When did the days begin to get longer?

After the solstice in winter, the days begin to get longer.

The winter solstice is the 22nd solar term in the "24 solar terms", and the solar calendar reaches 270 degrees. Every year, the festival is held on 65438+February 2 1-23 in the Gregorian calendar. The winter solstice is the limit of the sun's southward travel, and the height of the sun in the northern hemisphere is the smallest on this day. On the solstice of winter, the sun shines directly on the tropic of Capricorn, and the sun is most inclined to the northern hemisphere. The solstice in winter is the turning point of the sun. After this day, it will go back. The direct point of the sun will move northward from the Tropic of Capricorn (23 26' s), and the northern hemisphere (China is located in the northern hemisphere) will increase day by day.

Extended data

Astronomical significance:

According to modern astronomical science, during the winter solstice, the sun moves to 270 (winter solstice), and the position where the sun directly hits the ground reaches the southernmost point of the year. The sun shines almost directly on the tropic of Capricorn (also known as the winter solstice daily line), and the sun is most biased towards the northern hemisphere. Therefore, the winter solstice is the place with the shortest day and the longest night in the northern hemisphere. The higher the latitude, the shorter the day and the longer the night.

For all parts of the northern hemisphere, the winter solstice is also the day with the lowest sun height at noon all year round. North of the Arctic Circle, the sun is below the horizon all day, which is the widest day of the year in the northern hemisphere. In winter solstice, the northern hemisphere gets the least solar radiation, which is about 50% less than that in the southern hemisphere in hot summer.

The winter solstice is the southernmost day of the sun in a year, and it is also the limit of the sun's southward travel. After this day, the direct point of the sun began to move from the tropic of Capricorn to the north, and the length of the day in the northern hemisphere began to lengthen gradually, and the height of the sun gradually increased at noon. It is worth noting that around the winter solstice, the earth is located near the perihelion, and its movement speed is slightly faster, which leads to that the time of the sun in the southern hemisphere is about 8 days shorter than that in the northern hemisphere, so the winter in the northern hemisphere is slightly shorter than that in summer.

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