What is the sign of a double day in the sky?

The reason why there are double days in the sky is that before the sun sets or rises, the moon appears above the horizon and appears in the sky at the same time with the sun, thus forming a scene of "the sun and the moon are in the same sky". This kind of scene will appear in the first half of the lunar calendar every month, but it can only be seen when the weather is fine and the atmospheric conditions are good.

Although there is no special symbol in science, in some cultures, the sun, the moon and the same day are considered ominous. For example, in China's ancient Book of Songs, there is a description that "the sun, the moon and the sky are all beautiful, which has plagued him all his life and caused terrible disasters all over the world".

In a word, the double day in the sky is only a natural phenomenon, and there is no special sign.