Lunar eclipse why it occurs. Historical events that occurred during lunar eclipses. Phases of a lunar eclipse
I have seen amazing things more than once moon eclipse. How it happens can be observed without special equipment, but, of course, it is better through a telescope or through the lens of a camera camera. Since the eclipse of the Moon is quite long in time, about 1.5 hours, even a beginner can prepare for this event and take excellent photographs. I think this is a great reason to go out of town, into nature and enjoy the astronomical miracle.
Lunar eclipse diagram
It occurs at the following necessary conditions:
- full moon;
- the proximity of the Moon to the node of its orbit;
- the entry of the Moon into the cone of the earth's shadow (if the shadow covers it completely, there will be a total lunar eclipse).
You can see the darkened celestial companion equally anywhere on our planet, unlike eclipses of the Sun, which are not visible everywhere.
Frequency of lunar eclipses
In total, it was calculated that a maximum of 3 lunar eclipses occur per year, and a minimum of none. In exactly the same order, the event will occur no earlier than in 18 years.
Surprisingly, scientists can accurately calculate and determine at what time and place the next total eclipse of the celestial body will occur. This cyclicity greatly helped researchers to find out the dates of historical events from records of lunar eclipses in ancient chronicles.
I smiled when, reading about Christopher Columbus, I learned such an interesting real fact. He was a literate and smart man, and, knowing when the complete darkening of the Earth's satellite would occur, he intimidated the Indian leader that he would take the Moon away from them if he did not give water and food to his expedition. Horror gripped the Indians when they saw the foreigner’s threat coming true, and began to beg him to “return” the night star, giving him what he asked for. Columbus was a kind fellow and returned the “stolen” Moon to the sky.
I became interested: “But if astronauts or, as is possible in our time, just space tourists find themselves on the Moon at this time, what will they see?” It turned out that the lunar guest at the moment of her total eclipse can watch a total eclipse of the Sun!
– is this a bad omen?
Lunar eclipses inspired the present panic fear in ancient people. Entire generations of people considered lunar eclipses a bad omen until man mastered science and some laws of cosmic and universal scales. It was believed that the burgundy color of the Moon signifies the approach of war, blood, and death. Fortunately, science was able to remove the veil of mystery from this phenomenon, and all supernatural ideas about lunar eclipses have sunk into oblivion.
When do lunar eclipses occur?
They appear at certain times, but only when there is a full moon. At this time, the night star begins to pass away from the Earth, opposite the Sun. Here the Moon can fall into the shadow cast by the Earth at this time. That's when people can watch.
How do lunar eclipses occur?
They occur differently from solar ones. The fact is that the Moon does not disappear completely, as the Sun does during a solar eclipse. The moon is only faintly visible. This happens for the following reason: part of the sun's rays, passing through the earth's atmosphere, are refracted in it and enter inside the earth's shadow, falling directly on the Moon. It is known that the air transmits red rays of light, which is why the night star turns brown or copper-red.
It is known that the diameter of the Earth is exactly 4 times greater than the diameter of the Moon. Accordingly, the shadow of the Earth is 2.5 times larger than the Moon. All this leads to the fact that the night luminary can sometimes completely enter the earth's shadow, which causes a total lunar eclipse. Scientists have calculated and come to the conclusion that total lunar eclipses are longer than total solar eclipses and can last up to 1 hour 40 minutes!
According to astronomers' observations, up to three lunar moons can occur in one year. It is worth noting that they repeat exactly after the same period of time as solar eclipses, which is equal to 18 years 11 days and 8 hours. Scientists even gave this period a name: saros (repetition). It is curious that saros was calculated in ancient times, so calculating and predicting the exact day is not difficult. But predicting the exact time of its onset, as well as the conditions for its visibility, is a more difficult task: different generations Astronomers have been studying the motion of the Moon and Earth for centuries to solve this problem. Currently, possible errors in calculating the moments of lunar eclipses do not exceed 4 seconds!
A lunar eclipse is observed when the Earth's satellite enters the shadow that our planet casts from the Sun, that is, the Earth in this case is between the luminary and the Moon. In this case, the Moon can only partially fall into the shadow, or it can be completely covered by it, so a distinction is made between partial and total eclipses. Every year two or more lunar eclipses can be observed from different phases.
Instructions
When the Sun shines on the Earth, a cone of dense shadow is formed on the other side of the planet, surrounded by penumbra. If the Moon at this moment partially or completely enters this cone, a lunar eclipse will be observed from the surface of the planet on the side where our satellite is visible. It does not look as impressive as the sun, but it is easier to observe. The brightly lit Moon slowly begins to veil, but remains visible thanks to scattered rays of sunlight in the Earth's atmosphere, which illuminate its surface with a reddish light. An eclipse can last for more than 30 minutes; the Moon gradually emerges from the shadow and is illuminated by the Sun again. If the eclipse is partial, then only part of the satellite becomes dark. In some cases, the Moon does not enter total shadow, but remains in partial shadow - the eclipse is called penumbral.
On average, 2-3 lunar eclipses occur every year, but in some years this phenomenon is not observed at all, and in other years you can see 4 or even 5 lunar eclipses. The number of eclipses varies from year to year with a certain frequency, which repeats every 18 years and 11 days. This period is called the saros or draconic period. During this period, 29 lunar eclipses occur - 12 less than solar eclipses. Two thirds of all eclipses are partial, one third are total.
The moon is shining reflected light Sun; therefore, when it falls into the shadow of the Earth (Fig. 30), it stops shining - a lunar eclipse occurs. Strictly speaking, the Moon continues to shine due to the fact that part of the Sun’s rays, refracted in the Earth’s atmosphere, illuminates the Moon, and we see it in the form of a dark red disk. Blue rays are scattered in the earth's atmosphere, as a result a person sees during the day blue sky and the red Sun at sunset.
The Earth's shadow has the shape of a cone, the cross-sectional diameter of which at the distance of the Moon is 2.5 times greater than the diameter of the Moon, which is why a lunar eclipse lasts quite a long time. The maximum duration of a total lunar eclipse is 1 hour 45 minutes. The eclipse is visible across the entire night hemisphere of the Earth. There may be an eclipse complete, if the Moon enters the shadow completely, or private, if only part of the Moon falls into the shadow.
When the shadow of the Moon falls on the Earth, it comes solar eclipse(Fig. 30). It may be complete where the shadow falls and private in the semi-shade area. If at the moment of an eclipse the Moon is at the farthest point in its orbit from the Earth, and the Earth is at the closest point to the Sun, then the disk of the Moon does not completely cover the disk of the Sun, and annular eclipse.
The Moon's shadow traces a long strip on Earth no more than 200 km wide; the width of the penumbra can be several thousand kilometers. Therefore, total solar eclipses are visible in each specific area very rarely, on average once every 300 years. In Moscow, the next total eclipse of the Sun will be in 2126 (the previous one was in 1887). The maximum duration of a total solar eclipse (at the equator) is 7.5 minutes. In areas far from the equator, an eclipse, as a rule, lasts no more than 2-2.5 minutes.
An eclipse can only occur on a full moon (lunar) or a new moon (solar). Figures 31, 32 show the projections onto the celestial sphere of the disks of the Moon and the Sun for the moments of three consecutive new moons and two consecutive full moons. The angle between the ecliptic and the lunar orbit is greatly exaggerated.
Transit of Venus across the sun
Twice per century, Venus passes between the Earth and the Sun so that its disk is projected onto the disk of the Sun (Fig. 9). Such a passage, for example, took place on June 8, 2004 at 9:10-20 minutes Moscow time. It lasted about 6 hours (for each observation location, the start and end times of the passage are slightly different). You need to observe the passage on a screen on which the image of the Sun is projected. The planet is visible as a small dark circle moving against the background of the solar disk. If the diameter of the projection of the solar disk is 10 cm (which is accessible to a school telescope), then the diameter of the projection of Venus is 3 mm. Only people with very acute vision can see it with the naked eye (protected by a dense filter). It is very interesting to observe the moment when the planet crosses the edge of the Sun's disk. It was at such a moment, in 1761, that M.V. Lomonosov noticed that the disk of Venus, which had already partially crossed the edge of the disk, was surrounded by radiance (Fig. 10). He quite correctly concluded that this is the result of the refraction of light from the Sun in the upper layers
The moon does not have its own light, but its surface reflects the sun's rays, so it serves as our night luminary. During eclipses, our satellite turns red, which is why lunar eclipses are sometimes called “blood moons.”
Why do lunar eclipses occur?
These celestial phenomena occur when the Sun, Earth and Moon line up in a straight line. The Sun is behind the Earth, as a result the Earth casts a shadow on the Moon, and a lunar eclipse occurs.
They always occur on a full moon, but we cannot observe a lunar eclipse on every full moon. This is because the Moon's orbit is inclined at an angle of 5 degrees to the Earth's orbital plane, also known as the ecliptic (Earth's path around the Sun). The points where the two orbits intersect are called the lunar nodes, and eclipses can only occur when the full moon occurs near the lunar node. In other cases, the Earth cannot cast a shadow on the surface of the Moon.
Thus, for a lunar eclipse to occur, two conditions must be met:
Full Moon in the heavens;
The proximity of the Earth to one of the lunar nodes.
Types of lunar eclipses
There are 3 types: full, partial and penumbra.
A total lunar eclipse occurs when the central (dark) part of the Earth's shadow covers the entire visible side Moons. The Earth's shadow is about 1.4 million kilometers wide.
A partial lunar eclipse can be observed when only part of the visible surface of the Moon is covered by the Earth's shadow.
When the Sun, Earth and Moon are not aligned perfectly straight line, only the outer part of the Earth's shadow (penumbra) eclipses the Moon. Such an eclipse is called a penumbral eclipse.
Why does the moon turn red
Even if the Earth completely blocks sunlight from hitting the surface of the Moon, our satellite is still visible in the sky. This occurs because the Earth's atmosphere refracts sunlight and indirectly illuminates the lunar surface. During a total lunar eclipse, the Moon darkens and turns red because the Earth's atmosphere is most permeable to rays of the red color spectrum. However, the Moon can also turn yellow, orange, or brown colors, because in earth's atmosphere There are clouds and dust particles, it is they that allow waves of different lengths to reach the surface of our satellite.
Where can you see lunar eclipses?
This celestial phenomenon can be seen by everyone who is on the night side of the Earth. It can be observed with the naked eye. The chance of seeing a lunar eclipse is much higher than a solar eclipse (it is visible only in a narrow band in certain areas of the Earth), although both occur at similar intervals. In one calendar year there can be two lunar eclipses (about six months apart), sometimes three, but in some years none occur.
Myths and beliefs about eclipses
The ancient Incas believed that lunar eclipses were caused by a jaguar trying to devour the moon. The red or blood-red color that the earth's satellite turns during a total lunar eclipse was explained by the attack of a big cat. The Incas were afraid that after attacking the Moon, a huge jaguar would crash to Earth and start eating people. They tried to drive him away with noise and screams, and teased the dogs to bark loudly.
However, jaguars were not the only predators in mythology that wanted to eat the heavenly body. Residents ancient Mesopotamia also saw eclipses as attacks on the moon, but in their story the attackers were seven demons. Other peoples had similar beliefs, which included bloodthirsty dragons and other mythical creatures.
The Hupa American Indians of Northern California believed that Luna had 20 wives and many animals, most of them mountain lions and snakes. If they did not bring enough food, they attacked and inflicted wounds, then the blood turned the Moon red. The eclipse ended when the wives came to protect them, drove away the predators and healed the Moon.
The Indians of Southern California believed that the eclipse signaled that the moon was ill, so they sang chants and prayed for her to return to health.
Not all ancient cultures attributed negative meanings to lunar eclipses. According to a myth from Benin, the Sun and Moon fight each other, and people come to their aid to judge them. The ancient inhabitants of Benin believed that on the days of lunar eclipses it was necessary to get together, resolve old feuds and restore good relations.
Astronomical knowledge is an interesting part general knowledge necessary for a person to understand what is happening in environment. We direct our gaze to the sky whenever dreams take over our minds. Sometimes certain phenomena strike a person to the core. We will talk about these in our article, namely what a lunar and solar eclipse is.
Although today the disappearance or partial concealment of luminaries from our eyes does not cause such superstitious fear as it did among our ancestors, a special aura of mystery of these processes remains. Nowadays, science has facts that can be used to explain this or that phenomenon in a simple and accessible way. We will try to do this in today’s article.
and how does it happen?
A solar eclipse is one that occurs as a result of the Earth's satellite eclipsing the entire solar surface or part of it facing observers located on the ground. However, it is possible to see it only during the new moon, when the part of the Moon facing the planet is not completely illuminated, that is, it becomes invisible to the naked eye. We understand what an eclipse is, and now we will find out how it happens.
An eclipse occurs when the Moon is not illuminated by the Sun from the side visible on Earth. This is possible only in the growing phase, when it is near one of the two lunar nodes (by the way, the lunar node is the point of intersecting lines of two orbits, solar and lunar). Moreover, the lunar shadow on the planet has a diameter of no more than 270 kilometers. Therefore, it is possible to observe an eclipse only at the location of the passing shadow strip. In turn, the Moon, rotating in orbit, maintains a certain distance between it and the Earth, which at the moment of an eclipse can be completely different.
When do we observe a total solar eclipse?
You've probably heard about the concept of a total eclipse. Here we will once again clearly outline what a total solar eclipse is and what conditions are needed for it.
The shadow of the Moon falling on the Earth is a certain spot of a certain diameter with a possible change in size. As we have already said, the diameter of the shadow does not exceed 270 kilometers, while the minimum figure is approaching zero. If at this moment the observer of the eclipse finds himself in dark stripe, he has a unique opportunity to witness the complete disappearance of the Sun. At the same time, the sky becomes dark, with the outlines of stars and even planets. And around the solar disk, previously hidden from view, the outline of a crown appears, which usual time impossible to see. A total eclipse lasts no more than a few minutes.
The photographs of this unique phenomenon presented in the article will help you see and understand what a solar eclipse is. If you decide to observe this phenomenon live, you must follow safety precautions regarding vision.
With this, we finished the information block in which we learned what a solar eclipse is and what conditions are necessary to see it. Next we have to get acquainted with the lunar eclipse, or, as it sounds in English, lunar eclipse.
What is a lunar eclipse and how does it happen?
A lunar eclipse is a cosmic phenomenon that occurs when the Moon falls into the shadow of the Earth. At the same time, as with the Sun, events can have several development options.
Depending on certain factors, a lunar eclipse can be total or partial. Logically, we can well assume what this or that term that characterizes a particular eclipse means. Let's find out what a total lunar eclipse is.
How and when does a planet's satellite become invisible?
Such an eclipse of the Moon is usually visible where it is located above the horizon at the appropriate moment. The satellite appears in the shadow of the Earth, but at the same time a total eclipse is not able to hide the Moon completely. In this case, it is only slightly shaded, acquiring a dark, reddish tint. This happens because, even being completely in the shadow, the lunar disk does not cease to be illuminated by the sun's rays passing through the earth's atmosphere.
Our knowledge has expanded with facts about the lunar eclipse. However, that's not all possible options eclipse of a satellite by the earth's shadow. We'll talk about the rest further.
Partial lunar eclipse
As in the case of the Sun, the darkening of the visible surface of the Moon is often incomplete. We can observe a partial eclipse when only a certain part of the Moon is in the shadow of the Earth. This means that when part of the satellite is eclipsed, that is, obscured by our planet, then its second part continues to be illuminated by the Sun and remains clearly visible to us.
A penumbral eclipse will seem much more interesting and unusual, differing from others in astronomical processes. We will talk further about what a penumbral lunar eclipse is.
Unique penumbral lunar eclipse
This type of eclipse of the Earth's satellite occurs a little differently than a partial eclipse. From open sources or it’s easy to find out from your own experience that there are areas on the surface of the Earth where the sun’s rays are not completely obscured, and therefore cannot be a shadow. But there is no direct sunlight either. This is the penumbra region. And when the Moon, which finds itself in this very place, finds itself in the penumbra of the Earth, we can observe a penumbral eclipse.
When entering the penumbral region, the lunar disk changes its brightness, becoming slightly darker. True, such a phenomenon is almost impossible to notice and recognize with the naked eye. For this you will need special devices. It is also interesting that at one edge of the Moon's disk the darkening may be more noticeable.
So we have finished the second main block of our article. Now we can easily explain ourselves what a lunar eclipse is and how it happens. But Interesting Facts The story about solar and lunar eclipses does not end there. Let's continue the topic by answering some questions related to these amazing phenomena.
Which eclipses occur more often?
After everything that we have learned from the previous parts of the article, the question naturally arises: which of the eclipses do we have a better chance of seeing in our lives? Let's also say a few words about this.
Incredible, but true: the number of eclipses of the Sun is greater, even though the Moon is smaller in size than. After all, knowing what an eclipse is and why it occurs, one might think that the shadow of a larger object is more likely to block a smaller one than vice versa. Based on this logic, the size of the Earth allows us to hide the lunar disk in no time.
Nevertheless, it is precisely solar eclipses that happen more often on the planet. According to statistics from astronomers and observers, for every seven eclipses there are only three lunar and solar eclipses, respectively, four.
The reason for the amazing statistics
The disks of the celestial bodies closest to us, the Sun and the Moon, are almost identical in diameter in the sky. It is for this reason that solar eclipses can occur.
Typically, solar eclipses occur during the new moon period, that is, when the Moon approaches its orbital nodes. And since it is not perfectly round, and the nodes of the orbit move along the ecliptic, during favorable periods the disk of the Moon on the celestial sphere can be either larger, smaller, or even equal to the solar disk.
In this case, the first case contributes to a total eclipse. The decisive factor is the angularity. At its maximum size, the eclipse can last up to seven and a half minutes. The second case involves complete shading for just seconds. In the third case, when the moon's disk is smaller than the sun's, a very beautiful eclipse occurs - an annular one. Around the dark disk of the Moon we see a shining ring - the edges of the solar disk. This eclipse lasts 12 minutes.
Thus, we have supplemented our knowledge of what a solar eclipse is and how it occurs with new details worthy of amateur researchers.
Eclipse factor: location of luminaries
An equally important reason for an eclipse is the uniform distribution of heavenly bodies. The Moon's shadow may or may not fall on the Earth. And sometimes it happens that only the penumbra of an eclipse falls on the Earth. In this case, you can observe a partial, that is, incomplete eclipse of the Sun, which we already talked about when we talked about what a solar eclipse is.
If a lunar eclipse can be observed from the entire night surface of the planet, from which the circumference of the lunar disk is visible, then a solar eclipse can only be observed when you are in a narrow strip with an average width of 40-100 kilometers.
How often can you see eclipses?
Now that we know what an eclipse is and why some happen more than others, one more exciting question remains: how often can these amazing phenomena be observed? After all, in our lives, each of us has heard only one news about an eclipse, a maximum of two, some - not a single one...
Despite the fact that a solar eclipse occurs more often than a lunar eclipse, it can still be seen in the same area (remember the strip with an average width of 40-100 kilometers) only once every 300 years. But a person can observe a total lunar eclipse several times in his life, but only if the observer has not changed his place of residence throughout his life. Although today, knowing about the blackout, you can get anywhere and by any means of transport. Those who know what a lunar eclipse is will probably not stop walking a hundred or two kilometers for the incredible spectacle. Today there are no problems with this. And if you suddenly receive information about the next eclipse in some place, do not be lazy and spare no expense in order to get to the place of maximum visibility at the moment when you can observe the eclipse taking place. Believe me, no distance can compare with the impressions received.
Nearest visible eclipses
You can learn about the frequency and schedule of eclipses from the astronomical calendar. Moreover, about significant events like a total eclipse will definitely be talked about in the media. The calendar says that the next solar eclipse visible in the Russian capital will take place on October 16, 2126. Let us also recall that the last eclipse in this territory could be observed more than a hundred years ago - in 1887. So Moscow residents won’t have to watch a solar eclipse for many years. The only opportunity to see this amazing phenomenon is to go to Siberia, to Far East. There you can observe a change in the brightness of the Sun: it will only darken a little.
Conclusion
With our astronomical article, we tried to explain clearly and briefly what an eclipse of the Sun and Moon is, how these phenomena occur, and how often they can be seen. The conclusion of our research in this area: eclipses of different celestial bodies occur according to different principles and have their own characteristics. But understanding some of the details necessary for the average person to fully understand the environment is very important.
Nowadays, thanks to developed science and technology, the temporarily extinguished star is no longer frightening, but remains just as alluringly mysterious. Today we know what a lunar and solar eclipse are and what they bring to us. Let the interest in them now be purely cognitive as a rare outlandish phenomenon. Finally, we wish you to see at least one eclipse with your own eyes!
