The red moon
As for the cause of the formation of the "red moon", we must first be familiar with what is a total lunar eclipse. It is an astronomical phenomenon of lunar eclipse. When the moon, the earth and the sun are completely in a straight line, the earth is in the middle, and the whole moon enters the umbra of the earth, forming a total lunar eclipse. The process of total lunar eclipse can be divided into initial loss (the moon just touches the umbra of the earth), lunar eclipse (the umbra of the moon and the earth is cut in the west) and lunar eclipse.
Total lunar eclipse-red moon process
The best viewing effect of the "red moon" is in the eclipse stage, when the three are in the closest linear sense. Because sunlight is scattered and absorbed in the atmosphere, long-wavelength red and orange light is refracted to the surface of the moon, and the moon itself does not emit light, so the reflected red and orange light forms a rare "red moon". Strictly speaking, from the earth's point of view, the whole moon presents an older look.
In fact, in daily life, we slow down and observe carefully, and the phenomenon of "red moon" is quite easy to see. It usually appears when there is smog or dawn accompanied by the moon or total lunar eclipse, and their formation principle is essentially the same. When there is fog or haze, small water droplets or dust particles in the air will absorb or scatter short-wavelength light, leaving only long-wavelength red or orange light near the ground, and the moon looks red. Similarly, when the moon appears with the dawn, the moon has not completely set. As soon as the sun rose to the horizon in the morning, the sky began to brighten, making a small amount of light shine on the moon, which was filtered, scattered and absorbed and then reflected back to the earth, and then the red moon was seen.
Blood Moon
Therefore, the formation of the "red moon" is more of a physical phenomenon, and the probability of encountering it on the fifteenth and sixteenth nights of the lunar calendar is greater than usual, because most of the time the moon passes above or below the shadow of the earth, and there will be no eclipse. But at the same time, we should also understand that the "red moon" is a normal astronomical phenomenon and a special manifestation of the total lunar eclipse, which may happen every year. As long as the weather conditions permit, you can see this scene with the naked eye anywhere on the earth where you can see the moon.
Then why should we pay special attention to the "Red Moon"? This is related to the rumors of a total lunar eclipse. In ancient China, it was thought that an eclipse of the moon was "a dog swallowing the moon", and it was necessary to beat gongs and drums to drive away the dogs and regain the light. The "red moon" is also called the "blood moon", and the folklore "when the blood moon comes out, evil appears" is an ominous sign. In geomantic omen, the blood moon is the phase from cold to yin, indicating that the world is weak in healthy qi, strong in evil spirits, strong in resentment and hostility. Therefore, when the ancient blood moon appeared, the door was generally closed and we rarely went out. But in modern times, we have found out the cause of the "red moon" with scientific principles, so we no longer worry about fear, but more appreciate it as an astronomical landscape, just like meteors, eclipses and lunar halos.
It is said that the next "Red Moon" will appear on September 8, 2025. Let's wait and see.
The red moon