while.
- Usually carried by matter
- Regarding the origin of the earth's magnetic field, there were legends from the North Star in early history, but the earth itself was recognized as a huge magnet by the early 17th century AD, but it was still unclear how the earth's magnetic field was generated. With the development of science, research on the observation and structure of the Earth's magnetic field has been increasing and deepened. More than 10 kinds of theories have been proposed on the source of the Earth's magnetic field. Here is a brief introduction to some doctrines of the source of the earth's magnetic field based on the history: [2]
Earth's magnetic field theory
- It is the earliest theory that holds that there is a huge permanent magnet inside the earth, and this permanent magnet generates the earth's magnetic field. This is a hypothesis of a permanent magnetic field, and the earth originated from a huge magnet. At the end of the 19th century, the famous physicist Pierre Curie discovered that the physical properties of magnets are that when the magnets are heated to a certain temperature, the original magnetism disappears [3] . It can be proved that the earth was only a very large magnet at the beginning of its birth. He attracted nearby asteroids with iron, cobalt, and nickel elements. Meteorites and magnets, for some reason, the high temperature caused the magnetism of this magnet to disappear and become The magnetic core in the middle of the electromagnet .. Because this magnetic core is not fixed, the magnetic pole reversal will occur. The gravity of the earth discovered by Newton is actually the magnetic force. Of course, these still need to be verified by scientists ... ..... According to the conclusion of the "Curie point", there cannot be a permanent magnet inside the earth, but it does not mean that it was not originally a permanent magnet.
Earth's magnetic field current theory
- It is believed that there is a huge current inside the earth, and a huge electromagnet is formed to generate the earth's magnetic field. However, such a huge current has not been observed, and the huge current will quickly decay and will not exist for a long time.
Earth's magnetic field charge rotation theory
- It is thought that the surface and the inside of the earth are respectively distributed with opposite signs and equal amounts of charges, and the earth rotates to form a closed current, which generates a magnetic field, but this theory lacks theoretical and experimental basis.
Earth's magnetic field piezoelectric effect theory
- It is thought that in the earth's internal matter, the charges in the material are separated under ultra-high pressure, and the electrons move in such an electric field to generate a current and a magnetic field. But theoretically calculated that such a magnetic field is only about one thousandth (10-3) of the geomagnetic field.
Earth magnetic field gyromagnetic effect theory
- It is believed that the rotation of ferromagnetic materials in the earth can generate the earth's magnetic field, but the magnetic field generated by this spin-magnetic effect is only about one hundred billionth of the earth's magnetic field.
Earth's magnetic field temperature difference electrical effect theory
- It is believed that the heat generated by the radioactive material inside the earth causes continuous and uneven convection of the molten material, which generates a temperature difference electromotive force and an electric current, and the electric current generates the earth's magnetic field, but the theoretical estimation is also inconsistent with the earth's magnetic field.
Geomagnetic Generator Theory
- It is believed that the conductive liquid inside the earth generates a steady current when flowing, and this current generates the earth's magnetic field.
Earth's magnetic field rotating body effect theory
- It is based on the empirical rules obtained from observations of a small number of celestial bodies. It is believed that rotating objects with angular momentum will generate magnetic moments and therefore magnetic fields. This doctrine requires the use of a constant without scientific basis, which was rejected by scientists who proposed the doctrine five years later based on sophisticated experimental results.
Kink theory of magnetic field lines of the earth's magnetic field
- It is believed that the tension characteristics of the magnetic field lines of the Earth's magnetic field and the poor rotation of the Earth's core will amplify the original weak Earth's magnetic field, thereby generating the Earth's magnetic field.
Hall Effect Theory of the Earth's Magnetic Field
- It is thought that under the simultaneous use of the temperature difference current and the original weak magnetic field generated by the uneven temperature inside the earth, the Hall effect will generate Hall electromotive force and Hall current, thereby generating the Earth's magnetic field.
Earth magnetic field electromagnetic induction theory
- It is believed that after the strong magnetic activity of the sun reaches the earth through the solar wind of charged particles, it will generate the current inside the earth through the electromagnetic induction and rectification in the earth, thereby generating the earth magnetic field. Among these theories, only the generator theory (also known as the magnetic fluid generator theory) has been more recognized in observations, experiments and theoretical studies, and it is the earth magnetic field theory that has been studied and applied more.