It is rare that any natural or astronomical phenomenon can surpass a solar eclipse in terms of its dramatic impact and impact on humans. Understanding its internal processes and hidden mechanisms will allow you to broaden your horizons and take a step into the world of stellar science.
Solar eclipses past and present
The oldest written sources telling about the sudden onset of night in the middle of a clear day were Chinese manuscripts written more than 2 thousand years ago. They, like later sources from other countries, tell of extreme excitement and fear of the population at the sudden disappearance of the Sun.
For many thousands of years of human history, eclipses were considered exclusively harbingers of great misfortunes and catastrophes. But times changed, knowledge increased, and in an insignificant period from a historical perspective, from a harbinger of catastrophes, short-term disappearances of the sun turned for people into a grandiose show staged by nature itself.
Predicting the exact time of the beginning of astronomical events was also once the lot of dedicated priests. By the way, they used this knowledge based on considerations of benefits and assertion of their power in society.
Today's scientists, on the contrary, willingly share such information. For decades in advance, the years of solar eclipses and the places in which they will be observed are known. After all, what more people participate in observations - the more information flows into astronomical centers.
Below is a chart of solar eclipses for the near future:
- September, 01, 2016. It will be observed in the Indian Ocean, Madagascar, and partly in Africa.
- February 26, 2017. South part Africa, Antarctica, Chile and Argentina.
- August 21, 2017. Most US states, northern Europe, Portugal.
- February 15, 2018. Antarctica, Chile and Argentina.
- July 13, 2018. Southern coast of the Australian continent, Tasmania Peninsula, part of the Indian Ocean.
- August, 11, 2018. Most countries in the Northern Hemisphere, incl. territory of Russia, the Arctic, part of Northern Asia.
Conditions and causes of solar eclipses
In the infinite space of the Universe, the Sun and the planets of the system surrounding it move at a speed of 250 kilometers per second. In turn, within this system, all of its constituent celestial bodies move around the central body, along different trajectories (orbits) and at different speeds.
Most of these planets have their own satellite planets, called satellites. The presence of satellites, their constant movement around their planets and the existence of certain patterns in the ratios of the sizes of these celestial bodies and the distances between them explain the causes of solar eclipses.
Each of the celestial bodies included in our system is illuminated by the sun's rays and every second casts a long shadow into the surrounding space. The same cone-shaped shadow is cast by the Moon on the surface of our planet when, when moving along its orbit, it finds itself between the Earth and the Sun. In the place where the lunar shadow falls, an eclipse occurs.
Under normal conditions, the apparent diameters of the Sun and Moon are almost the same. Being at a distance 400 times less than the distance from the Earth to the only star in our system, the Moon is 400 times smaller in size than the Sun. Thanks to this amazingly accurate ratio, humanity has the opportunity to periodically observe a total solar eclipse.
This event can only occur during periods when several conditions are met simultaneously:
- New Moon - The Moon faces the Sun.
- The moon is on the line of nodes: this is the name of the imaginary line of intersection of the lunar and earth's orbits.
- The Moon is at a fairly close distance to the Earth.
- The line of nodes is directed towards the Sun.
Mechanism and timing of a solar eclipse
Descriptions of how a solar eclipse occurs have generally remained unchanged throughout recorded history. At the edge of the Sun, a dark spot of the lunar disk creeping to the right appears, which gradually increases in size, becomes darker and clearer.
The more the surface of the star is covered by the Moon, the darker the sky becomes, on which bright stars appear. The shadows lose their usual outlines and become blurry.
The air is getting significantly colder. Its temperature, depending on the latitude through which the eclipse passes, can decrease by up to 5 degrees Celsius. Animals at this time become anxious and often rush around in search of shelter. The birds fall silent, some go to bed.
The dark disk of the Moon is creeping further and further onto the Sun, leaving behind an increasingly thin crescent. Finally, the Sun disappears completely. Around the black circle that covered it, you can see the sun's corona - a silvery glow with blurred edges. Some illumination is provided by the dawn, an unusual lemon-orange hue, flashing across the entire horizon around the observer.
The moment of complete disappearance of the solar disk usually lasts no more than three to four minutes. Maximum possible time A solar eclipse, calculated using a special formula based on the ratio of the angular diameters of the Sun and the Moon, is 481 seconds (a little less than 8 minutes).
Then the black lunar disk moves further to the left, exposing the blinding edge of the Sun. At this moment, the solar corona and glow ring disappear, the sky brightens, the stars go out. The gradually freeing Sun gives off more and more light and heat, nature returns to its normal form.
It is important to note that in the northern hemisphere the Moon moves along the solar disk from right to left, and in the southern hemisphere, on the contrary, from left to right.
Main types of solar eclipses
The area of the globe on which the above can be observed total solar eclipse, is always limited by a narrow and long strip formed in the path of the cone-shaped shadow of the Moon, rushing along the earth's surface at a speed of more than 1 kilometer per second. The width of the strip usually does not exceed 260-270 kilometers; its length can reach 10-15 thousand kilometers.
The orbits of the Earth around the Sun and the Moon around the Earth are an ellipse, so the distances between these celestial bodies are not constant values and can fluctuate within certain limits. Thanks to this principle of natural mechanics, solar eclipses are different.
At a much greater distance from the total eclipse band, one can observe partial solar eclipse, which in common parlance is often also called partial. In this case, for an observer located in a place outside the shadow band, the orbits of the night and daylight bodies intersect in such a way that the solar disk is only partially covered. Such phenomena are observed much more often and over a much larger area, while the area of a solar eclipse can be several million square kilometers.
Partial eclipses occur annually in almost every part of the globe, but for most people outside the professional astronomical community, they go unnoticed. A person who rarely looks at the sky will see such a phenomenon only when the Moon covers the Sun halfway, i.e. if its phase value approaches 0.5.
Calculation of the phase of a solar eclipse in astronomy can be done using formulas of varying degrees of complexity. In the very simple version it is determined through the ratio of the diameters of the part covered by the Moon and the total diameter of the solar disk. The phase value is always expressed only as a decimal fraction.
Sometimes the Moon passes from the Earth at a distance slightly greater than usual, and its angular (apparent) size is less than the apparent size of the solar disk. In this case there is annular or annular eclipse: The sparkling ring of the Sun around the black circle of the Moon. At the same time, observing the solar corona, stars and dawn is impossible, since the sky practically does not darken.
The width of the observation band with a similar length is significantly higher - up to 350 kilometers. The width of the penumbra is also greater - up to 7340 kilometers in diameter. If during a total eclipse the phase is equal to one or maybe even greater, then during an annular eclipse the phase value will always be greater than 0.95, but less than 1.
It is worth noting an interesting fact that the observed diversity of eclipses occurs precisely during the period of existence of human civilization. Since the formation of the Earth and the Moon as celestial bodies, the distance between them has been slowly but continuously increasing. When distances change, the pattern of a solar eclipse generally remains the same, similar to that described above.
More than a billion years ago, the distance between our planet and its satellite was smaller than it is now. Accordingly, the apparent size of the lunar disk was much larger than the size of the solar one. Only total eclipses with a much wider shadow band occurred; observation of the corona was practically impossible, as was the formation of annular eclipses.
In the distant future, millions of years from now, the distance between the Earth and the Moon will become even greater. The distant descendants of modern humanity will only be able to observe annular eclipses.
Scientific experiments for amateurs
The observation of solar eclipses at one time helped to make a number of significant discoveries. For example, back in the days of the ancient Greeks, the sages of that time drew conclusions about the possible movement of celestial bodies and their spherical shape.
Over time, research methods and tools made it possible to draw conclusions about chemical composition our star, about the physical processes occurring in it. A well-known chemical element helium was also discovered during an eclipse observed by the French scientist Jansen in India in 1868.
Solar eclipses are one of the few astronomical phenomena that can be observed by amateurs. And not only for observations: anyone can make a feasible contribution to science and record the circumstances of a rare natural phenomenon.
What can an amateur astronomer do:
- Mark the moments of contact of the solar and lunar disks;
- Record the duration of what is happening;
- Sketch or photograph the solar corona;
- Participate in an experiment to clarify data on the diameter of the Sun;
- In some cases or when using instruments, prominences can be seen;
- Take a photograph of the circular glow on the horizon line;
- Make simple observations of environmental changes.
Hence the main rule for observing the sun: be sure to wear eye protection. These can include special light filters for telescopes and binoculars, and chameleon masks for welding work. As a last resort, simple smoked glass will do.
What a solar eclipse looks like - watch the video:
It is relatively safe to observe only a short period, only a few minutes, while the total eclipse lasts. Take special care in the initial and final phases, when the brightness of the solar disk is close to maximum. It is recommended to take breaks from observation.
If you do not delve into the essence of the phenomenon, then we can say that an eclipse is a temporary disappearance of the Sun or Moon from the sky. How does this happen?
Solar and Lunar Eclipse
For example, the Moon, passing between the Earth and the Sun, completely or partially blocks the Sun from an earthly observer. This is a solar eclipse. Or the Moon, making its way around the Earth, finds itself in such a position that the Earth appears on a straight line connecting the Moon and the Sun.
The shadow of the Earth falls on the Moon, and it disappears from the sky. This is a lunar eclipse. Eclipses happen because celestial bodies constantly change location. The Earth revolves around the Sun, and the Moon revolves around the Earth. Both of these processes occur simultaneously. If for a few minutes the Moon, Earth and Sun are on the same line, an eclipse begins. A total solar eclipse is a very rare and dramatic event.
During a total solar eclipse, it seems as if some huge monster is devouring the Sun piece by piece. When the Sun disappears, the sky darkens and stars are visible in the sky. The air is rapidly cooling. Soon there is nothing left of the Sun except a thin luminous ring, as if hanging in the sky, this is what we see as part of the blazing solar corona.
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Interesting fact : During a total solar eclipse, the air temperature drops, the sky darkens and stars appear on it.
What happens during a solar eclipse
Ancient Chinese artists depicted a solar eclipse as a dragon devouring the Sun. In fact, after a few minutes the Sun comes out of its “shelter” and the night turns into a clear day again. This dragon turns out to be the Moon, passing between the Earth and the Sun. To finally understand what happens during an eclipse, carry out a simple experiment. Turn on table lamp, and look at her.
Now take a piece of cardboard and slowly move it in front of your eyes so that at the end of the movement the cardboard is between your eyes and the lamp. The moment when the cardboard covers the lamp from your eyes corresponds to the moment the solar eclipse begins. The cardboard is far from the lamp, but once in front of your eyes, it blocks the light of the lamp from you. If you move the cardboard further, the lamp will again open to your view.
Total and partial solar eclipse
The same can be said about the Moon. You see a solar eclipse when the Moon, crossing the daytime sky, comes between the Sun and the illuminated face of the Earth, blocking the light of the Sun from it. If the Moon blocks only part of the Sun, then a partial solar eclipse occurs.
An eclipse is an astronomical situation during which one celestial body completely blocks the light of another celestial body. The most famous are the eclipses of the Moon and the Sun. Eclipses are considered interesting natural phenomena, familiar to humanity since ancient times. They occur relatively often, but are not visible from every point on the earth. For this reason, eclipses seem to be a rare event to many. As everyone knows, planets and their satellites do not stand in one place. The Earth revolves around the Sun, and the Moon moves around the Earth. Periodically, moments arise when the Moon completely or partially covers the Sun. So why do solar and lunar eclipses occur?
Moon eclipse
During its full phase, the moon appears coppery red, especially as it approaches the center of the shadow region. This shade is due to the fact that the rays of the sun, tangent to the surface of the earth, passing through the atmosphere, are scattered and fall into the shadow of the Earth through a thick layer of air. This works best with rays of red and orange shades. Therefore, only they paint the lunar disk this color, based on the state of the earth’s atmosphere.
Eclipse of the sun
Solar eclipse- This is the lunar shadow on the surface of the Earth. The diameter of the shadow spot is about two hundred kilometers, which is several times less land. For this reason, an eclipse of the sun can only be seen in a narrow strip along the path of the moon's shadow. An eclipse of the Sun occurs when the Moon comes between the observer and the Sun, blocking it.
Since the Moon on the eve of an eclipse is turned towards us with the side that does not receive light, a new moon always occurs on the eve of an eclipse of the Sun. Simply put, the Moon becomes invisible. It seems that the Sun is covered with a black disk.
Why do solar and lunar eclipses occur?
The phenomena of solar and lunar eclipses are clearly observed through. Observers were able to achieve great achievements by confirming the effect of gravity of large space objects on light rays.
It is unlikely that any eyewitness will remain indifferent to such a remarkable phenomenon associated with the Moon as a total solar eclipse. For thousands of years, the black circle engulfing the Sun in broad daylight has inspired superstitious fear and awe in people. To understand the cause of solar eclipses, ancient sky watchers spent centuries painstakingly counting all eclipses, trying to find a pattern and determine the sequence of eclipses. In the end, it turned out that solar eclipses are possible only at the time of new moon, when the Moon passes between the Earth and the Sun.
The Moon, illuminated by the Sun, blocks the path of the sun's rays and casts into space a converging cone of shadow and a diverging cone of penumbra surrounding it, which, under certain circumstances, fall on small areas surface of the Earth, where observers at this moment see the Sun being covered by a black disk.
Geometry of the onset of a solar eclipse
In the earth's sky, the diameters of the Moon and the Sun almost coincide, which allows the Moon to completely eclipse our daylight in the sky. This is despite the fact that the diameter of the Sun is almost 400 times the diameter of the Moon. And all because the Sun is about 400 times farther from the Earth than the Moon. This exceptional coincidence, not repeated on any other planet, allows us to observe solar eclipses.
Solar eclipses do not occur at all new moons. The reason for this is that the Moon's path in the sky is tilted about 5° to the Sun's path, the ecliptic. Therefore, eclipses occur only near the intersection points (“nodes”) of their trajectories, where the luminaries are sufficiently close. Depending on the distance to the Moon and the Sun, the size of this zone changes. For solar eclipses, its boundaries are 16°-18° away from the node in each direction. The closer to the node the eclipse occurs, the longer it will last. The longest central eclipses occur at the nodes themselves; in this case, the strip of the main phase passes through the tropical latitudes of the Earth.
Nodes of the lunar orbit and eclipse zones
During new moons that occur far from the lunar nodes, solar eclipses are impossible - the Moon passes above or below the Sun in the sky. Only during new moons near the lunar nodes are eclipses possible.
Sliding along the earth's surface, the end of the moon's shadow draws on it " solar eclipse visibility band". The diameter of the lunar shadow on the earth's surface during a total solar eclipse does not exceed 270 km (most often from 40 to 100 km), and the diameter of the lunar penumbra is close to 6750 km (with an annular eclipse, the width of the central stripe can reach 380 km, and the diameter lunar penumbra - 7340 km). In this case, the lunar shadow and penumbra on the earth's surface have the form of oval spots, the shape of which depends on the position of the Sun and the Moon above the horizon. The lower their height, the more gently the axis of both cones is directed towards the earth's surface. spots of shadow and penumbra are elongated.
The path of the moon's shadow across the earth's surface in 2017
The lunar shadow runs along the Earth from 6,000 to 12,000 km. A solar eclipse begins in the western regions at sunrise and ends in the east at sunset. The total duration of all phases of a solar eclipse on Earth can reach six hours.
TYPES OF SOLAR ECLIPSE
There may be an eclipse complete, ring-shaped And private. 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.
Phase (magnitude) of solar eclipses
Since the Moon’s orbit is not circular, but elliptical, at moments favorable for the onset of eclipses, the lunar disk may appear slightly larger or smaller than the solar one. In the first case, a total eclipse occurs. In the second case, an annular eclipse occurs: a shining ring of the Sun's surface is visible around the dark disk of the Moon.
Total solar eclipse - a phenomenon when the Moon completely covers the Sun in the Earth's sky. If the observer is in the central band of the shadow, he sees a total solar eclipse, in which the Moon completely hides the Sun, the solar corona (the outer layers of the Sun's atmosphere that are not visible in normal light of the Sun) is revealed, the sky darkens, and planets and planets may appear on it. bright stars. For example, Venus and Jupiter will be the easiest to spot due to their brightness.
Diagram of a total solar eclipse
Changes in the appearance of the sky during a total solar eclipse
Observers on either side of the central band of totality can only see a partial solar eclipse. The Moon does not pass across the Sun's disk exactly in the center, hiding only part of it. At the same time, the sky does not darken, the stars do not appear.
At annular eclipse The Moon passes across the disk of the Sun, but turns out to be smaller in diameter than the Sun, and cannot hide it completely. This happens because the distance of the Moon from the Earth varies from 405 thousand km (apogee) to 363 thousand km (perigee), and the length of the full shadow cone from the Moon is 374 thousand km, so the top of the lunar shadow cone sometimes does not reach the earth’s surface . In this case, for an observer below the apex of the axis of the lunar shadow cone, the solar eclipse will be annular.
Diagram of an annular solar eclipse
Partial solar eclipse - an eclipse in which the earth's surface is crossed only by lunar penumbra. This occurs when the Moon's shadow passes above or below the Earth's polar regions, leaving only the lunar penumbra falling on our planet.
Scheme of a partial solar eclipse (without the central eclipse band)
During partial eclipses, the weakening of sunlight is not noticeable (with the exception of eclipses with a large phase), and therefore the phases of the eclipse can only be observed through a dark filter.
On the use of protective filters when observing solar eclipses in the material:
DURATION AND FREQUENCY OF SOLAR ECLIPSE ON EARTH
The maximum duration of a total solar eclipse is 7.5 minutes. This is possible from the end of June to mid-July, when the diameter of the solar disk in the sky is minimal (the Sun passes the aphelion of its orbit), and the Moon is at its smallest distance from the Earth (perihelion). The previous long solar eclipse lasted 7 minutes and 7 seconds ( Southeast Asia, June 20, 1955). And the shortest solar eclipse (1 second) occurred on October 3, 1986 (North Atlantic Ocean). The nearest eclipse, lasting 7 minutes 29 seconds, will occur on July 16, 2186.
The longest duration of the annular phase cannot exceed 12.3 minutes, and the duration of a partial eclipse can reach approximately 3.5 hours. The vast majority of eclipses last up to 2.5 hours (partial phases), and their total or annular phase usually does not exceed 2-3 minutes.
Every year there are two eras of eclipses, the interval between which is 177 - 178 days. One eclipse zone occupies about 34°; the Sun spends about 34 days in each zone. And the period between new moons is 29.5 days (synodic month), which means the Moon must necessarily pass through the eclipse zone while the Sun is there, and can visit it twice during this period. Therefore, with each passage of the Sun through the eclipse zone (once every six months), one eclipse should occur, but two can occur. Thus, from 2 to 5 solar eclipses can occur on Earth per year. Over the course of six months (about 183 days), eclipse epochs shift five days ahead, to earlier calendar dates, and gradually move to different seasons of the year - from summer and winter to spring and autumn, again to winter and summer, etc.
Five solar eclipses per year are possible, if the first pair of partial solar eclipses in one zone occurs in early January and February, then the next pair of partial eclipses in another zone may occur at the very beginning of July and August, and from the next probable pair of partial eclipses only one is possible at the very end of December, and the second will occur in January of the next calendar year. Thus, the largest number of solar eclipses in one calendar year does not exceed five, and all of them are necessarily partial with small phases.
Central visibility bands of total and annular eclipses from 1981 to 2100
Most often, there are 2-3 solar eclipses every year, and one of them is often total or annular. Four partial eclipses last occurred in 2000 and 2011. Next years, when four partial eclipses are expected - 2029 and 2047. The last time there were five partial solar eclipses (all of them necessarily partial with small phases) in one calendar year was in 1935. The next time such a phenomenon is expected is in 2206.
The pattern of recurrence of solar eclipses is very complex. Each solar eclipse repeats itself over a period of time of 6585.3 days or 18 years 11.3 days (or 10.3 days if the period contains five leap years), called a saros. During Saros, on average, 42-43 solar eclipses occur, of which 14 are total, 13-14 annular and 15 partial. However, after the end of Saros, each eclipse is repeated under different conditions, since Saros does not contain a whole number of days, and for an excess of about 0.3 days (over 6585 days), the Earth will rotate around its axis by approximately 120° and therefore the lunar shadow will run across the Earth’s surface the same 120° to the west than 18 years ago, and the Sun and Moon will be at slightly different distances from the lunar node. On average, every hundred years there are 237 solar eclipses on Earth, of which 160 are partial, 63 are total, 14 are annular.
In one locality, total solar eclipses occur on average once every 360 years, with rare exceptions. Partial solar eclipses occur in each area much more often - on average every 2-3 years, but since during solar eclipses with a small phase the sunlight almost does not weaken, they are not of great interest and usually go unnoticed.
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To understand why solar eclipses occur, people have been observing them for centuries and keeping score, recording all the circumstances surrounding them. At first, astronomers noticed that a solar eclipse occurs only on a new moon, and not on every moon. After this, paying attention to the position of our planet’s satellite before and after the amazing phenomenon, its connection with this phenomenon became obvious, since it turned out that it was the Moon that was blocking the Sun from the Earth.
After this, astronomers noticed that two weeks after a solar eclipse a lunar eclipse always occurs; what was especially interesting was the fact that the Moon was always full. This once again confirmed the connection between the Earth and the satellite.
A solar eclipse can be seen when the young Moon completely or partially obscures the Sun. This phenomenon occurs only on a new moon, at a time when the satellite is turned to our planet with its unlit side, and therefore is absolutely invisible in the night sky.
A solar eclipse can only be seen if the Sun and new Moon are within twelve degrees on either side of one of the lunar nodes (the two points at which the solar and lunar orbits intersect), and the Earth, its satellite and star line up, with the Moon in the middle.
The duration of eclipses from the initial to the final stage is no more than six hours. At this time, the shadow moves in a strip along the earth's surface from west to east, describing an arc with a length of 10 to 12 thousand km. As for the speed of movement of the shadow, it largely depends on latitude: near the equator - 2 thousand km/h, near the poles - 8 thousand km/h.
A solar eclipse has a very limited area, because due to its small sizes the satellite is not able to hide the Luminary on such long distance: its diameter is four hundred times less than the solar one.
Since it is four hundred times closer to our planet than the star, it still manages to block it from us. Sometimes completely, sometimes partially, and when the satellite is at its greatest distance from the Earth, it is ring-shaped.
Since the Moon is smaller not only than the star, but also the Earth, and the distance to our planet at the closest point is at least 363 thousand km, the diameter of the satellite’s shadow does not exceed 270 km, therefore, an eclipse of the Sun can be observed along the path of the shadow only within this distance . If the Moon is at a great distance from the Earth (and this distance is almost 407 thousand km), the stripe will be significantly smaller.
Scientists suggest that in six hundred million years the satellite will move so far away from the Earth that its shadow will not touch the surface of the planet at all, and therefore eclipses will be impossible. Nowadays, solar eclipses can be seen at least twice a year and are considered quite rare.
- Since the satellite moves around the Earth in an elliptical orbit, the distance between it and our planet during an eclipse is different each time, and therefore the size of the shadow fluctuates within extremely wide limits. Therefore, the totality of a solar eclipse is measured in quantities from 0 to F:
- 1 – total eclipse. If the diameter of the Moon turns out to be larger than the diameter of the star, the phase can exceed unity;
- From 0 to 1 – private (partial);
0 – almost invisible. The Moon's shadow either does not reach the earth's surface at all, or only touches the edge.
It will be possible to see a total eclipse of a star only when a person is in the band along which the shadow of the Moon moves. It often happens that just at this time the sky is covered with clouds and disperses no earlier than the moon’s shadow leaves the area.
If the firmament is clear, with the help special means To protect your eyes, you can observe how Selena begins to gradually obscure the Sun from its right side. After the satellite finds itself between our planet and the star, it completely covers the Sun, twilight sets in, and constellations begin to appear in the sky. At the same time, around the disk of the Sun hidden by the satellite one can see outer layer the solar atmosphere in the form of a corona, which is invisible during normal times.
A total solar eclipse does not last long, about two to three minutes, after which the satellite, moving to the left, opens right side Luminaries - the eclipse ends, the corona goes out, begins to quickly brighten, the stars disappear. Interestingly, the longest solar eclipse lasted about seven minutes (the next event, lasting seven and a half minutes, will only be in 2186), and the shortest was recorded in the North Atlantic Ocean and lasted one second.
You can also observe the eclipse while staying in the penumbra not far from the passage of the Moon's shadow (the diameter of the penumbra is approximately 7 thousand km). At this time, the satellite passes by the solar disk not in the center, but from the edge, covering only part of the star. Accordingly, the sky does not darken as much as during a total eclipse, and the stars do not appear. The closer to the shadow, the more the Sun is covered: while at the border between the shadow and penumbra the solar disk is completely closed, with outside the satellite only partially touches the star, so the phenomenon is not observed at all.
There is another classification, according to which a solar eclipse is considered total when the shadow at least partially touches the earth's surface. If the lunar shadow passes near it, but does not touch it in any way, the phenomenon is classified as private.
In addition to partial and total eclipses, there are annular eclipses. They are very similar to total ones, since the Earth's satellite also covers the star, but its edges are open and form a thin, dazzling ring (while a solar eclipse is much shorter in duration than an annular eclipse).
This phenomenon can be observed because the satellite, passing the star, is as far away from our planet as possible and, although its shadow does not touch the surface, visually it passes through the middle of the solar disk. Since the diameter of the Moon is much less than diameter stars, it is not able to completely block it.
When can you see eclipses?
Scientists have calculated that over the course of a hundred years, about 237 solar eclipses occur, of which one hundred and sixty are partial, sixty-three total, and fourteen annular.
But a total solar eclipse in the same place is extremely rare, and they do not differ in frequency. For example, in the capital of Russia, Moscow, from the eleventh to the eighteenth centuries, astronomers recorded 159 eclipses, of which only three were total (in 1124, 1140, 1415). After that, scientists here recorded total eclipses in 1887 and 1945 and determined that the next total eclipse in the Russian capital will be in 2126.
At the same time, in another region of Russia, in southwestern Siberia, near the city of Biysk, a total eclipse could be seen three times over the past thirty years - in 1981, 2006 and 2008.
One of the largest eclipses, the maximum phase of which was 1.0445 and the width of the shadow stretched over 463 km, occurred in March 2015. The penumbra of the Moon covered almost all of Europe, Russia, the Middle East, Africa and Central Asia. A total solar eclipse could be observed in the northern latitudes of the Atlantic Ocean and in the Arctic (as for Russia, the highest phase of 0.87 was in Murmansk). The next phenomenon of this kind will be observed in Russia and other parts of the northern hemisphere on March 30, 2033.
Is it dangerous?
Since solar phenomena are quite unusual and interesting spectacles, it is not surprising that almost everyone wants to observe all phases of this phenomenon. Many people understand that it is absolutely impossible to look at a star without protecting your eyes: as astronomers say, you can look at this phenomenon with the naked eye only twice - first with the right eye, then with the left.
And all because with just one glance at the brightest star in the sky, it is possible to remain without vision, damaging the retina of the eye to the point of blindness, causing a burn, which, damaging the cones and rods, forms a small blind spot. A burn is dangerous because a person does not feel it at all at the beginning and its destructive effect appears only after a few hours.
Having decided to observe the Sun in Russia or anywhere else on the globe, you must take into account that you cannot look at it not only with the naked eye, but also through sunglasses, CDs, color photographic film, X-ray film, especially filmed, tinted glass, binoculars and even a telescope, if it does not have special protection.
But you can look at this phenomenon for about thirty seconds using:
- Glasses designed to observe this phenomenon and provide protection from ultraviolet rays:
- Undeveloped black and white photographic film;
- A photo filter, which is used to observe a solar eclipse;
- Welding glasses with protection not lower than “14”.
If it was not possible to obtain the necessary funds, but amazing phenomenon I really want to see nature, you can create a safe projector: take two sheets of cardboard white and a pin, then punch a hole in one of the sheets with a needle (do not widen it, otherwise you will only be able to see the beam, but not the darkened Sun).
After this, the second cardboard must be placed opposite the first in the direction opposite to the Sun, and the observer himself must turn his back to the star. The sun's ray will pass through the hole and create a projection of the solar eclipse onto the other cardboard.
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