How to explain the phenomenon of "mirage"

Interpretation of stork: Hacha, the legendary stork can exhale into the shape of a balcony. In fact, it is a natural phenomenon in the atmosphere because of the refraction of light. Metaphor is illusory, something that doesn't actually exist.

The language "Historical Records of Heaven": "Meteorological Tower of Mirage (Mirage); Wide wild gas into the palace. Clouds and gases are like people piling up in their mountains and rivers.

Comprehensive application of law; As subject, object and attribute; derogatory sense

Take Ba Jin's Spring 28th as an example: "She knows they won't play tricks on her with ~".

A castle in the air is a mirage in the desert.

Two-part allegorical saying: Gobi makes faces.

Lantern riddle: a city in the Pacific Ocean

In calm seas, rivers, lakes, snowfields, deserts or Gobi, occasionally towering towers, city walls and trees appear in the air or "underground", which is called a mirage. This illusion often appears on the sea surface of Penglai, China. The ancients attributed it to the dragon, exhaling and forming the tower wall, hence the name.

Mirages can be seen not only in the sea and desert, but also occasionally on asphalt roads. Mirage is the result of light refraction in vertical gas layers with different densities. There are many kinds of mirage, which can be divided into Shanghai mirage, Xiahai mirage and seaside mirage according to their position relative to the original objects. According to its symmetrical relationship with the original object, it can be divided into positive, lateral, positive and negative; According to the color, it can be divided into colored mirage and colorless mirage.

Mirages have two characteristics: first, they appear repeatedly in the same place, for example, mirages often appear over Alaska in the United States; Second, there is a certain time. For example, the mirage in Penglai, China often appears in May and June every year, the mirage near Zimlensk, Russia often appears in spring, and the mirage in Alaska, USA generally appears within 20 days after June 20th.

Mirages have been concerned by the world since ancient times. In western mythology, a mirage is depicted as the incarnation of the devil, a harbinger of death and misfortune. In ancient China, a mirage was regarded as a fairyland. Qin Shihuang, Emperor Wudi and others led people to Penglai to seek immortality, and also sent people to Penglai for a panacea many times. Modern science has correctly explained most mirage, which is considered as a virtual image formed by the refraction of light reflected by objects on the earth through the atmosphere. The so-called mirage is an optical illusion.

Mirages are closely related to the geographical location, geophysical conditions and meteorological characteristics of those places at a specific time. The abnormal distribution of temperature is the meteorological condition for the formation of most mirage.

Let's write down the structure of the bullet. In summer, when the sun burns in the desert, the sand is burnt. Because of the small specific heat of sand, the temperature of low-level air near sand rises rapidly, while the temperature of high-level air is still very low, thus forming an abnormal distribution of temperature. Due to thermal expansion and contraction, the density of hot air in the lower layer near the sand is small, and the density of cold air in the upper layer is large, so that the refractive index of air is small and the air in the upper layer is large. When the light reflected by a distant higher object enters the sparse air in the lower layer from the dense air in the upper layer, it is constantly refracted, and its incident angle gradually increases, which is equal to the critical angle, and total reflection occurs. At this time, if people look against the reflected light, they will see the cockroaches below.

Because of the dark color of asphalt pavement, it has strong absorption ability in the hot summer sun, and it will also form the distribution characteristics of cold and dense upper air and hot and dense lower air, so it will also form underflow.

A mirage in the desert is the refraction of sunlight when it meets air with different densities. In the desert, the sand is baked by the sun during the day, and the temperature on the surface of the sand layer rises rapidly. Due to the poor heat transfer performance of air, when there is no wind, the vertical temperature difference over the desert is very significant, with high air density in the upper layer and low air density in the lower layer. When sunlight enters the low-density air layer from the high-density air layer, the speed of light changes, and after the refraction of light, the oasis in the distance appears in front of people. On the sea or river, this kind of "mirage" phenomenon happens from time to time.

A mirage is an optical illusion, a virtual image formed by the refraction of light reflected by objects on the earth through the atmosphere. Phantom is a mirage for short. According to the principle of physics, a mirage is because different air layers have different densities, and the refractive index of light in air with different densities is different. That is, because the density between warm air on the sea surface and cold air in the high air is different, it refracts light. Mirages are closely related to the geographical location, geophysical conditions and meteorological characteristics of those places at a specific time. The abnormal distribution of temperature is the meteorological condition for the formation of most mirage. Historical Records "Historical Records?" Collection of Zen Books: "Self-prestige, publicity and Zhao Yan sent people to the sea to seek Penglai, the abbot and Yingzhou. These three sacred mountains are scattered in the vast sea, not far from people. If they suffer, they will be taken away by the wind Those who cover the taste are the best, the fairy medicine is in the clouds, the animals are all white, and the gold and silver are the palaces. If you don't reach it, it will be like a cloud; As far as I know, Sanshen Mountain lives underwater; When you are near, the wind will lead you, and you will never get there. "

In Song Dynasty, Shen Kuo wrote in "Talk about Meng Xi": "When you are in the sea, there are clouds, such as palaces, terraces, city walls, figures, chariots and horses, and crowns, which are vivid in your mind, so it is called" Haicheng ". Or "jiaozi Qi Fei", I doubt it. Ouyang Wenzhong once sent messengers to Heshuo, crossing Gaotang County, and ghosts and gods passed through the air in the middle of the night. The sounds of horses, cars, people and animals can be distinguished one by one, which is very detailed. This is disorganization. I asked my elders, and the cloud said,' Twenty years ago, I tried the county in Japan, and I saw people vivid.' The locals are also called "Haicheng", which is similar to what they saw in Dengzhou. "

Lin Jingxi, a adherent of the Southern Song Dynasty, wrote The Story of a Mirage, with a full text of 100 words, which is the best prose to describe a mirage.

Lu Rong's Garden Miscellaneous Notes in the Ming Dynasty: "The evil tower is far more than the official book. Or take the stork as a big clam, and make the so-called pheasant into the sea as a stork every month. Or thought it was a snake. There are many such things in the sea. However, there is no balcony by the sea. However, I went to Guangzhou and Shanghai to preach, suspecting that it was caused by suffocation. The preface of Su Chang's Poems on the High Seas says that he tasted it in spring and summer and will never see it again at the end of the year. He's praying in temple of poseidon. See you tomorrow. If you think you can pray, it's not suffocating. "

Yang Guang Miscellaneous Notes by Liu Xianting in the Qing Dynasty: "Laiyang East Qiao Yun: Boasting in Haicheng, not only in the shape of a magic tower, but also with more than 100 warships a day, the situation is solemn and the drums are loud. After a while, dehydrate. Another cloud, in the third year of Chongzhen, Joe went to Dengzhou, the magistrate tried fish, and the officials reported to Shanghai. Cover its customs, when you meet Haicheng, you must beat the drums and report to the official. Xiao Ling took a look at the guys and saw the mountains and holes of the foreign minister in the north gate, like the city gate. Water came out of it and boiled over a hectare, splitting the mountain in two. From morning till noon, I recovered. There are clouds, those involved in the sea are clouds, and those who look at the shore from the sea, as seen on the shore. " Pu Songling Mountain City: Surrounded by mountains, the mountain city is "high walls, stretching for six or seven miles, and the city is completely destroyed" (Volume 6 of Strange Tales from a Lonely Studio), which describes a "mirage in the mountains", similar to a mirage.

[Edit this paragraph] The formation of a mirage

Sailing on the calm sea or overlooking the seaside, you will often see images of distant ships, islands or towers reflected in the air; People who travel in the desert sometimes suddenly find a lake in the desert in the distance, and the shadow on the lake is swaying, which is desirable. But a gust of wind came and these scenes suddenly disappeared. It turns out that this is a mirage, commonly known as a mirage, or a mirage for short. Phantom diagram

Why is this happening? To answer this question, we must start with the refraction of light.

When light propagates in a uniform medium with the same density, the speed of light is constant, and it propagates in a straight line. However, when light obliquely enters another medium with different density, the speed of light will change and the propagation direction will be tortuous. This phenomenon is called refraction. When you insert a straight rod obliquely into the water, you can see that the underwater part of the rod and its exposed part seem to be broken, which is the result of light refraction. Someone once used a device to project light from water to the interface between water and air. You can see that light is divided into two parts at this interface: one part is reflected into water and the other part is refracted into air. If the mirror in the water is rotated to make the light incident on the interface more inclined, then the refraction of light in the air will be more intense. When the light incident on the interface is shown in the figure on the left, all the light is reflected into the water, and no light is refracted into the air. This phenomenon is called total reflection.

Air itself is not a homogeneous medium. Generally speaking, its density decreases with the increase of height. The higher the height, the smaller the density. When light passes through the air layer at different heights, it will always cause some refraction, but this kind of refraction phenomenon has become accustomed to our daily life, so we don't feel anything strange.

However, when the air temperature changes vertically, it will lead to different refraction and total reflection, resulting in a mirage. Mirages appear in different forms because of the different specific conditions of abnormal air density.

In summer, the humidity of seawater is relatively low during the day, especially on the sea surface where cold water flows, and the water temperature is even lower. The low-level air is affected by the water temperature, which is colder than the high-level air, resulting in the abnormal phenomenon of cooling and heating (under normal circumstances, the average temperature drops by about 0.6℃ for every rise of 100m). Because the air pressure in the lower air layer is very high, and now the temperature is lower than that in the upper air layer, the difference between density and rareness under the air layer is extremely significant.

If there is a ship under our eastern horizon, it is usually invisible. If the difference between the denser air and the thinner air is too big at this time, the light from the ship will gradually refract from the dense air layer to the thin air layer, which will be totally reflected in the upper layer and then return to the dense air layer below; After such a curve, it finally enters our eyes and we can see its image. Because people's vision always feels that objects come from a straight line, the ship image we see is much higher than the real thing, so it is called a mirage.

There is a miaodao islands in Bohai Sea, China. In summer, the sea water temperature is low during the day, and the air density will be significantly different between underground density and sparse density. In Penglai County (called Dengzhou in ancient times) on the south bank of Bohai Sea, you can often see the phantom of miaodao islands. In the Song Dynasty, Shen Kuo recorded this in his famous Meng Qian Bi Tan:

"When you are in Zhangzhou Sea, there are clouds, such as watching the palace, the people in the city, and the crown of horses and chariots."

This is a mirage he saw in Penglai. 1In the early morning of May 22, 933 1 1 point, a mirage was also found on Zhucha Island in Qianhai, Qingdao (the outer mouth of Jiaozhou Bay), which spread all over the city for a time and many people went to watch it. 1975, a 6-hour mirage appeared in the sea near Guangdong province.

Mirages can be seen not only on the sea in summer, but also on the river sometimes. For example, 1934 appeared on the river near Nantong on August 2. It was cold that day, and it was particularly hot. In the afternoon, I suddenly found balcony walls and tree houses over the Yangtze River, both of which are more than 20 miles long. About half an hour later, it moved eastward and suddenly disappeared. Then three mountains appeared, towering into the sky, with a mountain in the middle, much like a censer; It took half an hour to disappear.

In the desert, the sand is scorched by the sun during the day, and the temperature near the sand layer rises very quickly. Because air is not good at heat transfer, when there is no wind, the heat exchange between the upper and lower air is very small, which makes the vertical difference between cold and hot temperatures very significant, leading to the abnormal phenomenon that the density of the lower air is less than that of the upper air. In this case, if there is a tree in front of it, and it grows in a relatively humid place, the light projected obliquely downward from the top of the tree will be refracted because it enters the low-density air layer from the dense air layer. When the refracted light reaches the hot and thin air layer near the ground, total reflection occurs, and the light is reflected from the low-density air layer near the ground back to the higher-density air layer above. In this way, after a concave arc light, the image of the tree is sent to people's eyes, and the reflection of the tree appears.

Because the reflection is below the real thing, it is also called a mirage. This kind of reflection can easily give people the illusion that there are trees by the water, thinking that there must be a lake in the distance. Most people who have traveled in the desert have had similar experiences. A photographer who filmed the film "Climbing Mount Everest in Hishapang" saw such a mirage while walking on a vast arid grassland. He ran in the direction of a mirage, trying to fetch water for cooking. When he ran there and saw that there was no water, he found himself cheated by a mirage. This is because hay, like sand, can be heated by the scorching sun, which gradually increases the density of the air layer from bottom to top, thus creating a mirage.

No matter what kind of mirage, it can only appear in windless or extremely weak weather conditions. When strong winds combine, which causes the agitation and mixing of the upper and lower air, the air density difference between the upper and lower air decreases, and there is no abnormal refraction and total reflection of light, then all illusions disappear immediately.

In short, it's interesting and scientific.

[Edit this paragraph] Where is the easiest place to see a mirage?

According to the data, Long Island is the most frequent mirage area in China, especially after the rain in July and August.

Long Island, known as miaodao islands in ancient times, also known as Changshan Islands, consists of 32 islands, with a land area of 56 square kilometers, a sea area of 8,700 square kilometers and a coastline of 146 kilometers. It is the only island county in Shandong Province and belongs to Yantai City. The county has jurisdiction over 2 towns and 8 townships with a population of 45,000. The county seat is located in Nanchangshan Island.

Long Island belongs to the continental climate in the East Asian monsoon region, with the characteristics of warm winter and cool summer. The annual average temperature is 1 1.9℃, and the frost-free period is 243 days. The forest coverage rate of the county is 53.2%, and its unique geographical location and superior natural conditions make it the only place for migratory birds to migrate. Every year, more than 200 species of migratory birds pass by, with a number of millions, enjoying the reputation of "post station" for migratory birds and being listed as a national nature reserve.

Long Island, called miaodao islands in Chinese territory (called Shamen Island in ancient times), is located between Shandong Peninsula and Liaodong Peninsula, at the intersection of Yellow Sea and Bohai Sea, and is the only island county in Shandong Province. * * * consists of 32 islands with a total area of 56 square kilometers. The total length of coastline 146 km, with a permanent population of 45,000.

Long Island is the blessing of the four seas in China. There are four myths and folklore figures: "Mazu protects the sea", "Eight Immortals cross the sea", "Changyu cooks the sea" and "Jingwei fills the sea". Going to Long Island, you can eat hundreds of kinds of seafood, live in a fisherman's kang, visit the island scenery, buy desirable specialties and entertain folk customs. The mountains on Long Island are "the beauty of Wuling Shili Gallery", and the sea on Long Island is "the beauty on both sides of Lijiang River". "The East China Sea is rich in water and fish, and the South China Sea is rich in Na Xiang's beautiful fruit country", "The Yellow Sea sets sail at dusk, and the fishing boats in the Bohai Sea sing late" are the most simple, bold, true and vivid portrayal of the life of fishermen in Jing Xian.

Long Island is a blessed land of China, with the reputation of "the hometown of abalone, scallop and kelp in China". Long Island is the Hawaiian island of China, and has the title of "National Nature Reserve, National Scenic Area, National Forest Park, Provincial Seal Nature Reserve and Provincial Geopark". Long Island is a primitive, natural, unprocessed and unique tourist virgin land. Here, there is an island miracle and a beautiful scene. All kinds of strange reefs and rocks formed by marine erosion landforms are simple, quiet and exquisite.

In 2003, Long Island Tourism Bureau created "Fairy Mountain on the Sea", "Well-off Fisherman" and "Fisherman's Sea Tour", and paid attention to the management of this brand, integrated tourism resources, and created a green, safe and healthy tourist destination, especially Mazu Stone, which is a blessed land and a happy place and has become a magnificent flower in the island folk culture of our country.

Haishang xianshan

On the foggy sea, there are a group of islands as green as jewels. This is the beautiful archipelago known as "Fairy Mountain on the Sea"-miaodao islands, also known as Long Island. Long Island is located in the Bohai Strait between Liaodong Peninsula and Shandong Peninsula, facing the ancient city of Dengzhou (Penglai) across the sea. According to Records of the Historian, Qin and Emperor Wu of the Han Dynasty took pains to rest their horses at the side of Ya Dan Mountain in Penglai, looking at the sea fairy mountain and seeking longevity. This fairy mountain refers to Long Island. Ceng Yun, a Tang poet, said, "Then he heard a magical island on the sea, and the mountain was in nothingness ..." Su Dongpo, a great writer in the Song Dynasty, once looked at the Changshan Islands and could not help but exclaim: "Real immortals live here!" The Journey to the West's Fairy Tales such as "The Flower in the Mirror" describe this place as an illusory paradise.

[Edit this paragraph] Historical records about a mirage.

castles in the air

Shen Kuo

Being in the sea of Zhangzhou, the clouds are lingering, and palaces, terraces, city walls, figures, chariots and horses, and crowns are vivid, so it is called Haicheng. Or: "jiaozi flies did it together", but I doubt it. Ouyang Wenzhong once sent messengers to Heshuo, crossing Gaotang County, and ghosts and gods passed through the air in the middle of the night. The sounds of horses, cars, people and animals can be distinguished one by one, which is very detailed. This is disorganization. I would like to ask Mr. Yun: Twenty years ago, I tried to cross the county seat by day, and I also saw people vividly. The local people are also called Haicheng, which is similar to what they saw in Dengzhou.

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In the sea of Dengzhou, there are sometimes clouds, and palaces, pavilions, city walls, figures, chariots and horses, roofs, etc. are clearly visible, so it is called "Haicheng". Some people say: "(This is) formed by the dragon exhaling." I doubt whether this is the case. Ouyang Wenzhong once went to Heshuo to preach and passed Gaotang County. In the house of the posthouse, he heard ghosts and gods falling from the sky at night, and the voices of horses, cars and people could be distinguished one by one. What he said is very detailed, so I won't extract it in detail here. Asked the local old man, he said, "Twenty years ago, I passed this county town during the day and saw people and things clearly." Locals also call it a "sea city". It's roughly the same as what I saw in Dengzhou.

mountain city

Pu Songling

The mountain around the city, one of the eight scenic spots, has not been seen for several years. Yu Nian, the grandson, was drinking with his colleagues upstairs. Suddenly, he saw a lonely tower standing high in the sky on the top of the mountain. He looked at each other in surprise, but there was no such monastery in his mind. Nothing. I didn't know it was a mountain city until I saw dozens of palaces and blue tiles flying. A few days later, the high wall was towering for six or seven miles, which was really a battleground for military strategists. Hundreds of millions of people own a building, a hall and a square. Suddenly, the wind is blowing, the dust is boundless, and the city is just blurred. As soon as the wind clears up, everything is gone, leaving only a dangerous building and going directly to lonely people. There are five buildings with wide windows; There is a queue at five o'clock, also outside the building. Layer by layer index, the higher the building, the less bright it is. Count to the eighth floor and cut it like a star. On top of it, it is hazy and there are countless levels. And the people upstairs come and go, or rely on or rely on, not the same. Over time, the building is getting lower and lower, revealing the top; Gradually return to normal buildings; Gradually fell in love with tall houses; Suddenly, like a fist, like a bean, out of sight. I also heard that there were early walkers who saw the crowded shops on the mountain, which was unparalleled in the world, so it was also called the "ghost market" cloud.

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The "mountain city" around the mountain is one of the eight scenic spots in Zichuan County, but it often does not appear once every few years. One day, Sun and his friends were drinking upstairs. Suddenly, he saw a lonely pagoda on the top of the mountain, towering into the sky. (Two people) You look at me, I look at you, surprised and confused, thinking that there is no Buddhist temple near here. Not long after, I saw dozens of palaces with high roofs with blue tiles, only to know that they were originally "mountain cities". Not long after, the high city wall (appeared again) and the short concave-convex wall (at the top) stretched for six or seven miles, which turned out to be a city. There are pavilions (buildings), halls (buildings) and neighborhoods (buildings) in the city, all of which are clearly presented in front of us. Suddenly there was a strong wind, and the flying dust was boundless, and the scene of the whole city became blurred. After a while, the wind stopped and the sky was mysterious. All the previous scenes have disappeared, leaving only tall buildings, which are in direct contact with the sky and Tianhe. There are five rooms (each floor) with windows open, and five bright places are the sky outside the building.

Point to the number layer by layer, the higher the room, the smaller the bright spot; Counting to the eighth floor, the bright spot is only as small as a star; Further up, it becomes dim, as if there is nothing, and its level cannot be seen clearly. People come and go upstairs, each doing his own thing, some leaning against (the railing) and some standing with different postures. After a while, the building became lower and the roof could be seen. Gradually, it becomes the same as ordinary buildings; Gradually, it became a high bungalow; Suddenly, it shrunk to the size of a fist, then to the size of a bean, and finally disappeared completely. It is said that people who get up early and hurry on the mountain see other people's houses, markets and shops, which is no different from the situation on earth, so people call it "ghost market".

[Edit this paragraph] How to distinguish a mirage or a real scene in the desert?

A mirage is an optical phenomenon. Hot air rising on sandy or stony surfaces refracts light, and a mirage is formed. Mirages will appear in desert areas about 6 miles (9.6 kilometers) away from the coastline, which will make objects outside 1 mile (1.6 kilometers) or farther seem to be moving. This makes land navigation very difficult, because in a mirage environment, natural features are vague. A mirage will make it difficult for a person to distinguish distant objects, and it will also blur the outline of distant vision. You feel like you are surrounded by a piece of water, and the rising part of that area looks like an "island" in the water. Phantom will also make it difficult for you to identify the target, estimate the range and find someone. But if you go to a higher place, which is 10 feet (about 3 meters) higher than the desert ground, you can avoid the hot air near the surface, thus overcoming the mirage. In short, as long as the height of the wait-and-see is slightly adjusted, the mirage phenomenon will disappear, or its appearance and height will change.