The order of counting large time intervals. Time reference

Throughout virtually the entire history of mankind, outstanding physicists and philosophers have tried to comprehend time. However, it was still not fully understood by the phenomenon. And humanity, instead of understanding its nature, has learned at least to measure it. How does the time count, from which point is it conducted and in what order? Let's find out more about this.

What is time

Before you deal with the measurement of temporality, it is worth refreshing your knowledge about this concept. A time is a measure of the duration of the existence of all objects and beings in the universe from the moment of their appearance to disappearance. In fact, this concept is a kind of marker for determining events.

In classical physics, there is such a concept as the "axis of time". In it, this phenomenon is viewed as a one-dimensional straight line, moving from the past, through the present, into the future.

It is generally believed that the very concept of "time" arose at the time of the birth of the universe, as a result of the Big Bang. To refute or confirm this assumption is not yet possible.

Time properties

Like any quantity, this has special properties:

• One-dimensionality.
• Irreversibility. In other words, time does not just move in a straight line, but it does it only in one direction (from the past to the future). If you take 2 arbitrary points on the temporal axis, then one will necessarily be future with respect to the other. And that, in turn, will be for the first past.
• Uniformity. It is the equality of every moment. The so-called initial longing for timing is just a convention. Since practically from any event it is possible to start a new temporal calculus.
• Objectivity. Time exists, regardless of a person's consciousness and from his acceptance of this phenomenon. It's like with the law of World gravitation: although for many centuries mankind did not know about its existence, he still continued to act.
• The universality. There can not be anything that exists outside of time.

What is called the countdown

Despite the fact that the phenomenon under consideration is homogeneous, throughout the history of the world people have been trying to find a way to learn how to count it.

The fact is that every civilization at a certain moment of existence noticed the change of seasons. For the sake of survival, its representatives faced the need to learn how to calculate the arrival of favorable and unfavorable periods of time in order to make early supplies and not die of hunger and cold. So there was a chronology.

Calendar, its types and history

This word from different peoples looked and was written differently. However, his meaning has always been one. Calendar is a kind of system (order) of counting large time intervals. And it all started from small.

The first repetitive cycle that a person noticed was a change of day and night - a day. Gradually it was noted that at regular intervals the moon passes through all the phases. A little later, people noticed that in 12 moons the seasons are repeated, that is, a year passes. Based on these observations, the lunar calendar was invented. According to him, the year consisted of 354 days.

Unfortunately, this order of counting large time intervals did not coincide with the solar year. Therefore, the peoples who used it had to resort to various tricks to correct inaccuracies. For example, the Romans once every 3 years inserted an additional month - marcedony.

In some modern countries calendars created on the basis of the lunar calendar are still used.

The people of Ancient Egypt, who worshiped the god of the Sun Ra, based his chronology on the motion of not the moon, but the sun. However, such a system was also far from perfect, since the number of days in the year exceeded 365. In later periods (when the country alternately turned out to be under the power of the Greeks, then the Romans), the new owners of the state tried to introduce amendments to the Egyptian solar calendar, And did not get accustomed.

The Greeks had a special order of reading large time intervals. He called the Methonov cycle and lasted for 19 years. This system, developed by the astronomer Meton in the V century. BC. E., took into account the movement of the Sun and the Moon. Despite its complexity, it was quite accurate and progressive for its time. It is worth noting that the Jewish people still use it. In addition, the time of the Passover of Christ is calculated annually according to this principle.

The Romans, who granted their entire system of chronology to the entire Christian world, initially had a very awkward calendar consisting of 10 months. However, Julius Caesar conducted his reform and introduced a new system of counting the years. After the death of the emperor, his followers got a little confused in the new calendar, because of which he accumulated more leap years for 4 leap years, and Octavian Augustus was forced to cancel them for as long as 16 years.

After Christianity became the main religion of Rome, with its spread across the world, many countries switched to the Julian calendar.

That's just it was not perfect, and after several centuries the confusion with leap years led to the fact that the actual time interval between the vernal equinoxes (according to them the year was considered) did not coincide with the calendar one.

In this regard, the head of the Catholic Church, Pope Gregory XIII, in 1582, together with the mathematician Aloisius Lilia, created a new system of chronology, which the whole civilized world enjoys today.

Chronology

The order of counting large time intervals is inherently associated with such a concept as chronology. It is formed from the Greek word combination "the doctrine of time" (from the words "chronos" and "logos"). From his etymology it is clear that this science specializes in the study of time and methods of its measurement. It is divided into 3 types:

• Astronomical. He specializes in studying the motion of celestial bodies. Based on its cyclicity, it helps to calculate the exact astronomical time.
• Historical. Unlike the previous one (which is aimed at establishing the exact time), this focuses on the study of calendars and systems of chronologies of different civilizations and states. It also helps to synchronize the chronologies of different peoples to know exactly when an important event occurred.
• Geochronology. He studies time according to the state of geological rocks of the Earth. This industry has its own geochronological time scale. The beginning of time on it is the moment of the formation of our planet, about 4.6 billion years ago.

Time reference

Since each great civilization had its own calendar and chronology, it is worth paying attention to the beginning of its countdown. Although in practice time is a homogeneous phenomenon, in each system of its counting its own starting point was chosen.

The Egyptians had chronology from the beginning of the reign of the next pharaoh or a whole dynasty. In the Roman state the starting point of reference was the date of the founding of Rome. In the modern world, most chronological systems are based on some important religious events. For example, in Christianity this is the expected date of the birth of Christ, the Muslims - the time of the passage of the prophet Muhammad from Mecca to Medina, the Buddhists - the time of the death of the Buddha, and the Jews - the moment of the creation of the world (in their opinion).

Minimum calendar time intervals: day, week, month

Having dealt with the starting points of counting chronology, it is worthwhile to consider the most important units that are used by all of them.

The minimum period of time used in all calendar frames of reference is a day (day and night, lasting 24 hours). By this concept is meant the period of the complete revolution of the Earth around its own axis.

In the future, on the basis of this unit, weeks are formed. In the modern world, they last for 7 days. However, in the past, this was not always the case. For example, for the Slavs this period of time was 9 days, and in the Soviet period - 5, and sometimes 6 days.

The ancient Egyptians had a week of 10 days, and Maya - from 13 (sometimes from 20).

The next in order of increase is the month. Initially, this was the period of the passage of the Moon full turn around the Earth. However, today it does not necessarily coincide, at least in the Julian and Gregorian calendars.

Quarter, season

Months are impoverished in seasons and quarters. Each season (the same time of the year) consists of 3 calendar months. There are only 4 of them: winter, spring, summer and autumn. The quarter also consists of 3 months, but they are not counted according to the seasons, but strictly according to the calendar. This unit is allocated in order to simplify the preparation of the reporting documentation.

Year and its varieties

Months, quarters and seasons form a year. This is the first large time interval during which the Earth makes a complete revolution around the Sun. It consists of 12 months, 4 seasons or quarters.

The traditional Christian year consists of 365 days, but every 4th is a leap year, and it has 366 days. In the Jewish and Islamic calendars, it consists of 355 days.

Also, one should not forget about such a concept as the academic year. This is a period of 9 months, during which classes are held in educational institutions.

Century, millennium, megayod and gigad

100 years form a century or a century. This is one of the largest periods of time for a person, since only a few are able to live so much.

The millennium consists of 1000 years, or 10 centuries.

It is also worthwhile to find out what the time interval is called the longest relative to the chronology. It is a gigagod, it consists of 1 000 000 000 years. In addition, an intermediate unit is allocated - a mega-year (1,000,000 years).

Megadog and gigad in historical chronology are not used, because at the moment there is no evidence of the existence of intelligent life during these periods. However, they are important for geochronology.