Names of ancient times

The sun is a unit of time for measuring the rotation of planets. It is often called heaven in spoken language.

A solar day is about 24 hours.

A sidereal day is equal to 23 hours, 56 minutes and 4.09894 seconds.

Step 2 wait

In ancient times, five days was called "first class";

It is still used in meteorology: ~ temperature (average temperature every five days);

There are 24 solar terms and 72 seasons in a year.

3. Week

Week, also called week or worship, is a unit of time created by the ancient Babylonians, and a week is seven days.

The origin of the week should be the cycle connected with the moon, because seven days is about a quarter of the moon's week.

Later, the Jews spread it to ancient Egypt and from ancient Egypt to Rome. After the 3rd century, it spread widely to European countries. In the late Ming Dynasty, it was introduced into China with Christianity, so it was called worship.

In China, probably through the introduction of Zoroastrianism in the 8th century, China got the concept of Zhou and named it "Seven Obsidian" respectively. Japan Obsidian Day is Sunday, Month Obsidian Day is Monday, Fire Obsidian Day is Tuesday, Water Obsidian Day is Wednesday, Obsidian Day is Thursday, Jin Obsidian Day is Friday and Earth Obsidian Day is Saturday.

After the founding of the Republic of China, it was renamed Zhou, and the word "star" in it refers to these seven obsidians, but Japan, South Korea and North Korea still use this name.

4, ten days

Ten days, originally meant ten days. The concept of ten-day has existed since Xia Dynasty, and there are also ten-day characters in Oracle Bone Inscriptions. In ancient China, the drought was repeated every ten days, which was called ten days. So use a word "ten days" to express this concept of time.

China people still use ten days to mean ten days. January can be divided into three days, namely morning, noon and evening. At the same time, ten years old can be said to be ten years old. Such as: octogenarians and so on.

May, month

A month is a unit of time in a calendar. It is assumed that its length should be equivalent to the natural orbital period of the moon's orbit around the earth, but traditionally the period of the moon's phase change is taken as the length of one month, that is, the length of one month (lunar month) is the rendezvous month (Wang Shuoyue), which is about 29.53 days.

Inferred from the study of unearthed cultural relics, in the early Paleolithic period, humans had already calculated the date according to the moon phase. Until now, the full moon is still the cornerstone of many calendars. A year is divided into 12 months; In China, the lunar year is 12 months and the leap year is 13 months. The extra month is called leap month.

6. Degree

The so-called "quarter" is to divide a year into four parts on average. According to the order of spring, summer, autumn and winter, a year can be divided into four quarters, and each quarter lasts for three months. The first quarter: 65438+1October-March; The second quarter: April-June; Third quarter: July-September; The fourth quarter: 65438+ 10-65438+February.

7. Year

A year is a unit of time in which events related to the earth's revolution around the sun in orbit occur repeatedly.

Generally speaking, the length of a year is taken as the time interval from a punctuation mark to the same punctuation mark on the celestial sphere along the ecliptic. Because the selected scale points are different, the definition of year is also different, which usually includes:

Last year =365.25964 days

Sidereal year = 365.2563004 solar day (≈ 10 second, 6: 09 in 365)

Tropical year (Bessel year) = 365.245438+099 174 days (≈365 days, 5 hours, 48 minutes and 45.5 seconds).

Leap year =346.62003 (346 days 14 hours, 52 minutes and 52.9 seconds)

Since 1984, Julian year (not to be confused with julian calendar in the calendar) has been adopted as a unified year unit in astronomy, and it is stipulated as 365.2425 days, with an error of 1 day every 3000 years compared with the tropical year.

In the modern Gregorian calendar, the average year is 365 days (including 52 weeks 1 day), and the leap year is 366 days (including 52 weeks and 2 days).

8. Year

We divide a century into 10 units, 1 unit, 10 year, and every 10 year is called 1 year. At the same time, age is often suitable for the use of advertising calendars. A century is 100 year, which is divided into 10 year according to every 10 year, which is called 10 year, 20 years, 30 years, 90 years and 100 year respectively.

9. Centennial

A century is a hundred years, which usually means a hundred years in a row. When used to calculate the date, the century usually starts from the year divisible by 100 or later, such as 2000 or 200 1.

This odd-numbered chronology comes from the post-Jesus era, where 1 usually means "the year of our Lord", so the first century was from 1 to 100, and the 20th century was from 190 1 to 2000, so in 2000,

However, some people set the year of 1 century as 99, and the following century is 100. According to this definition, 2000 is the first year of 2 1 century.

10, Millennium

Millennium is a time span that spans a thousand years. In the solar calendar, if a year is divisible by 1000, it is called the Millennium (or the year after that year), such as 2000 or 200 1, which can be considered as the new Millennium. When the world celebrated the arrival of the new millennium in 2000, there was a debate about whether 2000 or 200 1 was the beginning of the new millennium.

One school thinks that since the solar calendar starts from 1, the first millennium starts from 1 to 1000, and the second millennium starts from 100 1. If so, 200 1 will be the beginning of the new millennium.

Baidu Encyclopedia-Time Unit