Where the moon sets. How often do lunar eclipses occur? Frequency of observation of a lunar eclipse in a certain area

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

When observing artificial Earth satellites, the path of the satellite’s movement on the star map and the time of its passage near noticeable bright stars are noted. 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 man 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. Usually, astronomers calculate for each moment of observation not the total number of spots visible on the solar disk, but the so-called Wolf number, equal to the number of 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. The higher the Wolf number, 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 the solar atmosphere, prominences are more often formed - fountains of hot hydrogen with a small admixture of other elements. Solar flares appear more often, 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 tension 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, especially 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 of auroras - 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 of recent years seems to indicate this. 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 also 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 sheets will cover almost all of 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 in the average temperature of the Earth (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 by cosmic causes. 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, if the Earth was stationary, the planet’s “heat engine” would work.

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, the earth's topography should acquire contrast.

On the other hand, in cold eras, significant ice loads apparently stimulate vertical movements in the earth's crust, that is, they intensify 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 axis of rotation of the Earth also changes, which causes its insignificant, but still quite real movements and changes the speed of rotation of the Earth. 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 how it is possible (of course, in the most general terms) to 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, 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.

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.

The Earth's axis is 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 appear and disappear from the dome of the sky at different times 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, moonrise occurs. 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.

Stationary observations are usually used when carried out in particularly difficult conditions during the construction of important structures. Moreover, stationary observation is used both at the stage of pre-design research and in subsequent stages of this process. In the event that there is a danger of hazardous engineering-geological processes occurring, this type of observation is carried out directly during the construction or operation of finished buildings and structures. This process is also called local monitoring of components of the geological environment.
Carrying out stationary observations ensures obtaining quantitative and qualitative characteristics of changes in local components of the environment in space and time. This data is usually sufficient to assess or predict any changes in geological conditions in the study area that are possible in the future. The choice of design solutions and justification of the necessary protective processes is also determined by the results of stationary observations.

Such observations are most often carried out at specially prepared observation network points. Some points must be used for observations after construction is completed. For the most effective implementation of stationary observations, geophysical regime studies are usually used. These are measurements that are carried out with periodic frequency at the same points and along the same profiles, measurements with special receivers and sensors, and observations that are carried out at hydrogeological wells.

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 are completely rare. 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.