Calendar is usually called some system, with the help of which it becomes possible to differentiate the flow of time into certain intervals, which helps to streamline the course of life. Throughout the history of mankind, there have been a huge number of calendars, and they were based on different principles. In this article, we'll discuss the main types of calendars, as well as what form our modern timekeeping system can take.
Origin of the word "calendar"
Before proceeding to the description of the types of number systems themselves, let's find out where the word denoting them comes from. The term "calendar" etymologically goes back to the Latin verb caleo, which translates as "proclaim". Another variant that has become the origin of the word "calendar" is the calendarium. The last in ancient Rome was called the debt book. Caleo preserves for us the memory that in Rome the beginning of each month was solemnly proclaimed in a special way. As for the debt book, its significance is due to the fact that all interest on debts and loans in Rome was paid on the first day.
Origin of the calendarsystems
The fact that time flows in a certain circle, humanity has long realized on the basis of cyclically repeating events and phenomena, of which there are quite a lot. This, for example, is the change of day and night, the seasons, the rotation of the celestial spheres, and so on. Based on them, various types of calendars developed over time. The basic unit of time of any of them is a day, which includes one rotation of the Earth around its own axis. Then the moon played an important role in history, the change of phases of which forms the so-called synodic month. It is named after the Greek word "synodos", which translates as "rapprochement". We are talking about the convergence in the sky of the sun and moon. And finally, the change of four seasons makes up the tropical year. Its name comes from the Greek "tropos", meaning "turn".
Why do different peoples living on the same planet have different kinds of calendars? The answer is that the length of the circle, the synodic month and the tropical year are not correlated with each other, which provides a lot of choice when compiling the calendar.
Three types of calendar
Based on the values described, attempts were made at various times to compile a calendar suitable for society. Some of them were guided only by lunar cycles. Thus, lunar calendars appeared. As a rule, they numbered twelve months, focused only on the movement of the night star, and did not correlate with the change of seasons. Others, on the contrary, made their calculations only on the basis of the circleseasons, regardless of the moon and its rhythm. This approach gave rise to solar calendars. Still others took into account both cycles - solar and lunar. And, starting from the latter, they tried, one way or another, to reconcile both with each other. They gave rise to mixed solar-lunar calendars.
Lunar calendar
Now let's discuss the nuances of the time calculation system based solely on the movement of the moon. The lunar calendar, as already mentioned, is based on the synodic month - the cycle of changing lunar phases from new moon to full moon. The average length of such a month is 29.53 days. Therefore, in most lunar calendars, a month lasts 29 or 30 days. The year usually consists of twelve months. Thus, it turns out that the length of the year is about 354.36 days. As a rule, it is rounded up to 354, while periodically introducing a leap year of 355 days. They do it differently everywhere. For example, the Turkish cycle is known, where there are three leap years for eight years. Another option, with a ratio of 30/11, offers the Arabic system, on the basis of which the traditional Muslim calendar is compiled.
Since the lunar calendars have nothing to do with the movement of the sun, they gradually diverge from it due to a difference of more than ten days a year. So, the solar calendar cycle of 34 years corresponds to 35 lunar years. Despite this inaccuracy, this system satisfied many peoples, especially at an early stage of development, when they were characterized by a nomadic lifestyle. The moon is easily visible onsky, and this calendar does not require significant complex calculations. Over time, however, when the role of agriculture increased, its capabilities turned out to be insufficient - a more rigid binding of months to the seasons and the range of agricultural work was required. This stimulated the development of the solar calendar.
Lack of the lunar calendar
In addition to the fact that a calendar based entirely on the lunar cycle differs significantly from the tropical year, it has another significant drawback. It consists in the fact that, due to a very complex orbit, the duration of the synodic month is constantly changing. The difference in this case can be up to six hours. It should be said that the starting point of the new month in the lunar calendar is not the new moon, which is difficult to observe, but the so-called neomenia - the first appearance of the young moon at sunset. This event follows the new moon 2 or 3 days later. At the same time, the time of neomenia depends on the time of year, the duration of the current month and the location of the observer. This means that a calendar calculated in one place will be completely inaccurate for another area. And in general, no system based on lunar cycles is capable of accurately reflecting the real movement of the night star.
Solar calendar
The history of the calendar cannot be complete without mentioning the solar cycle. I must say that today it is the main form of time calculation. It is based on a tropical year of 365.24 days. To make calculations more accurate,leap years are periodically introduced, which collect the accumulated "surplus" in one "extra" day. There are various systems of leap years, due to which many types of calendars based on the movement of the sun are known. The starting point is traditionally considered the day of the spring equinox. Therefore, one of the requirements of the solar calendar is that every year this event falls on the same date.
The Julian calendar had the first system of leap years. Its weak point was that for 128 years it gained one extra day, and the equinox point shifted, respectively, back. This inaccuracy was tried to correct in various ways. For example, Omar Khayyam proposed a special 33-year cycle, which then became the basis of the Persian calendar. Later, at the initiative of Pope Gregory, the Gregorian calendar was introduced, which is the main civil calendar of modern society. It also gradually gains one extra day, but this period stretches from 128 years to 3300.
Another attempt to improve the Julian system was made by Milutin Milankovitch. He developed the so-called New Julian calendar, which gained an error per day already in 50,000 years. This is done thanks to a special rule regarding secular years (they can be considered leap years only if, when divided by 900, the remainder is 2 or 6). The disadvantage of the Gregorian and New Julian calendars, with their accuracy, is the fact that the date of the equinox becomes floating, and falls on different days every year.
Solar-lunar calendar
Finally, let's touch on the solar-lunar calendar. Its essence is to reconcile the movement of the sun with the movement of the moon in one cycle. To do this, it was necessary to periodically extend the year by one month. This year was called embolismic. In ancient Greece and Babylon, three additional months were introduced over the course of eight years. Its error is one and a half days for the entire eight-year period. A longer cycle, according to the history of the calendar, was adopted in China, although it was known in both Babylon and Greece. Its margin of error is one day in 219 years.
Varieties of calendars
Now let's talk about what kind of calendar exist today. It will be about constructive, not about astronomical features. So, today flip, wall, pocket and tear-off calendars are most in demand.
Flip calendars
Another name for this type of printed edition is a "house". Although some options may have a different design, including a plastic stand. The latter often form one unit with a pencil holder and staple compartments. The bottom line is that the flip calendar is designed so that the tables of the months are located on different pages that need to be flipped in a timely manner. Together with the calendar, various information or simply beautiful images that are included in the overall design of the room are very conveniently placed on them. Such products are used most often in offices, conveniently located in the corner of the desktop. Desk calendar is also commonserves as a gift or souvenir.
Wall calendar
Many kitchens have this calendar attached to the wall, refrigerator door or door. Wall calendars are very popular because they are easy to use and their aesthetic value these days makes them a great home decoration. Sometimes they are combined with the technology of "houses". In this case, wall calendars, as a rule, are real albums dedicated to a particular topic. And the function, in fact, of calculating time fades into the background in them.
Pocket Calendar
This type is probably the most common in our time. Pocket calendars are small cards, on one side of which there is, in fact, a calendar plate, and on the other - some kind of drawing. Very often, such products serve as bookmarks, business cards. Often they are used for advertising purposes. Pocket calendars are a kind of postcards that carry an additional function. You can easily put them in your wallet and carry them with you, taking them out as needed.
Tear-off calendars
The Soviet tear-off calendar is familiar to everyone. Once they were found in almost every home, but today their popularity has fallen somewhat, although they are still often found. These products are real books, where each page is dedicated to one day of the year. When a new day dawns, the old page is torn off. That is why it is called detachable. On the back of the pagecontains some text. As a rule, each such calendar is dedicated to a topic and represents a rather informative source within its framework.
Church calendars
A few words should also be said about what a church calendar is, since many, coming to church or reading church literature, are faced with a double dating system. In fact, the church Orthodox calendar means the usual Julian calendar. Just for two thousand years, he began to lag behind the real astronomical course of time by almost two weeks. The Catholic Church corrected this, resulting in the Gregorian calendar. But the Orthodox did not accept this reform. The Russian Orthodox Church and several other independent jurisdictions, for example, still adhere to the Julian calendar. But most of the Orthodox churches of the world still switched to the New Julian calendar, which currently coincides with the Gregorian.
The church calendar thus has at least three varieties. In some countries, in addition, churches use their own national calendars. For example, in Egypt, the Coptic system of chronology is common. Other religious organizations also have their own calendars. Known, for example, Vedic, Buddhist, Islamic, Baha'i and other systems of organizing time.
Mayan calendar
In conclusion, let's say a few words about what the ancient Mayan calendar is. In fact, this is not one, but a whole system of differentreckoning. The civil calendar for the year of the Mayan Indians was sunny and consisted of 365 days. Its main purpose was to streamline agricultural life. There was also a ritual calendar called the Tzolkin. It translates as "counting days." It is somewhat unusual in its structure. So, the calendar for the year according to Tzolkin contained not 365, but 260 days. The latter were divided into two cycles - twenty-day and thirteen-day. The days of the first of them had their own name, and the second contained only a serial number. The Mayan time counting system also included such periods as tuns (360 days), katuns (20 tuns), baktuns (20 katuns). The epoch of 260 katuns was considered the largest. In terms of the counting system familiar to us, this is 5125 years. On December 21, 2012, one such era, called the fifth sun, ended and a new era of the sixth began.
