The mechanism of planetary magnetic field is still a mystery. There are many hypotheses about its cause. Although these hypotheses can explain some phenomena, they all have their theoretical defects. According to modern electromagnetic theory, magnetic field is produced by moving electric field. As far as the specific forms of magnetic field generated by electric field are concerned, there are mainly the following: 1, molecular current-electrons in molecules and atoms rotate around the nucleus to generate magnetic field, which is the generation mechanism of permanent magnetic field; 2. Ordinary current-this is the mechanism of magnetic field generated by ordinary electromagnet; 3. Mechanical motion of point charge-this is the mechanism of magnetic field generated by Roland disk in Roland experiment. Therefore, the generation of planetary magnetic field comes from the above reasons; One is generated by molecular current (that is, the traditional permanent magnet hypothesis); This view holds that there is a huge iron-nickel permanent magnet core inside the planet, which produces the planetary magnetic field. Some people have put forward a negative reason for this view: permanent magnets have Curie point, that is, permanent magnets will lose their magnetism at a certain temperature. The Curie point of iron-nickel permanent magnets is about 770 degrees Celsius, and the temperature inside many planets generally exceeds 1000 degrees Celsius. At this temperature, the iron-nickel permanent magnet has lost its magnetism. Therefore, the view that the planetary magnetic field comes from the permanent magnet inside the planet is gradually denied. Second, constant current generation; This hypothesis holds that the core is a positively charged plasma. The central part of the planetary core "squeezes out" electrons due to high temperature and high pressure, making it positively charged; The outer layer of the planet's core is a shell full of electrons. This shell is a superconductor, and it is the constant current of the superconductor that produces the magnetic field of this planet. This hypothesis accords with certain scientific truth and can explain some phenomena, so it is a promising hypothesis. Third, the third point of view: it is caused by the macroscopic mechanical movement of point charge. That is to say, it is consistent with the magnetic field generation mechanism of Roland disk in Roland experiment. As far as the first two hypotheses are concerned, it is difficult for them to explain the phenomenon that the intensity of planetary magnetic field is closely related to planetary rotation. Judging from the data of nine planets, it seems that the magnetic field strength of the planets is closely related to the rotation of the planets. For example, Venus, which is close to other parameters of the earth, has a slow rotation speed and almost no magnetic field; Almost all planets with short rotation periods have strong magnetic fields, such as Jupiter and Saturn. So the magnetic field of the planet comes from the mechanical motion of its own charge. That is to say, a certain area on the earth is charged for some physical and chemical reasons. These charges do circular mechanical motion with the rotation of the planet, and this circular mechanical motion charge will inevitably produce a magnetic field, which is the source of the planetary magnetic field. There are two immature views on the source of charge: one is the unequal capture of charged particles by the solar wind; The other is the principle of piezoelectric ceramics, which presses charges out of the core of the planet; The first is that the charge comes from the solar wind. After being captured, these charges are bound to be distributed in a circle of the planet's outer atmosphere, and will inevitably move around the planet's rotation axis with the atmosphere. These circular charges will inevitably produce a magnetic field, which may be the source of the planetary magnetic field. The two problems mentioned in this view must be explained here: 1. Why is the charge distributed in the outer atmosphere? 2. Why do planets selectively capture some charges in the solar wind? Question 1: Based on such a common sense, if an object is charged, due to repulsion, these charges must be distributed around the object. Similarly, if the planet has some kind of charge, these charges are distributed in the periphery of the planet's atmosphere, that is, the outer atmosphere, because of repulsion. Question 2: I think the positive and negative charges in the solar wind are equal. How do planets choose to catch some particles? Based on the electronegativity of matter (a chemical concept, different from negative charge), that is, different atoms have different forces with charged particles. For example, a neutral oxygen atom or molecule may have electromagnetic interaction with an electron or proton, but the force of Venus, the only planet in his solar system without a magnetic field, is different. Oxygen is so electronegative that it tends to capture an electron instead of a proton. Similarly, potassium atoms should tend to capture positive charges rather than negative charges. From the material composition of the planet, the sum of oxygen station 49%, silicon 26% and other metallic elements is less than 20%, so on the whole, the elements with strong electronegativity account for a relatively high proportion. In the outer layer of the planet, the planetary atmosphere is a mixture of many elements, which may be due to the imbalance of material ratio, which eventually leads to the tendency of the planet to capture negative charges. For the above reasons, these negative charges are concentrated in the outer atmosphere of the planet (possibly in the ionosphere). When they mechanically move around the earth axis with the rotation of the planet, they will inevitably produce a magnetic field, which may be the planetary magnetic field. If there is another planet whose material composition is different from that of the planet, it may have the opposite charge to that of the planet. Even if it rotates in the same direction as the planet, it is possible to form a magnetic field opposite to the planet. Similarly, planets with different rotation directions may form magnetic fields in the same direction as the planets. Therefore, according to the above assumptions, the intensity of planetary magnetic field should depend on several factors such as rotational speed, planetary radius and atmospheric thickness. So if we use this hypothesis, it fits the following phenomenon well: 1, why does Venus have almost no magnetic field? 2. Why do wooden planets have strong magnetic fields? According to the principle of piezoelectric ceramics, the charge is pressed out from the core of the planet. In other words, this hypothesis can be said to be the development of hypothesis 2. That is, in the constant current hypothesis in hypothesis 2, although the charge source is solved, the constant current driving force cannot be solved. Because theoretically, the superconducting ring conductor will not stop as long as there is current, and it can also generate a constant magnetic field without external influence. Therefore, this theoretical point of view also encountered a problem, that is, with superconductors, but without power supply, what provided them with a suitable voltage, or what provided them with an original driving force of current. If we borrow this hypothetical charge source, we should follow the principle of piezoelectric ceramics. These accumulated charges are mechanically moved by the rotation of the planet in the earth's magnetic field, which may be the source of the planetary magnetic field. Because the negative charge is concentrated in the periphery, the linear velocity of its circular motion with the earth's rotation must be greater than that of the internal positive charge. The generated magnetic field is naturally stronger than the inside. Although the number of internal positive charges is basically equal to the number of external negative charges, because they are located inside and have a relatively small radius, their linear velocity with the earth's rotation is bound to be relatively small, so the magnetic field generated by them is bound to be weaker than that generated by negative charges. Although the direction of the magnetic field is opposite to that of the negative charge, it still cannot completely cancel the magnetic field generated by the negative charge. In this way, the vector sum of the magnetic fields in the two directions will inevitably show the magnetic field generated by the negative charge accompanying the rotation of the planet. The earth is one of the eight planets in the solar system, and the mechanism of its magnetic field should be the same.

[Edit this paragraph] Learn about the findings.

About the planetary magnetic field, except the geomagnetic field, there is only a little preliminary knowledge. Due to the development of space exploration technology, this situation is changing rapidly. So far, the magnetic fields of Mercury, Venus, Mars, Jupiter and Saturn have been explored in space. Mariner 10 found that the magnetic field of Mercury is much stronger than that of Mars and Venus. The detection results also show that the magnetic moment of Mercury is 5.2× 1022 electromagnetic unit, which is less than11500 of the earth's magnetic moment. Mercury's magnetic polarity is the same as that of the earth, and its dipole moment points to the south; The intersection angle between the magnetic axis and the rotating shaft is about12; The equatorial field strength is 4× 10-3 gauss. It has been proved that the interaction between mercury's magnetic fields stretches Jupiter's outermost ring field, which is inherent in the planet itself, but the explanation of its origin is still controversial. So far, Ad Astra has not found enough evidence to prove that Venus has an inherent magnetic field, only the solar wind shock wave has been found near Venus. The configuration of this shock wave can be explained by the direct collision between the solar wind and the top of Venus' atmosphere. The turbulence and small-scale magnetic field behind the shock wave are the result of the interaction between the solar wind and Venus. However, C.T. Rosso of 1976 thinks that the dipole field with magnetic moment of 1.4× 1023 can better explain the obtained space observation data. This problem needs further study. The interplanetary probes "Mars" No.2, No.3 and No.5 explored Mars and obtained the evidence that Mars has a magnetic field. The magnetic moment is 2.5× 1022 electromagnetic unit, which is 1/3000 of the earth's magnetic moment. The equatorial magnetic field intensity is 0.6× 10-3 gauss; The polarity of the magnetic pole is opposite to that of the earth, that is, the dipole moment points to the north; The included angle between the magnetic axis and the rotating shaft is 15. However, after reanalyzing the space exploration data of 1978, C.T. Russell thinks that the observed magnetic field is only a compressed interplanetary magnetic field around Mars. Therefore, it is inconclusive whether there is an inherent magnetic field on Mars. Evidence of Jupiter's magnetic field and Saturn's magnetic field is obtained in woody planets.

[Edit this paragraph] Solar and planetary magnetic fields

Compared with Saturn's dazzling and spectacular aura, Jupiter's dim aura is very inconspicuous, but it has been puzzling astronomers for many years because of the asymmetry of its peripheral aura. Now, researchers report that the tug-of-war between Jupiter's powerful magnetic field and solar energy effect has deformed the planet's outer ring. This discovery will help to change the understanding of the forces that form rings around Saturn and other planets. It is difficult for people to find Jupiter's aura on the earth. 1979, two American "Voyager" probes flew to Jupiter, and astronomers discovered Jupiter's rings for the first time with the help of light from the back of the sun. Observations show that the width of Jupiter's ring is about 6.5438+0.3 million kilometers, which is close to half of the famous Saturn's ring. Another difference between the two planetary rings is their shapes. Saturn can keep the shape of Saturn's rings, while the farthest end of Jupiter's rings extends outward to Enceladus. Now, two astronomers think they have found the answer to the question. DouglasHamilton of the University of Maryland and HaraldKrüger of Max Planck Institute of Nuclear Physics in Heidelberg, Germany, analyzed the data sent back by NASA's Galileo spacecraft, which briefly visited Jupiter's ring before falling into the planet's atmosphere in 2003. The researchers reported the research results in the British journal Nature published on May 1. They found that the particles in the planetary ring move slowly around Jupiter, and they get electric charge from the energy from the sun. Then, when these particles fall into Jupiter's shadow area, they will be pulled from several directions by the planet's powerful magnetic field. The end result is to keep the orbit on the back of Jupiter's ring away from Jupiter until it reaches Europa. So, why is there no similar deformation phenomenon in Saturn's rings? This is because the magnetic field intensity of Jupiter is 10 times that of Saturn, and the sunlight reaching Jupiter is stronger than Saturn. Hamilton explained that the final result of these two effects makes Jupiter's shadow area more important. As a member of NASA's Cassini probe science team, Cornell University astronomer Joseph Burns said: "Scientists have finally figured out the mystery of Jupiter's ring, and this discovery is of great significance." The Cassini probe is now orbiting Saturn, and Burns hopes it can find similar-perhaps subtle-features in Saturn's rings. [ 1][2]

[Edit this paragraph] Some conclusions of planetary magnetic field

(1) The magnitude of the planetary magnetic field is directly proportional to the mass (density) and radius of the inner core. The calculated values of the magnetic field intensity in the polar regions of terrestrial planets are basically consistent with the measured values, which shows that the idea of * * * spin theory is correct. The calculated value is slightly different from the measured value, including mercury and Mars. The calculated value of mercury's magnetic field strength is even smaller, because the estimated value of mercury's core radius is smaller according to two to one, which is actually five to four. However, the core radius of Mars is estimated to be 2: 1, but it is larger. Because the crust of Mars is very thick and the ratio of the radius of the star to the core is 3: 1, the calculated magnetic field intensity in the polar region of Mars is larger than the measured value. After correction, the calculated values are basically consistent with the measured values. (2) Earth-like planets are all self-rotating planets with heavy metal conductor cores, all of which will "spin and electrify", generate different charges and form different potentials on different surfaces of the core; So as to generate a vortex and melt the outer core into a liquid state. At the same time, the core of the star leaks into space, keeping the earth-like planet a quasi-electrostatic sphere with negative charge. Because the counterclockwise rotation of a negatively charged planet is equivalent to the clockwise rotation of a positively charged planet's magnetic field charge, the magnetic fields of Mercury and Mars are in the same direction as the earth's magnetic field, and their magnetic polarities are: their N poles are at the planet's south pole, the magnetic lines of force point from the geographical north pole to the south pole inside the planet, and from the south pole to the north pole in the outer space of the planet, which is in a right-handed spiral (thumb points to the north pole) relationship with the spin direction. Venus rotates in the opposite direction, so its magnetic field is opposite to that of the earth. (3) The magnitude of the planetary magnetic field is directly proportional to the angular velocity of the planetary rotation. Planets with slow rotation angular velocity have little magnetic field strength. For example, the calculated value of Venus' magnetic field strength is one thousandth of the earth's value, and the measured value is zero. The reason is that the negatively charged quasi-electrostatic Venus planet tends to gather positively charged metal ions outside the sphere. Venus' atmosphere and Venus' magnetic field rotating with Venus will make the negatively charged electrons in the atmosphere rotating with Venus disperse into outer space under the Lorentz force. But plays an adsorption and aggregation role on positively charged ions. The positively charged metal ions also have the function of shielding the magnetic field, and Venus's magnetic field direction is opposite to that of other terrestrial planets, so it is not easy to be detected. (4) The direction of the planetary magnetic field is related to the material electrical structure and the spin direction of the metal conductor core. The magnetic fields generated by the planetary rotation of the heavy metal conductor core and the metal hydrogen (superconducting) core are in opposite directions. The direction of the planetary magnetic field has a great influence on the particles in the atmosphere that follow the rotation of the planet. For example, the magnetic fields of Venus, Jupiter and Saturn are opposite to those of other terrestrial planets, and the negatively charged electrons in the atmosphere following the rotation of the planets will be dispersed into outer space under the action of Lorentz force. But plays an adsorption and aggregation role on positively charged ions. This is why these three planets have dense atmospheres. Due to the large amount of electricity, lightning will appear in the atmosphere of planets such as Venus and Jupiter. The beautiful optical rings on Jupiter and Saturn may also be the result of the interaction of Lorentz force brought by the strong magnetic fields of these two planets and the spiral step force of these two planets. [