The spread of folk blood moon is very bad. Many people in Europe believe that the blood moon will awaken the dark magic and release Satan. Many Asians believe that the blood moon indicates disaster. If the moon changes color, there will be disaster.
In fact, when an eclipse occurs, the moon enters the shadow of the earth, and sunlight cannot directly reach the surface of the moon and refract through the earth's atmosphere. Because the red light in visible light has the longest wavelength and the smallest refraction angle, it will hit the surface of the moon more and reach the human eye through the atmosphere, so the moon is mostly red when the eclipse occurs.