Imagine a clear sunny day, in the sky there is a brightly shining solar disk, Nature lives its ordinary life. But on the right edge of the Sun, at first a small amount of damage gradually appears, then it slowly increases, and as a result, the previously round disk takes the shape of a sickle. sunlight gradually weakens and becomes cooler. The resulting crescent becomes very small, and eventually the last flashes of light disappear behind the black disk. A clear day instantly turns into night, stars appear in the darkened sky, a lemon-orange dawn flashes on all sides, and in the place of the Sun there is a black circle surrounded by an indistinct silvery glow. Frightened by the ensuing darkness, animals and birds suddenly fall silent, and almost all plants curl up their leaves. But a few minutes will pass, and the Sun will again show its triumphant face to the world and Nature will come to life. For thousands of years, the phenomenon of a solar eclipse has inspired both fear and awe in people.

If total solar eclipses were visible in every area often enough, people would become accustomed to them as quickly as changes in the phase of the moon. But they happen so rarely that not every generation of local residents manages to see them at least once at one point earth's surface Total solar eclipses can only be observed once every 300400 years. Lunar eclipses, especially total ones, were feared no less than solar ones. After all, this night luminary sometimes completely disappeared from the vault of heaven, and the darkened part of the Moon quite soon took on a gray color with a reddish tint, becoming more and more bloody dark. In ancient times, lunar eclipses were credited with a special ominous influence on earthly events. The ancients believed that the Moon was bleeding at this moment, which promised great disasters for humanity. The first lunar eclipse recorded in ancient Chinese chronicles dates back to 1136 BC.

To understand the cause of solar and lunar eclipses, priests for centuries kept count of total and partial eclipses. First it was noticed that lunar eclipses occur only on the full moon, and solar eclipses only on the new moon, then that solar eclipses do not occur at every new moon and lunar eclipses not at every full moon, and also that solar eclipses did not occur when the Moon was visible. Even during a solar eclipse, when the light completely faded and the stars and planets began to appear through the unnaturally dark twilight, the Moon was nowhere to be seen. This aroused curiosity and gave rise to a thorough study of the place where the Moon should have been immediately after the end of the solar eclipse. It was soon discovered that on the night following the day of a solar eclipse, the Moon was always in its nascent form very close to the Sun. Having noticed the location of the Moon before a solar eclipse and immediately after it, they determined that during the eclipse itself the Moon actually passed from the western to the eastern side of the place occupied by the Sun, and complex calculations showed that the coincidence of the Moon and the Sun in the sky occurred precisely at the time when The sun was eclipsed. The conclusion became obvious: the Sun is obscured from the Earth by the dark body of the Moon.

After finding out the causes of the solar eclipse, we moved on to unraveling the mystery of the lunar eclipse. Although in in this case it was much more difficult to find a satisfactory explanation, since the light of the Moon was not obscured by any opaque body that stood between the night luminary and the observer. Finally, it was observed that all opaque bodies cast a shadow in the direction opposite to the light source. It was suggested that perhaps the Earth, illuminated by the Sun, gives that shadow that even reaches the Moon. It was necessary to either confirm or refute this theory. And it was soon proven that lunar eclipses occur only during the full moon. This confirmed the assumption that the cause of the eclipse was the shadow of the Earth falling on the Moon; as soon as the Earth came between the Moon and the light source, the Sun, the light of the Moon in turn became invisible and an eclipse occurred.

As a result of long-term observations, it turned out that both lunar and solar eclipses inevitably repeat in the same order after the expiration of the period of time through which the relative positions of the Sun, Moon and nodes of the lunar orbit are repeated. The ancient Greeks called this gap saros. It is 223 revolutions of the Moon, that is, 18 years, 11 days and 8 hours. After Saros, all eclipses are repeated, but under slightly different conditions, since in 8 hours the Earth rotates 120°, and therefore the lunar shadow will move across the Earth 120° to the west than it was 18 years ago. The ancient Egyptians, Babylonians, Chaldeans and other “cultured” peoples even 2,500 years BC, without knowing the causes of eclipses, were able to predict their occurrence with an accuracy of 1 x 2 days within their limited territory. But since they could not have the results of observations over the entire globe, they used for calculations a triple, or large, saros, containing an integer number of days. The sequence of solar and lunar eclipses after triple saros is repeated on the same geographic longitude. It is believed that the great saros namely 19,756 days was first calculated by ancient Babylonian astronomer-priests. The establishment of Saros was one of greatest discoveries antiquity, since it led to the discovery of the true cause of eclipses already in the 6th century BC.

The earliest written evidence of a solar eclipse dates back to October 22, 2137 BC. Moreover, this eclipse was not predicted by the court astronomers, and therefore the horror of the unexpected night that came was extremely great. However, those ancient astronomers could hardly be accused of negligence, since at that time foreseeing such phenomena in any particular place was not at all an easy matter. It is impossible to make an accurate forecast of the eclipse using Saros; it was only possible to indicate the approximate date and area of ​​\u200b\u200bits visibility. Accurately calculating the time of the eclipse, as well as its visibility conditions, was a difficult task. And to solve it, astronomers studied the movement of the Earth and the Moon for several centuries. There are currently eclipses from high degree Accuracies are calculated both thousands of years ago and hundreds of years ahead.

The study of ancient solar eclipses helps modern scientists correct the dates of many historical events and even make changes to their sequence. After all, every complete solar eclipse occurs in a certain and fairly narrow strip of the earth's surface, the position of which varies from year to year. Therefore, based on the area where it took place, it is possible, using calculations, to absolutely accurately determine their date. In addition, by comparing the movements of the lunar shadow on the earth's surface, it is possible to establish the natural evolution of the movement of the Moon. It was this comparison that first led scientists to think about the secular slowdown of the Earth’s rotation, which is 0.0014 seconds per century.

A total solar eclipse is a unique opportunity to study the outer layers of the Sun's atmosphere - the chromosphere and corona. And although their observations are carried out on a daily basis, this is not enough. The corona is visible only during a total solar eclipse, since the brightness of the light from the corona is a million times less than the brightness of the light from the disk. In addition, light from the Sun's disk is scattered by the Earth's atmosphere and the brightness of this scattered light is close to the brightness of the corona. The brightest part of the Sun, the part that appears yellow to us, is called the photosphere. During a total eclipse, the lunar disk completely covers the photosphere. Only after the photosphere disappears behind the Moon can the chromosphere be seen for a short time in the form of a ragged red ring surrounding a black disk.

The solar corona extends far from the Sun to the orbits of Jupiter and Saturn. Over an 11 year cycle solar activity Both the shape of the crown and its overall brightness change. The spectra of the corona taken near the solar disk turned out to be extremely interesting. Against the background of the continuous spectrum, bright emission lines were visible, which for many years were one of the greatest mysteries for science. It was allowed only in the 40s of the 20th century. It turned out that these lines emit highly ionized atoms of iron and calcium, the existence of which requires temperatures reaching up to a million degrees.

A major role in clarifying the physical conditions existing in solar corona, played a role in the so-called eclipse observations, in particular radio astronomy. Today, one of the main tasks is to study the infrared radiation of interplanetary dust. During eclipses, photometric, colorimetric, spectrophotometric and polarimetric observations are also performed. There is no doubt that eclipse observations of the Sun have made an invaluable contribution to scientists’ understanding of the Sun and the interstellar medium.

To make the best use of the few minutes during which an eclipse occurs, astronomers spend many months preparing for it, making accurate calculations of the eclipse band, studying weather reports in the eclipse band, and searching for the optimal location for observations. At the same time, issues of transportation and provision of necessary services, such as electricity and water, are being resolved; in parallel, observation programs are being drawn up, and appropriate instruments are being designed. The more inaccessible the observation location, the more necessary it is to insure yourself against various accidents.

Observing a solar eclipse can also be successfully used to study the earth's atmosphere. For this purpose, observations of changes in temperature, pressure, humidity, wind, cloud formation, photometric observations of the brightness and color of the sky, and so on are carried out. During eclipses, it also becomes possible to recognize deviations in the movement of the Moon and the rotation of the Earth. The study of the ionosphere using radio waves carried out during eclipses makes it possible to study the influence of the Sun on the upper layers of the earth's atmosphere.

Testing the effect can rightfully be considered a significant achievement for eclipse observers. gravitational influence massive cosmic objects (in particular, the Sun) on light rays, predicted within the framework of Einstein's theory of relativity. To do this, it was necessary to use the same telescope to take pictures of stars located as close as possible to the edge of the Sun during an eclipse, and a few months later to take pictures of the same stars in the night sky. By measuring the relative positions of the images of these stars in the two photographs, it was possible to judge whether they had moved. This experiment was first carried out in 1919, confirming the validity of the conclusions of Einstein’s theory.

It remains to add that the nearest total solar eclipse will occur on December 4, 2002. It will start at South Africa and will end in Australia and will have a maximum duration of 2 minutes 4 seconds. All professional astronomers, as well as amateur astronomers, are already preparing for this event.

Solar eclipses are not visible from all areas of the Earth's daytime hemisphere, since due to its small size the Moon cannot hide the Sun from the entire Earth's hemisphere. Its diameter is approximately 400 times smaller than the diameter of the Sun, but at the same time, the Moon, compared to the Sun, is almost 400 times closer to the Earth, therefore the apparent sizes of the Moon and the Sun are almost the same, so that the Moon, although in a very limited area, can block from us Sun.
The nature of the eclipse depends on the distance of the Moon from the Earth, and since the Moon’s orbit is not circular, but elliptical, this distance changes, and depending on this, the apparent size of the Moon also changes slightly. If at the moment of a solar eclipse the Moon is closer to the Earth, then the lunar disk, being slightly larger than the solar one, will completely cover the Sun, which means the eclipse will be total. If it is further away, then its visible disk will be smaller than the solar one and the Moon will not be able to cover the entire Sun; a light rim will remain around it. This type of eclipse is called an annular eclipse.

Illuminated by the Sun, the Moon casts into space a converging cone of shadow and surrounding penumbra. When these cones intersect with the Earth, the lunar shadow and penumbra fall on it. A spot of the lunar shadow with a diameter of about 300 km runs along the earth's surface, leaving a trail 10 x 12 thousand km long, and where it passes, a total solar eclipse occurs, while in the area captured by the penumbra, a partial eclipse, when only part of the Moon is covered solar disk. It often happens that the lunar shadow passes the Earth, and the penumbra partially captures it, then only partial eclipses occur.

Since the speed of movement of the shadow on the surface of the Earth, depending on geographical latitude ranges from 2000 km/h (near the equator) to 8000 km/h (near the poles), a total solar eclipse observed at one point lasts no more than 7.5 minutes, and maximum value achieved in very in rare cases(the nearest eclipse lasting 7 minutes 29 seconds will occur only in 2186).

The solar eclipse begins at western regions the earth's surface at sunrise and ends in the east at sunset. The total duration of all phases of a solar eclipse on Earth can reach 6 hours. The degree to which the Sun is covered by the Moon is called the eclipse phase. It is defined as the ratio of the closed part of the diameter of the solar disk to its entire diameter. During partial eclipses, the weakening of sunlight is not noticeable (except for eclipses with a very large phase), and therefore the phases of the eclipse can only be observed through a dark filter.

Lunar eclipses occur when the full moon passes near the nodes of its orbit. Depending on whether it is partially or completely immersed in the earth's shadow, both partial and total shadow lunar eclipses occur. Near the lunar nodes, within 17° on either side of them, there are zones of lunar eclipses. The closer to the lunar node an eclipse occurs, the greater its phase, determined by the proportion of the lunar diameter covered by the earth's shadow. The Moon's entry into the Earth's umbra or penumbra usually goes unnoticed. A total eclipse is preceded by partial phases, and at the moment of the final immersion of the Moon in the earth's shadow it occurs, lasting about two hours. The frequency of lunar eclipses for any particular place on Earth is higher than the frequency of solar eclipses only because they are visible from the entire night hemisphere of the Earth. Moreover, the duration of the total phase of a solar eclipse on the Moon can reach 2.8 hours.

Observations of total lunar eclipses make it possible to study the structure and optical properties of the earth's atmosphere, as well as the thermal properties of various parts of the lunar surface, including changes in their temperature during different phases of the eclipse.

Observations of lunar eclipses

Just like solar eclipses, lunar eclipses occur relatively rarely, and at the same time, each eclipse is characterized by its own characteristics. Observations of lunar eclipses make it possible to clarify the orbit of the Moon and provide information about the upper layers of the Earth's atmosphere.

A lunar eclipse observation program may consist of the following elements: determining the brightness of the shadowed parts of the lunar disk by the visibility of details of the lunar surface when observed through 6x recognized binoculars or a telescope with low magnification; visual assessments of the brightness of the Moon and its color both with the naked eye and through binoculars (telescopes); observations through a telescope with a lens diameter of at least 10 cm at 90x magnification throughout the entire eclipse of the craters Herodotus, Aristarchus, Grimaldi, Atlas and Riccioli, in the area of ​​which color and light phenomena may occur; registration using a telescope of the moments when the earth's shadow covers some formations on the lunar surface (a list of these objects is given in the book “Astronomical Calendar. Permanent Part”); Determination using a photometer of the brightness of the lunar surface during various phases of the eclipse.

Observations artificial satellites Earth and the influence of the Sun on life on Earth

When observing artificial Earth satellites, mark the path of the satellite on star map and the time of its passage is about noticeable bright stars. Time must be recorded with an accuracy of 0.2 s using a stopwatch. Bright satellites can be photographed.

Solar radiation - electromagnetic and corpuscular - is a powerful factor that plays a huge role in the life of the Earth as a planet. Sunlight and solar heat created the conditions for the formation of the biosphere and continue to support its existence. With amazing sensitivity, everything on earth - both living and inanimate - reacts to changes in solar radiation, to its unique and complex rhythm. So it was, so it is and so it will be until a person is able to make his own adjustments to solar-terrestrial connections.

Let's compare the Sun with... a string. This will make it possible to understand the Physical essence of the rhythm of the Sun and the reflection of this rhythm and the history of the Earth.

You pulled back the middle of the string and released it. The vibrations of the string, amplified by the resonator (the soundboard of the instrument), generated sound. The composition of this sound is complex: after all, as is known, not only the entire string as a whole vibrates, but also its parts at the same time. The string as a whole produces the fundamental tone. The halves of the string, vibrating faster, produce a higher, but less powerful sound - the so-called first overtone. The halves of the halves, that is, the quarters of the string, in turn give rise to an even higher and even weaker sound - the second overtone and so on. The full sound of a string consists of the fundamental tone and overtones, which in different musical instruments give the sound a different timbre and shade.

According to the hypothesis of the famous Soviet astrophysicist Professor M.S. Eigenson, once upon a time, billions of years ago, in the depths of the Sun, the same proton-proton cycle of nuclear reactions began to operate, which maintains the radiation of the Sun in the modern era; the transition to this chicle was probably accompanied by some kind of internal restructuring of the Sun. From the previous state of equilibrium it moved abruptly to a new one. And at this jump the Sun began to sound like a string. The word “sounded” should be lowered, of course, in the sense that some kind of rhythmic oscillatory processes arose in the Sun, in its gigantic mass. Cyclic transitions from activity to passivity and back began. Perhaps these fluctuations that have survived to this day are expressed in cycles of solar activity.

Outwardly, at least to the naked eye, the Sun always appears to be the same. However, behind this external constancy lies relatively slow but significant changes.

First of all, they are expressed in fluctuations in the number of sunspots, these local, darker areas of the solar surface, where, due to weakened convection, solar gases are somewhat cooled and therefore, due to contrast, appear dark. Typically, astronomers calculate for each moment of observation not total number spots visible on the solar disk, and the so-called Wolf number, equal to the number spots added to ten times the number of their groups. Characterizing the total area of ​​sunspots, the Wolf number changes cyclically, reaching a maximum on average every 11 years. How larger number Wolf, the higher the solar activity. During the years of maximum solar activity, the solar disk is abundantly dotted with spots. All processes on the Sun become violent. IN solar atmosphere More often, prominences are formed - fountains of hot hydrogen with a small admixture of other elements. Appear more often solar flares, these powerful explosions in the surface layers of the Sun, during which dense streams of solar corpuscles - protons and other atomic nuclei, as well as electrons - are “shot” into space. Corpuscular flows - solar plasma. They carry with them a weak magnetic field with a strength of 10 -4 oersted “frozen” in them. Reaching the Earth on the second day, or even earlier, they disturb the Earth's atmosphere and disturb the Earth's magnetic field. Other types of radiation from the Sun are also increasing, and the Earth is sensitive to solar activity.

If the Sun is like a string, then there must certainly be many cycles of solar activity. One of them, the longest and largest in amplitude, sets the “main tone”. Cycles of shorter duration, that is, “overtones,” should have smaller and smaller amplitudes.

Of course, the analogy with a string is incomplete. All vibrations of the string have strictly defined periods; in the case of the Sun, we can talk about only a few, only on average, certain cycles of solar activity. And yet, different cycles of solar activity should be, on average, proportional to each other. Surprising as it may seem, the expected similarity between the Sun and the string is confirmed by facts. Simultaneously with the clearly defined eleven-year cycle, another, doubled, twenty-two-year cycle operates on the Sun. It manifests itself in a change in the magnetic polarities of sunspots.

Each sunspot is a strong “magnet” with a strength of several thousand oersteds. Typically, spots appear in close pairs, with the line connecting the centers of two adjacent spots parallel to the solar equator. Both spots have different magnetic polarities. If the front, head (in the direction of rotation of the Sun) sunspot has a northern magnetic polarity, then the spot following it has a southern polarity.

It is remarkable that during each eleven-year cycle, all the head spots of the different hemispheres of the Sun have different polarities. Once every 11 years, as if on command, the polarities of all spots change, which means that the initial state is repeated every 22 years. We do not know what is the reason for this phenomenon, but its reality is undeniable.

There is also a triple, thirty-three-year cycle. It is not yet clear in what solar processes it is expressed, but its terrestrial manifestations have long been known. For example, particularly harsh winters recur every 33-35 years. The same cycle is noted in the alternation of dry and wet years, fluctuations in lake levels and, finally, in the intensity polar lights- phenomena known to be associated with the Sun.

On tree cuts, alternation of thick and thin layers is noticeable - again with an average interval of 33 years. Some researchers (for example, G. Lungershausen) believe that thirty-three-year cycles are also reflected in the layering of sedimentary deposits. Many sedimentary rocks exhibit microlayering due to seasonal changes. Winter layers are thinner and lighter due to their depletion in organic material, spring-summer layers are thicker and darker, since they were deposited during a period of more vigorous manifestation of rock weathering factors and the vital activity of organisms. In marine and oceanic biogenic sediments, such phenomena are also observed, since they accumulate the remains of microorganisms, which are always much more numerous during the growing season than in the winter (or during the dry period in the tropics). Thus, in principle, each pair of microlayers corresponds to one year, although it happens that two pairs of layers can correspond to a year. The reflection of seasonal changes in sedimentation can be traced over almost 400 million years - from the Upper Devonian to the present day, however, with rather long breaks, sometimes taking tens of millions of years (for example, in the Jurassic period, which ended about 140 million years ago).

Seasonal layering is associated with the movement of the Earth around the Sun, the inclination of the Earth's axis of rotation relative to the plane of its orbit (or the solar equator, which is practically the same thing), the nature of atmospheric circulation, and much more. But as we have already mentioned, some researchers see in seasonal layering a reflection of the thirty-three-year cycles of solar activity, although if we can talk about this, then only for the so-called belt deposits (in clays and sands) of the last glaciation. But if this is so, then it turns out that an amazing and so far poorly understood mechanism of solar activity has been operating for at least millions of years. It should be noted once again that in geological deposits it is difficult to clearly identify any specific cycles associated with solar activity. Climate fluctuations in ancient epochs are associated primarily with changes on the Earth's surface, with an increase or, conversely, a decrease in the total area of ​​seas and oceans - these main accumulators of solar heat. Indeed, ice ages were always preceded by high tectonic activity of the earth's crust. But this activity, in turn (as will be discussed below), can be stimulated by an increase in solar activity. The data seems to say so recent years. In any case, there is still a lot of uncertainty in these issues, and therefore further considerations in this chapter should be considered only as one of the possible hypotheses.

Even in the last century, it was noticed that the maxima of solar activity are not always the same. In the changes in the magnitudes of these maxima, a “secular” or, more precisely, 80-year cycle is outlined, approximately seven times longer than the eleven-year one. If "secular" variations in solar activity are compared to waves, cycles of shorter duration will look like "ripples" in the waves.

The “secular” cycle is quite clearly expressed in the frequency of solar prominences, fluctuations in their average heights and other phenomena on the Sun. But its earthly manifestations are especially noteworthy.

The “secular” cycle is now expressed in the next warming of the Arctic and Antarctic. After some time, warming will be replaced by cooling, and these cyclical fluctuations will continue indefinitely. “Secular” climate fluctuations are noted in the history of mankind, in chronicles and other historical chronicles. Sometimes the climate became unusually harsh, sometimes unusually mild. For example, in 829 even the Nile was covered with ice, and from the 12th to the 14th centuries the Baltic Sea froze several times. On the contrary, in 1552 an unusually warm winter complicated Ivan the Terrible’s campaign against Kazan. However, not only the “secular” cycle is involved in climate fluctuations.

If on a graph of changes in solar activity we connect the maximum and minimum points of two adjacent “secular” cycles with straight lines, it will turn out that both straight lines are almost parallel, but inclined to the horizontal axis of the graph. In other words, some long, centuries-long cycle is emerging, the duration of which can only be determined by means of geology.

On the shores of Lake Zurich there are ancient terraces - high cliffs, in the thickness of which layers of different eras are clearly visible. And in this layering of sedimentary rocks, an 1800-year rhythm appears to be recorded. The same rhythm is noticeable in the alternation of silt deposits, the movement of glaciers, fluctuations in humidity and, finally, in cyclical climate changes.

In the book of the Soviet geographer Professor G.K. Tushinsky summarizes everything known about the 1800-year cycle, and most importantly, traces its manifestations in the history of the Earth. Here we will only briefly mention that the 1800-year cycle is probably associated with periodic drying and wetting of the Sahara, a strong and long-term warming of the Arctic, during which the Normans settled Greenland (Green Land) and discovered America. On the waves of the 1800-year cycle, even the “secular” cycle looks like “ripples”.

If the Earth's average temperature drops just four to five degrees, a new ice age will begin. Ice shells will cover almost the entire North America, Europe and most of Asia. On the contrary, an increase in the average annual temperature of the Earth by only two to three degrees will cause the ice cover of Antarctica to melt, which will raise the level of the World Ocean by 70 m with all the ensuing catastrophic consequences (flooding of a significant part of the continents). Thus, small fluctuations average temperature Lands (just a few degrees) can throw the Earth into the arms of glaciers or, conversely, cover most of the land with ocean.

It is well known that in the history of the Earth, ice ages and periods were repeated many times, and between them came eras of warming. These were very slow, but enormous climatic changes, which were superimposed by smaller amplitude, but more frequent and rapid climate fluctuations, when ice ages gave way to warm and humid periods.

The intervals between ice ages or periods can only be characterized on average: after all, here too cycles operate, and not exact periods. According to the research of the Soviet geologist G.F. Lungershausen, ice ages repeated themselves in the history of the Earth approximately every 180-200 million years (according to other estimates, 300 million years). Ice periods within ice ages alternate more frequently, on average every few tens of thousands of years. And all this is recorded in the thickness of the earth’s crust, in rock deposits of different ages.

The reasons for the change of ice ages and periods are not known with certainty. Many hypotheses have been proposed to explain glacial cycles cosmic reasons. In particular, some scientists believe that, revolving around the center of the Galaxy with a period of 180-200 million years, the Sun, together with the planets, regularly passes through the thickness of the plane of the Galaxy’s arms, enriched with dust matter, which weakens solar radiation. However, on the galactic path of the Sun there are no nebulae visible that could act as a dark filter. And most importantly, cosmic dust nebulae are so rarefied that, plunging into them, the Sun would still remain dazzlingly bright for an earthly observer.

According to the hypothesis of M.S. Eigenson, all cyclical fluctuations in climate, from the most insignificant to alternating ice ages, are explained by one reason - rhythmic fluctuations in solar activity. And since in this process the Sun is like a string, then all cycles of solar activity should appear in the fluctuations of the earth’s climate - from the “main” cycle of 200 or 300 million years to the shortest, eleven years. The very “mechanism” of the Sun’s influence on the Earth in this case boils down to the fact that fluctuations in solar activity immediately cause changes in the geomagnetosphere and the circulation of the Earth’s atmosphere.

If the Earth did not rotate, the circulation of air masses would be extremely simple. In the warm tropical zone of the Earth, heated and therefore less dense air rises. The pressure difference between the pole and the equator causes these air masses to rush towards the pole. Here, having cooled, they sink down and then move again to the equator. So in the case of the Earth's immobility it would work " heat engine» planets.

The axial rotation of the Earth and its orbit around the Sun complicate this idealized picture. Under the influence of the so-called Coriolis forces (which force rivers flowing in the meridional direction to erode the right bank in the northern hemisphere, and the left bank in the southern hemisphere), air masses circulate from the equator to the pole and back in spirals. During the same periods when the air near the equator heats up especially strongly, wave circulation of air masses occurs. Spiral motion is combined with wave motion, and therefore the direction of the winds is constantly changing. In addition, the uneven heating of different parts of the earth's surface and the topography complicate this complex picture. If air masses move parallel to the earth's equator, air circulation is called zonal, if along the meridian - meridional.

For the eleven-year solar cycle, it has been proven that with increasing solar activity, the zonal circulation weakens and the meridional circulation intensifies. The earth's “heat engine” works more energetically, increasing heat exchange between the polar and equatorial zones. If you pour a little boiling water into a glass of cold water, the water will heat up more quickly if you stir it with a spoon. For the same reason, during periods of increased solar activity, the atmosphere “excited” by solar radiation provides, on average, a warmer climate than during years of “passive” Sun.

The above is true for any solar cycle. But the longer the cycle, the more strongly the earth’s atmosphere reacts to it, the more significantly the Earth’s climate changes.

“The cosmic cause of glacial or, better, cold eras,” writes M.S. Eigenson, - cannot in any way consist in lowering the temperature. The situation is “only” in a drop in the intensity of meridional air exchange and in the growth of the meridional thermal gradient caused by this drop...”

Therefore, the physical basis of climatic differences is the general circulation of the atmosphere.

The role of solar rhythms in the history of the Earth is very noticeable. The general circulation of the atmosphere determines the speed of winds, the intensity of water exchange between geospheres, and therefore the nature of weathering processes. The sun obviously also influences the rate of formation of sedimentary rocks. But then, according to M.S. Eigenson, geological epochs with increased general circulation of the atmosphere and hydrosphere should correspond to soft, less pronounced forms of relief. On the contrary, during long periods of reduced solar activity landform should acquire contrast.

On the other hand, during cold periods, significant ice loads seem to stimulate vertical movements in earth's crust, that is, they activate tectonic activity. Finally, it has long been known that volcanism also increases during periods of solar activity.

Even in the vibrations of the earth’s axis (in the body of the planet), as I.V. believes. Maksimov, the eleven-year solar cycle has an effect. This is apparently explained by the fact that the active Sun redistributes the air masses of the earth's atmosphere. Consequently, the position of these masses relative to the Earth’s rotation axis also changes, which causes it to be insignificant, but still quite real movements and changes the speed of the Earth's rotation. But if changes in solar activity affect the entire Earth as a whole, then the more noticeable should be the impact of solar rhythms on the surface shell of the Earth.

Any, especially sharp, fluctuations in the speed of the Earth's rotation should cause tension in the earth's crust, movement of its parts, and this in turn can lead to the appearance of cracks, which stimulates volcanic activity. This is possible (of course, in the most general outline) explain the connection of the Sun with volcanism and earthquakes.

The conclusion is clear: it is hardly possible to understand the history of the Earth without taking into account the influence of the Sun. It must, however, always be borne in mind that the influence of the Sun only regulates or disturbs the processes of the Earth’s own development, which is subject to its geological internal laws. The Sun makes only some “corrections” to the evolution of the Earth, without, of course, being the driving force of this evolution.

In order for an eclipse to occur, it does not matter whether it is lunar or solar, the Moon, the Sun, and the Earth must be on the same line. So, during a solar eclipse, the Moon passes between the Earth and the Sun, and it seems to hide the Sun from view, covering it. But during a lunar eclipse, the Moon is already covered by the shadow of the Earth, which is cast from the planet illuminated by the Sun.

There are total, partial and penumbral lunar eclipses. With a total lunar eclipse, the Moon is completely “closed” by the earth’s shadow, with a partial eclipse, the Moon is only half immersed in the shadow, while the maximum possible darkening is half of the Moon’s disk. And during a penumbral eclipse, the Moon passes only through the Earth's penumbra. Lunar eclipses occur only when full moon. But the full moon occurs every month, however, for some reason we do not notice such frequent lunar eclipses. What is this connected with? But with this: in order for such a friendly company represented by the Sun, Moon and Earth to delight us with lunar eclipses every night with the participation of the full Moon, they must be “friends” in a completely different way. And this is what this “friendship” should look like: The Moon should rotate around the Earth in the same plane in which the Earth rotates around the Sun. But this does not happen, because the plane of the lunar orbit is slightly, very slightly, inclined relative to the plane of the Earth’s revolution around the Sun (in scientific terms, this plane is called the ecliptic plane). Thus, it turns out that an eclipse occurs only when the Moon is located near the nodes of its own orbit. The length of the lunar eclipse phase is determined by how close the eclipse is to the lunar node. So, the closer it is to it, the longer the phase will be. Since during an eclipse, the Moon is covered by the shadow of the Earth, then, logically, it should completely disappear from view. However, as we know, this never happens. And all because the earth’s atmosphere simply scatters the rays of the Sun, and they, in turn, fall on the Moon, darkened by the earth’s shadow. Most often, the darkened Moon has a reddish color. This is due to the fact that red and orange rays travel best through our planet's atmosphere.

This was a brief introduction to the basics of astronomy and lunar eclipses. But we still haven’t answered how often such a phenomenon as a lunar eclipse occurs. They answered more precisely, but illuminated some part of this phenomenon. That is, now we know that a lunar eclipse is possible only when the Moon is full. But it is still not clear how many times, for example, a year there are lunar eclipses? But even ancient astronomers calculated the frequency of lunar eclipses per year. So, they came up with such a concept as “saros”. Saros lasts exactly 18 years, 11 days and 8 hours. And during this time period, 43 solar and 28 lunar eclipses occur. Thus, at least two lunar eclipses are possible per year, sometimes the number of eclipses increases by one more, and there are also years without any eclipses at all. But this frequency of lunar eclipses is designed for the entire Earth. And if we consider individual areas of the globe, then their frequency will not be the same. In certain places, eclipses will be visible more often than in others.

In the end, I would like to note that both lunar and solar eclipses are the most beautiful phenomena that nature has given us. And this is a fairly common occurrence, but it may well seem to us that they happen no more often than once a decade, which is when the means mass media We are informed about another major eclipse.

Essentially, a solar eclipse is the shadow of the Moon that falls on the earth's surface. It is approximately 200 km in diameter, that is, many, many times smaller than the diameter of our planet. That is why the phenomenon is observed only in a specific band along which the lunar shadow passes.

If a person is in the shadow zone, he observes a total solar eclipse, when the Moon completely hides the Sun. At the same time, the sky darkens and stars may appear on it. Just like in the evening, it becomes cooler, and animals and birds fall silent, frightened by the sudden darkness. Some plants even curl their leaves.

If observers are near the band of such an eclipse, they can see a partial solar eclipse. In this case, the Moon does not completely cover the solar disk, but only part of it. The sky is no longer so dark, the stars are no longer visible. Usually a partial eclipse is observed at a distance of about two thousand km from the total eclipse zone.

Time of solar eclipse

This phenomenon occurs on a new moon. The satellite is not visible because the side that “looks” at the Earth is not illuminated by the Sun. Because of this, it appears as if the fireball is covering a black spot that appeared out of nowhere.

The shadow that the Moon casts towards our planet looks like a sharply converging cone. Its tip is located somewhat further than the Earth. And when the shadow falls on the surface of the planet, it appears as a black spot with a diameter of 150–270 km, and not a point. Following the satellite, this spot moves along the surface of the planet, moving at a speed of one kilometer per second.

Due to its high speed, the shadow cannot cover any place on the globe for a long time. During a total eclipse, the maximum possible duration of darkness is 7.5 minutes. During a partial eclipse - about two hours.

Frequency of solar eclipses

On Earth, between 2 and 5 eclipses occur annually, with only two of them being total or annular. Over a hundred years, 237 solar eclipses occur, 160 of them are partial, 63 are total, and 14 are annular. At some points on the earth’s surface, solar eclipses in a large phase occur very rarely, and total eclipses- an absolute rarity. For example, on the territory of Moscow in the period from the 11th to the 18th centuries. Only 159 solar eclipses were observed, of which only 3 were total. This is over 700 years!

Usually total solar eclipses are observed in Western countries, but it is absolutely known when the Moon will completely cover the disk in Russia. This will happen only 13 years later in 2026 on August 12, and after this date another 7 years - in 2033. Let us recall that the closest past eclipse took place on August 1, 2008.

You can watch the solar eclipse using video and photography footage on the Internet.

The Moon is visible in the sky because the Sun illuminates it. The phases of the Moon depend on the position of the night star relative to the Earth and the Sun. During a full moon, the Sun, Earth and its satellite are on the same line. At the same time, the Moon occupies the farthest position from the Sun, and when it is daylight, the night star begins to set.

On the contrary, on the new moon the Moon “rises” and “sets” together with the Sun. At the same time, it is not visible to the naked eye, since it is completely covered by the shadow of the Earth.

Earth's axis tilted relative to the planet's orbit by 23.5 degrees. As it moves around the Sun throughout the year, the planet turns to the star first on one side or the other. This, in turn, gives rise to the change of seasons, and during each season the Sun changes its trajectory across the sky.

Since with the change of seasons the Sun changes its position and movement in the sky relative to the horizon, the Moon will also appear on the dome of the sky and disappear from it in different time and in different places.

In this case, one should take into account the difference in seasons in northern and.

How to Predict Moonset

You can predict where the lunar sunset will be observed using the Sun as a guide. Every day, the Moon lags behind the Sun by 12 degrees, also sliding across the sky in an easterly direction. This means that its lag time from the Sun is 50 minutes per day.

The earth rotates from west to east, clockwise. Therefore, everything you observe in the sky moves across it in the opposite direction, from east to west: the stars, the Sun, the Moon and the planets.

If on a new moon the Moon sets below the horizon in the same place as the Sun, and also simultaneously with it, then in other phases the place and time of lunar sunset will differ from the sun, depending on the degree of lag of the Moon.

In a young photo, the thin horn of the Moon is visible above the horizon when the Sun has already set. The first quarter of the Moon coincides with the position of the night luminary 90 degrees to the left of the Sun. Then, if the Sun has set in the southwest, then the Moon will set below the horizon in the west. This happens in the northern hemisphere in winter, and in the southern hemisphere in summer.

The location of the moon setting relative to the horizon also depends on the degree of latitude.

The Full Moon is 180 degrees to the left of the Sun and 12 hours behind it. During sunset, the moon rises. And if in the northern hemisphere the winter Sun sets in the southwest, then the Moon will disappear below the horizon in the northwest.
The aging Moon in the last quarter is 270 degrees to the left of the Sun and appears in the sky 18 hours later. Its sunset will coincide with noon. In winter and summer in the northern hemisphere it will happen in the west, in spring - in the southwest, and in autumn - in the northwest.