Why does the phenomenon of "the sun and the moon shine together" sometimes occur?

This phenomenon is not unusual. In fact, it often occurs. During the first quarter moon and last quarter moon of each month, the sun and moon will shine together in broad daylight.

The moon revolves around the earth, and the earth revolves around the sun. This makes it possible for a positional relationship between the three to occur, so that the moon and the sun can be seen at the same time on the earth, but sometimes the moon The back side is facing us (the moon does not emit light) and we cannot see it, or the sun's light is too strong and we cannot see it either.

At this time of "the sun and the moon shine together", there are "stars" in any direction and any position in the universe that can be observed from existence (that is, without any obstruction), but because of the stars Due to various reasons, the brightness is not enough, so it is difficult to see with the naked eye.

Before the first quarter moon and before the sun sets, people can see the moon to the east of the sun. During the last quarter moon phase, people can see the moon in the morning before it has "gone off work". 's shadow. However, we do not often observe this situation. This is because observation requires certain conditions. From the weather conditions, if the sky is clear, the air is transparent, the sun is bright, and the visibility is good, it can be seen during the day during these two periods. "The sun and the moon shine together." Extended information

The sun and the moon shine together is a natural phenomenon caused by the different rotation periods of the earth around the sun and the moon around the earth. Certain conditions are required for direct observation of the sun and moon astronomical phenomenon with the naked eye. Generally, it can only be seen in broad daylight during the 21st to 23rd lunar calendar in the autumn months when the sky is clear and visibility is good.

The sun and the moon shine at the same time is just a natural phenomenon. For the sun and the moon to shine at the same time, the sun and the moon need to be above the horizon at the same time. Theoretically, as long as the atmospheric conditions are relatively good, this phenomenon may occur except on the fifteenth day of the lunar calendar.

But there is a second condition, which is that the limit magnitude of the sky (the faintest celestial object that can be seen) cannot be too low, so generally speaking, when the sun is rising or about to set, the Brightness easily meets this condition (even in cities).

So in the first half of the lunar calendar (after the fourth day of the lunar month), you can see the moon phases when the sun sets, in order from west to east.

In the second half of the lunar month (before the 27th), the moon can also be seen after the sun rises, from the western sky to the eastern sky.

Reference: The Sun and the Moon Shine Together - Baidu Encyclopedia