●Solar eclipse is the moon around the earth to the middle of the sun and the earth, if the sun, the moon, the earth three happen to line up or close to a straight line, the moon blocked the sunlight shot to the earth to go up, the moon behind the black shadow falls right on the earth, the phenomenon of solar eclipse. People in the shadow of the moon on the Earth began to see the sunlight gradually weakened, the face of the sun was rounded black shadow cover, the sky turned dark, all covered when the brightest stars and planets can be seen in the sky, a few minutes, from the edge of the moon's black shadow gradually revealed the sunlight, began to be born and resumed round. Since the Moon is smaller than the Earth, only people in the Moon's shadow can see the eclipse. A total solar eclipse occurs when the Moon blocks all of the Sun, a partial solar eclipse occurs when it covers part of it, and an annular solar eclipse occurs when it covers the central part of the Sun. Since the orbit of the Moon and the Earth is not circular, and the distance between the Sun and the Moon and the Earth is sometimes close and sometimes far away, the shadow formed by the Sunlight being covered by the Moon can be divided into the umbra, pseudo-umbra (formed when the Moon is farther away from the Earth) and penumbra on the Earth. Observers can see total solar eclipses within the umbra; annular solar eclipses within the pseudo umbra; and partial solar eclipses within the penumbra.
II. How long does a solar eclipse last?
●Total solar eclipses occur with a duration of no more than 7 minutes and 31 seconds. The maximum duration of an annular solar eclipse is 12 minutes and 24 seconds. A French astronomer delayed his observation of a total solar eclipse by chasing the moon's shadow in a supersonic airplane, extending the observation time to 74 minutes.
Third, what are the conditions for an eclipse to occur?
●The Moon's orbit to the middle of the Sun and the Earth does not occur every time an eclipse occurs, and two conditions need to be met for an eclipse to occur. First, a solar eclipse always occurs on the first day of the lunar month. Not all solar eclipses occur on the first day of the lunar month, because the Moon's orbit (the White Way) and the Sun's orbit (the ecliptic) are not in the same plane. There is an angle of 5°9′ between the plane of the White Way and the plane of the ecliptic. If, on the solstice, both the Sun and the Moon move near the intersection of the White Way and the ecliptic, and the Sun is at a certain angle from the intersection (the eclipse limit), a solar eclipse can occur, which is the second condition to be met.
Fourth, what is meant by the phenomenon of the Beelzebub?
● Due to the many high mountains on the surface of the Moon, the lunar limb is untidy. When the valley at the edge of the Moon fails to cover the Sun completely at the moment of an eclipse or the arrival of raw light, the uncovered part of the Moon forms a luminous area, like a crystal "diamond"; the surrounding reddish aperture constitutes the "ring" of a diamond ring, and the whole looks very much like a diamond ring set with brilliant gems. The overall appearance is very similar to a diamond ring set with sparkling gems. Sometimes the formation of a number of particularly bright rays or points of light, as if the sun around a string of pearls, called the beads of Pele (Pele is a French astronomer).
V. What are the phases of a solar eclipse?
● When a total solar eclipse occurs, according to the positional relationship between the Moon's circle and the Sun's circle, it can be divided into five eclipses:
1. First Loss. The Moon travels faster than the Sun's apparent motion. The Moon catches up with the Sun during an eclipse. The eastern edge of the moon just with the western edge of the sun phase "contact" is called the first loss, is the first "external cut", is the beginning of the eclipse.
2. Eclipse. About an hour after the first loss, the moon's eastern edge and the sun's eastern edge of the moment called the eclipse, is the beginning of a total solar eclipse, when the moon to the entire sun are covered;
3. Eclipse. It is the moment when the Sun is most y eclipsed, and the center of the Moon moves to the closest point with the center of the Sun;
4. The moment when the western edge of the Moon and the western edge of the Sun "cut inward" is called the birth of light, is the end of the total solar eclipse; from the eclipse to the birth of light is usually only two or three minutes, the longest not more than seven and a half minutes;
5. About one hour after the eclipse, the western edge of the Moon and the eastern edge of the Sun "touch" when it is called the recirculation, from this time onwards the Moon is completely "detached" from the Sun, the end of the solar eclipse.
When was the earliest solar eclipse recorded?
●The record of solar eclipse inscribed on an oracle bone is the earliest record of solar eclipse in human history. On May 26, 1217 B.C., people living in Anyang, Henan Province, China, were engaged in a variety of normal activities, but an amazing thing happened. When people looked up at the sky, the sun, which was shining brightly, suddenly created a gap and the color of its light dimmed. However, after missing a large part of it, it began to recover again. China's ancient observations of solar eclipses maintained the continuity of records. For example, in the Spring and Autumn Annals, 37 solar eclipses were recorded in 244 years, from 770 BC to 476 BC. Records of solar eclipses from the 3rd century AD have continued into the modern era for 1,600 to 1,700 years.
VII. What is the longest solar eclipse?
●The longest duration of a solar eclipse (when the Moon is between the Sun and the Earth) is 7 minutes and 31 seconds. 1955's eclipse in West Philadelphia, which lasted 7 minutes and 8 seconds, was the longest in recent years. An eclipse lasting 7 minutes and 29 seconds is predicted to occur in the mid-Atlantic region in 2186.
VIII. Is it harmful to view the eclipse directly with your eyes?
●The sunlight during an eclipse is much weaker than usual, but if you look directly at it, you may damage the cornea of your eyes. People will stare or squint at the sun out of curiosity. If you look at the sun for a longer period of time, your cornea will be damaged before you react. Eye damage during solar eclipses is not due to an anomaly in the sun, but rather people failing to take protective measures due to curiosity. Don't look directly at the sun with your eyes, whether an eclipse happens or not.
9. How to view the solar eclipse correctly?
● You should not observe a solar eclipse directly with the naked eye, lest your eyeballs will be burned, and in severe cases, blindness may result.
Correct observation methods:
A. Specialized observation glasses: There are special eclipse glasses for sale in the market. These glasses are good for observing and do not harm your eyes.
B, small hole imaging observation: with a needle in the paper through a small hole, through the small hole in another paper or other interface projection observation of total solar eclipse; in addition, you can also use the two fingers crossed to form a small hole to observe.
C, telescope projection: the image of the sun will be projected on the ground after passing through a telescope, and a total solar eclipse can be viewed by observing the projection. However, a total solar eclipse should never be viewed directly through a telescope, as it can lead to blindness in serious cases. Professional guidance is needed if observing with an astronomical telescope.
D, welding goggles: there are stores that specialize in selling welding goggles. However, it should be noted that welding goggles are not the same as sunglasses, and sunglasses cannot be used to observe a total solar eclipse.
Incorrect Methods:
A. Sunglasses: This is one of the most dangerous methods of observing a total solar eclipse, and also one of the most widely rumored methods. Sunglasses/sunglasses are not specifically designed for observing total solar eclipses, and wearing sunglasses/sunglasses directly to observe total solar eclipses will harm your eyes.
B. Exposed negatives: Some people have used this method to observe total solar eclipses in the past, but since everyone utilizes negatives at different levels of production, the degree of exposure of the negatives is not the same, and the safety of the observation cannot be fully guaranteed.
C. Candle blackening glass: this is also an early method, but there are still problems due to the unevenness of the degree of blackening, the thickness of the glass, and other problems, which can not completely guarantee the safety of observation.
D, exposure of the X-ray negative: this method has not been fully demonstrated to confirm that it is not recommended to use.
E, pouring ink into the water: although the water with ink has become a black background, but will still reflect more sunlight into the eyes of the observer, the eyes will still cause some damage.
X. What time will the 2009 total solar eclipse in China occur and which cities will be able to see it?
●The total solar eclipse on July 22, 2009 will occur at about 9:00 a.m. The total solar eclipse band will sweep from west to east over almost all the major cities in the Yangtze River Basin. People living in these areas will have a chance to see a once-in-a-century ultra-long total solar eclipse, with totality lasting as long as 4-5 minutes, which is a long dark night for a total solar eclipse.
Xi. What are the effects of total solar eclipse on people's lives?
● During the duration of a total solar eclipse, the brightness of the sky decreases abruptly, and the visual adaptation of the human eye is not adjusted in time, which is likely to bring about adverse effects on production, life and health.
1. Improper observation of vision will be impaired. During a total solar eclipse, many people will make observations. Before the eclipse, the sun is still very bright, and improper use of observation glasses or direct visualization of the sun will cause blindness and other visual damage. In particular, at the moment of the eclipse, when the sun suddenly brightens, observers may still be immersed in the excitement of what they can see with their naked eyes, and may accidentally get their eyes burned by the strong sunlight, or even lose their eyesight. Especially in remote areas, people may watch curiously as the sun disappears briefly. At this point, the sun's sudden reappearance is likely to burn the eyes.
2. It can easily lead to traffic accidents. A total solar eclipse has the potential to cause traffic safety issues due to the sudden darkening of the sky during the six minutes or so between the eclipse and the birth of the light. When a total solar eclipse occurs, if you have not done the relevant publicity and planning before, then it is possible to cause traffic congestion and even collision accidents near airports, highways and other transportation hubs.
3. Medical care may be disrupted. If the hospital's power supply, lighting and other responses are not timely during the eclipse, there is a possibility of patient panic, medical process errors and other problems, resulting in a number of medical safety incidents.
4. It causes fear in a few people. Rural, mountainous, forested and other remote areas, not enough science publicity will also cause psychological panic. In the past, people do not know the principle of this phenomenon, the legend is "the sky dog swallowed the sun", so there is a fear of solar eclipse, solar eclipse is seen as "ominous signs", there are some superstitious behavior.
Twelve: How to correctly respond to the 2009 total solar eclipse in China?
●1. Increase publicity, do a good job of publicizing the eclipse, so that the people can understand it in time and be prepared for it, and guide people to observe the total solar eclipse correctly
2. To avoid traffic accidents. Relevant parties should inform the public of the time when the sky will turn black through newspapers, television and radio. Workers at height, outdoor travelers and others should arrange their work and rest schedules in advance according to the time of the total solar eclipse blackout. Construction, transportation and other industries need to take safety measures in advance to prevent safety accidents caused by a few minutes of "darkness". Drivers on the road should turn on their headlights and slow down before the total eclipse occurs. At the same time, people working at heights should also avoid accidents when they are suddenly blinded.
3. All departments should coordinate and cooperate. The relevant departments should be based on the actual situation of the region, the department, early development of the work plan. Especially for the total solar eclipse during the high temperature and heat of the climate, in the crowded observation area, observation points, do a good job to prevent heat stroke and medical care and other services, to ensure the people's health, public **** safety and social stability.
4, traffic management departments, especially highway management should develop plans and take measures to ensure traffic safety.
Construction engineering management departments should put forward protection requirements for high-altitude and field operations in total solar eclipse areas during the total solar eclipse to avoid construction engineering safety accidents. Tourism authorities to strengthen the organization and coordination, the establishment of a joint mechanism, the development and implementation of work plans to ensure that the observation activities are safe and orderly.
Thirteen: types of total solar eclipse
Total solar eclipse: simply put, the sun indicates that it is completely covered by the moon. Earth's orbit and the moon's orbit are elliptical, whether it is the distance between the sun and the earth, or between the moon and the earth distance, is not fixed, but sometimes more distant, sometimes closer. If the Moon's umbra is larger than the distance between the Earth and the Moon at a certain moment, a total solar eclipse can be seen on the Earth in the zone swept by the Moon's umbra.
Partial Solar Eclipse: When the Moon orbits between the Earth and the Sun, the area covered by the outer penumbra of the Moon's shadow, where part of the Sun seen is blocked by the Moon, is a partial solar eclipse, which is the most common solar eclipse phenomenon.
Tropic of totality: Because the Moon's shadow cone is thin and long, when it falls on the Earth's surface, it occupies a very small area, at most no more than one ten-thousandth of the total area of the Earth, and its diameter is only a maximum of more than 260 kilometers. When the moon rotates around the earth, the shadow cone on the ground from west to east swept over a relatively long section of the belt, in the moon shadow swept over the belt, can see the eclipse, this band is called the eclipse band. If a total solar eclipse occurs within the belt, it is called the total eclipse belt.
Corona: The outermost layer of the Sun's atmosphere, which extends to several solar diameters and beyond. It is only one millionth as bright as the photosphere and can only be seen during a total solar eclipse or with a special coronagraph. During a total solar eclipse, the dark sun is surrounded by a silvery-white glow that clasps the sun like a hat, hence the name corona.
Helios: When a total solar eclipse occurs, the sun is surrounded by a red ring, which beats with a bright red tongue of fire, and this tongue of fire-like object is called Helios. Sunburst usually occurs in the chromosphere, like the "earrings" of the solar surface.