Main units of time: day, month, year. Physics for Dummies: What is Time Three Basic Units of Measurement of Time

Meter, second and kilogram are the most well-known SI units. And every schoolchild knows that distance is measured in meters, time in seconds, and mass in kilograms.

Meter, second and kilogram are the most well-known SI units. And every schoolchild knows that distance is measured in meters, time in seconds, and mass in kilograms. But for some reason the school curriculum is silent about the history of their birth. Indeed, where did these units of measurement come from? And why exactly them?

“You are from one
Build ten
And hide the deuce,
Don't howl about her.
Give the three a go
So that it becomes even
And you're rich.
Hide the four
Don't cry about her
And five and six
Connect with seven,
And until eight
Lift them up.
Nine is con
Ten - out.
Here's a witch's
multiplication table"
Goethe "Faust"

A lot of noise from one meter

“Death to the aristocrats!”, “Long live the nation!” and “Traitors on the lampposts!” - such slogans were heard throughout France when, in 1792, two astronomers Jean Baptiste Delambre and Pierre Francois Mechain were commissioned by the National Assembly to “measure the Earth.” In scientific terms, they had to carry out field work to measure the Paris meridian, i.e. a specific meridian, which between the Spanish Barcelona in the south and the French Dunkirchen in the north passes exactly through Paris. Expecting to complete this Herculean task in a few months, or at worst in a year, the astronomers did not take into account all the turmoil and excesses of the revolution, to which they themselves almost fell victims on suspicion of espionage, and therefore they ultimately had to solve this problem it took 6 years.

The idea was as follows: to determine the distance from the equator to the north pole, i.e. calculate a quarter of the earth's meridian by measuring only the distance of Barcelona from Dunkirchen. To do this, Delambre and Mechain had to first establish the geographical latitudes of Barcelona and Dunkirchen, which was not particularly difficult for them. And then, knowing that the difference in latitude between these settlements is an angle of 9°40′, and a quarter of the meridian is correspondingly 90°, using an elementary proportion, calculate the distance from the equator to the north pole. And so it was decided to take one ten-millionth part (1/10000000 = 1/10 7) of this meridian quadrant on the surface of the earth’s ellipsoid at the longitude of Paris as the standard of length for all times and peoples. A fairy tale is told quickly, but it takes a long time to get things done. After all, before starting these simple calculations, it was necessary to measure a continuous chain of imaginary triangles on the route Barcelona - Dunkirchen, the lengths of the sides of which were calculated from the measured angles.

Moreover, each of the 1800 routine angle measurements had to be repeated as many times as possible to reduce the statistical error.

The complexity of this enterprise was colossal, and dangers lurked at every step, and, frankly, it is not clear why not find a simpler solution for finding a standard measure of length? Why not take the distance between the two guillotines on the Place de la Concorde, divide it by 10, and thus establish a measure of length? Or take an object, preserve it and take its dimensions as a standard? But the times were too rational: the standard should not have carried the shameful stain of arbitrariness - there was already too much of it. The standard must have a universal property, generalized significance and have nothing to do with the unhealthy anatomical features of any kings and rulers. It was necessary to say goodbye to all these arshins and feet, fathoms and inches, ruts and yards at once.

And so on the 19th Brumaire of the VIII year (according to the Gregorian calendar, December 10, 1799), the titanic work of two scientists led to a preliminary official result - the first prototype of the meter standard was cast from platinum. The meter was born, and with it the metric system, in which the meter is also a unit of measurement for area and volume, and the unit of mass is tied to the meter, because The definition of a kilogram is based on the mass of 1 dm3 of water. All this was divided and multiplied using the number 10: in one meter there are 100 centimeters, in one centimeter there are 10 millimeters, etc. Moreover, it is interesting to note that the decimal number system is supposedly related to the number of fingers a person has.

During Napoleon's reign, the metric system spread throughout Europe. In 1918 it was introduced in Russia. Only in Great Britain, which was not conquered by Napoleon, did the traditional measures of length remain: inch, foot and yard. In 1889, a more accurate international standard meter was produced. This standard is also made of an alloy of platinum and iridium and has a cross section in the shape of the letter “X”. Copies of it were deposited in countries where the meter was accepted as the standard unit of length. This standard is still kept at the International Bureau of Weights and Measures (in Sevres near Paris), although it is no longer used for its original purpose.

The measure of length that Delambre and Mechain “snatched” from the Earth was, in modern parlance, a high-tech achievement, obtained using the best measuring instruments of that time. Indeed, if we compare modern data on the distance from Barcelona to Dunkirchen with the result obtained by astronomers 2 centuries ago, the difference will be only 2 km. The catch is that the Earth is not a perfect sphere, each meridian is different from its neighbor, and polar compression was not taken into account. Therefore, it must be admitted that the meter was and is not one ten-millionth of a quarter of the earth’s meridian, but just the length of a platinum rod stored in Paris. Such a result could have been achieved with less blood, as already noted, but then it would not have been a product of “universal thinking,” and Delambre and Mechain would not have gone down in history.

To be fair, it is worth noting that initially, on May 8, 1790, the French National Assembly was going to define the meter as the length of a pendulum with a half-period of swing at a latitude of 45° equal to 1 s (in modern units this length is approximately 0.981 m). This method has one significant advantage - every person with a more or less accurate clock could determine the unit of length at any time.

However, since the pendulum standard is not reproducible enough (the acceleration of gravity depends on latitude), the French Academy of Sciences proposed to the National Assembly to define the meter in terms of the length of the meridian.

Although, if a standard pendulum were placed in some fixed geographical location, then this method would be in no way inferior to the method of measuring the meridian. In this case, the history of metrology would be different: the definition of a meter would be tied to time, or more precisely, to the second. So what is a second?

Don't think down on a second

As you know, time is balanced and inexorably moves forward, not succumbing to any influence, much less influence from humanity.

Historically, the basic unit for measuring short intervals of time was the day (often called “day”), equal to the period of revolution of the Earth on its axis. As a result of dividing the day into smaller intervals, hours, minutes and seconds arose. The origin of division is probably related to the duodecimal number system followed by the ancients.

The day was divided into two equal consecutive intervals (conventionally “day” and “night”). Each of them was divided into 12 hours. Further division of the hour goes back to the sexagesimal number system. Each hour was divided into 60 minutes. Every minute – for 60 seconds.

To measure longer time intervals, the units of measurement “year”, “month” and “week”, consisting of an integer number of days, are used. A year is approximately equal to the period of revolution of the Earth around the Sun (approximately 365 days), a month is the period of complete change of phases of the Moon (the so-called synodic month, equal to 29.53 days). The 7-day week has no direct astronomical basis (although it was originally tied to the length of one of the four phases of the Moon, rounded to a whole number of days), but is widely used as a unit of time.

The decimal system of time measurement was actively used only in ancient China. The day of the ancient Chinese consisted of one hundred parts called “ke”, and the month consisted of 10 days called “xun”. Europe also decided to keep up: during the French Revolution, under the influence of “metric fever”, by decree of the Convention of October 5, 1793, an attempt was made to transfer all of humanity to decimal time. The day from midnight to midnight was divided into 10 decimal hours, an hour into 100 decimal minutes, and a minute into 100 decimal seconds. Thus, midnight was at 0:00:00, noon at 5:00:00, etc. In principle, why not? The French reformers did not take into account only one thing - it is very difficult to change something that has become firmly established throughout the world. In addition, nothing human is alien to us: just as the metric system is based on 10 fingers, a second is approximately equal to the interval between beats of the human heart. So, unlike the Republican calendar, this system of measuring time did not gain sufficient acceptance and was officially abolished in 1795. Today, 6 billion seconds, or 200 years later, an attempt is being made again to divide time by 10.

Several years ago, Swatch was puzzled by the problem of time zones that prevented people from communicating over the Internet. What to do? The company's specialists did not grieve and simply decided to introduce their own time measurement system. Hours and minutes in Internet time are replaced by “bits” (not to be confused with “bit” - here the word is “beat“, or “blow”). Each bit is equal to one minute and 26.4 seconds, and a day contains a thousand of these units. The meridian passing through the city of Biel (Switzerland), where the headquarters of Swatch is located, was taken as the starting point. Will this time measurement system become widespread? Wait and see.

Such a unique kilogram

The kilogram is defined as the mass of the international standard kilogram kept by the International Bureau of Weights and Measures, which is a cylinder with a diameter and height of 39 mm made of a platinum-iridium alloy (90% platinum, 10% iridium). Initially, a kilogram was defined as the mass of one cubic decimeter of water (liter) of pure water at a temperature of 4°C and standard atmospheric pressure. This definition is not entirely constructive: you need a very accurate cubic decimeter, completely clean water and an absolutely correct thermometer.

The birth of the kilogram was greatly facilitated by the famous chemist Lavoisier, who in his laboratory was conducting experiments on the composition of water just at the time when Delambre and Mechain were measuring the Paris meridian. The results of his work, unfortunately, did not bring him fame, because... Lavoisier was accused of participating “in a conspiracy with the enemies of France against the French people, with the goal of stealing from the nation huge sums necessary for the war against despots” and was sentenced to death. But meanwhile the kilogram was born and, like the meter, was tied to the decimal system: there are 1000 grams in one kilogram, 1000 milligrams in one gram, etc.

Currently, the kilogram is the only SI unit that is defined using an artifact - an object made by people - the platinum-iridium standard. All other units are now defined through the values of fundamental physical constants. Not only does this ensure proper quantum accuracy, but these units can also be adequately reproduced anywhere in the world. “Cloneing” a kilogram is much more difficult; in addition, it requires a complex bureaucratic procedure.

In addition, for various reasons, over a hundred years, the international standard loses part of its mass (3/100000000). However, by definition, the mass of the international standard is exactly equal to one kilogram. Therefore, its decrease leads to a change in the size of the kilogram. Nonsense!

Apparently, for a long time this unique position of the kilogram suited everyone, since there were not sufficient incentives to create its scrupulous formula. But the changeable kilogram drags with it the watt and other related units of measurement into its drifting voyage. Currently, to eliminate these inaccuracies, various options are being considered to redefine the kilogram based on the values of fundamental physical constants.

Read about this, as well as about modern methods of measuring meters and seconds, in the following issues.

Reprinted with permission from the German magazine Maβ stäbe.
Material based on the article by Jens Simon “Eine Finger”ü bung...”
using other Internet sources
preparedL. Lomina

Time flies. Time is flowing. It is money, it endures or not, it exists or not, it is also the fourth dimension in Minkowski space, one of the many rational projections of the little-knowable Universe. And this dimension is given a huge number of properties, real and fictitious.

Meanwhile, nowadays, in different countries of the world, calendars and alphabets, units of distance and mass may be different, but seconds, minutes and hours are accepted everywhere. Although no one is stopping you from highlighting your originality and acting like cashiers and salespeople who “will be with you in 5 minutes.” stretches out to several hours (and everyone remains alive).

Why did it happen so? Moreover, some people live clearly slower than others. Perhaps because those who wanted to live on Earth always had to “be able to spin” at different speeds - just as the planet itself can. From its revolutions around itself, days are formed, more precisely, days, around the Sun - years. In Nepal it is now 2071, in Ethiopia it is 2006.

History and various sciences have still preserved for us several alternative measures for time. For example, the word “moment” is known. But when it is used out loud, it is rarely meant that the interlocutor or client should wait exactly one and a half minutes. That is, the unit of time “moment” is historically equal to 90 seconds - one fortieth of an hour. This is how it was customary to split eternity and put divisions on dials in the Middle Ages. I wonder if the Russian equivalent of “moment” - the word “minute” - can be equated to 60 or another number of seconds?

All over the world, electronic and mechanical, they are configured according to the so-called. atomic clocks, the evolution of which, like computers, has already reached pocket size. Our current list of units of the “fourth dimension” will begin with the atom.

Atom

“Tom” means “cut”, “divide”, “atom” means “indivisible”, as the ancient Greeks established in their time. Until some time, an atom was considered the smallest particle of matter. And in the old English language (Anglisc) an “atom” was called something like an instant. That is, the shortest amount of time that can be measured.

In this sense of the word, 1 “indivisible” atom is equal to 1/376 of a minute. This is 0.15957 seconds. With the advent of cinema and modern physics, the need for such a unit of time obviously disappeared.

Gary

The Indian word "ghurry" is similar to the culinary term "curry", and also differs in its pungent approach to the issue. In the Middle Ages, Indians “switched bodies” between hours and minutes, as if there were 60 hours of 24 minutes each in a day.

The Gary water clock was a brilliant invention in its simplicity and precision. Take a wooden or metal cauldron of a certain size with holes determined by its design. Such an empty container is immersed in a pool or trough with water, liquid begins to flow into the vessel through the holes, and in the end the water-filled container sinks, sinking to the bottom of the pool. Usually 24-minute basins were used, so a day was equal to 60 gari.

Chandelier

The word “lustr” refers to a period of time equal to five years. The fashionable word “lustration” in Ancient Rome meant a cleansing sacrifice of animals on the Campus Martius after the next census of the empire’s population. They were given over to the ceremonial fire, and this supposedly protected all civilians registered by Rome from the wrath of the gods. Such fiery censuses in the Eternal City and its possessions have been carried out since 566 BC.

The last rite of fire lustration was performed by Vespasian in the year 74, then Caesar the reformer abolished the custom. Nowadays, if the procedure of the same name is performed, it is without murder, and the word “luster” to denote a period of time has forever been replaced by the “five-year plan.”

mile

Just as a light year is a measure not of the calendar, but of distance, so distance can be a measure of time. For example, land mile. Namely - mileway. In the Middle Ages, this term was sometimes used to refer to the time it would take an average pedestrian to cover a distance of one mile. Without an exact value, the time mile was usually converted to approximately 20 minutes.

Nundins

In Ancient Rome, nundines (from the words “novem dies” - 9th day) were called market days on which peasants came to cities to sell agricultural products. Many residents of the suburbs lived only from one nundina to another, and there was an 8-day break between market dates. Therefore, the periods of time from trade to trade themselves began to be called nundins in everyday life.

Kenzem

In French, the word "quinzième" literally means "fifteenth". After the Norman conquest of England, “kenzem” was borrowed by the newborn English language, and this term was used to refer to the 15-penny tax that was levied on every pound in the monarchy.

At the beginning of the fifteenth century, the word "kenzem" began to be used in a religious context. Meaning the day of some Christian holiday and the following two post-holiday weeks. That is, it turned out to be a 15-day period.

Scruple

The word comes from the Latin "scrupulus", which means "small pebble" or "pebble". Historically, scruple was a term from the professional language of pharmacists. A scruple was equal to 1/24 of an ounce, i.e. approximately 1.3 grams. In Russian they would say “pinch”.

In the figurative sense of “a small amount of something,” the word “scruple” began to be used as a name for a measure of time in the early 17th century. They began to call the distance from division to division on a 60-digit dial, i.e. 1/60th of a circle. It could be a minute (and 60 minutes are equal to an hour), or a second (1/60 of a minute), or 24 minutes (the sixtieth part of a day). Let us remember that the medieval inhabitants of India measured their times with the last measure.

Plan:

1 Day, hour, minute and second
- 1.1 Use to indicate time of day
- 1.2 Use to indicate a time interval
- 1.3 Standardization
- 1.4 Multiples and submultiples
2 Year, month, week
3 Century, millennium
4 Rare and obsolete units

Introduction

Modern units of time are based on the periods of revolution of the Earth around its axis and around the Sun, as well as the revolution of the Moon around the Earth. This choice of units is determined by both historical and practical considerations: the need to coordinate human activities with the change of day and night or seasons; The changing phases of the moon affect the height of the tides.

1. Day, hour, minute and second

Historically, the basic unit for measuring short intervals of time was the day (often said “day”), equal to the period of revolution of the Earth on its axis. As a result of dividing the day into smaller time intervals of precise length, hours, minutes and seconds arose. The origin of division is probably related to the duodecimal number system followed by the ancients. [ specify] The day was divided into two equal successive intervals (conditionally day and night). Each of them was divided into 12 hours. Further division of the hour goes back to the sexagesimal number system. Every hour is divided by 60 minutes. Every minute - for 60 seconds.

Thus, there are 3600 seconds in an hour; There are 24 hours in a day = 1440 minutes = 86,400 seconds.

Considering that there are 365 days in a year (366 in a leap year), we get that there are 31,536,000 (31,622,400) seconds in a year.

Hours, minutes and seconds have firmly entered our everyday life and have become naturally perceived even against the backdrop of the decimal number system. Now these units (primarily the second) are the main ones for measuring time intervals. The second became the basic unit of time in SI and GHS.

The second is indicated by “s” (without a dot); previously used notation "sec", which is still often used in speech (due to greater ease of pronunciation than “s”). The minute is indicated by “min”, the hour by “h”. In astronomy the notation is used h, m, With(or h, m, s) in superscript: 13 h 20 m 10 s (or 13 h 20 m 10 s).

1.1. Use to indicate time of day

Displaying time in hours

First of all, hours, minutes and seconds were introduced to make it easier to indicate the time coordinate within a day.

A point on the time axis within a specific calendar day is indicated by indicating the whole number of hours that have passed since the beginning of the day; then the whole number of minutes that have passed since the beginning of the current hour; then the whole number of seconds that have passed since the beginning of the current minute; if it is necessary to indicate the time position even more precisely, the decimal system is then used, indicating the elapsed fraction of the current second as a decimal fraction (usually to hundredths or thousandths).

The letters “h”, “min”, “s” are usually not written on the letter, but only numbers are indicated through a colon or dot. The minute number and second number can range from 0 to 59 inclusive. If high accuracy is not required, the number of seconds is not indicated.

There are two systems for indicating the time of day. The so-called French system does not take into account the division of the day into two 12-hour intervals (day and night), but considers that the day is directly divided into 24 hours. The hour number can be from 0 to 23 inclusive. The English system takes this division into account. The hours are indicated from the beginning of the current half-day, and after the numbers the letter index of the half-day is written. The first half of the day (night, morning) is designated AM, the second (day, evening) - PM from Lat. Ante Meridiem/Post Meridiem(noon, afternoon). The hour number in 12 hour systems is written differently in different traditions: from 0 to 11 or 12, 1, 2, ..., 11. Since all three time subcoordinates do not exceed one hundred, two digits are enough to write them in the decimal system; therefore, hours, minutes and seconds are written as a two-digit decimal number, adding a zero before the number if necessary (in the English system, however, the hour number is written as a one- or two-digit decimal number).

Midnight is taken as the starting point for counting time. Thus, midnight in the French system is 00:00:00, and in English it is 12:00:00 AM. Noon - 12:00:00 (12:00:00 PM). The point in time after 19 hours and another 14 minutes since midnight is 19:14 (in the English system 7:14 PM).

The dials of most modern watches (with hands) use the English system. However, dial watches are also produced that use the French 24-hour system. Such watches are used in areas where it is difficult to judge day and night (for example, on submarines or in the Arctic Circle, where there is a polar night and a polar day).

1.2. Use to indicate a time interval

For measuring time intervals, hours, minutes and seconds are not very convenient because they do not use the decimal number system. Therefore, only seconds are usually used to measure time intervals.

However, sometimes the actual hours, minutes and seconds are used. Thus, the duration of 50,000 s can be written as 13 hours 53 minutes 20 seconds.

1.3. Standardization

In fact, the duration of a sunny day is not a constant value. And although it changes very little (increases as a result of tides due to the attraction of the Moon and the Sun by an average of 0.0023 seconds per century over the last 2000 years, and over the last 100 years by only 0.0014 seconds), this is enough for significant distortions in the duration of a second, if we count 1/86,400 of the duration of a solar day as a second. Therefore, from the definition of “hour - 1/24 days; minute - 1/60 of an hour; second - 1/60 of a minute" moved on to define the second as a basic unit based on a periodic intra-atomic process not associated with any movements of celestial bodies (it is sometimes referred to as the SI second or "atomic second", when in the context of its may be confused with the second determined from astronomical observations).

Currently, the following definition of “atomic second” is accepted: one second is a time interval equal to 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground quantum state of the cesium-133 atom at rest at 0 K. This definition was adopted in 1967 (clarification regarding temperature and resting state appeared in 1997).

Starting from the SI second, a minute is defined as 60 seconds, an hour as 60 minutes, and a calendar (Julian) day as equal to exactly 86,400 s. Currently, the Julian day is shorter than the average solar day by about 2 milliseconds; To eliminate accumulating discrepancies, leap seconds are introduced. The Julian year is also determined (exactly 365.25 Julian days, or 31,557,600 s), sometimes called the scientific year.

In astronomy and in a number of other fields, along with the SI second, the ephemeris second is used, the definition of which is based on astronomical observations. Considering that there are 365.242 198 781 25 days in a tropical year, and assuming a day of constant duration (the so-called ephemeris calculus), we obtain that there are 31 556 925.9747 seconds in a year. It is then believed that a second is 1/31,556,925.9747 of a tropical year. The secular change in the length of the tropical year forces this definition to be tied to a specific era; Thus, this definition refers to the tropical year at the time of 1900.0.

1.4. Multiples and submultiples

The second is the only unit of time with which SI prefixes are used to form submultiples and (rarely) multiples.

2. Year, month, week

To measure longer time intervals, the units of year, month and week, consisting of a whole number of days, are used. A year is approximately equal to the period of revolution of the Earth around the Sun (approximately 365 days), a month is the period of complete change of phases of the Moon (the so-called synodic month, equal to 29.53 days).

In the most common Gregorian calendar, as well as in the Julian calendar, the year is taken as the basis. Since the Earth's rotation period is not exactly equal to a whole number of days, leap years of 366 days are used to more accurately synchronize the calendar with the Earth's movement. The year is divided into twelve calendar months of varying lengths (28, 29, 30, 31 days), the duration of which, the beginning and end are not associated with any astronomical event.

The Jewish calendar is based on the lunar synodic month and the tropical year, and a year may contain 12 or 13 lunar months. In the long term, the same months of the calendar fall at approximately the same time.

In the Islamic calendar, the basis is the lunar synodic month, and the year always contains strictly 12 lunar months, i.e. about 354 days, which is 11 days less than the tropical year. Thanks to this, the beginning of the year and all Muslim holidays occur every year at different times (relative to the dates of the Gregorian calendar).

A week, consisting of 7 days, is not tied to any astronomical event, but is widely used as a unit of time. The weeks can be considered to form an independent calendar, used in parallel with various other calendars. It is assumed that the length of the week originates from the duration of one of the four phases of the Moon, rounded to a whole number of days.

3. Century, millennium

Even larger units of time are century (100 years) and millennium (1000 years). A century is sometimes divided into decades. Sciences such as astronomy and geology, which study very long periods of time (millions and billions of years), sometimes use even larger units of time, such as gigagods (billion years).

4. Rare and obsolete units

In the UK and Commonwealth countries, the Fortnite time unit of two weeks is used.

In the USSR, at various times, instead of a week, six- and five-day plans were used, as well as, for the purposes of economic planning, five-year plans.

Basically, for accounting purposes, the unit quarter is used, equal to three months (a quarter of a year).

In the field of education, the unit of time used is the academic hour (45 minutes). Also in secondary schools, the word “hour” is often used to mean the duration of one lesson, that is, 40 minutes), “quarter” (about ¼ of the academic year), approximately equal to the last “trimester” (from Lat. tri- three, mensis- month; approximately 3 months) and “semester” (from Lat. sex- six, mensis- month; approximately 6 months), coinciding with the “half-year”. Trimester is also used in obstetrics and gynecology to indicate the timing of pregnancy, in this case it is exactly equal to three months.

Sometimes there is a unit of third, equal to 1/60 of a second.

The unit dekad, depending on the context, can refer to 10 days or (less commonly) to 10 years.

Indiction (indiction), used in the Roman Empire (since the time of Diocletian), later in Byzantium, ancient Bulgaria and Ancient Rus', is equal to 15 years.

The Olympiad in antiquity was used as a unit of time and was equal to 4 years.

Saros is a period of repetition of eclipses equal to 18 years 11⅓ days and known to the ancient Babylonians. Saros was also the name given to the calendar period of 3600 years; smaller periods were called neros(600 years) and sucker(60 years).

The day was divided into two equal consecutive intervals (conditionally day and night). Each of them was divided by 12 hours. Further division of the hour goes back to the sexagesimal number system. Every hour is divided by 60 minutes. Every minute - for 60 seconds .

Thus, there are 3600 seconds in an hour; there are 24 hours in a day, or 1440 minutes, or 86,400 seconds.

Hours, minutes and seconds have firmly entered our everyday life and have become naturally perceived even against the backdrop of the decimal number system. Nowadays these units are most often used to measure and express periods of time. Second (Russian designation: With; international: s) is one of the seven base units in the International System of Units (SI) and one of the three base units in the GHS system.

Units "minute" (Russian designation: min; international: min), "hour" (Russian designation: h; international: h) and “day” (Russian designation: days; international: d) are not included in the SI system, however, in the Russian Federation they are approved for use as non-system units without limiting the validity period of the approval with the scope of application “all areas”. In accordance with the requirements of the SI Brochure and GOST 8.417-2002, the name and designation of time units “minute”, “hour” and “day” are not allowed to be used with submultiple and multiple SI prefixes.

In astronomy the notation is used h, m, With(or h, m, s) in superscript: for example, 13 h 20 m 10 s (or 13 h 20 m 10 s).

Use to indicate time of day

First of all, hours, minutes and seconds were introduced to make it easier to indicate the time coordinate within a day.

There are two systems for indicating the time of day. The so-called French system does not take into account the division of the day into two 12-hour intervals (day and night), but considers that the day is directly divided into 24 hours. The hour number can be from 0 to 23 inclusive. In the “English system” this division is taken into account. The hours are indicated from the beginning of the current half-day, and after the numbers the letter index of the half-day is written. The first half of the day (night, morning) is designated AM, the second (day, evening) - PM; these designations come from lat. ante meridiem and post meridiem (before noon/afternoon). The hour number in 12-hour systems is written differently in different traditions: from 0 to 11 or 12, 1, 2, ..., 11. Since all three time subcoordinates do not exceed one hundred, two digits are enough to write them in the decimal system; therefore, hours, minutes and seconds are written as a two-digit decimal number, adding a zero before the number if necessary (in the English system, however, the hour number is written as a one- or two-digit decimal number).

Midnight is taken as the starting point for counting time. Thus, midnight in the French system is 00:00, and in the English system it is 12:00 AM. Noon - 12:00 (12:00 PM). The point in time after 19 hours and another 14 minutes since midnight is 19:14 (in the English system - 7:14 PM).

Use to indicate a time interval

For measuring time intervals, hours, minutes and seconds are not very convenient because they do not use the decimal number system. Therefore, only seconds are usually used to measure time intervals.

However, sometimes the actual hours, minutes and seconds are used. Thus, the duration of 50,000 s can be written as 13 hours 53 minutes.

20 sec.

Standardization

Based on the SI second, a minute is defined as 60 seconds, an hour as 60 minutes, and a calendar (Julian) day as equal to exactly 86,400 s. Currently, the Julian day is shorter than the average solar day by about 2 milliseconds; To eliminate accumulating discrepancies, leap seconds are introduced. The Julian year is also determined (exactly 365.25 Julian days, or 31,557,600 s), sometimes called the scientific year. 1 ⁄ 31 556 925,9747 In astronomy and in a number of other fields, along with the SI second, the ephemeris second is used, the definition of which is based on astronomical observations. Considering that there are 365.24219878125 days in a tropical year, and assuming a day of constant duration (the so-called ephemeris calculus), we obtain that there are 31,556,925.9747 seconds in a year. Then it is believed that a second is

Multiples and submultiples

The second is the only unit of time with which SI prefixes are used to form submultiples and (rarely) multiples.

Year, month, week

part of the tropical year. The secular change in the length of the tropical year forces this definition to be tied to a specific era; Thus, this definition refers to the tropical year at the time of 1900.0.

In the most common Gregorian, as well as in the Julian calendar, a year of 365 days is taken as a basis. Since the tropical year is not equal to the whole number of solar days (365.2422), to synchronize the calendar seasons with astronomical ones, the calendar uses leap years, lasting 366 days. The year is divided into twelve calendar months of varying lengths (from 28 to 31 days). Usually, there is one full moon for each calendar month, but since the phases of the moon change a little faster than 12 times a year, sometimes there are a second full moon in a month, called a blue moon.

Century, millennium

Even larger units of time are century (100 years) and millennium (1000 years). A century is sometimes divided into decades. In sciences such as astronomy and geology, which study very long periods of time (millions and billions of years), sometimes even larger units of time are used - for example, gigayears (billion years).

Megayear and gigagod

Megayear(designation Myr) - a unit of time that is a multiple of a year, equal to a million years; gigayear(designation Gyr) is a similar unit equal to a billion years. These units are used primarily in cosmology, as well as in geology and sciences related to the study of the history of the Earth. For example, the age of the Universe is estimated at 13.72±0.12 gigalets. The current practice of using these units contradicts the “Regulations on units of quantities allowed for use in the Russian Federation”, according to which the unit of time year(the same as, for example, a week, month, millennium) should not be used with multiple and submultiple prefixes.

Rare and obsolete units

To date, the smallest experimentally observed time interval is on the order of an attosecond (10 −18 s), which corresponds to 10 26 Planck times. By analogy with the Planck length, a time interval less than the Planck time cannot be measured.

In Hinduism, the “day of Brahma” - a kalpa - is equal to 4.32 billion years. This unit is included in the Guinness Book of Records as the largest unit of time.

Write a review about the article "Units of time"

Notes

An excerpt characterizing Time Units

Boris quietly walked out the door and followed Natasha, the fat boy angrily ran after them, as if annoyed at the frustration that had occurred in his studies.

Of the young people, not counting the countess's eldest daughter (who was four years older than her sister and already behaved like a grown-up) and the young lady's guest, Nikolai and Sonya's niece remained in the living room. Sonya was a thin, petite brunette with a soft gaze, shaded by long eyelashes, a thick black braid that wrapped around her head twice, and a yellowish tint to the skin on her face and especially on her bare, thin, but graceful, muscular arms and neck. With the smoothness of her movements, the softness and flexibility of her small limbs, and her somewhat cunning and reserved manner, she resembled a beautiful, but not yet fully formed kitten, which would become a lovely little cat. She apparently considered it decent to show participation in the general conversation with a smile; but against her will, from under her long thick eyelashes, she looked at her cousin [cousin] who was leaving for the army with such girlish passionate adoration that her smile could not deceive anyone for a moment, and it was clear that the cat sat down only to jump more energetically and play with your sauce as soon as they, like Boris and Natasha, get out of this living room.
“Yes, ma chere,” said the old count, turning to his guest and pointing to his Nicholas. - His friend Boris was promoted to officer, and out of friendship he does not want to lag behind him; he leaves both the university and me as an old man: he goes into military service, ma chere. And his place in the archive was ready, and that was it. Is that friendship? - said the count questioningly.
“But they say war has been declared,” said the guest.
“They’ve been saying this for a long time,” said the count. “They’ll talk and talk again and leave it at that.” Ma chere, that’s friendship! - he repeated. - He is going to the hussars.
The guest, not knowing what to say, shook her head.
“Not out of friendship at all,” answered Nikolai, flushing and making excuses as if from a shameful slander against him. – Not friendship at all, but I just feel a calling to military service.
He looked back at his cousin and the guest young lady: both looked at him with a smile of approval.
“Today, Schubert, colonel of the Pavlograd Hussar Regiment, is dining with us. He was on vacation here and takes it with him. What to do? - said the count, shrugging his shoulders and speaking jokingly about the matter, which apparently cost him a lot of grief.
“I already told you, daddy,” said the son, “that if you don’t want to let me go, I’ll stay.” But I know that I am not fit for anything except military service; “I’m not a diplomat, not an official, I don’t know how to hide what I feel,” he said, still looking with the coquetry of beautiful youth at Sonya and the guest young lady.
The cat, glaring at him with her eyes, seemed every second ready to play and show all her cat nature.
- Well, well, okay! - said the old count, - everything is getting hot. Bonaparte turned everyone's heads; everyone thinks how he got from lieutenant to emperor. Well, God willing,” he added, not noticing the guest’s mocking smile.
The big ones started talking about Bonaparte. Julie, Karagina’s daughter, turned to young Rostov:
– What a pity that you weren’t at the Arkharovs’ on Thursday. “I was bored without you,” she said, smiling tenderly at him.
The flattered young man with a flirtatious smile of youth moved closer to her and entered into a separate conversation with the smiling Julie, not noticing at all that this involuntary smile of his was cutting the heart of the blushing and feignedly smiling Sonya with a knife of jealousy. “In the middle of the conversation, he looked back at her. Sonya looked at him passionately and embitteredly and, barely holding back the tears in her eyes and a feigned smile on her lips, she stood up and left the room. All Nikolai's animation disappeared. He waited for the first break in the conversation and, with an upset face, left the room to look for Sonya.
– How the secrets of all these young people are sewn with white thread! - said Anna Mikhailovna, pointing to Nikolai coming out. “Cousinage dangereux voisinage,” she added.
“Yes,” said the countess, after the ray of sunshine that had penetrated into the living room with this young generation had disappeared, and as if answering a question that no one had asked her, but which constantly occupied her. - How much suffering, how much anxiety has been endured in order to now rejoice in them! And now, really, there is more fear than joy. You're still afraid, you're still afraid! This is precisely the age at which there are so many dangers for both girls and boys.
“Everything depends on upbringing,” said the guest.
“Yes, your truth,” continued the Countess. “Until now, thank God, I have been a friend of my children and enjoy their complete trust,” said the countess, repeating the misconception of many parents who believe that their children have no secrets from them. “I know that I will always be the first confidente [confidant] of my daughters, and that Nikolenka, due to her ardent character, if she plays naughty (a boy cannot live without this), then everything is not like these St. Petersburg gentlemen.
“Yes, nice, nice guys,” confirmed the count, who always resolved issues that confused him by finding everything nice. - Come on, I want to become a hussar! Yes, that's what you want, ma chere!
“What a sweet creature your little one is,” said the guest. - Gunpowder!
“Yes, gunpowder,” said the count. - It hit me! And what a voice: even though it’s my daughter, I’ll tell the truth, she will be a singer, Salomoni is different. We hired an Italian to teach her.
- Is not it too early? They say it is harmful for your voice to study at this time.
- Oh, no, it’s so early! - said the count. - How did our mothers get married at twelve thirteen?
- She’s already in love with Boris! What? - said the countess, smiling quietly, looking at Boris’s mother, and, apparently answering the thought that had always occupied her, she continued. - Well, you see, if I had kept her strictly, I would have forbidden her... God knows what they would have done on the sly (the countess meant: they would have kissed), and now I know every word she says. She will come running in the evening and tell me everything. Maybe I'm spoiling her; but, really, this seems to be better. I kept the eldest strictly.
“Yes, I was brought up completely differently,” said the eldest, beautiful Countess Vera, smiling.
But a smile did not grace Vera’s face, as usually happens; on the contrary, her face became unnatural and therefore unpleasant.
The eldest, Vera, was good, she was not stupid, she studied well, she was well brought up, her voice was pleasant, what she said was fair and appropriate; but, strangely, everyone, both the guest and the countess, looked back at her, as if they were surprised why she said this, and felt awkward.
“They always play tricks with older children, they want to do something unusual,” said the guest.
- To be honest, ma chere! The Countess was playing tricks with Vera,” said the Count. - Well, oh well! Still, she turned out nice,” he added, winking approvingly at Vera.
The guests got up and left, promising to come for dinner.
- What a manner! They were already sitting, sitting! - said the countess, ushering the guests out.

When Natasha left the living room and ran, she only reached the flower shop. She stopped in this room, listening to the conversation in the living room and waiting for Boris to come out. She was already beginning to get impatient and, stamping her foot, was about to cry because he was not walking now, when she heard the quiet, not fast, decent steps of a young man.
Natasha quickly rushed between the flower pots and hid.
Boris stopped in the middle of the room, looked around, brushed specks from his uniform sleeve with his hand and walked up to the mirror, examining his handsome face. Natasha, having become quiet, looked out from her ambush, waiting for what he would do. He stood in front of the mirror for a while, smiled and went to the exit door. Natasha wanted to call out to him, but then changed her mind. “Let him search,” she told herself. Boris had just left when a flushed Sonya emerged from another door, whispering something angrily through her tears. Natasha restrained herself from her first move to run out to her and remained in her ambush, as if under an invisible cap, looking out for what was happening in the world. She experienced a special new pleasure. Sonya whispered something and looked back at the living room door. Nikolai came out of the door.
- Sonya! What happened to you? Is this possible? - Nikolai said, running up to her.
- Nothing, nothing, leave me! – Sonya began to sob.
- No, I know what.
- Well, you know, that’s great, and go to her.
- Sooo! One word! Is it possible to torture me and yourself like this because of a fantasy? - Nikolai said, taking her hand.
Sonya did not pull his hands away and stopped crying.
Natasha, without moving or breathing, looked out with shining heads from her ambush. "What will happen now"? she thought.
- Sonya! I don't need the whole world! “You alone are everything to me,” Nikolai said. - I'll prove it to you.
“I don’t like it when you talk like that.”
- Well, I won’t, I’m sorry, Sonya! “He pulled her towards him and kissed her.
“Oh, how good!” thought Natasha, and when Sonya and Nikolai left the room, she followed them and called Boris to her.
“Boris, come here,” she said with a significant and cunning look. – I need to tell you one thing. Here, here,” she said and led him into the flower shop to the place between the tubs where she was hidden. Boris, smiling, followed her.
- What is this one thing? - he asked.
She was embarrassed, looked around her and, seeing her doll abandoned on the tub, took it in her hands.
“Kiss the doll,” she said.
Boris looked into her lively face with an attentive, affectionate gaze and did not answer.
- You do not want? Well, come here,” she said and went deeper into the flowers and threw the doll. - Closer, closer! - she whispered. She caught the officer's cuffs with her hands, and solemnity and fear were visible in her reddened face.
- Do you want to kiss me? – she whispered barely audibly, looking at him from under her brows, smiling and almost crying with excitement.
Boris blushed.
- How funny you are! - he said, bending over to her, blushing even more, but doing nothing and waiting.
She suddenly jumped up on the tub so that she stood taller than him, hugged him with both arms so that her thin bare arms bent above his neck and, moving her hair back with a movement of her head, kissed him right on the lips.
She slipped between the pots to the other side of the flowers and, lowering her head, stopped.
“Natasha,” he said, “you know that I love you, but...
-Are you in love with me? – Natasha interrupted him.
- Yes, I’m in love, but please, let’s not do what we’re doing now... Four more years... Then I’ll ask for your hand.
Natasha thought.
“Thirteen, fourteen, fifteen, sixteen...” she said, counting with her thin fingers. - Fine! So it's over?
And a smile of joy and peace lit up her lively face.
- It's over! - said Boris.
- Forever? - said the girl. - Until death?
And, taking his arm, with a happy face, she quietly walked next to him into the sofa.

The countess was so tired of the visits that she did not order to receive anyone else, and the doorman was only ordered to invite everyone who would still come with congratulations to eat. The Countess wanted to talk privately with her childhood friend, Princess Anna Mikhailovna, whom she had not seen well since her arrival from St. Petersburg. Anna Mikhailovna, with her tear-stained and pleasant face, moved closer to the countess’s chair.
“I’ll be completely frank with you,” said Anna Mikhailovna. – There are very few of us left, old friends! This is why I value your friendship so much.
Anna Mikhailovna looked at Vera and stopped. The Countess shook hands with her friend.
“Vera,” said the countess, addressing her eldest daughter, obviously unloved. - How come you have no idea about anything? Don't you feel like you're out of place here? Go to your sisters, or...
Beautiful Vera smiled contemptuously, apparently not feeling the slightest insult.
“If you had told me long ago, mamma, I would have left immediately,” she said, and went to her room.
But, passing by the sofa, she noticed that there were two couples sitting symmetrically at two windows. She stopped and smiled contemptuously. Sonya sat close to Nikolai, who was copying out poems for her that he had written for the first time. Boris and Natasha were sitting at another window and fell silent when Vera entered. Sonya and Natasha looked at Vera with guilty and happy faces.
It was fun and touching to look at these girls in love, but the sight of them, obviously, did not arouse a pleasant feeling in Vera.
“How many times have I asked you,” she said, “not to take my things, you have your own room.”
She took the inkwell from Nikolai.
“Now, now,” he said, wetting his pen.
“You know how to do everything at the wrong time,” said Vera. “Then they ran into the living room, so everyone felt ashamed of you.”
Despite the fact that, or precisely because, what she said was completely fair, no one answered her, and all four only looked at each other. She lingered in the room with the inkwell in her hand.
- And what secrets could there be at your age between Natasha and Boris and between you - they’re all just nonsense!
- Well, what do you care, Vera? – Natasha said intercedingly in a quiet voice.
She, apparently, was even more kind and affectionate to everyone than always that day.
“Very stupid,” said Vera, “I’m ashamed of you.” What are the secrets?...
– Everyone has their own secrets. We won’t touch you and Berg,” Natasha said, getting excited.
“I think you won’t touch me,” said Vera, “because there can never be anything bad in my actions.” But I’ll tell mommy how you treat Boris.
“Natalya Ilyinishna treats me very well,” said Boris. “I can't complain,” he said.
- Leave it, Boris, you are such a diplomat (the word diplomat was in great use among children in the special meaning that they attached to this word); It’s even boring,” Natasha said in an offended, trembling voice. - Why is she pestering me? You will never understand this,” she said, turning to Vera, “because you have never loved anyone; you have no heart, you are only madame de Genlis [Madame Genlis] (this nickname, considered very offensive, was given to Vera by Nikolai), and your first pleasure is to cause trouble for others. “You flirt with Berg as much as you want,” she said quickly.
- Yes, I certainly won’t start chasing a young man in front of guests...
“Well, she achieved her goal,” Nikolai intervened, “she said unpleasant things to everyone, upset everyone.” Let's go to the nursery.
All four, like a frightened flock of birds, got up and left the room.
“They told me some troubles, but I didn’t mean anything to anyone,” said Vera.
- Madame de Genlis! Madame de Genlis! - Laughing voices said from behind the door.
Beautiful Vera, who had such an irritating, unpleasant effect on everyone, smiled and, apparently unaffected by what was said to her, went to the mirror and straightened her scarf and hairstyle. Looking at her beautiful face, she apparently became even colder and calmer.

November 2nd, 2017

When people say they are “enough with the moment,” they probably don’t realize that they are promising to be free in exactly 90 seconds. Indeed, in the Middle Ages, the term “moment” defined a period of time lasting 1/40 of an hour or, as it was customary to say then, 1/10 of a point, which was 15 minutes. In other words, it totaled 90 seconds. Over the years, the moment has lost its original meaning, but is still used in everyday life to denote an indefinite, but very short interval.

So why do we remember the moment, but forget about the ghari, the nuctemeron, or something even more exotic?

1. Atom

The word "atom" comes from the Greek term meaning "indivisible", and is therefore used in physics to define the smallest particle of matter. But in the old days this concept was applied to the shortest period of time. A minute was thought to have 376 atoms, each lasting less than 1/6 of a second (or 0.15957 seconds to be precise).

2. Ghari

What kind of instruments and devices were not invented in the Middle Ages to measure time! While Europeans were making full use of hourglasses and sundials, Indians were using clepsydras - ghari. Several holes were made in a hemispherical bowl made of wood or metal, after which it was placed in a pool of water. The liquid, seeping through the slits, slowly filled the vessel until it was completely sank to the bottom from gravity. The whole process took about 24 minutes, which is why this range was named after the device - ghari. At that time it was believed that a day consisted of 60 gharis.

3. Chandelier

Lustre is a period lasting 5 years. The use of this term goes back to antiquity: then lustrum denoted the five-year period of time that completed the establishment of the property qualifications of Roman citizens. When the amount of the tax was determined, the countdown came to an end, and a solemn procession poured out into the streets of the Eternal City. The ceremony ended with lustration (purification) - a pretentious sacrifice to the gods on the Field of Mars, performed for the well-being of citizens.

4. Mileway

All that glitters is not gold. While the light year, seemingly created to define a period, measures distance, mileway, a mile-long path, serves to count time. Although the term sounds like a unit of distance, in the early Middle Ages it denoted a segment lasting 20 minutes. This is how long it takes on average for a person to cover a mile-long route.

5. Nundin

The inhabitants of Ancient Rome worked seven days a week, tirelessly. On the eighth day, however, which they considered the ninth (the Romans also included the last day of the previous period), they organized huge markets in the cities - nundines. The market day was called “novem” (in honor of November, the ninth month of the 10-month agricultural “Year of Romulus”), and the time interval between the two fairs was called nundin.

6. Nuctemeron

Nuktemeron, a combination of two Greek words “nyks” (night) and “hemera” (day), is nothing more than an alternative designation for the day we are familiar with. Anything considered nuctemeronic, accordingly, lasts less than 24 hours.

7. Point

In Medieval Europe, a point, also called a dot, was used to indicate the quarter hour.

8. Quadrant

And the neighbor of the point in the epoch, the quadrant, determined a quarter of the day - a period lasting 6 hours.

9. Fifteen

After the Norman Conquest, the word "Quinzieme", translated from French as "fifteen", was borrowed by the British to define the tax, which replenished the state treasury by 15 pence for every pound earned in the country. In the early 1400s, the term also acquired a religious context: it began to be used to indicate the day of an important church holiday and the two full weeks following it. So the “Quinzieme” became a 15-day period.

10. Scrupul

The word "Scrupulus", translated from Latin meaning "small sharp pebble", formerly served as a pharmaceutical unit of weight equal to 1/24 ounce (about 1.3 grams). In the 17th century, scruple, which had become a shorthand for small volume, expanded its meaning. It began to be used to indicate 1/60 of a circle (minute), 1/60 of a minute (second) and 1/60 of a day (24 minutes). Now, having lost its former meaning, scruple has been transformed into scrupulousness - attentiveness to detail.

And some more temporary values:

1 attosecond (one billionth of a billionth of a second)

The fastest processes that scientists can time are measured in attoseconds. Using the most advanced laser systems, researchers were able to produce light pulses lasting only 250 attoseconds. But no matter how infinitesimal these time intervals may seem, they seem like an eternity compared to the so-called Planck time (about 10-43 seconds), according to modern science, the shortest of all possible time intervals.

1 femtosecond (one millionth of a billionth of a second)

An atom in a molecule vibrates once in a time from 10 to 100 femtoseconds. Even the fastest chemical reaction occurs over a period of several hundred femtoseconds. The interaction of light with the pigments of the retina of the eye, and it is this process that allows us to see our surroundings, lasts about 200 femtoseconds.

1 picosecond (one thousandth of a billionth of a second)

The fastest transistors operate within a time frame measured in picoseconds. The lifetime of quarks, rare subatomic particles produced in powerful accelerators, is only one picosecond. The average duration of a hydrogen bond between water molecules at room temperature is three picoseconds.

1 nanosecond (billionth of a second)

A beam of light passing through airless space can cover a distance of only thirty centimeters during this time. The microprocessor in a personal computer will take two to four nanoseconds to execute a single command, such as adding two numbers. The lifetime of the K meson, another rare subatomic particle, is 12 nanoseconds.

1 microsecond (millionth of a second)

During this time, a beam of light in a vacuum will cover a distance of 300 meters, the length of about three football fields. A sound wave at sea level is capable of covering a distance of only one-third of a millimeter in the same period of time. It takes 23 microseconds for a stick of dynamite to explode, the fuse of which has burned to the end.

1 millisecond (thousandth of a second)

The shortest exposure time in a conventional camera. The fly we all know flaps its wings once every three milliseconds. Bee - once every five milliseconds. Every year, the moon orbits the Earth two milliseconds slower as its orbit gradually expands.

1/10 second

Blink an eye. This is exactly what we will have time to do within the specified period. It takes just that long for the human ear to distinguish the echo from the original sound. The Voyager 1 spacecraft, heading out of the solar system, moves two kilometers away from the sun during this time. In a tenth of a second, a hummingbird manages to flap its wings seven times.

1 second

The contraction of the heart muscle of a healthy person lasts just this time. In one second, the Earth, rotating around the sun, covers a distance of 30 kilometers. During this time, our star itself manages to travel 274 kilometers, rushing through the galaxy at tremendous speed. Moonlight will not have time to reach the Earth during this time interval.

1 minute

During this time, the newborn baby's brain gains up to two milligrams in weight. A shrew's heart beats 1000 times. An average person can speak 150 words or read 250 words during this time. Light from the sun reaches the Earth in eight minutes. When Mars is at its closest distance from Earth, sunlight reflected from the surface of the Red Planet reaches us in less than four minutes.

1 hour

This is how long it takes for reproductive cells to split in half. In one hour, 150 Zhiguli cars roll off the assembly line of the Volzhsky Automobile Plant. Light from Pluto, the most distant planet in the solar system, reaches Earth in five hours and twenty minutes.

1 day

For people, this is perhaps the most natural unit of time, based on the rotation of the Earth. According to modern science, the length of the day is 23 hours 56 minutes and 4.1 seconds. The rotation of our planet is constantly slowing down due to lunar gravity and other reasons. The human heart makes about 100,000 contractions per day, and the lungs inhale about 11,000 liters of air. During the same time, the baby blue whale gains 90 kg in weight.

1 year

The Earth makes one revolution around the sun and rotates on its axis 365.26 times, the average level of the world's seas rises by 1 to 2.5 millimeters, and Russia is holding 45 federal elections. It will take 4.3 years for light from the nearby star Proxima Centauri to reach Earth. It will take approximately the same amount of time for surface ocean currents to circle the globe.

1st century

During this time, the Moon will move another 3.8 meters away from the Earth, but the giant sea turtle can live as long as 177 years. The lifespan of the most modern CD can be more than 200 years.

1 million years

A spaceship flying at the speed of light will not cover even half the way to the Andromeda galaxy (it is located at a distance of 2.3 million light years from Earth). The most massive stars, blue supergiants (they are millions of times brighter than the Sun), burn out around this time. Due to shifts in the Earth's tectonic layers, North America will move away from Europe by about 30 kilometers.

1 billion years

This is approximately how long it took for our Earth to cool down after its formation. In order for oceans to appear on it, single-celled life would arise and instead of an atmosphere rich in carbon dioxide, an atmosphere rich in oxygen would be established. During this time, the Sun passed four times in its orbit around the center of the Galaxy.

Since the universe has only existed for 12-14 billion years, units of time greater than a billion years are rarely used. However, scientists, specialists in cosmology, believe that the universe may continue even after the last star goes out (in one hundred trillion years) and the last black hole evaporates (in 10,100 years). So the Universe still has a much longer path to go than it has already gone through.

sources
http://www.mywatch.ru/conditions/

------------------
I would like to draw your attention to the fact that today there will be an interesting conversation LIVE on the October Revolution. You can ask questions via chat