Xuanhuang refers to the color of heaven and earth. Xuan is the color of the sky and yellow is the color of the earth. If only taken literally, the meaning of these two sentences is: the color of the sky is black, and the color of the earth is yellow.

Xuan

In terms of color, it refers to a color that is dark blue and almost black, which is called Xuan. In a sense, it refers to something lofty and unfathomable, which is called mysterious. Although the color of the sky visible to the naked eye is blue, the blue color of the sky is due to the diffraction phenomenon of light. The red, orange, yellow, and green light in the sun has a longer wavelength and can be diffracted to the ground. .

Blue, indigo, and violet light have shorter wavelengths and can only be emitted back and forth among various impurities in the air, so the sky looks blue. However, the actual space is completely dark, with only stars emitting a little bit of light. It is indeed black, so Tianxuan is right in terms of color.

In addition, the way of heaven is lofty and far-reaching. As Laozi said, the metaphysical principles of the way of heaven are mysterious and mysterious, unfathomable and cannot be understood by existing wisdom. This is the metaphysical way of heaven that is unpredictable, so it is called Tianxuan.

Rehmannia glutinosa

also has two meanings. Chinese culture, especially traditional culture, in the Yanhuang culture, the color of the soil, the skin color of people, and the crops millet and millet are all yellow, so it is called rehmannia.

Another meaning is that the celestial bodies in the universe, including the earth, are all products of the Big Bang, and are all hot matter in their initial state. The earth condenses its temperature into the magma in the core and continuously replenishes it with the help of the sun.

Life is possible only if there is temperature. In chromatographic analysis, black is a cold color and yellow is a warm color. Rehmannia glutinosa also praises the warm earth for its growth and nurturing effects, so the Chinese also honor the earth as "mother". The heaven is high and the earth is deep, and yellow also represents the depth of the earth.

Extended information:

The origin of the word "Xuanhuang"

From the original origin, the sentence "The sky is mysterious and the earth is yellow" comes from "The Book of Changes" "Kun": "Those who are mysterious and yellow are the variegated colors of heaven and earth. The sky is mysterious and the earth is yellow." The Kun hexagram symbolizes the earth, and the earth is generally yellow. The upper six is ??the last line of the Kun hexagram. "The upper six, the dragon is fighting in the wild, and the other is yellow." The blood is black and yellow." When things reach their extremes, they will turn into opposites. As the saying goes, "the way is poor", Kun will turn into Qian.

Kun symbolizes the earth, the wilderness, and Qian symbolizes the dragon, so the line says: "The dragon fights in the wild." "War" means "intersection" and "connection", which means the qi of Qian and Kun combine; all things There must be "blood" at birth, and "blood" is the "yellow" color of heaven and earth. Therefore, the line says: "His blood is black and yellow."

As shown in the above six, it is the dragon coming out of the earth, yin and yang coming together, and when it is poor, it wants to change, and yin and yang are coordinated. The upper six are above the "Heaven Yao". This Yao has completed a process of change. Quantitative changes lead to qualitative changes. It is ready to meet new challenges and produce major changes. Therefore, "the dragon fights in the wild, and its blood is black and yellow."

In the history of thousands of years of research on the "Book of Changes", many people believe that the Yin pole must be Yang, and the Yang is unbearable. Both sides fight, and both sides suffer losses, resulting in "their blood is black and yellow", which refers to the bleeding of Yin and Yang due to the battle. It shows that this line is an evil line. When used as a metaphor for human affairs, it is a battle between top and bottom, resulting in death, injury and bloodshed.

The reasonable explanation is that the earth is connected to the sky, and the yin and yang are connected and auspicious; the yin pole must be yang, and when it is poor, it wants to change; life is endless, and the avenue is endless. This is the basic idea of ??Yili.

The blue sky is high and the yellow earth is thick. The way of heaven is high and the way of earth is profound.

Xuan represents the sublimity of heaven, and yellow represents the profundity of earth. The sky is dark, and the path is high and vast; the earth is yellow, and the path is deep and broad. Where the sky and the earth meet, every time new blood blooms, it is a bright red sunrise and sunset that fills the sky with colorful clouds. Today’s sun rises from the top of the mountain to sinks to the earth’s surface, collecting all its desolate remaining light. Tomorrow’s sun will surely climb to the top of the mountain and spread out. Dawn, illuminate a whole new world.

Baidu Encyclopedia-Heaven and Earth Xuanhuang