"But there's been something strange lately, and there's often a mirage on the southeast sea these days. However, because the weather is getting colder, it is normal for fog to occur at sea, and it is not without precedent for mirages, but it has not been so frequent. Grandmaster An said.

An Xiaoyu pondered for a moment, and did not take it lightly. At this juncture, anything unusual may be a harbinger of big changes, and we have to guard against it. She told the four Grandmasters of the An family what had happened to the night stalkers, and they were also aware that things might change.

"Anyway, I'll go check it out first." Ann whispered, flying in the direction they had spoken.

Mirage is an uncommon natural phenomenon. The earliest written record was in a certain era in the early antiquity, and coincidentally the mirage phenomenon recorded in the book for the first time was also in the Eastern Desert. The person who recorded this mirage was a scholar who traveled the world and came specifically to record various climates.

At that time, human beings had just escaped from the control of aliens and had a certain right to speak. At that time, the Eastern Wilderness was not the world of the Eastern Wilderness people. There are some races living in the desert here, and human beings often live in the Eastern Wilderness by communicating with these races, or even directly attaching themselves to them.

With communication, there will be caravans and convoys coming and going, not only between the East Wilderness, but also between the East Wilderness and the outside. After all, the desert aliens can be self-sufficient in the Eastern Wilderness, but humans cannot. They have to eat, they have to drink, they have to wear clothes, so there must be business communication with the outside.

It was at this time that the scholar followed the caravan into the Eastern Desert, he was very unlucky, when he came in, he only heard that the Eastern Wilderness was full of danger, but he didn't expect the danger to come so quickly. Not long after entering, they were caught in a sandstorm and lost their way.

Fortunately, although this sandstorm was widespread, it was not very violent, and although it engulfed them and ran somewhere, it did not bury them. By the time the sandstorm was over, the scholars and the caravan could no longer find their way back.

They can only rely on camels in the desert to find their way out, trying to find a recognizable landmark, or simply being captured by an alien race is better than dying in the desert. But unfortunately, by the time they ran out of water, they still couldn't find their way.

How huge the Eastern Desert is, according to the surface base, the total area of the Eastern Desert has even reached one-seventh of the total area of the empire, that is to say, on the main continent, one-fourteenth of the surface base is the scope of the Eastern Desert. According to the current administrative divisions of the empire, in addition to the Eastern Wilderness, there are one hundred and nine administrative districts.

Among the one hundred and nine administrative districts, the imperial capital occupies one, and the southeast, northwest, and northwest occupy twenty-seven each, and in this way, each province is already large enough. The regular garrison of a province can reach one million in normal times, and there are not a few with a total population of more than 100 million.

In antiquity, especially in the early antiquity, such a province was likely to be the area of dozens of dynasties or four or five dynasties. Some people may not be able to go beyond the borders of a dynasty in their lifetime, and only cultivators and caravans can travel through many countries.

If you calculate it like this, not to mention crossing the continent, even if it is through the Eastern Wilderness, it may take many people a lifetime. Of course, it is easy to be pushed by the wind in the Eastern Wilderness, and sometimes you don't have to walk when you jump up in a sandstorm, you just fly for a while and then fall.

It's normal to be pushed and walked for so long, and of course it is normal to not be able to find the way.

So in the end, the most experienced old captains of the caravan began to despair, and they began to struggle to the death, lying in the shade for most of the day, and only when the sun turned, would they change places, because they had to save their physical strength, and their brains began to faint.

On this very day, they were lying on the back of the sand dunes, when suddenly someone in the team shouted softly: "There is a city!" I saw the city! Look! ”

At first, everyone else thought that the man was stupid, they had been walking around the neighborhood for two days, where did they come from? But when they looked up, they realized that what the man said was true. In the distant sky, there really is a city, a city suspended in the sky.

The edge of the city was blurred by the desert heat, but they could clearly see that there were people coming and going in the city, and there were aliens walking. The buildings inside, the people and the aliens inside, are just like a normal city, they are simply lifelike!

Some people began to lose their brains, and regardless of the consumption of physical strength and water, they began to run frantically in that direction. The others were terrified, and the old captain, who was experienced, chased after him, telling him that it was a mirage in the desert, a mirage dream.

But although the scholar was also dizzy, he remembered these words. Later, while chasing the people in front of them, they miraculously found an oasis with a huge lake in the middle of the oasis. They were replenished with water and finally survived.

The old captain is the old captain, he knows that the scope of the Eastern Wilderness is huge, the scope of their usual activities is only a small part of the Eastern Wilderness, there are still many places they don't know, and there are many caravan routes they can't recognize. But it is certain that there are traces left in this oasis, and more than once, indicating that this must be the foothold of some caravan passing here, so they stayed here and waited for others to arrive.

Sure enough, within a dozen days, the caravan passed by and took them to the nearest city. It was at this time that the scholar recorded and passed down the mirage. This is the first recorded mirage in human history, probably in early antiquity.

In fact, rumors about mirages did not appear at this time, but earlier. Otherwise, the old captain would not have known that this kind of thing is called a mirage, and the reason why it is called a mirage is also because the place where this phenomenon often appears is actually above the sea.

There are also many rumors of mirages in human and alien legends, which can be traced all the way back to before the Voice of the Extinction. Because at that time, there was a legend that human beings had found the fairyland, which also involved the space of the cyan stone gate.

At that time, the Heavenly Spirit Clan created human beings, and they had long known that the Heavenly Dao might exterminate human beings, so they prepared in advance to cultivate a huge number of human beings and disperse them to various parts of the continent. But not long after this plan began, the Heavenly Dao woke up in advance and lowered the sound of world destruction.

The human beings in the Burial Gold Secret Realm are one of them. At that time, these scattered human beings also had their own cultural development, including oral transmission and literary and artistic processing of various natural phenomena. Especially after the Voice of Destruction, the mirage began to become sacred.

At the beginning, it is impossible to verify how human beings viewed the mirage, but there is no doubt that when these people inexplicably left the ancestral land of mankind and began to live in the dangerous mountains and forests, they will always miss the life they were sheltered in the first place.

As a result, when humans by the sea see the appearance of a mirage, they often think that it is where they came from, where the fairyland is. And they live here in order to find their way back to Wonderland. Especially after the Voice of Annihilation, for many seaside tribes, the mirage has even become their only spiritual support.

Therefore, the legend of the mirage did originate from the human tribe by the sea at first, and then spread as humans communicated with each other, and after many people's observation, it also began to become common, and it was not regarded as a fairyland, but realized that it was just a strange natural phenomenon.

Of course, according to the theory of modern science, the appearance of the mirage can be perfectly explained, but it is an anomalous refraction phenomenon.

The root cause of the mirage on the ocean is that there is plenty of water vapor on the sea surface, and the water vapor rises to fill the atmosphere above the ocean, because the temperature of water vapor changes more slowly than the air, so when the sunlight is deflected, or for some reason the sea surface temperature begins to change, the temperature difference is greater the higher the upward.

The temperature difference will cause the density of the air to change, and the density determines the refractive index of light in the air, so the difference in the refractive index will lead to the abnormal refraction of light, and only then will the distant scene be projected into the sky, forming a mirage phenomenon.

As for the mirage in the desert, it is even simpler, there is no need for water vapor as an influence, the ground in the desert is already greatly affected by the temperature of sunlight, and the air temperature close to the ground is much higher than that of the sky above, which will also produce a difference in density and refractive index.

The story recorded by the scholar, according to modern analysis, is actually more complicated and weird, and I have to say that their lives are really good. If it were a different time, I am afraid that they would not be able to see such a mirage until they died, and it would be impossible for them to follow the illusion to find the oasis.

Generally speaking, the appearance of mirages is regular, and the same place will appear many times in a relatively fixed place. This is because the principle of nature is certain, the terrain and environment are the same, and the same phenomenon will always occur under the same conditions.

This is also the reason why people gradually accepted that mirages are ordinary natural phenomena.

But the mirage recorded by the scholar is a relatively special kind, and it may have appeared once in tens of thousands of years. According to the analysis, the mirage should not only be the cause of refraction, but also two reflection phenomena as an auxiliary, so the formation conditions are quite harsh.

Although the sandstorm did not cause rainfall, it also caused the accumulation of water vapor in the Eastern Wilderness. At that time, the season was the rainy season, and the cause of this sandstorm was probably caused by the low pressure on the other side of Changshan, and with the generation of sandstorms, some of the water vapor outside Changshan also came to the sky above the East Wilderness, and of course, it was sent to the sky after arriving in the East Wilderness.

In the rainy season outside, which is the driest time in the Eastern Wilderness, the temperature of the ground, and even the air temperature close to the ground, is not high. Even if a large amount of water vapor arrives, there is no condition for it to condense into rain. Even if it condenses into raindrops, it will be evaporated back into water vapor before it can reach the ground from a high altitude.

Under this repetition, the water vapor brought by the sandstorm formed a cloudless layer of water vapor in the high sky. The person below can't see clearly, but for the light, this water vapor layer, almost quite a mirror, can reflect the light reflected from the ground downward.

At that time, the mirage they saw was the scenery reflected through the water vapor layer, and these scenery were reflected upward through the huge lake in the oasis. But at this time, due to the presence of oases and water vapor layers, the air temperature above and on the ground has dropped, so an even more strange area than the normal air layer has formed.

So, the scenery that was reflected twice on the surface of the lake was refracted not far from the scholars and their caravan through this strange air. Although it was refraction, the light still maintained a certain direction after all, so they could follow the mirage to find the oasis.

As for when they found the oasis, the water vapor layer above them had begun to spread out under the mediation of natural conditions, and no longer formed a mirror, or the reflected scenery had deviated from other places than reflected on the surface of the lake, so they did not see the view of the city again.

It can be said that this time the mirage is already quite harsh for the conditions for formation. Neither the low pressure and the way the water vapor rolls on the side of Cheung Shan nor the direction of the sandstorm can be controlled. And the oasis was in the right place, fitting in with the reflection of the water vapor layer above.

Moreover, from the perspective of the water vapor layer above, only in those ten minutes will a sufficient mirror effect be formed, if it is too early, it has not stabilized, and if it is too late, it has already spread and thinned. In addition, the height and thickness of the water vapor layer are also affected by the sunlight and hot air on the ground at that time, which controls the range of water vapor condensation, falling and re-evaporation in the air.

At the same time, the heat transport generated by the water vapor layer also transports the heat below to higher altitudes, which leads to the temperature difference between the ground and the high altitude just enough to produce this strange temperature ladder, so that the mirror image reflected by the lake surface can be projected into the hot air.

Therefore, this mirage, there may be no next time for tens of thousands of years, it is simply a coincidence.

Coincidences will appear once, twice, but not many times in a row. According to the four Grandmasters of the An Family, there have been four consecutive mirages on the surface of the sea recently, and the mirages can't see exactly what they are.

At first, they thought it was an abnormal weather phenomenon, after all, there was everything in the East China Sea. But after listening to An Xiaoyu's words, they also began to realize that these mirages were probably not so simple. How can a place where a mirage has never been seen appear several times in a row?

An Xiaoyu let them stay where they were, and went to the southeast sea by themselves, and after looking for a while in the place they said, they found nothing. Even below the surface of the sea has been probed, and there is nothing. Of course, even if it is An Xiaoyu, it is impossible to find out.

But what's the difference? An Xiaoyu has not been able to explore the deep sea, even if a foreign race comes, I am afraid it is impossible to go deep into that depth, and if you go down, you will die. An Xiaoyu frowned and came back in a big circle, but found nothing.

After returning to the Donghuang base at the junction of Changshan and the South China Sea, An Xiaoyu shook his head and said, "I haven't found anything for the time being, but I can't be sure yet." When did the mirage appear in the last two days? ”

The four grandmasters said, "It's about eight or nine in the morning and four or five in the afternoon. ”

That's right, a mirage is an optical phenomenon after all, the sun declination and intensity of these two time periods are basically the same, although the direction is reversed, but there is always something in common. Is it really just an ordinary mirage? An Xiaoyu thought for a while, and did not rush to conclusions.

The appearance of the mirage must have caused a change in the refractive index for some reason, and for this reason, An Xiaoyu did not find it just now. And according to the calculation of time, the alien race that left the South China Sea at night four days ago, if the speed is fast, is a race that is good at underwater action, and it is not impossible to reach the East China Sea in about one day and one night, maybe it is the action of the alien race that caused the anomaly?

After looking at the time, the current time in the East Wilderness is more than three o'clock at noon, and there is still an hour, so she found a place to sit down and said, "Anyway, wait and see, and when the mirage appears, I will go and see." ”

She also knows that mirages are very weird, and it is likely that you will not see them when you go to the sea. So An Xiaoyu waited quietly on the coast, and the four grandmasters left to come here, obeying An Xiaoyu's instructions to guard the base and investigate if there was anything strange near the base.

If they hadn't heard about the South China Sea, they might not have been so cautious, but if they knew that alien races might appear here, they couldn't help but be careful. At present, the empire has not yet found out how many alien races have come, and what kind of races and masters they have, so we still have to be vigilant at all times.

So, An Xiaoyu sat here quietly, waiting for the mirage to appear.

Meditating quietly, An Xiaoyu disappeared on the shore as if she did not belong to this world. As time passed, slowly reaching four twenty in the afternoon, An Xiaoyu suddenly opened her eyes suddenly. I saw a large illusion suddenly appear on the sea in the distance.

An Xiaoyu knew that this kind of thing didn't work to ask cultivators, what kind of mirage was this? Do you have such a small mirage in your house? I'm afraid ordinary people can't see it, right? From the coast, there is a small apparition about the size of a thumb, no wonder you can't see anything clearly.

The next moment, An Xiaoyu disappeared on the shore.