The meaning of the summer solstice: the longest day of the year.

The summer solstice is one of the earliest solar terms among the 24 solar terms. Every year on June 2 1 day or 22/year in Gregorian calendar, when the sun reaches 90 degrees longitude, it is the summer solstice. "Zhi Zhi" means "extreme", and the summer solstice is also called "the longest day". After the summer solstice, the direct point of the sun gradually moves southward, and the days in the northern hemisphere will be shorter and the nights will be longer.

Zhao Zhi Heng, an expert in astronomy education in China and director of Tianjin Astronomical Society, said that the summer solstice was the longest day in the northern hemisphere. The longest day in China is Mohe, which is nearly 17 hours; The shortest is Zengmu shoal, with the daily length exceeding 12 hour. There is a difference of nearly 5 hours between the northern and southern days in China.

What does the summer solstice mean?

Interpretation of the summer solstice: 1. For residents in the northern hemisphere, it refers to the time when the sun arrives at the summer solstice; For residents in the southern hemisphere, it refers to the moment when the sun reaches the winter solstice. 2. One of the 24 solar terms, June 2 1 day or 22, is the longest day and the shortest night in the northern hemisphere.

Characteristics of 24 solar terms Summer Solstice

1. The temperature is high and there is much rain.

In the 7th century BC, our ancestors measured the sun's shadow with earth gauge, so they decided the summer solstice, which is the earliest solar term among the 24 solar terms. There is plenty of sunshine, high temperature and rain during the summer solstice, and the rainy season and dog days are also in the summer solstice.

2. The days are long and the shadows are short.

The ancients said: the days are long, the shadows are short, and the days are extreme, so it is called the summer solstice. On this day in summer, the sun's direct exposure to the northern hemisphere reaches the northernmost point of the year, on the Tropic of Cancer (23 27' north latitude). On this day, the sun in the northern hemisphere has the largest elevation angle, the shortest shadow, the longest day and the shortest night. The farther north, the longer the days.

The summer solstice is the northernmost day of the sun in a year, the longest sunshine day in the northern hemisphere, and the longest day that exceeds the night time. However, the days in different places are decreasing from north to south. This is due to the long day and short night effect caused by the tilt of the earth's rotation axis. The closer to the two levels, the more obvious.

On this day in summer, the sun will shine directly on the Tropic of Cancer. There are "peepholes" on the five signs of the Tropic of Cancer in mainland China. At that time, people can verify whether the sun shines vertically on the ground at noon on the summer solstice, and there will be a strange sight of "standing on a pole without a shadow". They can be found in Shantou, Conghua, Fengkai, Guiping and Mojiang respectively.

The origin of the summer solstice

In ancient China, the summer solstice was divided into three periods: "The first period was when the antlers dissolved; Waiting for cicadas to start singing; Wait for three pinellias. " In the ancient summer solstice, people prayed for disaster and prosperity by offering sacrifices to gods. "Zhou Li Chun Guan" contains: "With the arrival of summer, go to local things." Instead, offering sacrifices to the gods means eliminating epidemic diseases, famine years and starvation.

As an ancient festival, the Summer Solstice began in the Song Dynasty, and officials had a three-day holiday. In the Liao Dynasty, it was called "the Summer Solstice", and women entered the colorful fans to give gifts in powder bags.