Expert of this article: Shao Lin, an author of ancient folklore literature
The Spring Festival is coming, I don't know if you have found an interesting thing?
Open the calendar and take a look, huh?! Why is the last day of the waxing moon this year twenty-nine, and why is there no "Chinese New Year's Eve"?
In fact, because of some characteristics of the lunar calendar, this phenomenon is not uncommon.
Let's take a look at science today, why is this year's Chinese New Year's Eve "absent"?
Why haven't there been Chinese New Year's Eve this year?
The Gregorian calendar we use on a daily basis is 31 days in January, March, May, July, August, October, and December, and 28 or 29 days in February, every year.
The lunar calendar is different, there are 29 or 30 days in each month, the former is called a small month and the latter is a large month.
It should be noted that the lunar calendar does not have a 31-day month or a 28-day month like the Gregorian calendar, nor does it have a layout pattern similar to the Gregorian calendar.
For example, the past lunar month of November is 30 days, and October is 29 days. Next year, in turn, November is 29 days and October is 30 days. If the last month of a lunar year, that is, the waxing moon, happens to have 29 days, then there will only be "twenty-nine days of the great year" and no "Chinese New Year's Eve" in this year. That's the case this year.
Similar situations are not uncommon, with no Chinese New Year's Eve in 2000, 2001, 2003, 2006, 2012, 2013, and 2016. And, from 2025 to 2029, there will be no Chinese New Year's Eve for five consecutive years.
This will not affect the New Year, just look for the last day of the Waxing Moon as the Chinese New Year's Eve.
How is the lunar calendar divided?
Some friends may ask, why is the lunar calendar designed to be such an inconvenient memory model?
The answer is that the months of the lunar calendar are determined according to the phases of the moon.
In the "year, month, and day" that people often say, the day is a cycle determined by the rise and fall of the sun, and the month is a cycle determined by the phase of the moon.
We all know that the moon itself does not emit light, but reflects the sun's rays. Because the mutual positions of the Earth, the Moon, and the Sun are constantly changing, so do the parts of the Earth that see the Moon illuminated:
When the sun and the moon are in the same direction as the earth, the moonlight is completely invisible, which is called synodic; and when the moon and the sun are separated on both sides of the earth, roughly in a straight line, what we see is the full moon, that is, looking at the moon. The law of change is shown in the following figure:
Based on 3D Moon software production
Astronomers stipulate that the day of heshuo is called shuo day, which is set as the first day of the lunar calendar, and the next heshuo is the first day of the next month.
That is to say, the number of days in a month of the lunar calendar is completely determined by the synodic cycle, which is also called the synodic lunar cycle, the average of this cycle is 29.53 days, but the moon itself is not uniform.
Therefore, in order to ensure that the first day of each month must be a New Year's Day, the large month (30 days) and the small month (29 days) of the lunar calendar cannot be arranged according to a set of fixed rules.
Is the lunar calendar a lunar calendar?
Understanding the previous knowledge, it can be found that the formulation of the lunar calendar is very dependent on the moon, so is it right for the folk to call the lunar calendar "lunar calendar"?
In fact, the lunar calendar is called the "lunar calendar" from the beginning of the Republic of China, and it can certainly be used when it does not affect our understanding in daily life. But this is just a customary term, not strict.
Strictly speaking, the lunar calendar is a yin-yang calendar. Because it also has an important part of the solar calendar , the twenty-four solar terms.
Many carefully observed friends have found that the twenty-four solar terms are always fixed on a certain date in the Gregorian calendar. For example, the Qingming holiday is often around April 5th, and Lichun is often on February 4th.
This is not to say that the two have "copied" each other, but because the Ancients in China and the West have well summarized the laws of the sun and applied them to their respective calendars.
The Gregorian calendar is called the solar calendar because its length of year is based on the year of regression and does not care about changes in the phases of the moon.
The so-called regression year refers to the length of time that the sun passes through the vernal equinox twice. That's about 365.2422 days — not a whole number, so the Gregorian calendar has 365 days per common year, with an extra day added every few years in February.
The lunar calendar relies on the phases of the moon when it is fixed, and there are also twenty-four solar terms, thus developing a "leap month" system, so that the year that complies with the rules has 13 months, about 384 days.
Thus the average length of the lunar year will be similar to the length of the regression year, and this comprehensive lunar phase and the calendar of the regression year is more accurately a yin-yang calendar.
Cold knowledge
A relatively rare word can often be seen on the calendar in the lunar part: "Twenty".
The word is pronounced "niàn", which means twenty. Its glyph is two tens: [ten].
By analogy, is thirty or ten the same? There is really this word, thirty, pronounced "sà";
Forty should be [ten ten ten], swastika, pronounced "xì".
However, the longest month of the lunar calendar is only 30 days, which is generally not used.
At this point, I finally understand why I didn't Chinese New Year's Eve this year, right?
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