Full Moon: In ancient China, the full moon represented family reunion, happiness and harmony; Life is beautiful; Round lack: In ancient China, the lack of the moon was the pain of parting from acacia; The poem in the famous "Mink Head": "People have joys and sorrows, and the moon is full of rain and shine." Therefore, in ancient China, most of the time, the full moon represents reunion, and the lack of the moon represents separation.
On the night of Mid-Autumn Festival, the moonlight is bright. The ancients regarded the full moon as a symbol of reunion, so August 15 was also called "Reunion Festival". Throughout the ages, people often describe "joys and sorrows" as "the moon is full and the moon is absent", and the wanderers living in other places rely on the moon to express their deep affection. Li Bai, a poet in the Tang Dynasty, wrote poems such as "Looking up, it's moonlight, then leaning back, suddenly thinking about hometown", "Knowing that the dew is frost tonight, the moonlight at home is bright!" Du Fu's "Spring Breeze is Green in Jiang Nanan" and Wang Anshi's "When Will the Moon Shine on Me" in the Song Dynasty are all timeless masterpieces.
How long does it take for a cycle of moon phase change?
It takes about 30 days to change the phase of the moon. When the earth is between the moon and the sun, we can see the whole part of the moon directly illuminated by the sun. This is the full moon. When the moon is between the earth and the sun, we can only see the part of the moon that is not illuminated by the sun, which is the new moon; When the bright part of the moon is first seen again, it is called the "new moon".
When the local moon line is at right angles to the heliocentric line, we can just see half of the part of the moon that is directly illuminated by the sun, which is the first quarter moon.
The period of the moon phase is 29.53 days, which is called the new moon. It is the source of calendar months and weeks. This time is longer than the moon's revolution (sidereal moon), because the moon revolves around the earth at the same time, and the moon will revolve around it for a lunar month (360+360 * 29.53/365.24) = 389.438+01degree (revolution only revolves around 360 degrees). So a sidereal month is about 29.53 * 360/389.11= 27.32 days.
The above contents refer to Baidu Encyclopedia-Full Moon.