1. Confused geomagnetic field
The earth is a large natural magnet, and the existence of geomagnetic field can be felt on land, sea and sky. The ancients in our country knew geomagnetic phenomena very early. One of four great inventions of ancient china's compasses is made by using the pointer polarity of a magnetic needle in the geomagnetic field.
In history, Gilbert, an Englishman, first put forward the concept of geomagnetic field theory. 1600, he put forward an argument that the earth itself is a huge magnet, and its magnetic pole coincides with the geographical magnetic pole. This theory establishes the relationship between geomagnetic field and the earth, and points out that the cause of geomagnetic field should not be outside the earth, but inside the earth.
1893, in the book Absolute Strength of Geomagnetic Force, the mathematician Gauss established a mathematical method to describe the geomagnetic field based on origin of the geomagnetic field's hypothesis inside the earth, so that the measurement and origin study of the geomagnetic field can be expressed by mathematical theory. But this is only a formal theory, and it does not clarify the origin of geomagnetic field in essence.
Now scientists have basically mastered the distribution and changes of the geomagnetic field, but the academic circles have not found a satisfactory answer to the origin of the geomagnetic field.
At present, the hypotheses about origin of the geomagnetic field can be divided into two categories. The first category is based on the existing physical theory; The second hypothesis is unique, which holds that there are special laws different from the existing known theories for cosmic objects like the earth.
The rotating charge hypothesis belongs to the first hypothesis. It assumes that there are equal amounts of charges of opposite sex on the earth, one distributed inside the earth and the other distributed on the surface of the earth, and the charges rotate with the earth, thus generating a magnetic field. This hypothesis can naturally explain the cause of geomagnetic field through the relationship between electricity and magnetism. However, this assumption has a fatal flaw. First of all, it cannot explain how the charges inside and outside the earth are separated. Secondly, there is not much charge on the earth, and the magnetic field generated is very weak. According to the calculation, if the magnetic field intensity similar to the geomagnetic field is to be obtained, the earth's charge reserve needs to be expanded by 65.438+0 billion times, which is quite different from the actual situation. At the same time, the theory is hard to justify. The observer on the earth's surface rotates with the charge. For charge, there is no relative motion. Without current, what about magnetic field?
The hypothesis of geomagnetic field based on the core also belongs to the first hypothesis, in which Frank put forward the theory of generator effect. He believes that the formation of current in the earth's core should be caused by induction when the metal substances in the earth's core do vortex motion in the magnetic field. At the same time, the magnetic field in the form of current itself is a continuous regenerative magnetic field, just like in a generator. Frank's model shows how to realize the regeneration process of geomagnetic field and explains that geomagnetic field has a certain value. However, when applying this model, it is difficult to explain how this circuit in the core is closed by a ring. In addition, this model does not consider the reaction of ocean current to vortex motion, and vortex motion is not allowed to be distributed in the plane parallel to the equatorial plane.
Other hypotheses belonging to the first category include drift current hypothesis, thermal effect hypothesis and Hall effect hypothesis, but they can't fully explain the strange characteristics of geomagnetic field.
There are two hypotheses about the origin of geomagnetic field, and the most representative one is gravity rotation hypothesis.
In 1947, blackett proposed that any rotating body has a magnetic moment, regardless of whether there is charge in the rotating body. This hypothesis holds that the magnetic fields of the earth and other celestial bodies are generated by rotation, which means that stars naturally produce magnetism, just as the rotation of charges can produce magnetic fields. However, this hypothesis has encountered difficulties in both experiments and astronomical observations. Under the existing experimental conditions, the magnetic effect produced by rotating objects has not been observed. The observation results of celestial bodies show that the magnetic field distribution of each planet is very complicated, which cannot prove that there is an inevitable dependence between the rotation of the planet and the magnetic field.
Therefore, in theory, the academic circles are still exploring and arguing about the origin of geomagnetic field, and there is no convincing theory to explain the origin of geomagnetic field.
2. Morphological field hypothesis
How to solve the mystery of origin of the geomagnetic field? In this paper, it is believed that to study the causes of geomagnetic field, we must first solve the essence of magnetism.
1820, Danish scientist Oster discovered the magnetic effect of current, and revealed the relationship between magnetism and electricity for the first time, thus linking electricity with magnetism. In order to explain the phenomenon of permanent magnets and magnetization, Ampere put forward the famous molecular current hypothesis in 182 1 year. Ampere believes that there is a ring current in the molecule of any substance, which is called molecular current, and molecular current is equivalent to an elementary magnet. When there is no magnetism macroscopically, the orientation of these molecular currents is irregular, and their magnetic effects on the outside cancel each other out, so the whole object is not magnetic. Under the action of an external magnetic field, every molecular current equivalent to a basic magnet tends to be oriented along the direction of the external magnetic field, thus making the object appear magnetic. Ampere hypothesis also explains why the N pole and S pole of the magnet cannot exist independently, because the two poles of the basic magnet correspond to the two sides of the plane where the annular current lies. Obviously, these two aspects cannot exist independently. Ampere Hypothesis attributed the essence of magnetism to the magnetic effect of current, that is, all magnetic phenomena originated from the movement of current or charge.
According to the theory of modern physics, whether the charge moves or not, it will excite the electric field around it, and the moving charge (current) will certainly excite the magnetic field around it. Just as the electric field is a special substance, the magnetic field is also a special substance, and the charge (current) moving in the magnetic field will receive the force (magnetic field force) given by the magnetic field.
Ampere's molecular current hypothesis explains the formation process of magnetic field from a microscopic point of view, and expounds the relationship between magnetic field and moving charge. There is something to think about here. Why can a charge "excite" a magnetic field only when it is moving? It stands to reason that the rest and motion of charged particles are relative. If the observer moves with the particles, will the charged particles still be magnetic? There is no doubt that the magnetic field of charged particles will not disappear because of the synchronous motion of the observer; Then, the magnetism of a charged particle that is stationary relative to the observer can only be related to its direction of motion. In view of this, we might as well assume that when the motion direction of charged particles is determined, the vector direction of field material representing magnetic field is also determined, so that charged particles show magnetic effect in the process of motion.
Based on the above considerations, this paper puts forward the hypothesis of basic particle morphology field. The so-called morphological field refers to the spatial form of the field. In the past, it was generally believed that the spatial form of the field was spherically symmetric (spherically symmetric field is also called three-dimensional field), such as the gravitational field of macroscopic objects. The hypothesis of elementary particle morphology field holds that in the microscopic world, the energy field carried by elementary particles consists of two-dimensional plane field and one-dimensional linear field. Specifically, in nature, the mass field carried by charged particles such as protons and electrons is a two-dimensional plane field, while the electric field is a one-dimensional linear field, which is vertical and passes through the center of the two-dimensional mass field. Under the action of external electric field or magnetic field, the direction of electric field of particles is consistent with the direction of motion of particles.
Why do elementary particles have such a field structure? This is determined by the formation process of the field. The initial form of the field is one-dimensional linear quantized energy flow, which is divided into two types, one is mass flow and the other is current. The two kinds of energy flows are perpendicular to each other in spatial distribution and are the original substances that constitute the basic particle field. Due to the spin of particles, the original one-dimensional linear performance flow is transformed into a rotating two-dimensional plane field.
Because the plane field of elementary particles is formed in the process of rotation, the two-dimensional field is a vector field, and the direction of the field is the same as the spin direction of particles. Here, we can vividly compare a free-moving elementary particle to a rotating bicycle wheel. The axis is a particle, the rotating spokes form a mass field, the rotating direction of the wheel is the vector direction of the mass field, and the axis passing through the axis is a one-dimensional linear electric field. One-dimensional linear electric field is also a vector. The direction of the electric field of positively charged particles is determined by the left hand, that is, the left hand holds the spin axis of the particles, and the four fingers bent are consistent with the direction of the mass field. At this time, the direction pointed by the thumb is the direction of the electric field. The same is true for determining the direction of the electric field of negatively charged particles with the right hand. On the other hand, according to the direction of the two-dimensional vector field, the charge properties of particles can also be judged, that is, left-handed spin particles are positively charged and right-handed spin particles are negatively charged.
The interaction between vector fields follows the principles of the same attraction and the opposite repulsion. Specifically, when the one-dimensional linear fields of two particles are on the same axis, if the one-dimensional vector fields are in the same direction, they attract each other; One-dimensional vector fields are mutually exclusive if their directions are opposite. For example, if an electron meets a positron, although their directions of motion are opposite, their one-dimensional electric field direction is the same, so the positive and negative electron pairs show the characteristics of mutual attraction. However, when two freely moving electrons meet (move in opposite directions), they show the characteristic that like charges repel each other. Electrons moving in the same direction in a conductor form a current, and the electrons are not repelled by the same charge, but are arranged in order. For two-dimensional fields in the same plane, if the two fields rotate in the same direction, they attract each other; If two magnetic fields rotate in opposite directions, they will repel each other. The attraction or repulsion of two charged wires is the result of the interaction of two-dimensional mass fields.
Now, taking the simplest hydrogen atom as an example, the distribution of the internal morphological field of the atom is analyzed. In atoms, the positively charged nucleus is located in the center, and the electrons outside the nucleus move around the nucleus in a circle. The nucleus of hydrogen is proton, and the mass fields of proton and electron are rotating two-dimensional plane fields, so the mass field of proton will act on electron. Under the effect of angular momentum transfer principle, the extranuclear electrons can only run in the plane of proton mass field, and the direction of motion and spin is always consistent with the vector direction of proton mass field. At the same time, the one-dimensional electric fields of protons and electrons are perpendicular to the plane of their mass fields, but in opposite directions, so the two electric fields will be connected and a closed circular action trajectory will be formed by the two linear fields. At this time, there is mutual attraction between the electrons outside the nucleus and the electric field of the nucleus.
It is not difficult to see that the internal morphological field of atoms presents a dual role relationship. In terms of spatial structure, atoms can be compared to the solar system. The nucleus is the sun, and the electrons outside the nucleus are like planets. Planets run on the solar mass field plane-ecliptic plane, and the mass field plane-equatorial plane of each planet coincides with the ecliptic plane, and the rotation direction is the same as that of the sun (the rotation direction of the solar mass field). Nuclei and electrons carry not only a two-dimensional mass field, but also a one-dimensional electric field, which is equivalent to the magnetic field of the planet, and the direction of the planetary magnetic field is perpendicular to the ecliptic plane. Compared with the nucleus, the sun also has a magnetic field, but its direction is just the opposite to that of the planet. The one-dimensional electric field interaction between nucleus and electron is equivalent to the interaction between solar magnetic field and planetary magnetic field. The trajectory is that the magnetic field lines start from the north pole of the sun, connect to the north pole of the planet, and then connect to the south pole of the sun from the south pole of the planet, thus forming a closed circular route.
At that time, when Rutherford considered the atomic model, he naturally regarded the electric field force as the centripetal force of electrons moving around the nucleus. But this hypothesis has a fatal flaw and is insurmountable, because according to Maxwell's theory, accelerated charged particles will radiate electromagnetic waves. In this way, electrons moving around the nucleus will eventually fall on the nucleus due to the energy released by radiated electromagnetic waves, and the life of a hydrogen atom is only 10-6 seconds. However, in the atomic morphological field structure model, the direction of one-dimensional linear electric field is perpendicular to the movement direction of electrons, so there is no problem of radiating electromagnetic waves and no energy loss.
Moreover, the movement of electrons outside the nucleus is also limited by the rotating mass field of the nucleus. Like the sun and planets, nuclei and electrons are also undergoing angular momentum conversion. Attracted by the electric field of the nucleus, electrons will move closer to the nucleus; In the process of angular momentum transfer with the nucleus, electrons will constantly gain orbital angular momentum, resulting in a movement trend away from the nucleus. Only when these two effects are balanced can the electrons outside the nucleus move stably in a circular orbit.
In short, under the joint action of angular momentum transmission and electric field force, the electrons outside the nucleus maintain the stability of circular motion, and the orbital radius of the electrons corresponds to the motion speed of the electrons, so they will not radiate electromagnetic waves. Influenced by the quantum properties of the mass field, the orbital angular momentum transmitted from the nucleus to the electron has quantization characteristics, which determines the quantization of the electron orbit outside the nucleus. It can be said that the particle morphology field hypothesis fills the theoretical gap of Bohr's hydrogen atom model from classical mechanics to quantum mechanics.
Inside the atom, when the electrons outside the nucleus jump from high-energy orbit to low-energy orbit, their electric field and mass field will radiate energy at the same time, which is electromagnetic wave. In other words, electromagnetic waves are composed of electric field waves and mass waves. Because the direction of electric field is perpendicular to the radial direction of electron transition, electromagnetic wave shows shear wave characteristics. In Zeeman effect, electromagnetic wave is polarized in magnetic field, which reflects the characteristics of mass wave.
If the electric field of an electron interacts directly with the electric field of a proton, a neutron will be formed. But neutrons are unstable, because the directions of the mass fields of electrons and protons that make up this composite particle are opposite, and there is repulsive force between them, so neutrons will decay soon after they are formed.
In the nucleus, the so-called strong interaction between protons and neutrons is actually the effect of an electron neutralizing a proton's electric field to make it in a neutron state, and the neighboring protons disappear due to the repulsive force of the electric field and the mutual attraction of the mass field. Because neutrons tend to decay spontaneously, electrons move back and forth between two protons in a dynamic form. The number of dynamic electrons in the nucleus reaches saturation, and when it exceeds the corresponding needs of the nucleus, the nucleus will decay. Neutrinos are always absorbed and released during the combination and separation of electrons and protons. This particle composed of electrons and neutrinos is the π meson predicted by Hideki Yukawa in theory.
In the structure of nuclei, due to the interaction of mass fields between nuclei, the nuclei will be arranged in a spatial plane. When the number of nuclei is large, this single-layer plane will be very fragile and easy to break. One of the best options is to fold the plane. If two nucleon planes overlap and the electric fields of the upper and lower layers of protons are in the same direction, then the proton electric fields of the two planes are still in an attractive state and the nuclei will not split.
Therefore, it can be concluded that the interaction of nucleon mass fields produces the attraction of coplanar nucleons; The interaction of proton electric field provides the binding force between nucleons, which is the essence of strong interaction. It can be seen that the nuclear model constructed by the morphological field is multi-layered like a building. There are swimming electrons between nuclei, and the binding force between the same layer and between layers is different. Mass field and electric field play their respective roles. The nuclear field of nuclear superposition is one-dimensional, while its mass field is still a two-dimensional plane field. The orderly arrangement of atomic nuclei constitutes a nuclear building, which shows various properties because of its different structures.
Because the two-dimensional mass field is a vector field, there are two effects of attraction and repulsion between the nuclear (proton) mass fields. The combination of two hydrogen atoms into a hydrogen molecule is the result of the mutual attraction of mass field vectors between hydrogen nuclei (protons) in the same direction. The macroscopic effect of the interaction between vector mass fields in nature is the universal gravitation of objects.
Naturally, there are two forms of interaction between vector mass fields-attraction or repulsion. Why do macroscopic objects in nature only show "gravity" effect?
To answer this question, let's do a hypothetical experiment. Suppose that a number of bar magnets are randomly distributed in a certain spatial range, and their magnetic fields are roughly the same and interact with each other. How will these magnets be distributed after a period of time? According to common sense, because each magnet has N pole and S pole, like poles repel each other and opposite poles attract each other, so the probability of attraction and repulsion of each randomly distributed magnet is the same. Therefore, it can be concluded that these magnets still maintain an irregular random distribution.
However, if we can find out through experiments, the above inference is wrong. Because the interaction between magnets is dynamic, each bar magnet is always adjusting its orientation in the process of magnet interaction. When two magnets are opposite to each other in the same pole, the repulsive force will immediately change the direction of the magnetic poles to reduce the repulsive force. When two magnets have opposite magnetic poles, they will attract each other and get close to each other, which will inevitably lead to the trend of aggregation. In this way, the gravitational effect will gradually appear, while the repulsive effect will gradually weaken. After a period of time, it is inevitable that all the magnets will gather together and eventually converge into one. That is to say, although there are two forms of action between bar magnets-attraction and repulsion, there can only be one result in the end, that is, all bar magnets are aggregated together under the action of "attraction".
The interaction between the vector mass fields of matter is the same as that of magnets. Each nucleus (proton) is equivalent to a bar magnet, and there are two forms of interaction between vector mass fields: attraction and repulsion. When these mass fields act, the nucleus (proton) will constantly adjust its orientation like a bar magnet, and finally produce a dynamic result, and all atoms will gather together, which is the gravitational effect of macroscopic objects. It can be seen that gravity is the function of degenerate mass fields and the result of dynamic balance of repulsion and attraction between vector mass fields. From this, it is not difficult to understand the reason for the weak gravity.
Each electron carries two forms of fields, and the electrons moving directionally in the conductor form a current. These electrons not only have the same one-dimensional electric field direction, but also have the same vector direction of two-dimensional mass field, so the directionally moving electrons form a rotating mass field around the conductor. The rotating mass field will show the corresponding field energy effect, which is the magnetic field "excited" by the charged conductor. That is to say, the essence of magnetic field is rotating mass field effect, and the field energy of magnetic field comes from the spin of electrons. According to this reasoning, the magnetic field of the atom mainly comes from the nucleus, and it is the mass field of the nucleus rotation that makes the atom magnetic, but the so-called ampere molecular current does not exist. The mass field of the vector has the characteristics of the same attraction and the opposite repulsion, which determines the law that the same poles repel each other and the different poles attract each other.
The polarity of the magnetic field is determined by the rotation direction of the mass field. According to the theoretical definition of electromagnetism, the polarity of the magnetic field generated by the energized solenoid is determined by Ampere's Law, that is, the right hand holds the solenoid and the four points bend in the direction of the current in the solenoid, then the end pointed by the thumb is the north pole (N pole) of the solenoid magnetic field. If the magnetic field of a single-turn solenoid is described by magnetic lines of force, and the magnetic lines of force are closed into concentric circles from the cross section of the conductor, it can be judged that the direction of closed magnetic lines corresponds to the right-hand direction of positive charge (the thumb of the right hand points to the moving direction of charge, and the curved four fingers are magnetic lines). In fact, positively charged particles are all left-handed spin particles, and the mass field is rotated by the left hand around a one-dimensional electric field. Therefore, if we want to judge the N-pole direction of the magnetic field by the rotating direction of the mass field, we must use the left-hand rule, that is, the left-hand bending is consistent with the rotating direction of the mass field, and the direction pointed by its thumb is the N-pole direction of the magnetic field. In other words, the theoretically defined direction of magnetic field lines is just opposite to the rotation direction of mass field. This is a universal principle, which applies to all objects in nature.
The essence of magnetic field is rotating mass field, so the charged conductor excites the surrounding magnetic field; On the contrary, when a conductor moves in a magnetic field, the magnetic field will certainly act on the mass field of free electrons in the conductor, making them move and form a current, which is the phenomenon of electromagnetic induction. The generation of induced current is the reaction process of the mass field of free electrons in the conductor to the external magnetic field, and the direction of current is suitable for the right-handed rule; According to Lenz's law, the direction of induced current in closed loop always makes the magnetic field it produces hinder the change of magnetic flux that causes induced current. This process conforms to the laws of energy transformation and conservation.
Magnetic fields can also interact directly with moving charges. It can be observed in the laboratory that the moving charged particles deflect in the magnetic field, which is the direct result of the mass fields of the two vectors. Because positively charged particles are left-handed and negatively charged particles are right-handed, the deflection direction of charged particles can be judged according to the definition of magnetic field polarity formed by rotating mass field. The motion of a charged conductor under the action of a magnetic field also belongs to this form of motion. The energy of this mechanical motion comes from the reaction of the mass field of the directionally moving electrons in the conductor to the magnetic field.
3. The origin and change of geomagnetic field
There are many phenomena of material rotation in nature, such as galaxy rotation, star rotation, seawater vortex, atmospheric vortex, elementary particle spin and so on. The rotation of these objects is accompanied by the rotation of the mass field, so they all produce magnetic effects, which is the reason why sunspots, various seawater eddies and atmospheric eddies on the earth produce magnetic fields. Of course, all kinds of celestial bodies and celestial systems in the universe are no exception, and the geomagnetic field is formed during the rotation of the earth. According to the rotation direction of the earth, the left-handed rule can be used to judge that the N-pole direction of the geomagnetic field points to the geographical south pole.
It should be noted that in the macro world, the mass field of the vector has degenerated and is replaced by the gravitational field. Therefore, the magnetic field intensity formed by the rotation of macroscopic objects decreases with the decrease of mass field intensity. The order of magnitude of the drop is basically equivalent to the ratio of electromagnetic force to universal gravitation, which is why the magnetic field generated by rotating objects has not been observed under the existing experimental conditions.
The geomagnetic field is the magnetic field produced by the macroscopic objects that we are most familiar with. Let's use the theory of rotating mass field to explain the distribution and change of geomagnetic field.
The formation of geomagnetic field has certain particularity. According to the rotating mass field hypothesis, the earth produces a magnetic field during its rotation. However, from the point of view of motion relativity, people living on the earth should not feel the geomagnetic field, because people are still on the surface of the earth and rotate with the earth, so people on the earth cannot feel the magnetic field effect brought by the rotation of the earth. So, what about the geomagnetic field measured by people on the surface of the earth?
It turns out that what we usually call geomagnetic field can only be counted as the surface magnetic field of the earth, not the global magnetic field of the earth (also called space magnetic field), but the rotation of the core. The internal structure of the earth can be divided into crust, mantle and core. American scientists found in experiments that the rotation speed inside and outside the earth is different, and the rotation speed of the core is greater than that of the crust. That is to say, although people on the surface of the earth can't feel the rotation of the earth, they can feel the mass field effect produced by the rotation of the core, that is, it produces the surface magnetic field of the earth. Scientists also found that the rotation axis of the earth's core is not in a straight line with the rotation axis of the earth, so the two poles of the geomagnetic field formed by the rotation of the earth's core do not coincide with the geographical poles, which is the reason for the formation of the geomagnetic declination.
In the study of geomagnetic field, scientists found that the geomagnetic field is changing, not only the intensity is not constant, but also the magnetic poles are changing, and the phenomenon of magnetic pole inversion will occur every once in a while.
As early as the beginning of the 20th century, French scientist Fran? ois Bruni discovered that the geomagnetic field reversed 700,000 years ago. 1928, Japanese scientist Matsuyama Kifan also got the same research results. After World War II, with the rapid development of paleomagnetism research, people have obtained more and more evidence of geomagnetic field inversion. For example, when magma cools and solidifies into a rock, it will be magnetized by the geomagnetic field and retain its magnetism like a magnet, and its magnetic field direction is the same as that when the rock is formed. Scientists found in their research that the magnetic field direction of some rocks is the same as that of modern geomagnetic field, while the magnetic field direction of some rocks is just the opposite. Through the magnetic measurement of rocks and seabed sediments on land and the analysis of submarine magnetic anomaly zones, scientists finally found that 17 1 sub-magnetic pole inversion occurred on the earth in the past 76 million years. As brunet pointed out, the latest one happened 700,000 years ago.
Why do the two poles of the geomagnetic field reverse? According to the origin theory of geomagnetic field, this paper thinks that the reversal of magnetic pole is caused by the change of angular velocity of core rotation. We know that the rotation speed of the crust and the core is not synchronous, and the rotation speed of the core is greater than that of the crust at this stage. However, 580 million years ago, this was not the case. At that time, the surface of the earth was molten and the moon had just been captured. The rotation speed of the earth is the same from the inside out, and there is no magnetic field on the surface of the earth. However, as the earth transmits angular momentum to the moon, the angular velocity of the earth's rotation becomes smaller and smaller. At the same time, the earth has gradually formed a three-layer structure of crust, mantle and core. The change of the angular momentum of the earth's rotation is first reflected in the crust, and the rotation speed of the crust is less than that of the core. At this time, the earth's surface can feel the existence of magnetic field for the first time, and the core forms geomagnetic field at a speed greater than that of the crust. According to the left-handed rule, the N pole of the magnetic field is near the geographical south pole, and the S pole of the magnetic field is near the geographical north pole. The rotational angular velocities of the earth's crust and the earth's core are not synchronous, and this situation cannot last for a long time. The core will inevitably transfer angular momentum to the crust through the mantle asthenosphere. As a result, the rotational angular velocity of the core will gradually decrease and the rotational angular velocity of the crust will gradually increase. When the rotational angular velocity of the crust and the core increases and decreases and eventually tends to be consistent, the geomagnetic field will disappear on the earth's surface. The angular momentum transfer between the core and the crust will not stop there. Under the action of inertia, the rotational angular velocity of the crust continues to increase and the rotational angular velocity of the core continues to decrease, so the rotational angular velocity of the crust is greater than that of the core. At this time, the earth's surface will feel the rotating mass field effect from the core against the earth's rotation direction. According to the left-handed rule, the N pole of the newly formed geomagnetic field is near the geographical North Pole and the S pole is near the geographical South Pole. For a long time, the rotation speed of the whole earth is slowing down, but the relative speed of the crust and the core changes periodically, which is why the earth's magnetic field will reverse every once in a while.
According to the measurement, there is an obvious omen before the reversal of the geomagnetic field, and the intensity of the geomagnetic field weakens until it is zero. Then, after about ten thousand years, the magnetic field strength slowly recovered, but the magnetic field direction was completely opposite. At present, the intensity of the earth's magnetic field is gradually weakening. In the past 4000 years, the magnetic field intensity in North America has weakened by 50%, which shows that the speed difference between the core and the crust is narrowing.
It is worth noting that no matter how the direction of geomagnetic field measured on the earth's surface changes, the direction of geomagnetic field in space remains unchanged. Because the geomagnetic field measured in space is a rotating mass field effect produced by the rotation of the whole earth, it will not change because of the change of the relative speed between the crust and the core. According to the left-handed rule, the N direction of the geomagnetic field measured in space is always above the geographical south pole.
In the electromagnetic induction effect, the magnetic field intensity generated by a charged conductor is proportional to the current intensity, that is, to the number of "directionally moving" free electrons in the conductor. The spin angular momentum of each electron is constant, so the magnetic field strength is actually proportional to the sum of the spin angular momentum of all electrons. Similarly, the magnetic field intensity generated by macroscopic objects should also be proportional to the angular momentum of the rotating mass field, that is, proportional to the mass and spin angular velocity of the object, and inversely proportional to the rotating radius of the mass field (the distance from the observation point to the center of mass of the object). Expressed as:
H = f mω/r = f 0 m / T r
(f 0 is a constant, t is the rotation period, and r is the radius of the rotating mass field)
According to this formula, the magnetic field intensity H measured on the earth's surface is only proportional to the mass of the core, the angular velocity ω is the difference between the rotational angular velocities of the crust and the core, and r is the radius of the earth (the geomagnetic field intensity is 5× 10-5 Tesla). The space magnetic field formed by the earth in space is directly proportional to the mass of the whole earth, directly proportional to the angular velocity of the earth's rotation (approximate value) and inversely proportional to the distance from the observation point to the center of the earth. Therefore, in the space near the earth, the space magnetic field formed by the earth is stronger than the surface. The biggest feature of the space magnetic field is that the magnetic pole is unchanged and will not reverse like the magnetic field on the earth's surface.
Due to the existence and high intensity of space magnetic field, a large number of charged particles in the solar wind deflect, resulting in aurora at the poles of the earth. At present, scientists have discovered the existence of "magnetosphere" and "radiation belt" in the outer space of the earth through artificial satellites. The magnetosphere is like an egg, with its head facing the sun, which is extremely asymmetrical under the action of the solar wind. On the side facing away from the sun, the distance from the center of the earth is only about 8- 1 1 radius of the earth, and on the side facing away from the sun, it extends far beyond the distance between the earth and the moon.
The earth is just an ordinary star in the solar system, so origin of the geomagnetic field's theory is also applicable to other celestial bodies in the solar system.
The moon, the earth's only natural satellite, used to be considered to have no magnetic field, but the moon rocks retrieved by Apollo astronauts showed that the moon once had a magnetic field and then mysteriously disappeared. As for the magnetic field of the moon, it can be explained that the moon once had a hot moon core, which rotated faster than the whole moon, thus forming the early magnetic field of the moon. Hundreds of millions of years later, with the loss of heat inside the moon, the inner core of the moon slowly solidified and merged with the outer shell of the moon. The rotation speed inside and outside the moon has tended to be consistent, and then the lunar magnetic field naturally disappears.
Mercury, similar to the moon, used to think that Mercury, a planet with slow rotation, had no magnetic field, so scientists were surprised when Mariner 10 detected Mercury's magnetic field. When the spacecraft flew to Mercury for the first time, it was detected that Mercury had a global magnetic field. During the flight, the spacecraft measured the magnetic field intensity in interplanetary space as 6× 10-9 Tesla. When it flies near Mercury, the magnetic field strength increases continuously, reaching 10-7 Tesla when it is closest to the surface of Mercury, which is about 1% of that of the Earth. When the spacecraft passed near the North Pole of Mercury for the third time,