What is the blue moon?

The blue moon is a full moon that does not appear on the calendar according to the law.

There are only 12 full moons in most years, about once a month. However, except for 65,438+02 lunar months, there are about 65,438+065,438+0 days in each calendar year. These extra days are accumulated, so there will be an extra full moon every two or three years (average 2.765,438+08284). This extra full moon is called the blue moon.

But different definitions will make this extra full moon appear at different times. Google search "onceinabluemoon" will get the result of1.1669 9016×10 -8 Hz, which is the frequency of the blue moon. At present, the most popular definition is the second full moon in a month.

Blue moon folklore

In folklore, every full moon in twelve months of a year has a name, which corresponds to the season of the year and the needs of crops. For example, the full moon around the autumnal equinox is the harvest month, as well as the growth month and the snow month (which will vary according to different regions and cultures).

But there are twelve or thirteen full moons every year, and the blue moon is the name of the full moon that can't correspond to the season, that is, the full moon other than the twelve full moons.

The word blue moon has existed in folklore for a long time, and its meaning will change slightly or have new meanings with the passage of time. Some folk stories believe that when the blue moon appears, the moon has a face that speaks under the light.