Eclipse ~ eclipse ~ total solar eclipse ~ total lunar eclipse, what is it?

Lunar eclipse means that the moon goes around the earth and moves between the sun and the earth. At this time, it is the first day of the first lunar month. If the sun, the moon and the earth are in a straight line, the moon blocks the sunlight that hits the earth, and the shadow behind the moon just falls on the earth, then a solar eclipse occurs. People in the shadow of the moon on the earth began to see the sun gradually weakening, and the sun was covered by a circular shadow. When the sky is dark and completely covered, the brightest stars and planets can be seen in the sky. After a few minutes, the sun gradually emerged from the shadow edge of the moon and began to shine and make the last contact. Because the moon is smaller than the earth, only people in the shadow of the moon can see the solar eclipse. Total lunar eclipse occurs when the moon blocks all the sun, partial solar eclipse occurs when the moon blocks part of the sun, and annular solar eclipse occurs when the moon blocks the central part of the sun. The total solar eclipse lasts no more than 7 minutes and 58 seconds. China has the oldest solar eclipse record in the world, and there have been exact solar eclipse records for over 0/000 years BC.

lunar eclipse

The principle of lunar eclipse is similar to that of solar eclipse. On the fifteenth and sixteenth days of each month in the lunar calendar, the moon runs in the opposite direction to the sun. At this time, if the centers of the earth and the moon are roughly on the same straight line, the moon will enter the umbra of the earth and produce a total lunar eclipse. If only a part of the moon enters the umbra of the earth, a partial lunar eclipse will occur. When the moon enters the penumbra of the earth, it should be a penumbral eclipse, but it is not called an eclipse because the brightness drops very little, so there are only two kinds of eclipses: total eclipse and partial eclipse.

Eclipses all occur at the "moon", but not every "moon", which is the same as not every "new moon" has a solar eclipse. Under normal circumstances, the moon either passes above the Earth's umbra or leaves under the Earth's umbra, and rarely or partially passes through the Earth's umbra, so an eclipse will not occur under normal circumstances. Eclipses occur up to three times a year, and sometimes they never happen at all. From now until 2000, China can see two total lunar eclipses (1September 1997 17, July 2000 16) and a partial lunar eclipse (1July 28, 1999).

In ancient times, people did not understand the scientific truth of solar eclipse, and the fear of solar eclipse was no less than that of solar eclipse. It is said in foreign countries that Columbus sailed to Jamaica in South America at the beginning of the16th century, and there was a conflict with the local aborigines. Columbus and his sailors were trapped in a corner, without food and water. The situation is very critical. Knowing that there would be a total lunar eclipse that night, Columbus, who knew something about astronomy, shouted to the natives, "No food, no moonlight!" " In the evening, Columbus's words came true, and there was no moonlight. When the natives saw this scene, they were afraid, so they quickly made peace with Columbus.

The solar eclipse in Mesopotamia in 2283 BC was the earliest in the world, followed by that in China in 1 136 BC. Eclipses have been promoting the development of human understanding. As early as 2,000 years ago, Zhang Heng, an astronomer in Han Dynasty in China, figured out the principle of lunar eclipse. In the 4th century BC, Aristotle saw that the shadow of the earth was round from the solar eclipse, but inferred that the earth was spherical. Alistair, an ancient Greek astronomer in the 3rd century BC, and Hipparchus in the 2nd century BC both proposed to measure the relative size of the Sun-Earth-Moon system through solar eclipse. The latter also proposed to observe the lunar eclipse in two distant places at the same time to measure the geographical longitude. In the 2nd century AD, Ptolemy used the ancient lunar eclipse records to study the movement of the moon, and this method has continued to this day. Before the appearance of rockets and artificial earth satellites, scientists have been exploring the atmospheric structure of the earth by observing eclipses.

Chariot cycle of solar eclipse

A solar eclipse is called a lunar eclipse. From the principle of solar eclipse, we can see that the appearance of solar eclipse is closely related to the rendezvous of the sun, the earth and the moon, and it is periodic, so the solar eclipse should naturally be periodic. The period of copulation was discovered by the Babylonians in Cuba, and it is called "Shaluo period" ("Shaluo" means repetition), which is 18+ 1 1 day. That is 6585.32 days.

How many eclipses can occur a year? For the whole earth, it occurs at most three times a year, sometimes 1 time does not occur, and solar eclipses occur at most five times a year and at least two times. In this way, there are more eclipses every year, but why do people always see more eclipses than eclipses? This is because the scope of the solar eclipse belt is small, and only local areas can be seen on the earth; For a certain place, it takes about three years to see a partial solar eclipse and 300 years to see a total solar eclipse. Once an eclipse occurs, people on half the earth can see it at night. On average, the probability of seeing an eclipse in a certain area is half of the number of eclipses, so people are more likely to see an eclipse than to see an eclipse.

Explain the eclipse

The celestial phenomena when the moon enters the earth's shadow cone. Total lunar eclipses occur on a full moon night. Due to the refraction of solar light by the earth's atmosphere, part of the red light reaches the moon's apparent circle, forming a copper-red moon surface. Eclipses occur 2 to 5 times a year, and the moon itself does not give off light, so residents in the night hemisphere can see eclipses when they occur. There are three kinds of solar eclipses: total solar eclipse, partial solar eclipse and penumbral eclipse. The eclipse occurs at the full moon. When the earth is between the sun and the moon, only a few full moons can have a solar eclipse, because the intersection angle between the ecliptic and the ecliptic is 50'9 ". Only when the moon and the sun are at the same latitude will the shadow of the earth touch the surface of the moon.

The diameter of the earth is about four times that of the moon, and the diameter of the umbra of the earth in the orbit of the moon is about 2.5 times that of the moon, so there will be no eclipse. When the umbra of the earth covers a part of the moon, a partial lunar eclipse will occur, and when the moon enters the umbra of the earth, a total lunar eclipse will occur. When the moon enters the penumbra of the earth, a penumbral eclipse will occur.

The number of total lunar eclipses in each century is 70.4, accounting for 28.94% of the total lunar eclipses. The frequency of partial eclipse in each century is 83.3 times, accounting for 34.46%; The number of penumbral eclipses in a hundred years is 89.0, accounting for 36.60%.

The process of total solar eclipse can include the following five periods: initial loss, eclipse, eclipse, luminescence and last contact.

The first solar eclipse always starts from the western edge of the sun's circular surface, because the moon revolves around the earth from west to east. When the eastern edge of the moon just touches the round surface of the sun (that is, when the eastern edge of the moon is tangent to the western edge of the moon), it is called the initial loss. The first loss is the moment when the eclipse begins.

The eclipse begins with the initial loss, that is, the partial eclipse stage. The moon continues to move eastward, the part of the sun's circular surface covered by the moon gradually increases, and the intensity and heat of sunlight are obviously reduced. When the eastern edge of the moon surface is inscribed with the eastern edge of the sun surface, it is called eclipse. At this time, the entire circular surface of the sun is covered, so the solar eclipse is the moment when the total solar eclipse begins.

When the sun is about to be completely blocked by the moon, a diamond-like arc light will suddenly appear on the eastern edge of the sun, just like the striking shining light on a diamond ring. This is the diamond ring, and at the same time it will form a string of bright spots in an instant, hanging high in the dark sky like a string of dazzling pearls. This phenomenon is called pearl eclipse, which was first described by British astronomer Billy, so it is also called Billy Pearl. This is because there are many rugged peaks on the surface of the moon. When the sun shines on the edge of the moon, it forms a "pearl-like bead" phenomenon. Belle pearls appear for a short time, usually only one or two seconds, and then the sun is completely blocked, resulting in a total solar eclipse.

During the total solar eclipse, the earth became dark and animals returned to their nests. At this time, there will be wonderful scenery in the sky: bright stars come out, and in the original position of the sun, I can only see the dark moon wheel, which presents a beautiful reddish light around it, which is the chromosphere of the sun; Outside chromosphere, there is still silvery white or light blue light, which is the outer atmosphere of the corona; In some areas of the red ball, you can also see some clouds that erupt upward like flames. This is a prominence. Prominence is a gas "fountain" formed by the violent movement of gas in the upper part of chromosphere. Chromosphere, solar decoy and corona are all components of the sun's outer atmosphere, which can be observed under certain conditions at ordinary times, but these phenomena are particularly clear during the total solar eclipse.

After the eclipse, the moon wheel continues to move eastward, and when the center of the moon wheel is closest to the center of the sun, it reaches the eclipse. For partial solar eclipse, the solar eclipse is the moment when the sun is covered by the moon the most. The moment when the moon continues to move eastward and the western edge of the moon meets the western edge of the sun is called luminescence, which is the moment when the total solar eclipse ends. Before the birth of light, the phenomenon of diamond rings and beads will reappear on the western edge of the sun, but will soon disappear. Then, a dazzling light shines on the west of the sun. Chromosphere, prominence and corona, which can be seen during the total solar eclipse, disappeared in the sun, the stars disappeared and the sun lit up again.

After the last contact with raw light, the moon continued to move away from the sun, and the part covered by the sun gradually decreased. The moment when the western edge of the moon is tangent to the eastern edge of the sun is called the last contact. At this time, the sun showed a disc shape again, and the whole process of total solar eclipse came to an end.

The process of partial solar eclipse and total solar eclipse is roughly the same. Because it only has a partial solar eclipse, there are only two stages: initial loss, heavy food and last contact, and there is no food and light. There are also stages of annular eclipse, such as initial loss, heavy food, heavy food, light production and final contact.

When forecasting a total solar eclipse or an annular solar eclipse, the Observatory often reports the time of these five stages. According to these reports, people can understand the whole process of solar eclipse and observe it. As for the partial solar eclipse, of course, the Observatory only gave it three times in the forecast: the first deficit, the worst eclipse and the last contact.

In the solar eclipse forecast, we can often see the word "eclipse" to indicate the degree of solar eclipse. For solar eclipse, solar eclipse does not refer to the area covered by the circular surface of the sun, but refers to the ratio of the covered part of the diameter of the sun to the diameter of the sun. Take the diameter of the sun as 1, and if the solar eclipse is 0.5, it means that the diameter of the sun is covered by half; If the solar eclipse is 1, it means that the entire round surface of the sun is covered, and that is a total solar eclipse. Obviously, the larger the part, the greater the degree to which the sun is covered. The food fraction of partial solar eclipse is less than 1.0, and that of total solar eclipse is less than 1.0.

Where food belts and moon shadows sweep. The duration of the eclipse is related to the speed of the lunar cone moving on the ground and the direction of the earth's rotation. For the total solar eclipse, the apparent diameter of the moon is only slightly larger than that of the sun, and the shadow of the moon moves quickly on the ground, so the total solar eclipse time is very short. The total solar eclipse time seen somewhere in the total solar eclipse belt is usually only two or three minutes, not more than seven minutes at most. If the total solar eclipse belt passes through the equator, the total solar eclipse can last for 7 minutes and 40 seconds, which is the best time to observe the total solar eclipse.

When an annular eclipse occurs, the moon is always near the apogee, and at this time the speed of the moon is slow, so the annular eclipse lasts for a long time. If the annular eclipse occurs near the equator, the time for observing the annular eclipse near the equator can be as long as 12 minutes and 42 seconds.

On a global scale, if you count the time when the penumbra of the moon begins to cover the sun, the whole process from the initial loss of contact to the last contact can be as long as three and a half hours.

During a partial solar eclipse, because the range of the moon shadow is larger than its umbra, the length of the eclipse depends on the size of the eclipse, and the larger the eclipse, the longer it takes.

Because the shadow cone of the moon is thin and long, when it falls on the earth's surface, it occupies a very small area, no more than one tenth of the total area of the earth, and the maximum diameter is only more than 260 kilometers. When the moon revolves around the earth, the shadow cone sweeps a relatively long area from west to east on the ground, and a solar eclipse can be seen in the area swept by the shadow of the moon. So this belt is called "Eclipse Belt". If there is a total solar eclipse in the belt, it is called a total solar eclipse belt; If there is an annular eclipse in the belt, it is called an annular eclipse belt. It can be seen that the range of partial solar eclipse is very wide, not like a strip, but a large area.

The total solar eclipse belt is a narrow path with a width of only two or three hundred kilometers and a length of several thousand to 10000 kilometers (sometimes the width of the total solar eclipse belt is only a few kilometers). Only in the area swept by the total solar eclipse belt can we see the occurrence of total solar eclipse or annular solar eclipse. On both sides of the total solar eclipse belt is a relatively wide penumbra swept area, where you can see the partial solar eclipse. The closer to the total eclipse zone, the greater the degree of partial eclipse; The farther away from the belt, the smaller the degree of partial eclipse; You can't see the eclipse beyond the penumbra.

Because the moon moves from west to east, its shadow also moves in the same direction, so the time to watch the solar eclipse varies from place to place. When the western area on the ground is already in the shadow area, people in this area have already seen the solar eclipse, but people in the eastern area can't see the solar eclipse at the same time, and they can't see the solar eclipse until the moon shadow moves eastward. Therefore, westerners always see eclipses before orientals.

Eclipses occur every year, but because the total eclipse belt is a narrow strip, it is estimated that every 200 ~ 300 years, a certain area or city will have the opportunity to be swept by the total eclipse belt. Therefore, for people living in a city, they may have never seen a total solar eclipse in their lives.

Solar eclipse is a phenomenon in nature. When the sun, the earth and the moon are exactly or almost on the same straight line (the earth is between the sun and the moon), the light from the sun to the moon will be partially or completely blocked by the earth, resulting in an eclipse.

When an eclipse occurs, the direction difference between the sun and the moon is 180 for the earth, so the eclipse must occur in Wangwang (that is, around the fifteenth day of the lunar calendar). It should be noted that the orbits of the sun and the moon in the sky (called ecliptic and ecliptic respectively) are not on the same plane, but have an intersection angle of about 5, so only when the sun and the moon are located near the intersection of ecliptic and ecliptic respectively can they form a straight line and produce an eclipse.

Eclipses can be divided into three types: partial eclipse, total eclipse and penumbral eclipse. When only a part of the moon enters the umbra of the earth, there will be a partial lunar eclipse; When the whole moon enters the umbra of the earth, a total lunar eclipse will occur. As for the penumbral eclipse, it means that the moon just passes through the penumbral region of the earth, which causes the brightness of the moon to be extremely slightly weakened, so it is difficult for the naked eye to see the difference, so it is not noticed by people. (Source: Beijing Youth Daily) The process of an eclipse can be divided into five stages: first loss, eating, eating, giving birth to light and last contact.

First loss: The moon has just touched the umbra of the earth, marking the beginning of the eclipse.

Eclipse: The western edge of the moon is inscribed with the western edge of the Earth's umbra, and the moon just enters the Earth's umbra.

Eclipse: The center of the moon is closest to the center of the Earth's umbra.

Luminescence: the eastern edge of the moon is inscribed with the eastern edge of the umbra of the earth, and the total solar eclipse phase ends at this time.

Final contact: the western edge of the moon is tangent to the eastern edge of the umbra of the earth. At this time, the whole eclipse was over.

The degree of eclipse is called "eclipse", which is equal to the ratio of the farthest distance from the edge of the moon wheel to the umbra of the earth and the meridian of the moon when the eclipse is serious.

Observation of total lunar eclipse

The moon can be observed directly with the naked eye, and the following two total lunar eclipses can be observed without any special equipment.

1. Record the whole process of total lunar eclipse.

Prepare some observation paper before observation, draw a big circle on the paper, and mark 0 to 360 counterclockwise on the circle. The position of 0 indicates the true north pole of the moon. During the total solar eclipse, draw a sketch of the eclipse every 4 minutes. From this, we can get a group of eclipse pictures of the whole process of total lunar eclipse.

2. Observe the brightness and color of the moon.

During the eclipse, the brightness and color of the lunar surface can be divided into the following five levels: level 0, which is very dim and almost invisible; 1, slightly bright, black and yellow, the details are difficult to distinguish; Grade 2, slightly bright, dark red or brown, with some dark spots in the middle and quite bright outside; Level 3, brick red, you can see the details of the moon, but it is very vague; Level 4, copper red, very bright, very bright outside, slightly blue, you can see big details. When observing the total lunar eclipse, it is necessary to judge the brightness and color scale of the lunar surface and record it. At the same time, record the weather at that time.