A low solar eclipse is when the moon goes around the earth and moves between the sun and the earth. If the sun, the moon and the earth are arranged in a straight line or close to a straight line, the moon blocks the sunlight that hits the earth, and the shadow behind the moon falls right on the earth. A solar eclipse will occur. 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. Because the orbits of the moon and the earth are not perfect circles, and the distance between the sun and the moon is near or far, the shadow formed by the sun being blocked by the moon can be divided into umbra, pseudo-umbra (formed when the moon is far away from the earth) and penumbra on the earth. The observer can see the total solar eclipse in the umbra; Annular eclipse can be seen in the range of pseudoumbra; Only a partial solar eclipse can be seen in the penumbra.

2. How long will the eclipse last?

● The duration of total solar eclipse shall not exceed 7 minutes 3 1 sec. The longest time of annular eclipse is 12 minutes and 24 seconds. In order to postpone the observation of the total solar eclipse, a French astronomer chased the shadow of the moon by supersonic plane and extended the observation time to 74 minutes.

3. What are the conditions for the solar eclipse?

When the moon moves between the sun and the earth, it is not always like this. When a lunar eclipse occurs, two conditions need to be met. First of all, the solar eclipse always happens on the first day of the lunar calendar. Not all eclipses will happen on the first day of the lunar calendar, because the orbit of the moon (ecliptic) and the orbit of the sun (ecliptic) are not on the same plane. There is an included angle of 59 between the ecliptic plane and the ecliptic plane. On the first day, if both the sun and the moon move near the intersection of the ecliptic and the ecliptic, and the sun and the intersection form a certain angle (eclipse limit), an eclipse will occur, which is the second condition to be met.

4. What is the phenomenon of "Belle Pearl"?

Because there are many mountains on the surface of the moon, the edge of the moon is irregular. At the moment of the lunar eclipse or the arrival of light, when the valley on the edge of the moon fails to completely cover the sun, the uncovered part forms a luminous area, like a crystal diamond; The reddish aperture around constitutes the "ring" of the diamond ring, which looks like a diamond ring inlaid with bright gems. Sometimes a lot of particularly bright lights or spots are formed, like a string of pearls embedded around the sun. This phenomenon is called Bell Pearl (Belle is a French astronomer).

5. What is the eclipse stage?

When a total solar eclipse occurs, it can be divided into five kinds of eclipse images according to the positional relationship between the round surface of the moon and the round surface of the sun:

1. Initial loss. The moon moves faster than the apparent speed of the sun. The moon caught up with the sun during the eclipse. When the eastern edge of the moon just "touches" the western edge of the sun, it is called the first loss, which is the first "circumscribed" and the beginning of the solar eclipse.

2. Eat well. About an hour after the initial loss, the moment when the eastern edge of the moon "cuts in" with the eastern edge of the sun is called an eclipse, which is the beginning of the total solar eclipse, when the moon covers the whole sun;

3. Eat a lot. It is the deepest eclipse moment of the sun, and the center of the moon moves to the center closest to the sun;

4.light. The moment when the western edge of the moon and the western edge of the sun "cut in" is called light, which is the end of the total solar eclipse; It usually takes only two or three minutes from eating to lighting, and the longest is no more than seven and a half minutes;

5. Last contact. About an hour after the birth of light, when the western edge of the moon "touches" the eastern edge of the sun, it is called the last contact. Since then, the moon has completely "left" the sun, and the eclipse is over.

6. When was the earliest recorded solar eclipse?

● The solar eclipse record engraved on the Oracle Bone Inscriptions is the earliest solar eclipse record in human history. On May 26th, 65438 BC+0265438 BC+07 BC, people living in Anyang, Henan Province were carrying out various normal activities, but amazing things happened. People looked up at the sky, and the radiant sun suddenly appeared a gap, and the light was dim. However, after missing a large part, it began to recover. The observation of solar eclipse in ancient China kept the continuity of records. For example, in Spring and Autumn Annals, 37 eclipses were recorded in 244 years from 770 BC to 476 BC. The record of solar eclipse from the 3rd century A.D. continued to modern times, lasting 16700 years.

7. What is the longest solar eclipse?

● The longest duration of an eclipse (the moon is between the sun and the earth) is 7 minutes, 365,438+0 seconds. 1955 occurred in western Philadelphia, and the solar eclipse lasting 7 minutes and 8 seconds was the longest in recent years. It is predicted that there will be a solar eclipse lasting 7 minutes and 29 seconds in the middle of the Atlantic Ocean in 2 186.

Is it harmful to watch the eclipse directly with your eyes?

● Although the sunlight during the solar eclipse is much weaker than usual, if you look straight, it may damage the cornea. People stare or squint at the sun out of curiosity. If you watch the sun for a long time, your cornea will be damaged before you know it. During the eclipse, the eyes were damaged not because of the abnormality of the sun, but because people were curious and didn't pay attention to protective measures. Whether there is an eclipse or not, don't look directly at the sun with your eyes.

How to watch the solar eclipse correctly?

● You can't observe directly with the naked eye during the eclipse, so as not to burn your eyes and even lead to blindness.

Correct observation method:

A. Special observation glasses: There are special eclipse glasses on the market. This kind of glasses has a good observation effect and does not hurt the eyes.

B, pinhole imaging observation: a pinhole is punched in the paper with a needle, and the total solar eclipse is observed through the projection of the pinhole on another paper or other interfaces; In addition, two fingers can cross to form a small hole for observation.

C. Telescope projection: After passing through the telescope, the image of the sun will be projected on the ground, and the total solar eclipse will be watched by observing the projection. But don't watch the total solar eclipse directly through the telescope, which will lead to blindness in severe cases. If you use an astronomical telescope for observation, you need professional guidance.

D, welding goggles: There is a shop specializing in welding goggles. However, it should be noted that welding goggles are different from sunglasses, and sunglasses cannot be used to observe the total solar eclipse.

Incorrect method:

A. Sunglasses/Sunglasses: This is one of the most dangerous methods to observe the total solar eclipse, and it is also one of the most easily misunderstood methods. Sunglasses/sunglasses are not specially designed for observing the total solar eclipse. Wearing sunglasses/sunglasses to directly observe the total solar eclipse will hurt your eyes.

B. Exposure film: Some people have observed the total solar eclipse by this method before, but the exposure of the film is different because of the different level of making the film, so the observation safety cannot be completely guaranteed.

C. Candles painted with black glass: This is also an early indigenous method, but there are still problems. Due to the uneven blackening degree and glass thickness, the observation safety cannot be completely guaranteed.

D. Exposure to X-rays: This method has not been fully demonstrated and confirmed, and it is not recommended for everyone.

E. Water splashed with ink: Although the water splashed with ink has turned into a black background, it will still reflect more sunlight into the observer's eyes, which will still cause some damage to the eyes.

X when will the total solar eclipse occur in China in X.2009, and which cities can see it?

● The total solar eclipse on July 22, 2009 will occur around 9: 00 a.m., and the total solar eclipse belt will sweep from west to east, almost being the major city in the Yangtze River basin. People living in these areas will have the opportunity to see the once-in-a-century total solar eclipse for a long time, lasting for 4-5 minutes. It was a long night for the total solar eclipse.

What effect does the total solar eclipse have on people's lives?

● During the total solar eclipse, the brightness of the sky drops sharply, and the visual adaptability of human eyes cannot be adjusted, which is likely to bring adverse effects on production, life and health.

1, improper observation will damage vision. During the total solar eclipse, many people will observe. Before eating, the sun is still bright. Improper use of observation glasses or direct observation of the sun will cause blindness and other visual damage. Especially at the moment when light is generated, the sun suddenly brightens, and the observer may still be immersed in the excitement visible to the naked eye. If he is not careful, he will be burned by the strong sunlight and even become blind. Especially in remote areas, people may watch curiously because the sun disappears briefly. At this time, the sudden sun is likely to burn your eyes again.

2. It is easy to cause traffic accidents. During the six-minute total solar eclipse, the sky suddenly darkens, which may cause traffic safety problems. When the total solar eclipse occurs, if the relevant publicity and plans are not made before, it may cause traffic jams and even crashes near transportation hubs such as airports and highways.

3. Medical treatment may be disturbed. If the power supply and lighting in the hospital are not timely during the eclipse, there may be problems such as patient panic and medical process errors, resulting in some medical safety accidents.

4. Arouse the fear of a few people. In rural areas, mountainous areas, forest areas and other remote areas, the lack of popular science propaganda will also cause people's psychological panic. In the past, people didn't know the principle of this phenomenon, and the legend was that "dogs swallowed the sun", so they were afraid of solar eclipse. The solar eclipse was regarded as an ominous sign, and some superstitious behaviors appeared.

How to deal with the total solar eclipse in China in 2009?

● 1, increase publicity, do a good job of publicity, let the people know in time, get ready, and guide the people to correctly observe the total solar eclipse.

2. To avoid traffic accidents. Relevant parties should inform the public through newspapers, television and radio when the sky will turn black. Aerial workers, outdoor tourists, etc. According to the shady time of the total solar eclipse, arrange their schedule in advance. Construction, transportation and other industries need to take safety measures in advance to prevent a few minutes of "dark night" from causing safety accidents. Drivers on the road should turn on the lights to slow down before the total solar eclipse, and drive carefully. At the same time, aerial workers should also avoid accidents caused by suddenly reaching out and not seeing five fingers.

3. All departments should coordinate and cooperate. The relevant departments should formulate the work plan as soon as possible according to the actual situation of the region and the department. Especially in view of the hot and humid climate during the total solar eclipse, we should do a good job in heatstroke prevention and medical security in densely populated observation areas and observation points to ensure people's health, public safety and social stability.

4. Traffic management departments, especially highway management departments, should make plans and take measures to ensure traffic safety.

The construction project management department should put forward the protection requirements for aerial work and field work during the total solar eclipse to avoid the occurrence of safety accidents in construction projects. Tourism authorities should strengthen organization and coordination, establish linkage mechanism, formulate implementation work plan, and ensure the safe and orderly observation activities.

Thirteen: Types of total solar eclipse

Total solar eclipse: Simply put, the sun display is completely obscured by the moon. The orbit of the earth and the orbit of the moon are both ellipses, and the distance between the sun and the earth or between the moon and the earth is not fixed, but sometimes it is far and sometimes it is close. If the umbra of the moon is larger than the distance between the earth and the moon at a certain moment, the total solar eclipse can be seen in the area swept by the umbra of the moon on the earth.

Partial solar eclipse: when the moon moves between the earth and the sun, the area covered by the outer penumbra of the moon shadow is partially blocked by the moon, which is the most common solar eclipse.

Total lunar eclipse zone: Because the shadow cone of the moon is thin and long, when it falls on the earth's surface, it occupies a small area, which will not exceed one tenth of the total area of the earth at most, and the maximum diameter is only over 260 kilometers. When the moon revolves around the earth, the shadow cone sweeps across a relatively long area from west to east on the ground. A solar eclipse can be seen in the area swept by the moon shadow. This area is called the eclipse belt. There is a total solar eclipse in this zone, which is called the total solar eclipse zone.

Corona: the outermost layer of the solar atmosphere, which can extend to several solar diameters or even beyond. Its brightness is only one millionth of that of the photosphere, and it can only be seen during a total solar eclipse or with a special coronagraph. During the total solar eclipse, the dark sun is surrounded by silvery white light and buckled on the sun like a hat, so it is called a corona.

Prominence: When a total solar eclipse occurs, the sun is surrounded by a red ring with a bright red flame beating on it. This flame-like object is called a prominence. Prominences usually appear in chromosphere, just like "earrings" on the sun.