Side views of summer solstice, winter solstice, vernal equinox and autumn equinox

On the day of the vernal equinox (February1March), the sun shines directly on the equator, and the whole world is as long as day and night, without extreme day and night.

On the solstice of summer (June 22nd), the sun shines directly on the Tropic of Cancer, with long days and short nights in the northern hemisphere, short days and long nights in the southern hemisphere, extremely bright days in the Arctic Circle and extremely dark nights in the Antarctic Circle.

On the autumnal equinox (September 23rd), the sun shines directly on the equator, and the whole world is as long as day and night, without extreme day and night.

During the winter solstice (65438+February 22nd), the sun shines directly on the Tropic of Cancer, and the days in the northern hemisphere are short, the nights in the southern hemisphere are short, the Arctic circle is extremely night, and the Antarctic circle is extremely day.

On the equator, the whole world is divided equally day and night. On the vernal equinox, the sunrise and sunset time is 6 o'clock all over the world.

Summer solstice is one of the 24 solar terms, which occurs on June 20th, or 2 1, or 22nd of the Gregorian calendar every year. For the Tropic of Cancer and its northern area, the summer solstice is also the highest day of the year at noon. On this day, the northern hemisphere received the most solar radiation, almost twice as much as the southern hemisphere.

Every year around September 23rd, when the sun reaches longitude 180 degrees, it enters the "autumnal equinox" solar term. The autumnal equinox, like the vernal equinox, is the earliest solar term established by the ancients.

When the sun reaches the longitude of the Yellow River at 270 degrees, it is about 1 day within 30 days before and after the Gregorian calendar 65438+February 22nd or the lunar calendar1month15th (full moon). On this day, the sun shines almost directly on the tropic of Capricorn, with the shortest day in the northern hemisphere, the extreme night in the northern hemisphere and the extreme sun in the southern hemisphere. Later, the position of direct sunlight moved northward and the days became longer.