LIPETSK STATE PEDAGOGICAL INSTITUTE

DEPARTMENT OF THEORETICAL AND GENERAL PHYSICS

Course work in physics.

DETERMINATION OF THE HORIZONTAL COMPONENT OF THE EARTH'S MAGNETIC FIELD.

Completed by a student of group FPO-3

Kazantsev N.N.

Head of the Associate Professor of the Department of Pacific Fleet

Gryzov Yu.V.

Lipetsk

2. A magnetic field.

A magnetic field is a special form of matter through which the interaction between moving electrically charged particles is carried out.

Basic properties magnetic field:

a magnetic field is generated by an electric current (moving charges).

A magnetic field is detected by the action on an electric current (moving charges).

The magnetic field was discovered in 1820 by the Danish physicist H.K. Oersted.

The magnetic field has a directional character and must be characterized by a vector value. This value is usually denoted by the letter V ... It would be logical by analogy with the electric field strength E to name V the strength of the magnetic field. However, for historical reasons, the main force characteristic of the magnetic field was called magnetic induction ... The name "magnetic field strength" was assigned to an auxiliary characteristic D electric field.

A magnetic field, unlike an electric one, does not affect a resting charge. Force arises only when the charge moves.

So, moving charges (currents) change the properties of the surrounding space - they create a magnetic field in it. This is manifested in the fact that forces are acting on the charges (currents) moving in it.

Experience gives. What is true for the magnetic, as well as for the electric superposition principle:

fieldV generated by several moving charges (currents) is equal to the vector sum of the fieldsB I generated by each charge (current) separately:

II. General characteristics of the earth's magnetic field.

The earth as a whole is a huge ball magnet. Humanity began to use the Earth's magnetic field a long time ago. Already at the beginning of the XII-XIII centuries. the compass is widely used in navigation. However, in those days it was believed that the compass needle was oriented by the North Star and its magnetism. The hypothesis of the existence of the Earth's magnetic field was first expressed in 1600 by the English naturalist Hilbert.

At any point in space surrounding the Earth, and on its surface, an action is found magnetic forces... In other words, a magnetic field is created in the space surrounding the Earth, the lines of force of which are shown in Fig. 1.

The magnetic and geographic poles of the Earth do not coincide with each other. Magnetic north pole N lies in the southern hemisphere, near the coast of Antarctica, and the south magnetic pole S is located in the Northern Hemisphere, near the northern coast of Victoria Island (Canada). Both poles are continuously moving (drifting) by earth surface at a rate of about 5 per year due to the variability of the processes generating the magnetic field. In addition, the axis of the magnetic field does not pass through the center of the Earth, but lags behind it by 430 km. The Earth's magnetic field is not symmetrical. Due to the fact that the axis of the magnetic field is only at an angle of 11.5 degrees to the axis of rotation of the planet, we can use a compass.

The main part of the Earth's magnetic field, according to modern views, is of intraterrestrial origin. The Earth's magnetic field is created by its core. The outer core of the Earth is liquid and metallic. Metal is a conductive substance, and if constant currents existed in the liquid core, then the corresponding electric current would create a magnetic field. Due to the rotation of the Earth, such currents exist in the core, because In some approximation, the Earth is a magnetic dipole, i.e. a kind of magnet with two poles: south and north.

An insignificant part of the magnetic field (about 1%) is of extraterrestrial origin. The origin of this part is attributed to electric currents flowing in the conducting layers of the ionosphere and the Earth's surface. This part of the Earth's magnetic field is subject to slight variation over time, which is called the secular variation. The reasons for the existence of electric currents in secular variation are unknown.

In an ideal and hypothetical assumption, in which the Earth would be alone in outer space, the lines of force of the planet's magnetic field were located in the same way as the lines of force of an ordinary magnet from a school physics textbook, i.e. in the form of symmetrical arcs stretching from the south pole to the north. The line density (magnetic field strength) would decrease with distance from the planet. In fact, the earth's magnetic field interacts with the magnetic fields of the sun, planets, and the streams of charged particles emitted in abundance by the sun. If the influence of the Sun itself and even more so of the planets can be neglected due to remoteness, then you cannot do this with particle fluxes, otherwise - with the solar wind. The solar wind is a stream of particles rushing at a speed of about 500 km / s, emitted by the solar atmosphere. In moments solar flares and also during the formation of a group of large sunspots on the Sun, the number of free electrons, which bombard the Earth's atmosphere, sharply increases. This leads to a disturbance of the currents flowing in the Earth's ionosphere and, due to this, a change in the Earth's magnetic field occurs. Arise magnetic storms... Such flows generate a strong magnetic field, which interacts with the Earth's field, strongly deforming it. Due to its magnetic field, the Earth holds captured particles of the solar wind in the so-called radiation belts, preventing them from passing into the Earth's atmosphere, and even more so to the surface. Particles of the solar wind would be very harmful to all living things. During the interaction of the above-mentioned fields, a boundary is formed, on one side of which there is a disturbed (subject to changes due to external influences) magnetic field of the solar wind particles, on the other side - the disturbed field of the Earth. This border should be considered as the limit of near-earth space, the border of the magnetosphere and the atmosphere. Outside this boundary, the influence of external magnetic fields prevails. In the direction towards the Sun, the Earth's magnetosphere is flattened under the onslaught of the solar wind and extends only up to 10 planetary radii. In the opposite direction, there is an elongation of up to 1000 Earth radii.

Most of the Earth's magnetic field detects anomalies in various regions of the earth's surface. These anomalies, apparently, should be attributed to the presence of ferromagnetic masses in the earth's crust or to the difference magnetic properties rocks... Therefore, the study of magnetic anomalies is of practical importance in the study of minerals.

The existence of a magnetic field at any point on the Earth can be established using a magnetic needle. If you hang the magnetic arrow NS on a thread l (Fig. 2) so that the suspension point coincides with the center of gravity of the arrow, then the arrow will be set in the direction of the tangent to the line of force of the Earth's magnetic field.

In the northern hemisphere - the southern end will be tilted towards the Earth and the arrow will be with the horizon inclination angleQ (at the magnetic equator, the inclination Q is zero). The vertical plane in which the arrow is located is called the plane of the magnetic meridian. All planes of magnetic meridians intersect in a straight line NS and traces magnetic meridians on the earth's surface converge at the magnetic poles N and S ... Since the magnetic poles do not coincide with the geographic poles, the arrow will be deflected from the geographic meridian. The angle that the vertical plane passing through the arrow (i.e. the magnetic meridian) forms with the geographic meridian is called magnetic declination a(fig. 2). Vector

fields of strength of the Earth's magnetic field can be decomposed into two components: horizontal and vertical (Fig. 3). The values ​​of the angles of inclination and declination, as well as the horizontal component, make it possible to determine the magnitude and direction of the total strength of the Earth's magnetic field at a given point. If the magnetic needle can freely rotate only around the vertical axis, then it will be installed under the action of the horizontal component of the Earth's magnetic field in the plane of the magnetic meridian. Horizontal component, magnetic declination a and inclination Q are called the elements of terrestrial magnetism. All elements of terrestrial magnetism change over time.

"The likelihood of a change in the Earth's magnetic poles in the near future. Investigation of the detailed physical reasons for this process.

Once I watched a popular science film on this issue, filmed 6-7 years ago.
It provided data on the appearance of an anomalous area in the southern part Atlantic Ocean- polarity reversal and weak tension. It seems like when satellites fly over this territory, they have to be turned off so that the electronics do not deteriorate.

And in time it seems like how this process should take place.It also spoke about the plans of the European Space Agency to launch a series of satellites in order to study in detail the strength of the Earth's magnetic field. Maybe the data of this study have already been published, if satellites were launched on this occasion? "

The Earth's magnetic poles are part of the magnetic (geomagnetic) field of our planet, which is generated by streams of molten iron and nickel that surround inner core Earth (in other words, turbulent convection in the Earth's outer core generates a geomagnetic field). The behavior of the Earth's magnetic field is explained by the flow of liquid metals at the border of the Earth's core with the mantle.

In 1600, the English scientist William Hilbert, in his book "On the Magnet, magnetic bodies and a big magnet - the Earth. " presented the Earth as a giant permanent magnet, the axis of which does not coincide with the axis of rotation of the Earth (the angle between these axes is called magnetic declination).

In 1702 E. Halley creates the first magnetic maps of the Earth. The main reason for the presence of the Earth's magnetic field is that the core of the Earth consists of red-hot iron (a good conductor of electrical currents that occur inside the Earth).

The Earth's magnetic field forms a magnetosphere extending 70-80 thousand km in the direction of the Sun. It shields the Earth's surface, protects against the harmful effects of charged particles, high energies and cosmic rays, and determines the nature of the weather.

Back in 1635, Gellibrand established that the earth's magnetic field was changing. Later it was found that there are permanent and short-term changes in the Earth's magnetic field.

The reason for the constant change is the presence of mineral deposits. There are areas on Earth where its own magnetic field is strongly distorted by the occurrence of iron ores. For example, the Kursk magnetic anomaly located in the Kursk region.

The reason for the short-term changes in the Earth's magnetic field is the action of the "solar wind", i.e. action of the flow of charged particles emitted by the sun. The magnetic field of this flow interacts with the magnetic field of the Earth, "magnetic storms" arise. The frequency and strength of magnetic storms is influenced by solar activity.

During the years of maximum solar activity (once every 11.5 years) such magnetic storms occur that radio communication is disrupted, and the arrows of compasses begin to "dance" unpredictably.

The result of the interaction of charged particles of the "solar wind" with the Earth's atmosphere in northern latitudes is such a phenomenon as the "polar lights".

The change of the Earth's magnetic poles (reversal of the magnetic field, English geomagnetic reversal) occurs every 11.5-12.5 thousand years. Other figures are also called - 13,000 years and even 500,000 years or more, and the last inversion occurred 780,000 years ago. Apparently, the polarity reversal of the Earth's Magnetic Field is a non-periodic phenomenon. Throughout geological history of our planet, the earth's magnetic field has changed its polarity more than 100 times.

The cycle of changing the poles of the Earth (associated with the planet Earth itself) can be attributed to global cycles (along with, for example, the cycle of fluctuations of the precession axis), influencing everything that happens on Earth ...

A legitimate question arises: when to expect a change in the Earth's magnetic poles (inversion of the planet's magnetic field), or a shift of the poles by a “critical” angle (according to some theories, to the equator)? ..

The process of displacement of magnetic poles has been recorded for over a century. The North and South magnetic poles (NMP and SMP) are constantly “migrating”, moving away from the geographic poles of the Earth (the angle of “error” is now about 8 degrees in latitude for the NSR and 27 degrees for the NMP). By the way, it was found that the geographic poles of the Earth also move: the axis of the planet deviates at a speed of about 10 cm per year.

The magnetic north pole was first discovered in 1831. In 1904, when scientists took measurements a second time, the pole was found to have moved 31 miles. The compass needle points to the magnetic pole, not the geographic. Research has shown that over the past thousand years, the magnetic pole has moved significant distances from Canada to Siberia, but sometimes in other directions.

The Earth's magnetic north pole is not sitting still. However, as well as to the south. The northern one “wandered” for a long time in Arctic Canada, but since the 70s of the last century its movement has taken on a clear direction. With a growing speed, now reaching 46 km per year, the pole rushed almost in a straight line into the Russian Arctic. According to the forecast of the Canadian Geomagnetic Survey, by 2050 it will be located in the Severnaya Zemlya archipelago.

An imminent change of the poles is indicated by the fact that the Earth's magnetic field is weakening near the poles, which was established in 2002 by the French professor of geophysics Gauthier Hulot. By the way, the Earth's magnetic field has weakened by almost 10% since it was first measured in the 30s of the 19th century. Fact: In 1989, the inhabitants of Quebec (Canada), as a result of the fact that solar winds broke through a weak magnetic shield and caused severe breakdowns in electrical networks, were left without light for 9 hours.

From school course physicists, we know that an electric current heats up the conductor through which it flows. In this case, the movement of charges will heat the ionosphere. The particles will penetrate into the neutral atmosphere, this will affect the wind system at an altitude of 200-400 km, and hence the climate as a whole. The displacement of the magnetic pole will also affect the operation of the technique. For example, in mid-latitudes during the summer months it will not be possible to use shortwave radio communications. The operation of satellite navigation systems will also be disrupted, since they use models of the ionosphere, which in the new conditions will be inapplicable. Geophysicists also warn that as the north magnetic pole approaches, induced induced currents in Russian power lines and power grids will rise.

However, all this may not happen. The magnetic north pole can change direction or stop at any moment, and this cannot be foreseen. And for South Pole there is no forecast at all for 2050. Until 1986, he moved very briskly, but then his speed dropped.

So, here are four facts that indicate an approaching or already begun reversal of the geomagnetic field:
1. Decrease in the intensity of the geomagnetic field over the past 2.5 thousand years;
2. Acceleration of the drop in field strength in recent decades;
3. Sharp acceleration of the displacement of the magnetic pole;
4. Features of the distribution of magnetic field lines, which becomes similar to the picture corresponding to the stage of preparation of the inversion.

There is a wide discussion about the possible consequences of the change of the geomagnetic poles. There are a variety of points of view, from quite optimistic to extremely disturbing. Optimists refer to the fact that hundreds of reversals have occurred in the geological history of the Earth, however, it was not possible to establish a connection between mass extinctions and natural disasters with these events. In addition, the biosphere has significant adaptability, and the inversion process can take quite a long time, so there is more than enough time to prepare for change.

The opposite point of view does not exclude the possibility that the inversion can occur during the life of the next generations and will turn out to be a disaster for human civilization. It must be said that this point of view has been largely compromised by a large number of unscientific and simply anti-scientific statements. As an example, we can cite the opinion that during the inversion, human brains will experience a reboot, similar to what happens with computers, and the information contained in them will be completely erased. Despite such statements, the optimistic point of view is very superficial.

The modern world is far from what it was hundreds of thousands of years ago: man gave rise to many problems that made this world fragile, easily vulnerable and extremely unstable. There is reason to believe that the consequences of the inversion will indeed be truly catastrophic for world civilization. And the complete loss of the working capacity of the World Wide Web due to the destruction of radio communication systems (and it will certainly come at the time of the loss of the radiation belts) is just one example of a global catastrophe. For example, due to the destruction of radio communication systems, all satellites will fail.

An interesting aspect of the impact of geomagnetic inversion on our planet, associated with a change in the configuration of the magnetosphere, is considered in his recent works by Professor V.P. Shcherbakov from the Borok Geophysical Observatory. In the normal state, due to the fact that the axis of the geomagnetic dipole is oriented approximately along the axis of rotation of the Earth, the magnetosphere serves as an effective shield for high-energy streams of charged particles moving from the Sun. In the case of inversion, a situation is quite likely when a funnel is formed in the frontal sunflower part of the magnetosphere in the region of low latitudes, through which the solar plasma can reach the Earth's surface. Due to the rotation of the Earth in each specific location low and partly temperate latitudes, this situation will be repeated every day for several hours. That is, a significant part of the planet's surface will experience a strong radiation impact every 24 hours.

However, NASA scientists suspect the fallacy of the statement that the pole reversal could briefly deprive the Earth of the magnetic field that protects us from solar flares and other cosmic hazards. However, the magnetic field can weaken or increase over time, but there is no indication that it can completely disappear. The weaker field will certainly result in a slight increase in solar radiation on Earth, as well as the observation of beautiful auroras at lower latitudes. But nothing fatal will happen, but dense atmosphere perfectly protects the Earth from dangerous solar particles.

Science proves that pole reversal - from the point of view of the geological history of the Earth - is a common phenomenon that occurs gradually over millennia.

The geographic poles are also constantly shifting along the surface of the Earth. But these displacements are slow and natural. The axis of our planet, rotating like a top, describes a cone around the pole of the ecliptic with a period of about 26 thousand years, in accordance with the migration of the geographic poles, gradual climatic changes also occur. They are mainly caused by displacement. ocean currents transferring heat to the continents. Another thing is unexpected, sharp "somersaults" of the poles. But the rotating Earth is a gyroscope with a very impressive intrinsic angular momentum, in other words, it is an inertial object. resisting attempts to change the characteristics of his movement. A sudden change in the inclination of the Earth's axis and even more so its "somersault" cannot be caused by internal slow movements of magma or gravitational interaction with any passing cosmic body.

Such an overturning moment can occur only with a tangential impact of an asteroid no less than 1000 kilometers in diameter, approaching the Earth at a speed of 100 km / sec. A more real threat to the life of mankind and the entire living world of the Earth is a change in geomagnetic poles. The magnetic field of our planet, which is observed today, is very similar to that which would be created by a giant bar magnet located in the center of the Earth, oriented along the north-south line. More precisely, it should be installed so that its magnetic North Pole is directed to the Geographic South Pole, and the Magnetic South Pole to the Geographic North Pole.

However, this situation is not permanent. Research over the past four hundred years has shown that magnetic poles revolve around their geographic counterparts, shifting by about twelve degrees every century. This value corresponds to the velocities of currents in the upper core at ten to thirty kilometers per year. In addition to the gradual shifts of the magnetic poles approximately every five hundred thousand years, the earth's magnetic poles change places. The study of the paleomagnetic characteristics of rocks of different ages allowed scientists to conclude that the time of such reversals of magnetic poles took at least five thousand years. A complete surprise for scientists studying life on Earth was the results of an analysis of the magnetic properties of a lava flow about a kilometer thick, which poured out 16.2 million years ago and was recently found in the eastern Oregon desert.

Her research, led by Rob Coey of the University of California at Santa Cruz and Michel Privota of the University of Montpelier, made a splash in geophysics. The obtained results of the magnetic properties of the volcanic rock objectively showed that the lower layer solidified at one position of the pole, the core of the flow - when the pole moved, and, finally, the upper layer - at the opposite pole. And all this happened in thirteen days. The Oregon find suggests that Earth's magnetic poles may not be swapping over the course of several thousand years, but as little as two weeks. Last time it happened about seven hundred and eighty thousand years ago. But how can this threaten all of us? Now the magnetosphere envelops the Earth at an altitude of sixty thousand kilometers and serves as a kind of shield in the path of the solar wind. If a change of poles occurs, then the magnetic field during the inversion will decrease by 80-90%. Such a drastic change will surely affect various technical devices, animal world and, of course, per person.

True, the inhabitants of the Earth should be somewhat reassured by the fact that during the change of the Sun's poles, which occurred in March 2001, the disappearance of the magnetic field was not recorded.

Consequently, the complete disappearance of the protective layer of the Earth, most likely, will not happen. Magnetic pole reversal cannot be a global catastrophe. The very existence of life on Earth, which has repeatedly experienced an inversion, confirms this, although the absence of a magnetic field is an unfavorable factor for the animal world. This was clearly demonstrated by the experiments of American scientists, who built two experimental chambers back in the sixties. One of them was surrounded by a powerful metal shield, which reduced the strength of the earth's magnetic field hundreds of times. In another chamber, earthly conditions were preserved. They contained mice and seeds of clover and wheat. Several months later, it turned out that the mice in the shielded chamber lost their hair faster and died earlier than the control ones. Their skin was thicker than that of the other group. And she, swelling, forced out the root hair follicles, which caused early baldness. The plants in the non-magnetic chamber also showed changes.

It will be difficult for those representatives of the animal kingdom, for example, migratory birds, who have a kind of built-in compass and use magnetic poles for orientation. But, judging by the deposits, mass extinction of species during the inversion of the magnetic poles did not occur before. Apparently, it will not happen in the future either. Indeed, even despite the tremendous speed of movement of the poles, the birds cannot keep up with them. Moreover, many animals, such as bees, are guided by the Sun, and marine migratory animals use more of the magnetic field of rocks on the ocean floor than the global one. Navigation systems, communication systems created by people, will undergo serious tests that can disable them. Numerous compasses will have a very bad time - they will simply have to be thrown away. But with a change of poles, there can be "positive" effects - huge aurora borealis will be observed all over the Earth - albeit for only two weeks.

Well, now a few theories of the mysteries of civilizations :-) Someone takes this seriously ...

According to another hypothesis, we live in a unique time: there is a change of poles on Earth and a quantum transition of our planet to its twin located in parallel world four-dimensional space. Higher civilizations(CC) to reduce the consequences of a planetary catastrophe, this transition is carried out smoothly in order to create favorable conditions for the emergence of a new branch of the Supercivilization of God-manhood. Representatives of the Computing Center believe that the old branch of Humanity is not intelligent, since it could have destroyed all life on the planet at least five times over the past decades, if not for the timely intervention of the Computing Center.

There is no consensus among scientists today as to how long the pole reversal process can take. According to one version, this will take several thousand years, during which the Earth will be defenseless against solar radiation. On the other hand, the change of poles will take only a few weeks. But the date of the Apocalypse, according to some scientists, tells us the ancient peoples of the Maya and Atlanteans - 2050.

In 1996, the American popularizer of science S. Runcorn made the conclusion that the rotation axis moved more than once in the geological history of the Earth along with the magnetic field. He suggests that the last geomagnetic reversal occurred around 10,450 BC. NS. It is about this that the Atlanteans who survived the flood told us, sending their message to the future. They knew about the regular periodic reversal of the polarity of the Earth's poles approximately every 12,500 years. If by 10450 BC. NS. add 12,500 years, then again we get 2050 AD. NS. - the year of the next giant natural disaster... This date was calculated by experts in the course of solving the location in the Nile Valley of the three Egyptian pyramids - Cheops, Khafren and Mikerin.

Russian scientists believe that the wisest Atlanteans brought us to the knowledge of the periodic change in the polarity of the Earth's poles through knowledge of the laws of precession, which are inherent in the location of these three pyramids. The Atlanteans, apparently, were completely sure that someday in the distant future for them, a new highly developed civilization would appear on Earth, and its representatives would rediscover the precessional laws.

According to one hypothesis, it was the Atlanteans who most likely led the construction of the three largest pyramids in the Nile Valley. All of them are built at 30 degrees north latitude and are oriented to the cardinal points. Each face of the structure faces north, south, west, or east. No other structure on Earth is known that would be as accurately oriented to the cardinal directions with an error of only 0.015 degrees. Since the ancient builders achieved their goal, it means that they had the appropriate qualifications, knowledge, first-class equipment and instruments.

Let's go further. The pyramids are set to the cardinal points with a deviation of three minutes and six seconds from the meridian. And the numbers 30 and 36 are the signs of the precessional code! 30 degrees of the celestial horizon correspond to one sign of the zodiac, 36 - the number of years for which the picture of the sky is shifted by half a degree.

Scientists also established certain patterns and coincidences associated with the size of the pyramid, the angles of inclination of their inner galleries, the angle of increase of the spiral staircase of the DNA molecule, a twisted spiral, etc., etc. Therefore, scientists decided, Atlanteans were all available to them methods pointed to us on a strictly defined date, which coincided with an extremely rare astronomical phenomenon. It is repeated once every 25,921 years. At that moment, the three stars of Orion's Belt were in their lowest precessional position above the horizon line on the day of the vernal equinox. This is a biot in 10,450 BC. NS. This is how the ancient sages strenuously led mankind to this date through mythological codes, through a map of a section of the starry sky, drawn in the Nile Valley with the help of three pyramids.

And in 1993, the Belgian scientist R. Bewell used the laws of precession. Through computer analysis, he revealed that the three largest Egyptian pyramids installed on the ground in the same way as the three stars of Orion's Belt were located in the sky in 10 450 BC. e., when they were at the bottom, that is, the starting point of their precessional movement across the sky.

Modern geomagnetic studies have shown that around 10450 BC. NS. there was an instantaneous change in the polarity of the Earth's poles and the eye was displaced by 30 degrees relative to its axis of rotation. As a result, a planetary global instantaneous cataclysm occurred. Geomagnetic studies carried out in the late 1980s by American, British and Japanese scientists have shown something else. These nightmarish cataclysms have constantly occurred in the geological history of the Earth with a regularity of about 12,500 years! It was they, obviously, who killed the dinosaurs, mammoths, and Atlantis.

Survivors of the previous flood in 10,450 BC NS. and the Atlanteans who sent us their message through the pyramids hoped that a new highly developed civilization would appear on Earth long before the total horror and the end of the world. And maybe he will have time to prepare to meet the disaster fully armed. According to one of the hypotheses, their science failed to make a discovery about the obligatory "somersault" of the planet by 30 degrees at the moment of polarity reversal. As a result, all continents of the Earth shifted exactly by 30 degrees and Atlantis found itself at the South Pole. And then its entire population instantly froze, as mammoths instantly froze at the same moment on the other side of the planet. Only those representatives of the highly developed Atlantic civilization survived who were at that time on other continents of the planet in the highlands. They were lucky enough to escape the Flood. And so they decided to warn us, people of a distant future for them, that each change of poles is accompanied by a "somersault" of the planet and irreparable consequences.

In 1995, new additional studies were carried out with the help of modern instruments, created specifically for research of this kind. Scientists managed to make the most important clarification in the forecast of the upcoming change in polarity of the poles and more accurately designate the date of the terrible event - 2030.

American scientist G. Hancock calls the date of the universal end of the world even closer - 2012. He bases his hypothesis on one of the calendars of the South American civilization of the Maya Indians. According to the scientist, the calendar may have been inherited by the Indians from the Atlanteans.

So, according to the Mayan Long Count, our world is cyclically created and destroyed with a period of 13 baktuns (or approximately 5120 years). The current cycle began on August 11, 3113 BC. NS. (0.0.0.0.0) and will end on December 21, 2012. NS. (13.0.0.0.0). The Maya believed that the end of the world would come on this day. And after that, according to them, there will be the beginning of a new cycle and the beginning of a new World.

According to other paleomagnetologists, the change in magnetic poles Earth will happen exactly. But not in the common sense - tomorrow, the day after tomorrow. Some researchers say one thousand years, others - two thousand. Then the End of the World, the Last Judgment, the Great Flood, which is described in the Apocalypse, will come.

But humanity was already predicted the end of the world in 2000. But life still goes on - and it is beautiful!

sources
http://2012god.ru/forum/forum-37/topic-338/page-1/
http://www.planet-x.net.ua/earth/earth_priroda_polusa.html
http://paranormal-news.ru/news/2008-11-01-991
http://kosmosnov.blogspot.ru/2011/12/blog-post_07.html
http://kopilka-erudita.ru

V the last days appeared on scientific information sites a large number of news on the Earth's magnetic field. For example, the news that recently it has changed significantly, or that the magnetic field contributes to the leakage of oxygen from the earth's atmosphere, and even that cows are oriented along the lines of the magnetic field on pastures. What is a magnetic field and how important are all of the above news?

The Earth's magnetic field is the area around our planet where magnetic forces operate. The question of the origin of the magnetic field has not yet been finally resolved. However, most researchers agree that the presence of a magnetic field, the Earth is at least partly due to its core. The core of the earth is composed of a solid inner and liquid outer parts. The rotation of the Earth creates constant currents in the liquid core. As the reader may remember from physics lessons, the movement of electric charges creates a magnetic field around them.

One of the most widespread theories explaining the nature of the field - the theory of the dynamo effect - suggests that convective or turbulent motions of a conducting fluid in the core contribute to self-excitation and maintenance of the field in a stationary state.

The earth can be thought of as a magnetic dipole. Its south pole is located at the geographic North Pole, and the north, respectively, at the South. In fact, the geographic and magnetic poles of the Earth do not coincide not only in "direction". The axis of the magnetic field is tilted with respect to the axis of rotation of the Earth by 11.6 degrees. Due to the fact that the difference is not very significant, we can use a compass. Its arrow points exactly to the south magnetic pole of the earth and almost exactly to the north geographic one. If the compass were invented 720 thousand years ago, then it would point to both the geographic and magnetic north poles. But more on that below.

The magnetic field protects the inhabitants of the Earth and artificial satellites from the destructive effects of cosmic particles. Such particles include, for example, ionized (charged) particles of the solar wind. The magnetic field changes their trajectory, directing the particles along the lines of the field. The need for a magnetic field for the existence of life narrows the circle of potentially habitable planets (if we proceed from the assumption that hypothetically possible forms lives are like earthly inhabitants).

Scientists do not exclude that some of the terrestrial planets do not have a metal core and, accordingly, are devoid of a magnetic field. Until now, it was believed that rocky planets, like the Earth, contain three main layers: a hard crust, a viscous mantle, and a solid or molten iron core. In a recent work, scientists from Massachusetts Institute of Technology suggested the formation of "rocky" planets without a core. If the theoretical calculations of the researchers are confirmed by observations, then to calculate the probability of meeting humanoids in the Universe, or at least something resembling illustrations from a biology textbook, will have to be rewritten.

Earthlings can also lose their magnetic shielding. True, geophysicists cannot yet say exactly when this will happen. The fact is that the earth's magnetic poles are unstable. They change places periodically. Not so long ago, researchers found that the Earth "remembers" about the change of the poles. Analysis of these "memories" showed that over the past 160 million years, magnetic north and south have changed places about 100 times. The last time this event happened was about 720 thousand years ago.

The change of poles is accompanied by a change in the configuration of the magnetic field. During the "transition period", substantially more cosmic particles that are dangerous to living organisms penetrate the Earth. One of the hypotheses explaining the extinction of dinosaurs claims that the giant reptiles became extinct precisely during the next pole change.

In addition to the "traces" of planned measures to change the poles, the researchers noticed dangerous shifts in the Earth's magnetic field. Analysis of data on its condition over several years showed that in recent months it began to occur. Scientists have not registered such sharp "movements" of the field for a very long time. The area of ​​concern to researchers is in the South Atlantic Ocean. The "thickness" of the magnetic field in this region does not exceed a third of the "normal" one. Researchers have long noticed this "hole" in the Earth's magnetic field. Data collected over 150 years show that during this period the field has weakened by ten percent.

At the moment it is difficult to say how this threatens humanity. One of the consequences of a weakening of the field strength may be an increase (albeit insignificant) in the oxygen content in the earth's atmosphere. The link between the Earth's magnetic field and this gas was established using the Cluster satellite system, a project of the European Space Agency. Scientists have found that the magnetic field accelerates oxygen ions and "throws" them into space.

Despite the fact that the magnetic field cannot be seen, the inhabitants of the Earth feel it well. Migratory birds, for example, find their way, focusing on it. There are several hypotheses that explain exactly how they perceive the field. One of the latter suggests that birds perceive a magnetic field. Special proteins - cryptochromes - in the eyes of migratory birds are able to change their position under the influence of a magnetic field. The authors of the theory believe that cryptochromes can act as a compass.

In addition to birds, sea turtles use the Earth's magnetic field instead of GPS. And, as the analysis of satellite photographs presented in the framework of the Google Earth project has shown, cows. After examining photographs of 8510 cows in 308 regions of the world, scientists concluded that these animals are preferable (or from south to north). Moreover, the "reference points" for cows are not geographical, but the magnetic poles of the Earth. The mechanism of cows' perception of the magnetic field and the reasons for this very reaction to it remain unclear.

In addition to the listed remarkable properties, the magnetic field contributes. They arise as a result of abrupt field changes occurring in remote regions of the field.

The magnetic field was not ignored by the supporters of one of the "conspiracy theories" - the theory of the lunar hoax. As mentioned above, the magnetic field protects us from cosmic particles. The "collected" particles accumulate in certain parts of the field - the so-called Van Allen radiation belts. Skeptics who do not believe in the reality of landing on the moon believe that during the flight through the radiation belts, astronauts would receive a lethal dose of radiation.

The Earth's magnetic field is an amazing consequence of the laws of physics, a protective shield, a landmark and creator of the aurora borealis. If not for it, life on Earth might have looked very different. In general, if there was no magnetic field, it would have to be invented.

CHAPTER 2

EARTH'S MAGNETIC FIELD,

ITS CHANGES IN SPACE AND TIME

Earth's magnetic field

The space where the action of the earth's magnetic forces is detected is called the magnetic field. In a first approximation, the Earth's magnetic field can be considered as the field of a ball, magnetized along an axis located at an angle of 11.5 0 to the Earth's axis of rotation. The earth's magnetic moment is 8.3 10 22 Am 2. A complex picture of the distribution of the geomagnetic field in the first approximation can be represented by the field of a dipole (eccentric, with an offset from the center of the Earth by approximately 436 km). The lines of force of the dipole emerge from the South Pole and enter the North Pole, forming loops closed at distances of up to ten Earth radii (Fig. 2.1).

Rice. 2.1. Lines of force uniformly magnetized the globe

Geomagnetic poles (poles of a uniformly magnetized sphere) and magnetic poles, respectively, set a system of geomagnetic coordinates (geomagnetic latitude, geomagnetic meridian, geomagnetic equator).

Planet Earth is constantly in the flow of the solar wind, which is formed during the gas-dynamic expansion of the solar corona in interplanetary space under the influence of high temperatures. The solar wind, which is a continuous stream of plasma, is composed primarily of protons and electrons that propagate radially. Measurements carried out on satellites and rockets have shown that the interaction of the solar wind plasma with the geomagnetic field leads to a violation of the dipole structure of the field from a distance of 3R s from the center of the Earth. The solar wind localizes the geomagnetic field in a limited volume of near-earth space, "freezes" the magnetic field into the plasma. Colliding with the geomagnetic field, the solar wind bends around it, forming a comet-like cavity in which the movement of charged particles is controlled by the Earth's magnetic field.

The cavity, inaccessible for the penetration of the solar wind, was called the Earth's magnetosphere. The configuration of the magnetosphere and the spatial distribution of plasma, fields and currents in it are schematically shown in Fig. 2.2 / 18 /. The outer boundary of the magnetosphere is called the magnetopause. At the magnetopause of the magnetosphere, the dynamic pressure of the solar wind is balanced by the pressure of the Earth's magnetic field. The solar wind compresses the earth's magnetic field from the daytime side and carries the geomagnetic field lines of the polar regions to the night side, forming a magnetic tail of the Earth with a length of at least 5 million km near the ecliptic plane.

With typical parameters of the solar wind, the distance to the subsolar point of the magnetopause is 10 R s. In rare cases, when the solar wind pressure drops to almost zero, the frontal point of the magnetopause shifts far to the sun and the magnetic field becomes dipole up to very large distances.

The lines of force of the magnetic field on the daytime side are compressed by the pressure of the solar wind and are closed. In the vicinity of the frontal point at the magnetopause, the lines of force of the interplanetary magnetic field can be connected to the lines of force of the Earth's magnetic field, emerging from the polar regions. This process, called reconnection, is carried away by the solar wind to the night side, reducing the magnetic flux on the day side.

Figure 2.2. Schematic model of the magnetosphere

On the night side, the lines of force of the magnetic field stretch in the anti-solar direction, forming the tail of the magnetosphere. The field in the northern lobe of the tail is directed towards the Sun, in the southern lobe in the opposite direction. A pronounced neutral layer is formed between the lobes, which is immersed in a plasma layer filled with a rarefied plasma. The boundary between closed and open lines of force is projected into emergency ovals, areas where auroras are most often observed.

On the part of the magnetopause facing the Sun, in the region of the magnetic poles, neutral points are located, around which there are funnel-shaped regions of a weak magnetic field, called polar cusps. Caspians are projected onto magnetic latitudes of the order of 70-80 o and are "windows" to the solar wind.

The sizes of these regions of the magnetopause are small, and particles of the solar wind plasma can penetrate almost unhindered along the lines of force into the ionosphere. Unlike other regions, the cusps are areas where the ionosphere is exposed; therefore, here, first of all, collisions of the magnetosphere with discontinuities and wave fronts in the solar wind occur.

More than 90% of the volume of the magnetosphere is connected by magnetic field lines with the polar ionosphere, which is located at geomagnetic latitudes above 60 o. Here, at high latitudes, where the lines of force are almost perpendicular to the Earth's surface, the effects of precipitation of charged particles from the magnetosphere are manifested. The penetration depth of particles and the processes of their deceleration depend on the energy of the particles. Electrons penetrate to an altitude of 100-70 km, causing ionization of the upper atmosphere and x-ray... Avral luminescence, the so-called polar lights, are a colorful manifestation of complex processes taking place at great distances in the Earth's magnetosphere / 20 /.

When a solar plasma flow collides with the Earth's magnetic field, a shock wave propagating towards the flow is formed, the front of which from the Sun is on average localized at a distance of 13-14 Earth radii. The shock front is followed by a transition region 20 thousand km thick, where the magnetic field of the solar plasma becomes disordered, and the movement of its particles becomes chaotic. The transition zone is the boundary of the magnetosphere, which is called the magnetopause; it is located from the Sun at a distance of 10 - 12 Earth radii. The streams of solar plasma particles flow around the magnetosphere and sharply distort the structure of its magnetic field at a considerable distance.

Approximately up to a distance of 3R 3, the magnetic field is located close enough to the field of the magnetic dipole, the strength of this magnetic field decreases with a height of 1 / R h. Further, the magnetic field weakens more slowly than the field of the dipole, and its lines of force from the solar side are pressed against the Earth. The lines of the geomagnetic field emerging from the polar regions of the Earth are deflected by the solar wind to the night side of the Earth. There they form a "tail" or "plume" of the magnetosphere with a length of more than 5 million km. Beams of magnetic field lines of the opposite direction are separated in the tail by an area of ​​a very weak magnetic field (neutral layer), where hot plasma with a temperature of millions of degrees is concentrated.

Particles of the plasma tail of the planet fall into the nighttime part along the outgoing lines of force of the magnetosphere. It is these particles that cause the auroras. The zone of their manifestation is a narrow oval strip. The center of the oval is shifted to the night side relative to the geomagnetic pole. The earth turns about this oval in its diurnal movement. The size and position of the auroral oval are determined by the position and configuration of the magnetosphere and depend on solar activity. During periods of greatest solar activity, the auroral oval descends to lower latitudes.

In 1905, Einstein named the cause of terrestrial magnetism as one of the five main mysteries of the then physics.

At the beginning of the 20th century, the very fact of the existence of the geomagnetic field defied explanation (despite the fact that its most paradoxical feature was simply not suspected at that time). It was known that the magnetic poles move a little along the earth's surface, but no one imagined that they were capable of more radical behavior - this discovery was only on the way

In the same 1905, the French geophysicist Bernard Brunes measured the magnetism of Pleistocene lava deposits in the southern department of Cantal. The vector of magnetization of these rocks was almost 180 degrees with the vector of the planetary magnetic field (his compatriot P. David obtained similar results even a year earlier). Brunes concluded that three quarters of a million years ago, during the outpouring of lava, the direction of the geomagnetic field lines was opposite to the current one. This is how the effect of inversion (polarity reversal) of the Earth's magnetic field was discovered. In the second half of the 1920s, Brunhes' conclusions were confirmed by P.L. Mercanton and Monotori Matuyama, but these ideas did not gain acceptance until the middle of the century.

Now we know that the geomagnetic field has existed for at least 3.5 billion years, and during this time the magnetic poles have exchanged places thousands of times (Brunes and Matuyama investigated the most recent inversion, which now bears their names). Sometimes the geomagnetic field retains its orientation for tens of millions of years, and sometimes for no more than five hundred centuries. The inversion process itself usually takes several millennia, and after its completion, the field strength, as a rule, does not return to its previous value, but changes by several percent.

At the beginning of the 20th century, the very fact of the existence of the geomagnetic field defied explanation (despite the fact that its most paradoxical feature was simply not suspected at that time). It was known that the magnetic poles move slightly along the earth's surface, but no one assumed that they were capable of more radical behavior - this discovery was only on the way.

The mechanism of geomagnetic reversal is not entirely clear even now, and even a hundred years ago it did not admit of a reasonable explanation at all. Therefore, the discoveries of Brunes and David only reinforced Einstein's assessment - indeed, terrestrial magnetism was extremely mysterious and incomprehensible. But by that time it had been studied for over three hundred years, and in the 19th century such stars of European science as the great traveler Alexander von Humboldt, the brilliant mathematician Karl Friedrich Gauss and the brilliant experimental physicist Wilhelm Weber were studying it. So Einstein truly looked at the root.

168 magnetic poles

How many magnetic poles do you think our planet has? Almost everyone will say that two are in the Arctic and Antarctic. In fact, the answer depends on the definition of the concept of a pole. Geographic poles are the points of intersection of the earth's axis with the surface of the planet. As the earth spins like solid, there are only two such points and nothing else can be invented. But with magnetic poles, the situation is much more complicated. For example, a pole can be considered a small area (ideally, again a point) where the magnetic lines of force are perpendicular to the earth's surface. However, any magnetometer registers not only the planetary magnetic field, but also the fields of local rocks, electric currents of the ionosphere, solar wind particles and other additional sources of magnetism (and their average fraction is not so small, of the order of several percent). The more accurate the device, the better it does it - and therefore more and more complicates the selection of the true geomagnetic field (it is called the main one), the source of which is located in the depths of the earth. Therefore, the coordinates of the pole, determined by direct measurement, are not stable even for a short period of time.

Poles in reverse

Many people know that the generally accepted names of the poles are correct exactly the opposite. There is a pole in the Arctic, which is indicated by the northern end of the magnetic needle - therefore, it should be considered the southern one (the poles of the same name repel, the opposite ones attract!). Likewise, the magnetic north pole is based at the high latitudes of the southern hemisphere. However, traditionally we name the poles according to geography. Physicists have long agreed that the lines of force go out from the north pole of any magnet and enter the south one. From this it follows that the lines of terrestrial magnetism leave the south geomagnetic pole and contract towards the north. This is a convention, and you shouldn't violate it (it's time to recall Panikovsky's sad experience!).

You can act differently and establish the position of the pole on the basis of certain models of terrestrial magnetism. To a first approximation, our planet can be considered a geocentric magnetic dipole, the axis of which passes through its center. Currently, the angle between her and earth axis is 10 degrees (a few decades ago it was more than 11 degrees). With a more accurate simulation, it turns out that the dipole axis is offset from the center of the Earth in the direction of the northwestern Pacific Ocean by about 540 km (this is an eccentric dipole). There are other definitions as well.

But that is not all. The earth's magnetic field really does not have dipole symmetry and therefore has multiple poles, and in huge numbers. If the Earth is considered a magnetic quadrupole, a quadrupole, two more poles will have to be introduced - in Malaysia and in the South Atlantic Ocean. The octupole model sets the eight poles, etc. The modern most advanced models of terrestrial magnetism operate as many as 168 poles. It should be noted that during the inversion only the dipole component of the geomagnetic field temporarily disappears, while the others change much weaker.

The magnetic pole, no matter how you define it, does not stand still. North Pole of the geocentric dipole in 2000 had coordinates 79.5 N and 71.6 W, and in 2010 - 80.0 N and 72.0 W. The true North Pole (the one that is revealed by physical measurements) since 2000 has shifted from 81 , 0 N and 109.7 W to 85.2 N and 127.1 W. During almost the entire twentieth century, he did not more than 10 km a year, but after 1980 he suddenly began to move much faster. In the early 1990s, its speed exceeded 15 km per year and continues to grow.

The result of computer simulation of the geomagnetic field inversion in the Roberts and Glatzmeier model at intervals of tens and hundreds of thousands of years.

As told "Popular Mechanics" former leader Lawrence Newitt, Geomagnetic Laboratory of the Canadian Geological Survey, the true pole is now migrating to the northwest, moving 50 km annually. If the vector of its movement does not change for several decades, then by the middle of the XXI century it will be in Siberia. According to the reconstruction carried out several years ago by the same Newitt, in the XVII and XVIII centuries the north magnetic pole was mainly displaced to the southeast and only in about 1860 turned to the northwest. The true south magnetic pole has been moving in the same direction for the last 300 years, and its average annual displacement does not exceed 10-15 km.

Iron dynamo

Where does the Earth have a magnetic field at all? One possible explanation is simply striking. The earth has an inner solid iron-nickel core with a radius of 1220 km. Since these metals are ferromagnetic, why not assume that the inner core has static magnetization, which ensures the existence of the geomagnetic field? The multipolarity of terrestrial magnetism can be attributed to the asymmetry of the distribution of magnetic domains inside the core. Pole migration and geomagnetic reversals are more difficult to explain, but you can probably try.

However, nothing comes of it. All ferromagnets remain as such (that is, retain spontaneous magnetization) only below a certain temperature - the Curie point. For iron, it is 768 ° C (much lower for nickel), and the temperature of the Earth's inner core is well above 5000 degrees. Therefore, we have to part with the hypothesis of static geomagnetism. However, it is possible that there are cooled planets with ferromagnetic cores in space.

Consider another possibility. Our planet also has a liquid outer core approximately 2,300 km thick. It consists of a melt of iron and nickel with an admixture of lighter elements (sulfur, carbon, oxygen and, possibly, radioactive potassium - no one knows for sure). The temperature of the lower part of the outer core almost coincides with the temperature of the inner core, while in the upper zone at the border with the mantle it drops to 4400 ° C. Therefore, it is quite natural to assume that due to the rotation of the Earth, circular currents are formed there, which may be the cause of the emergence of terrestrial magnetism.

This is the scheme that geophysicists discussed about 80 years ago. They believed that the flows of the conducting fluid of the outer core, due to their kinetic energy, generate electric currents covering earth axis... These currents generate a magnetic field, predominantly of a dipole type, whose lines of force on the Earth's surface are elongated along the meridians (such a field is called poloidal). This mechanism is associated with the operation of a dynamo, hence its name.

The described scheme is beautiful and clear, but, unfortunately, it is erroneous. It is based on the assumption that the movement of matter in the outer core is symmetrical about the earth's axis. However, in 1933, the English mathematician Thomas Cowling proved the theorem, according to which no axisymmetric flows are capable of ensuring the existence of a long-term geomagnetic field. Even if it does appear, then its age will be short-lived, tens of thousands of times less than the age of our planet. We need a more complex model.

All power is in convection

“We don't know exactly when terrestrial magnetism arose, but it could have happened shortly after the formation of the mantle and outer core,” says one of the largest experts in planetary magnetism, professor at California Institute of Technology David Stevenson. - To turn on the geodynamo requires an external seed field, and not necessarily a powerful one. This role, for example, could be assumed by the magnetic field of the Sun or the field of currents generated in the core due to the thermoelectric effect. Ultimately, this is not too important, there were enough sources of magnetism. In the presence of such a field and circular motion of conductive fluid flows, the launch of an intraplanetary dynamo became simply inevitable. "

The aurora is generated by the interaction of the atmosphere and charged particles captured by the Earth's magnetic field, which is perpendicular to the surface in the polar regions.

Here is the generally accepted explanation for this launch. For simplicity, let the seed field be almost parallel to the Earth's axis of rotation (in fact, it is sufficient if it has a nonzero component in this direction, which is practically inevitable). The speed of rotation of the substance of the outer core decreases with decreasing depth, and because of its high electrical conductivity, the lines of force of the magnetic field move with it - as physicists say, the field is "frozen" into the medium. Therefore, the lines of force of the seed field will bend, going forward at great depths and lagging behind at smaller ones. Eventually they will stretch and deform enough to give rise to a toroidal field, circular magnetic loops that sweep the earth's axis and head in opposite directions in the northern and southern hemispheres. This mechanism is called the w-effect.

According to Professor Stevenson, it is very important to understand that the toroidal field of the outer core arose due to the poloidal seed field and, in turn, generated a new poloidal field observed near the earth's surface: "Both types of fields of the planetary geodynamo are interconnected and cannot exist without each other." ...

Magnetic shielding

Terrestrial magnetism is monitored using an extensive network of geomagnetic observatories, the creation of which began in the 1830s. For the same purposes, ship, aviation and space instruments are used (for example, scalar and vector magnetometers of the Danish satellite "Oersted", operating since 1999). The strength of the geomagnetic field ranges from about 20,000 nanotesla off the coast of Brazil to 65,000 nanotesla at the South Magnetic Pole. Since 1800, its dipole component has decreased by almost 13% (and since the mid-16th century - by 20%), while the quadrupole has slightly increased. Paleomagnetic studies show that for several millennia before the beginning of our era, the strength of the geomagnetic field steadily climbed up, and then began to decline. Nevertheless, the current planetary dipole moment is significantly higher than its average value over the past one and a half hundred million years (in 2010, the results of paleomagnetic measurements were published, indicating that three and a half billion years ago, the earth's magnetic field was twice weaker than the current one). This means that the entire history of human societies from the emergence of the first states to our time fell on the local maximum of the earth's magnetic field. It is interesting to think about whether this influenced the progress of civilization. This assumption ceases to seem fantastic if we consider that the magnetic field protects the biosphere from cosmic radiation. And here's another thing worth noting. In youth and even in adolescence of our planet, all the substance of its core was in a liquid phase. The solid inner core was formed relatively recently, perhaps only a billion years ago. When this happened, the convection currents became more orderly, which led to a more stable geodynamo operation. Because of this, the geomagnetic field has gained in size and stability. It can be assumed that this circumstance had a favorable effect on the evolution of living organisms. In particular, the strengthening of geomagnetism improved the protection of the biosphere from cosmic radiation and thereby facilitated the escape of life from the ocean to land.

Unpredictable magnetism

15 years ago, Gary Glatzmeier, together with Paul Roberts, published a very beautiful computer model of the geomagnetic field: “In principle, there has long been an adequate mathematical apparatus to explain geomagnetism - the equations of magnetohydrodynamics plus equations describing the force of gravity and heat fluxes inside the earth's core. The models based on these equations are very complex in their original form, but they can be simplified and adapted for computer calculations. This is exactly what Roberts and I did. A run on a supercomputer made it possible to construct a self-consistent description of the long-term evolution of the velocity, temperature, and pressure of flows of matter in the outer core and the associated evolution of magnetic fields. We also found out that if the simulation is played over time intervals of the order of tens and hundreds of thousands of years, then inversions of the geomagnetic field inevitably occur. So in this respect, our model does a good job of conveying the magnetic history of the planet. However, there is a difficulty that has not yet been resolved. The parameters of the substance of the outer core, which are laid in such models, are still too far from real conditions. For example, we had to accept that its viscosity is very high, otherwise the resources of the most powerful supercomputers will not be enough. In fact, this is not the case; there is every reason to believe that it almost coincides with the viscosity of water. Our current models are powerless to take into account the turbulence, which undoubtedly takes place. But computers are gaining strength every year, and in ten years, much more realistic simulations will appear. "

“The work of a geodynamo is inevitably associated with chaotic changes in the flows of iron-nickel melt, which turn into fluctuations in magnetic fields,” adds Professor Stevenson. - Inversions of terrestrial magnetism are simply the strongest possible fluctuations. Since they are stochastic in nature, they can hardly be predicted in advance - in any case, we do not know how. "