Solar terms and the night hemisphere

The days are long and the nights are short.

The length of day and night is closely related to the four solar terms in a year. In most parts of the earth, at the vernal equinox and the autumnal equinox, day and night are equally distributed. After the vernal equinox, the days are long and the nights are short. After the autumnal equinox, the nights are long and the days are short; In summer solstice, the day is the longest;

Winter solstice, the longest day and night. After the winter solstice, the days get longer and the nights get shorter. When the vernal equinox comes next year, it will be as long as day and night, and this change will continue until the summer solstice.

Extended data:

So at different time points, the sun shines directly at different latitudes of the earth. Under the irradiation of the sun, the earth is divided into two hemispheres: the hemisphere facing the sun is the day hemisphere and the hemisphere facing away from the sun is the night hemisphere. The dividing line between the two hemispheres is called the terminator line, and the length of day and night depends on the latitude division of the twilight circle.

Latitude is divided into two parts by the morning and evening circles: the part located in the daytime hemisphere is called the daytime arc; The part located in the night hemisphere is called the night arc. The arc length of the solar arc and the night arc determines the length of day and night in this place.