Why are the two solar terms on the earth, the summer solstice and the autumnal equinox, equally divided day and night on a global scale, and equally divided day and night in the equatorial region thro

Why are the two solar terms on the earth, the summer solstice and the autumnal equinox, equally divided day and night on a global scale, and equally divided day and night in the equatorial region throughout the year? The vernal equinox is March 2 1. At this time, the sun shines directly on the equator, and the global day and night are equal in length.

The summer solstice is June 22nd, when the sun shines directly on the Tropic of Cancer. The days in the northern hemisphere are long and the nights are short (the days in the southern hemisphere are short and the nights are long).

The autumnal equinox is September 23, and the sun shines directly on the equator. The whole world is as long as day and night.

The winter solstice is 65438+February 22nd, when the sun shines directly on the Tropic of Capricorn, and the days in the northern hemisphere are short and the nights are long (the days in the southern hemisphere are long and the nights are short).

So it should be the vernal equinox and the autumnal equinox, and the world is divided equally day and night. At this time, the altitude angle of the sun decreases from the equator to the poles at noon.