Popular science knowledge about the winter solstice: The earth at the winter solstice is closer to the sun than the earth at the summer solstice.

On the day of the winter solstice, the day is the shortest in the year and the night is the longest. Taking Beijing as an example, on the day of the winter solstice, the sun lazily rises from the southeast at 7:32, and by 4:52 p.m.

I clocked out of work early. The sun is only in the sky for 8 hours and 20 minutes, and the days get shorter the further north you go.

The reason is that the earth has its head held high. It turns out that there is an angle between the equatorial plane of the earth and the ecliptic plane of the earth's revolution around the sun, which is called the ecliptic angle. The ecliptic angle is about 23°26′.

The existence of the intersection angle causes the direct sun point to move back and forth between the earth's north and south latitudes 23°26′, thus causing changes in the height of the sun at noon and the length of day and night.

The historical origins of the winter solstice. China’s astrology culture has a long history and is profound. The twenty-four solar terms were originally formulated based on the changes in the stars. In different seasons and at different times, the Big Dipper will point in different directions, which is the so-called "the handle of the bucket points to the east, and the world is spring; the handle of the bucket is a guide."

, the world is summer; the handle of the bucket points to the west, the world is autumn; the handle of the bucket points to the north, the world is winter." The "twenty-four solar terms" are the product of ancient farming civilization.

It has a long historical origin.

During the period of Emperor Wu of the Western Han Dynasty, the "Twenty-Four Solar Terms" were absorbed into the "Taichu Calendar" as a calendar supplement to guide farming in the northern Central Plains region, and the "Twenty-Four Solar Terms" were measured in the Yellow River Basin using the Tugui sun shadow method.