Before the total solar eclipse on July 22, Gao Buxi, vice chairman of Hubei Astronomical Society, told readers about the experience of human exploration of solar eclipse.
Gao Buxi said that the solar eclipse is a phenomenon that the circular surface of the sun is covered by the moon. Because the distance between the sun and the earth changes slightly, the shadow cast by the moon on the earth is slightly longer, and the resulting solar eclipses are also divided into total solar eclipse, annular solar eclipse and partial solar eclipse.
The process of partial eclipse and annular eclipse is almost the same as that of total eclipse, but there are no two key links: solar eclipse and light production, only the first loss, lunar eclipse and the last contact, so the appreciation of partial eclipse and annular eclipse can not be compared with total eclipse.
According to some records, from 190 1 to 1999, there were 228 eclipses in the world, including 78 partial eclipses, 73 annular eclipses, 7/kloc-0 total eclipses and 6 mixed eclipses. The probability of three main eclipses is similar, and the mixed eclipse is obviously the rarest.
During the eclipse, the movement of the moon plays an important role in the change of the relative position between the sun and the moon. Every eclipse, the moon always enters from the western edge of the sun's visual plane, gradually blocks the sun, and finally moves out from the east. Gao Buxi said: "Within a few minutes of the total solar eclipse, the temperature will drop 15℃~ 20℃, the air pressure will also change, and the wind will increase, which will have an impact on aerial work."
How many years is the coming total solar eclipse on July 22nd? Gao Buxi said: "For a fixed point, the total solar eclipse usually occurs once every 300 to 400 years, and the time span in different places is not the same."
According to Gao Buxi, the total solar eclipse covers more than 230 kilometers. To the east of the Yangtze River, Chengdu, Chongqing, Wuhan, Hefei, Hangzhou, Shanghai and many other big cities are in the total solar eclipse zone. Partial solar eclipse can be seen in most parts of China.
"From a global perspective, total solar eclipse is not uncommon. But the problem is that when the solar eclipse occurs, only people on a long and narrow' food belt' on the earth can see it, unlike when the solar eclipse occurs, nearly half of the people on the earth can see it at a glance. " Gao Buxi explained that the total solar eclipse is "once every 300 years on average", and a qualifier needs to be added, that is, "for a certain place".
Gao Buxi said that no matter how many years the total solar eclipse occurs, it is certain that it is a very spectacular astronomical spectacle. For most Wuhan people, it may be this once in a lifetime, and it is worth stopping for.
Legend of solar eclipse: Ten Days of Dog
One of Sakyamuni's ten disciples is Mulian, who is very filial to his mother, but Mulian's mother is violent by nature. When the Jade Emperor in the sky knew about it, he sent Manglietia's mother to eighteen levels of hell and turned her into a vicious dog, which could never be reborn. Mulian practiced day and night and became a Tibetan bodhisattva. In order to save his mother, he opened the door of hell with Zhang Xi, and Mu Lian's mother and all the evil spirits escaped from hell.
After escaping from hell, Mulian's mother turned into a vicious dog and fled to heaven to settle accounts with the Jade Emperor. She couldn't find the jade emperor in the sky, so she chased the sun and the moon, trying to swallow them and turn heaven and earth into a dark world. Folks call it "Tengu eats the sun" and "Tengu eats the moon".
There are legends of solar eclipses everywhere.
Scandinavians believe that the cause of the solar eclipse is that two Sirius named "Skol" and "Heidi" are chasing each other.
In Indian mythology, people blamed the sudden disappearance of the sun on a devil named Lahu, who thought it bit the sun and caused the solar eclipse.
The Incas believe that there is a cat named Ccoa or K'owa in the myth, and it can call the shots by wagging its tail. Solar eclipse (locally called Inti Jiwana) and lunar eclipse are expressions of Ccoa's anger.
Sun worshippers in ancient Egypt believed that a python Apep ate the sun (referring to the sun god Ra). In addition, some Egyptian legends record that the solar eclipse occurred because a vulture trying to dominate heaven tried to take away the light of the sun god.
Some ethnic groups in Africa believe that the sun and the moon are lovers, and an eclipse occurred when they chased each other.
Legends and records of solar eclipse
With the development of human science and technology, human beings have gradually discovered the law of solar eclipse and learned to record the whole process of solar eclipse in words.
The first solar eclipse recorded in BC 196 1 year.
There is a story in Shang Zhang: During the reign of Zhongkang in the Xia Dynasty, there was a time when "Tiangou ate the sun". At this time, the celestial official should report to the imperial court and ask the emperor to lead the ministers to set up altars in front of the temple, burn incense and pray, contribute coins to the sky and recall the sun. However, Tianguan He did not observe this phenomenon at the first time and reported it to the court, which angered the emperor and he was beheaded.
This record has long been certified as a solar eclipse record, and it is the earliest record in China (and probably the earliest record in the world). Known as "book erosion" and "Zhong Kang erosion", it may occur in BC 196 1 year, 65438+1October 26th.
Basic forecast of solar eclipse and lunar eclipse in Han Dynasty in China
The astronomical calendar in Tang dynasty was developed scientifically, and Li was a strange man who was proficient in astronomical calendar and yin-yang theory.
Li thought that there were many mistakes in the popular Wuyin Yuanli in the Tang Dynasty, so he compiled a brand-new calendar and dedicated it to the court.
One year, according to Li's own calendar, there will be a solar eclipse on the first day of every month. However, there was no solar eclipse in the almanac issued by the court according to the old calendar, so he reported the exact time of the occurrence and end of the solar eclipse to the court, which proved that Li's calendar prediction was correct. In the second year of Linde (AD 665), the court decided to use Li's calendar as the calendar and named it Linde calendar.
1868, man discovered helium in the total solar eclipse.
In August 1868, 18, there was a good total solar eclipse near Bangladesh. French astronomer Ransang saw a strange yellow line in the prominence spectrum when observing the total solar eclipse. This yellow line is similar to the sodium line, but it is not sodium, but an unknown element. Later, scientists named it Helium (Helium), which originated from ancient Greek, meaning "solar element".
19 19 The most famous total solar eclipse in the history of science.
180 1 year, the german astronomer soldner predicted that when light passes near the sun, it will be deflected by gravity.
The most famous total solar eclipse observation in the history of science was1965438+May 29th, 2009, which was conducted in Eddington, England to verify the general theory of relativity. At that time, the stars near the sun during the total solar eclipse were photographed, and compared with the positions of the stars on the same day taken during the non-total solar eclipse, and the starlight deflection caused by the sun's gravity was measured.
1997 the last total solar eclipse in China in the 20th century.
1On March 9th, 997, the last visible total solar eclipse in China in the 20th century occurred in Mohe, the "Arctic" of China, and appeared in the sky together with comet hale-bopp, who only returned once in 2500. The occurrence and appearance of two special astronomical phenomena, total solar eclipse and bright comet, are very rare.
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From 975 to 2009, during 1034, Wuhan * * * experienced four total solar eclipses, which began at 2: 20 pm on May 20, 1575 (the third year of Ming Shenzong Wanli) and lasted for 4 minutes and 23 seconds. 164 1 year (14th year of Chongzhen in Ming dynasty) 65438+2: 07 pm on February 3rd, lasting 2 minutes and 04 seconds; 1941September 2 1 day 12, lasting 3 minutes and 05 seconds; It started at 9: 23 am on July 22, 2009 and lasted for about 5 minutes and a half. In contrast, the total solar eclipse, which started at 9: 23 am on July 22 this year, lasted the longest, reaching 5 minutes 15 seconds.
According to historical records, the last total solar eclipse with such good observation conditions was in Jiajing period of Ming Dynasty more than 400 years ago.