Uts time. GMT is what time? How to calculate time from Greenwich. Atomic Time, TAI

In 24 hours, the Earth makes a complete revolution. Therefore, in different parts of the globe, clocks show different times. For ease of reference, the entire territory of the Earth was divided into time zones. Their borders were to be determined by meridians and 15 degrees apart from each other. But such a division is inconvenient for many states. Therefore, small countries count local time according to the capital. And in large states, several time zones had to be allocated. But all the same, the main calculations, for example, the time of railway and flights, are carried out according to the capital time. In Russia, such a reference point is Moscow. The time zone of other cities is counted from it.

Time zone history

Until the 19th century, there was no question of temporary confusion. Each state lived in its own local time, and long distance travels were rare. But with the advent of railway communication, a problem arose in drawing up a train schedule. Therefore, at the International Congress in the 80s of the 19th century, it was decided to divide the Earth's territory into time zones. The countdown began from - Greenwich - to the east. The difference between them is one hour. Therefore, there were 24 belts in total. But until recently, all the issues related to this have not yet been settled, and there is a lot of confusion in the countdown.

How the division into time zones works

In theory, time zones run along the meridians and are 15 degrees apart from each other. But in practice, they are often displaced, it so happens that they even disappear. This is due to the division of the territory into states. And many countries, regardless of the belts, are introducing the capital time. Therefore, the division into belts is now often arbitrary. But in states that occupy a large territory, it is important not only the local time, but also the capital. For example, in Russia the countdown goes from the city to its second belt from Greenwich. But all Russian cities consider the time not from him, but from Moscow.

Introduction to Russia

Only in 1919, the international time zone system was introduced in Russia. The country's territory was divided into 11 zones. But not always their border runs along the meridians. For example, Moscow is considered the starting point in Russia. Its time zone from Greenwich was adopted UTC + 2. UTC is the worldwide designation for the world. But since the city is located on the border of the belts, summer time was introduced, and the difference became UTC + 3, which was more in line with natural rhythms.

What is the time zone in Moscow now

Several times in the history of the country, there have been changes in the division into time zones. In the 30s, the UTC + 3 zone was abolished and the UTC + 3 zone remained in Moscow. It was believed that this was the most suitable division, because in many countries, if a city lies on the border of the belts, it is referred to as the eastern one. But from 1981 to 2011, daylight saving time was again introduced in Russia. Moscow was ahead of Greenwich in the summer by 4 hours. And after the cancellation of the annual transfer of hands, the capital remained in the UTC + 4 time zone. And now we live 2 hours ahead of the time taken when dividing the country into time zones.

Time zones in Russia now

In 2010, the division into belts was changed in the country. And now Russia is located in 9 time zones. The Middle Volga and Chukotka-Kamchatka belts have completely disappeared. Udmurtia and Samara switched to Moscow time, and Chukotka and Kamchatka - to Magadan time. The difference between the belts is one hour. To calculate local time, you need to know which time zone you are in. How are time zones calculated relative to Moscow?

They are counted from Kaliningrad. This is the first time zone. The difference with Moscow time is 1 hour. After all, this city is located west of Moscow. All European Russia lives according to the time of the capital. It differs from Greenwich by 4 hours. In our country, this is the second time zone. It is the most populous. The next zone is the third, but the difference with Moscow is not 1, but 2 hours. It includes the Orenburg, Sverdlovsk, Tyumen and Chelyabinsk Territories, the Khanty-Mansiysk District, the Republic of Bashkortostan and some other administrative units.

The rest of the time zones differ from each other by one hour. Their borders are not always associated with international division into time zones. For example, the fourth zone was adopted only in Altai and in several neighboring regions, and the fifth - in Tuva, Khakassia and the Krasnoyarsk Territory.

Most often, the division into zones depends on the borders of the republics and regions, but there are exceptions. For example, Yakutia lies in three zones, and Sakhalin Oblast - in two. The most distant regions of Russia differ in time from Moscow by 8 hours. The time in them is calculated from the Moscow time according to the time zone formula - MSK + 8. The plus sign means that the zone is located to the east, and the minus sign means that it is west of Moscow.

Due to constant and confusion with time zones, Moscow time does not coincide slightly with astronomical time. But all the same, it is counted in the country from the city of Moscow. You need to know its time zone in order to set the time on the clock correctly when moving to another region.

Instructions

Determine the offset of your time zone from the Greenwich meridian. You can find it out, for example, from the system time settings in your operating system. Click the clock in the notification area of \u200b\u200bthe taskbar with the left mouse button, and an additional panel with a calendar and an analog clock will pop up on the screen. In the lower part of it there is a link "Changing the date and time settings" - click on it. The system will open an additional settings window with three tabs, one of which is "Date" and has a section "Time zone". In this section, you will see the shift of your local time relative to the Greenwich meridian - the corresponding inscription can be, for example, this: "UTC +04: 00 Volgograd, Moscow, St. Petersburg". It is that the time of the system clock of your operating system is shifted forward four hours in relation to time zone zero.

Subtract the time offset for your time zone from the current time in order to determine the corresponding GMT time. For example, if your clock shows 26 minutes past nine in the morning, and the time zone corresponds to Moscow time, then this shift is equal to four hours, which means that you have 26 minutes after five in the morning GMT.

Use online services to determine Greenwich Mean Time if you have Internet access. This is an even easier way. For example, you can follow the link http://time100.ru/gmt.html and you will see the current time by Greenwich Mean Time, without additional calculations.

Use the built-in functions of the programming language if you need to programmatically determine the Greenwich time - they are provided in most scripting languages. Most often, such functions refer to UTC time, and this is reflected in their names. For example, in PHP these are the gmdate and gmmktime functions, in JavaScript - a whole group of functions (getUTCDate, getUTCDay, getUTCMilliseconds and others), in MQL5 - TimeGMT, etc.

Sources:

Due to the fact that the dimensions of our planet are enormous, in the same period of time, in different points of the Earth - their local solar time. And to avoid confusion in clarifying the question: "So what time is it?", The standard time system was adopted. And the Earth was conditionally divided into 24 time zones. The zero meridian was taken as a starting point, from which time zones +1, +2, +3, etc. go to the east, and to the west: -1, -2, -3, etc. So, thanks to the time zone system, it is now quite easy to determine the desired one.

You will need

- computer
- time zone map
- world map showing degrees of longitude

Instructions

Turn on and click on the clock indicator in the lower right corner of the screen. Now, in the window that opens, click on the "Change date and time settings" function. And, already in a new window, select the "Change time zone" function. You will see a long one with a list of cities that belong to them. Of course, only capitals are listed here and no small towns. So, if you want to find out the time zone of a small town, just find the capital of its country in this list, because, usually, one time zone operates within one country.

Use an ordinary map of the world, which details the average meridians: 0 °, 15 °, 30 °, 45 °, 60 °, etc. The fact is that one time zone occupies approximately 15 °, but not clearly from 0 ° to 15 °, from 15 ° to 30 °, from 30 ° to 45 °, etc., but with an offset that is - 7 ° 30. And, in order to determine the boundaries, for example, of the UTC + 1 time zone, it is necessary to draw lines to the right and left of the middle meridian 15 ° east longitude at a distance of 7 ° 30 ". To determine the time zone of the place, which is located, for example, in the region of 60 ° west longitude, you need to calculate its position in relation to the prime meridian: 15 ° - one, 30 ° - two, 45 ° - three, 60 ° - four. So 60 ° west longitude is the UTC-1 time zone ...

Use a detailed map of time zones. Such a map is the easiest and most reliable way to determine the time zone of a particular point on the globe. Since here, not only the boundaries of each of the 24 time zones are indicated, but there is also a mark - whether the country is switching to daylight saving time. For example, it looks like this: +1 (+2), and means that the country belongs to the UTC + 1 time zone, but in summer time, it belongs to the UTC + 2 time zone. Of course, do not forget to take into account that in different hemispheres, summer and winter are at different times. Another big plus of such a map is the ability to determine whether different time zones operate on its territory, as in Russia, or, despite the large territory, only one zone is accepted, as in China.

note

Despite the generally accepted system of time zones, in reality, in order to maintain a uniform time within one country or administrative unit, the boundaries of the zones are shifted, so in some places some time zones are ousted by neighboring ones.

Useful advice

When determining the time zone, do not forget that in some countries the local time differs from the universal time not only by the standard hour, but also by an additional 30 or 45 minutes.

When trying to find out what time it is in another region and in another country, you most likely come across the concept of "time zone". But often it is denoted by the special abbreviation GMT. Where did it come from, and what does it mean?

GMT is the English phrase Greenwich Mean Time, which is like Greenwich Mean Time. Mean time is understood as the astronomical time of the meridian, at which the Greenwich Observatory was previously located. This place is considered the "reference point" for all time zones. The Royal Greenwich Observatory has become a reference point for a reason. It appeared in the 17th century in Greenwich (England). There were made important calculations for sailors, including those concerning time. When Great Britain became the largest empire, the calculation of the time "according to Greenwich" spread to the dependent states, and at the end of the 19th century this reporting system was adopted by almost the whole world. In 1884, even a special international conference was held on the definition of the "reference meridian". Time in other countries was determined by the distance from the Greenwich meridian, that is, from the time zone where Great Britain was located. In the seventies, the time reference system was replaced by a more accurate one - to calculate according to universal time, which is slightly different from the time on the Greenwich meridian. Nevertheless, the abbreviation GMT is still often used as a tribute to tradition. What do the numbers before the abbreviation GMT mean? This is the time difference between the Greenwich Observatory and another selected area. For example, if you are in the GMT + 3 time zone, for example, in Moscow, then the time difference with the reference meridian is three hours, while in Moscow the time is later. The minus sign in front of the number means that the time should be counted in the opposite direction: when it is 11 o'clock in London, then in the region with GMT-2 there is still 9 o'clock. time. In 2011, it was canceled in Russia as well. In this case, the GMT will change depending on the season.

The emergence of time zones on our planet was due to the banal convenience of communication and the separation of different countries and cities in accordance with the real time of day. Scientists divided the entire surface of the Earth into 24 time zones, while taking into account an interval of 15 degrees of longitude. The same time is considered to be within the same time zone.

Instructions

The decision on calculating time zones was made at the International Conference in 1884. The meridian passing through the Greenwich Observatory near London began to be considered the year as the time reference point. It was this observatory that became the unifying link. It was originally built by order of King Charles II for sailors.

Zone time is a time counting system based on dividing the Earth's surface into 24 time zones, every 15 ° in longitude. Time within one time zone is considered the same. In 1884, at the International Conference, it was decided to apply this system. In accordance with the international agreement of 1883, the initial ("zero") meridian is the one that passes through the Greenwich Observatory in the suburbs of London. Local Greenwich Time (GMT), agreed to be called Universal Time or "World Time"

On the territory of Russia, since March 28, 2010 - 9 time zones (before that there were 11 time zones). Samara region and Udmurtia switched to Moscow time (second time zone). Kemerovo region. (Kuzbass) - to Omsk (MCK + 3). Kamchatka Territory and Chukotka - to Magadanskoe (MSK + 8). In these five subjects of the Federation, on March 28, 2010, the hour hands were not moved.

Two belts are abolished - the third (Samara, MSK + 1) and the eleventh (Kamchatka, MSK + 9). There are 9 of them in total, and the maximum spread in time in our country is reduced from 10 to 9 hours.

In Russia, since March 2011, after the transition to daylight saving time, the clock hands are no longer moved during the year.

In 2012 - again discussed, at all levels, the advantages of constant winter time over summer time, therefore - a transition (this fall) to a constant, year-round winter time is possible.

A stable time is healthier. In the autumn-spring off-season, the body does not have to, especially, rebuild its biorhythms. Technical services and transport workers no longer have to, as before, when moving the clock hands, reconfigure equipment and change schedules.

Moscow time zone, according to stable time: +4 (GMT + 4:00)

The boundaries of zone time are drawn taking into account the physical and geographical features - along large rivers, watersheds, as well as along interstate and administrative boundaries. States can change these boundaries within the country.

The international system U T C (World Time; it is designated UTC / GMT or, which is the same - UTC) is applied, as well as the difference between local and Moscow time - MSK. The plus sign means - east, minus - west of the starting point

The transition to summer time (one hour ahead) and winter (one hour back) is carried out in spring and autumn, respectively. This rule is valid in the European Union, Egypt, Turkey, New Zealand ... Dates and order of transfer - may differ slightly in terms of time. Most countries have abandoned the autumn-spring translation of the clock hands: Russia and Belarus (since 2011), Kazakhstan, Turkmenistan, Uzbekistan, Tajikistan, India, China, Japan, Singapore, Taiwan ...

World Time - UTC / GMT - Greenwich Mean Time (G M T) is Coordinated Universal Time (U T C) with an accuracy of one second - GMT \u003d UTC). The name U T C, over time, will completely replace the term "Greenich time"

Figure: 2 Map - World time zones and their offsets from UTC / GMT (Greenwich Mean Time)

Table - time zones of cities in the world (UTC / GMT), in summer time

Kamchatka	UTC / GMT + 12
Magadan, Sakhalin.	UTC / GMT + 12
Vladivostok	UTC / GMT + 11
Yakutsk	UTC / GMT + 10
Irkutsk	UTC / GMT + 9
Krasnoyarsk	UTC / GMT + 8
Omsk	UTC / GMT + 7
Yekaterinburg	UTC / GMT + 6
Moscow Moscow time, city of Sochi	UTC / GMT + 4
Minsk "Eastern European Time" (EET)	UTC / GMT + 3
Paris "Central European (Central European) Summer Time" (CEST - Central Europe Summer Time Zone)	UTC / GMT + 2
London Greenwich Time / Western European Time (WET)	UTC / GMT + 1
"Mid-Atlantic time"	UTC / GMT-1
Argentina, Buenos Aires	UTC / GMT-2
Canada "Atlantic Time"	UTC / GMT-3
USA - New York "Eastern Time" (EDT - US Eastern Daylight Time Zone)	UTC / GMT-4
Chicago (Chicago) "Central Time" (CDT - US Central Dayligh Time)	UTC / GMT-5
Denver (Denver) "Mountain time" (MDT - US Mountain Dayligh Time)	UTC / GMT-6
USA, Los Angeles, San Francisco "Pacific Daylight Time" (PDT - Pacific Daylight Time)	UTC / GMT-7

An example of the designation of winter and summer time: EST / EDT (Eastern Standard / Daylight Time Zone).
If, somewhere, winter time is considered standard, then it can be abbreviated, for example: ET, CT, MT, PT

Table - time zones of cities and regions in Russia, since 2011.
Local time difference shown:
MSK + 3 - with Moscow;
UTC + 7 - with Coordinated Universal Time (UTC \u003d GMT)

Name winter / summer		Bias relatively Moscow time	UTC offset (World Time)
USZ1	Kaliningrad time - the first time zone	MSK-1	UTC + 3: 00
MSK / MSD MSST / MSDT	Moscow time	MSK	UTC + 4: 00
SAMT / SAMST	Samara	MSK	UTC + H: 00
YEKT / YEKST	Yekaterinburg time	MSK + 2	UTC + 6: 00
OMST / OMSST	Omsk time	MSK + 3	UTC + 7: 00
NOVT / NOVST	Novosibirsk, Novokuznetsk Kemerovo, Tomsk. Barnaul	MSK + 3	UTC + 7: 00
KRAT / KRAST	Krasnoyarsk time Krasnoyarsk, Norilsk	MSK + 4	UTC + 8: 00
IRKT / IRKST	Irkutsk time	MSK + 5	UTC + 9: 00
YAKT / YAKST	Yakut time	MSK + 6	UTC + 10: 00
VLAT / VLAST	Vladivostok time	MSK + 7	UTC + 11: 00
MAGT / MAGST	Magadan time Magadan	MSK + 8	UTC + 12: 00
PETT / PETST	Petropavlovsk-Kamchatsky	MSK + 8	UTC + I2: 00

Note: MSK \u003d MSD (Moscow Summer Time) all year round

Terms and Definitions

Daylight saving time (DST - Daylight Saving (Summer) Time) - moving the clock forward one hour, which was carried out annually on the last Sunday of March to get additional hours during daylight hours, to save energy (for lighting, etc. ). The return to winter time was carried out in the last. Sunday October. These transitions affected the biorhythms of the human body, its state of health, and it took a week of adaptation to get used to it. Manipulation of the clock hands is a common reason for employees and employees being late for work.

The initial (zero) meridian is the Greenwich meridian with a geographic longitude of 0 ° 00 "00", which divides the globe into the western and eastern hemispheres. Passes through the former Greenwich Observatory (in the suburbs of London)

GMT (Greenwich Mean Time) - "Greenwich Mean Time" - on the Greenwich meridian. Determined by astronomical observations of the diurnal movement of stars. It is unstable (within a second per year) and depends on a constant change in the speed of the Earth's rotation, the movement of geographic poles along its surface, and nutation of the planet's axis of rotation. Greenwich (astronomical) time is close in value to UTC (atomic time), and will still be used as its synonym. Another name - "Zulu Time"

In Russian-language meteorology, GMT is denoted as SGV (Greenwich Mean Time / or Geographic Time)

GMT \u003d UTC (accurate to within 1 second)

Time Zone (Standard Time Zone) - the difference from UTC / GMT World Time (example: UTC / GMT + 4 - the fourth time zone, east of Greenwich)

H: mm: ss - 24 hour format (example: 14:25:05). Minutes and seconds - with leading zeros

h: mm: ss - 12 hour format (example: 02:25:05 PM - "two and a half in the afternoon" - 14:25:05). Minutes and seconds - with leading zeros

AM - designation of time before noon in 12-hour format (abbreviated version - "A")
PM - designation of time in the afternoon in 12-hour format

Universal Time UT (Universal Time) is the mean solar time at the Greenwich meridian, determined by astronomical observations of the diurnal motions of stars. Its updated values \u200b\u200bare UT0, UT1, UT2

UT0 - time at the instantaneous Greenwich meridian, determined by the instantaneous position of the Earth's poles

UT1 - time on the middle Greenwich meridian, corrected for the movement of the earth's poles

UT2 - time, taking into account the change in the speed of rotation of the Earth

TAI - atomic clock time (International Atomic Time, since 1972). Stable, reference, never translated. Time and frequency standard

The time in the GPS navigation system has been in effect since January 1980. There are no amendments to it. It is ahead of the U T C time by one and a half dozen seconds.

UTC (from English Universal Time Coordinated) - Coordinated Universal Time for the coordinated distribution of standard frequencies and time signals on radio, television and the Internet - "World Time". Its synonym: "Universal time zone"

The UTC time scale has been introduced since 1964 to reconcile UT1 (astronomical measurements) and TAI (atomic clock) values.

Unlike Greenwich Mean Time, UTC is based on an atomic clock.

The speed of the earth's rotation slows down, and therefore, in the UTC scale, corrections (leap seconds - "Leap second") are regularly introduced in the UTC scale, after a year or two or three, June 30 or December 31, so that UTC is no more than a second ( more precisely - 0.9 s) differed from astronomical time (determined by the motion of the Sun), as UT1 lagged behind by a second. This international rule was adopted in 1972.

Time ratio in 2009: UTC (universal) lags behind TAI (atomic) by 35 seconds. The time in the GPS navigation system is 15 seconds ahead of UTC (the countdown has been started since 1980, the difference is increasing) T glonass \u003d Tutc + 3 hours (adjusted, so the difference between them does not exceed 1 ms.)

Exact time signals (for clock synchronization) are transmitted via radio channels, television, the Internet - in the UTC system. More precisely, you can put, for example, on the signal of the radio "Mayak", but only in the long-wave or medium-wave range (according to the "ground-surface wave"). On the VHF / FM radio band, the signal can be delayed up to several seconds from the true one.

In watches with automatic synchronization (English Radio controlled), the time correction comes from base stations, on super-long waves. This system was developed in Europe.

Exact local time numbers in Russian cities 100 - Moscow Voronezh Cheboksary Chelyabinsk 060 - Bryansk Kaliningrad Krasnodar Murmansk Saint Petersburg Samara Mobile operators do not have such a service, since the mobile phone is not limited geographically and can work not only in a certain city, but also in roaming ...

UTC time is not translated either in winter or in summer, therefore, for those places where there is a change to summer time, the offset relative to UTC changes (in Moscow, before winter time was canceled in 2011, the difference was: in winter - UTC + 3, in summer - UTC + 4).

Standard abbreviations for calendar months and days of the week in English (applicable in RSS and others): January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Monday Tuesday Wednesday Thursday Friday Saturday Sunday Mon Tue Wed Thu Fri Sat Sun

SGW - Greenwich Mean Time (GMT) - the time of the meridian passing through the old Greenwich Observatory, near London. Used as time stamp on weather maps. Synonyms for CGV are GMT and UTC.

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Literature

"Time and Calendar" - M .: Science. 1989

Global (satellite) navigation systems GLONASS (Russia), GPS (USA), Galileo (European Union) - make it possible to determine, using navigator devices, including portable ones, the current location (coordinates), trajectory and speed of movement of objects in any point of our planet and in near-earth space.

According to the method of operation and purpose, satellite GPS (Global Positioning System) navigators can be automobile (car navigators), portable, marine, etc. The most common imported ones are Garmin, Mio and others. There are completely autonomous configuration options - with battery charging from solar panels or miniature thermoelectric generators (thermocouples). The navigation system is built into modern communicators, smartphones and cell phones, allowing you to receive not only the geographical coordinates of the location of the receiver, but also the system time with an accuracy of a fraction of a microsecond.

Russian GLONASS (Glonass) has been operating since the mid-90s. The orbital constellation includes more than two dozen active satellites. The system works throughout Russia. Since 2009, transport, including passenger transport, has been massively equipped with this system.

Navigators are manufactured in Russia (Glospace SGK-70 and others) that can work simultaneously with several navigation systems - GLONASS, GPS, Galileo.

Glospace supports the SMILINK system (shows traffic jams) and knows how to create bypass routes. Signals can be received from several satellite systems at once.

Maps G P S - electronic maps for navigators and other mobile devices (communicators, PDA / PDA, smartphones, etc.) with a GPS function.

time, which in Russian meteorological terminology sounds like Greenwich Mean Time or geographic time, which got its name from the meridian passing through the Royal Observatory, located in Greenwich

Determination of GMT time, the history of its appearance and brief information about the Royal Observatory in Greenwich and the prime meridian, general characteristics, meaning and methods of determining the time according to Greenwich, GMT time zones with an explanation of why they have such a name, familiarization with the international standard of the time format ISO 8601 and time scale

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GMT is the definition

GMT is mean solar time in Greenwich, which in English sounds like Greenwich Mean Time, it is also called the astronomical time of the prime meridian passing through the Royal Greenwich Observatory in London, until 1972, Greenwich time was considered a single reference point for time zones, now such a reference point is Coordinated Universal Time or UTC (Universal Time Coordinated).

GMT time on timezone map

GMT is astronomical (or mean solar) time of the meridian passing through the Royal Greenwich Observatory in London (which is zero although it is located at 51 ° 28 ′ 40 ″ north latitude and 0 ° 0 ′ 5.31 ″ east longitude ). Now such a reference point is the Coordinated Universal Time (in English, Universal Time Coordinated, or UTC). Often (in Russian-language meteorological terminology) Greenwich Mean Time is translated as SGV, which means Greenwich Mean Time (or geographic).

GMT is is an abbreviation of the English phrase Greenwich Mean Time, which translates to Greenwich Mean Time.

GMT is Greenwich Mean Time, the time of the meridian passing through the former location of the Royal Greenwich Observatory near London (GMT is valid in Great Britain, Ireland, Portugal).

GMT is mean solar time of the meridian passing through the former location of the Royal Greenwich Observatory near London.

GMT is Greenwich Mean Time (GMT) is in the same time zone as Coordinated Universal Time (UTC).

GMT what is this obsolete Greenwich Mean Time, Coordinated Universal Time (UTC) was introduced instead.

GMT is time which is determined by astronomical observations of the diurnal movement of stars. It is unstable (within a second per year) and depends on a constant change in the speed of the Earth's rotation, the movement of geographic poles along its surface, and nutation of the planet's axis of rotation. Greenwich (astronomical) time is close in value to UTC (atomic time), and will still be used as its synonym.

GMT what is thisgreenwich Mean Time (GMT) equals Coordinated Universal Time (UTC) to the nearest second - GMT \u003d UTC. The name UTC, over time, will completely replace the term "Greenich time".

GMT is the time of the meridian passing through the former location of the Royal Greenwich Observatory near London. Previously, GMT was considered a reference point for time - time in other time zones was measured from Greenwich. Coordinated Universal Time (UTC) is now used in this capacity.

GMT, what is it? time, which is used as a designation for time on weather maps. Synonyms for CGV are GMT and UTC.

GMT, this is where istime that is used as a reference point in other time zones before the introduction of Coordinated Universal Time (UTC).

The history of the appearance of the geographic time GMT

In 1675 Charles II ordered "to establish the exact location of objects in latitude and longitude for the needs of navigation and astronomy." The assignment was mainly intended for the scientist John Flamsteed, the building for his work was built in Greenwich by the famous Christopher Wren. Flamsteed House, the main building of the Royal Observatory, was the first building to be built in the UK for scientific research.

The Astronomer Royal did it simply - he fixed the position of the prime meridian where he worked. And over the next two centuries, most navigators in the world made their maps based on the countdown from the Greenwich meridian.

However, until the end of the 18th century, no one knew exactly how to measure longitude - the distance to the east or west of a given meridian. People knew how to calculate latitude (the distance south or north of the equator) from the position of the North Star, but for longitude such a system did not exist.

In 1754, the British government promised a reward of £ 20,000 to anyone who could find a solution. As a result, the watchmaker John Harrison received the award - in 1772 he designed a clock that could accurately measure time on board the ship and allowed the navigator to determine the position of the ship to the east or west with an accuracy of 30 miles (48 km).

Greenwich Mean Time was adopted as the standard in 1884. According to an international treaty, it was established that "each new day begins exactly at midnight when the celestial meridian passes through the sighting axes of the Royal Observatory at Greenwich."

The conference was held in Washington in 1884 - in a vote in which 25 countries took part, it was accepted that Greenwich Mean Time is the standard for measuring time around the world. The voting results were 22 in favor, 1 against and 2 abstained. The Dominican Republic is the only country that voted against. The representatives of France and Brazil were not sure about the correctness of the decision and decided to abstain. France took Paris as the prime meridian and used this in its time measurement system until 1911, and in its navigation system until 1914. Brazilians believed that a neutral prime meridian that does not cross the US or the UK would be preferable. The poor Brazilians returned home to the disapproving exclamations of the rest of the representatives: "Someone had to show off."

At the same time, the International Meridional Conference in Washington, decided that Greenwich is assigned a zero degree of longitude. The decision was based on the fact that such a choice would inconvenience the least number of people.

In 1833, Astronomer Royal John Pond installed a "time ball" over the observatory to help others set their clocks exactly to Greenwich Mean Time. This balloon still continues to plunge sharply every day at exactly 13:00 (GMT in winter, British Summer Time in summer).

Until 1954, Greenwich Mean Time (GMT) was based on time measurements taken at the Greenwich Observatory. Later, GMT began to be calculated from astronomical observations from other observatories that remained active. GMT is now often referred to as "Universal Time" (UT). Today, UTC is computed from observations of extragalactic radio sources, and then recalculated into several forms, including UT0 (UT at a remote observatory), UT1 (pole-corrected UT), and Coordinated Universal Time (UTC).

In 1894, the observatory survived an attempted bombing. This was possibly the first case of "international terrorism" in Britain. The bomb was detonated by a 26-year-old French anarchist named Martial Bourdin. It is not known whether he deliberately chose the Greenwich Observatory to carry out the terrorist attack, or whether the bomb detonated there by accident. This incident prompted Joseph Conrad to write the book "Secret Agent".

However, even before the convening of the Washington Conference, some countries switched to the new system. Below we will look at how the standard time system gradually penetrated into various countries, and at first it was mainly used only on railways and telegraphs, but soon it received legal rights and began to be applied everywhere.

The first four countries to switch to GMT (1848-1883)

The first, even before the convening of the Washington Conference in 1884, four countries moved to the new Greenwich time system - Great Britain, Sweden, USA and Canada:

Great Britain - 1848;

Sweden - 1879

Canada and the United States - 1883.

The transition to Greenwich time in different parts of the world (1994-1905)

By 1905, among the leading countries in the world that did not accept the new system were France, Portugal, Holland, Greece, Turkey, Russia, Ireland, as well as most of the countries of Central and South America, excluding Chile.

Thirty-six states have already introduced standard time, and in twenty of them the Greenwich meridian served as the basis for counting time; of the remaining sixteen, only two countries did not agree to switch to this system. France, together with Algeria, at first did not recognize this system and used the mean Paris time as state time (according to the law of March 14, 1891). In all other countries - since the time on the railways there was already ubiquitously reckoned in the new system - the transition to standard time was carried out. In December 1891, Pasquier wrote in Ciele et Terre that “the almost unanimous agreement of civilized states on the Greenwich meridian should help the adherents of other meridians to lay down their arms; and from that time on, all efforts should be directed towards the implementation of clock unification, simple, rational and practical. "

France's transition to GMT time (1996-1911)

On October 27, 1896, Deputy Deville introduced a bill in the Chamber of Deputies proposing to establish Greenwich Mean Time (GMT - Greenwich Mean Time) in France. This bill, with some amendment - daylight saving time should be expressed in Paris mean time, reduced by 9 minutes 21 seconds (which in general corresponded to Greenwich mean time, which, however, was not mentioned) - passed through the Senate on February 24, 1898, after which was sent to the parliamentary commission, where he stayed for twelve long years. Apparently, the ministries of trade, industry, post and telegraph and public works were ready to pass this bill, but it provoked vigorous opposition from the ministries of education and the navy.

Finally, on March 9, 1911 (radio had already become a reality), a law was passed in France, according to which, starting from the night of March 10-11, the Paris mean time with a delay of 9 minutes 21 seconds should be considered "the daylight saving time in France and Algeria." ... This law was in effect until August 9, 1978, when a decree was passed requiring the determination of French standard time on the basis of the coordinated universal time (UTC - Coordinated Universal Time, which, by definition, cannot differ from GMT by more than 0.9 s) by adding or subtracting from it the exact number of hours

Countries that were the last to switch to the GMT system (1912-1972)

In other countries, Portugal switched to a time system based on the Greenwich meridian in 1912; Brazil and Colombia - in 1914; Greece, Ireland, Poland and Turkey - in 1916; RSFSR-in 1919; Argentina and Uruguay in 1920.

Holland, on whose railways Greenwich time was established as early as 1892, until 1909 used Amsterdam mean time for all other purposes instead of local time; it was forced to move to Central European time on May 19, 1940 during the German occupation; its application was finally approved in 1956. The last state to adopt the new system was Liberia, where until January 1972 the daylight saving time was 44 minutes 30 seconds behind Greenwich.

Royal Observatory in Greenwich and Greenwich Meridian

Royal Observatory in Greenwich (Royal Observatory, Greenwich) is the oldest scientific institution in the UK. Greenwich is an east London area (formerly a suburb). Thanks to the work of the observatory, the word "Greenwich" has become a household word all over the world, associated with the clock and the prime meridian.

Now the Royal Observatory is a whole complex of small museums. First of all, it is an astronomical gallery with interactive instruments designed to make the sky understandable for humanity. In 1990, astronomers and telescopes moved to Cambridge, and at the end of 1998, by a special decree of the Queen, the observatory was closed altogether.

British astronomers have long used the Royal Observatory as the basis for measurements: four different meridians were drawn through the building. The zero meridian - the origin of longitude - was established in 1851 and adopted at an international conference in 1884. It passed through the George Airy meridian circle established at the observatory. For a long time, the prime meridian was marked with a brass ribbon stretched through the courtyard of the observatory. Then brass was replaced by stainless steel, and since December 16, 1993, in the night sky of London, the prime meridian is marked by a green beam of a bright laser from the observatory, directed strictly to the north.

Currently, the Greenwich Observatory houses the Museum of Astronomical and Navigational Instruments, which is part of the National Maritime Museum. Among them is the famous marine chronometer "H4" by John Garrison, along with three predecessors (now these chronometers belong to the British Department of Defense ).

There you can also see a few more exhibits representing the history of the development of accurate time measuring instruments, which are necessary in astronomy and in maritime navigation. The astronomical clock, invented in the middle of the 20th century, is also presented. Soviet scientist F.M. Fedchenko - the most accurate among the mass-produced pendulum clocks. And outside, on the wall at the gates of the observatory, another famous clock is installed - Shepherd gate clock. This is one of the first electric slave clocks.

Another unique exhibit at this museum is the Howard Grubb 28-inch refractor telescope, created in 1893 and remains the largest refractor in the UK.

In February 2005, work began on the reconstruction of the observatory, including the creation of a new planetarium, exhibition galleries and classrooms, at a cost of £ 15 million. On May 25, 2007, the 120-seat Peter Harrison Planetarium was officially opened.

In May 2013, a monument to Yuri Gagarin was unveiled on the territory of the observatory.

The main "tourist attraction" of Greenwich is, of course, the Greenwich meridian, which can be seen here! It runs in stripes across the paved courtyard and under the wall. This is the prime meridian that separates the Eastern and Western hemispheres, from which time zones are counted.

General characteristics of Greenwich time

Greenwich time (GMT) or, as it is also called, universal time (UT) is associated with the movement of the Sun, which is recorded by an observer on the Greenwich meridian with a longitude of 0 °. This time is used in the UK as local standard time during the winter months. In the summer months, British summer time is introduced, which is obtained by increasing GMT by one hour, thereby achieving a more convenient coincidence of the working day with daylight hours. In many other countries, a similar clock conversion system is also adopted.

The time we use in our daily life is called mean solar time. It is based on the average length of a sunny day. The true length of a solar day varies throughout the year; This is due to the uneven motion of the Earth around the Sun and the fact that the length of a solar day is determined by the change in the right ascension of the Sun, measured along the equator, and the Sun is moving along the ecliptic.

The correction that must be added to the mean solar time to obtain true solar time is called the equation of time. Average solar time at this point is called local time; it changes with longitude.

To avoid difficulties in using local time, the entire globe was divided into 24 time zones, and a single time zone was established within each time zone, corresponding to the position of the central meridian of that zone.

Universal Time (UT)

In astronomical reference books and calendars, as well as when making observations, universal time (Universal Time, UT) is used, or, as it is also called, Greenwich Mean Time - the mean solar time of the prime meridian, which is taken as the meridian passing through the Greenwich Observatory in England.

It varies from 0 to 24 hours and is counted from midnight. Since universal time is the same for all points on the Earth, its use eliminates any confusion in time. Every real observatory (and every self-respecting observer) has a clock showing universal time.

There are tables that allow you to go from normal local time to UTC. Sidereal time, or sidereal time, is another time frame based on the length of a sidereal day of time between two successive passages of a star through the same point of the meridian.

Sidereal days are about 3 minutes 56 s shorter than average solar days. A sidereal day beginning at the moment of the upper climax of the vernal equinox point, like a solar day, is divided into 24 sidereal hours. Local sidereal time is determined by the right ascension of the celestial meridian (the hour angle of the vernal equinox point.

To determine local sidereal time, you can use a clock that is "in a hurry" by about 4 minutes every day. Unlike electric watches, conventional mechanical watches are not difficult to adjust for these purposes. Most yearbooks indicate sidereal time in Greenwich, i.e. Time is midnight GMT (0h UT).

The difference between local and universal time is equal to the longitude of the given place of observation, expressed in hourly measure; longitude also determines with sufficient accuracy the difference between sidereal time and sidereal time according to Greenwich Mean Time. The time zones into which the Earth's surface is divided can be used to calculate Universal Time (UT) according to local (winter) time.

Greenwich Mean Time

Greenwich Mean Time is astronomical (the time of the meridian passing through the Royal Greenwich Observatory in London (which is zero although it is located at 51 ° 28 ′ 40 ″ north latitude and 0 ° 0 ′ 5.31 ″ east). Now such a point Coordinated universal time (in English Universal Time Coordinated, or UTC) is used as a reference.Often (in Russian-language meteorological terminology) Greenwich Mean Time is translated as GWT, which means Greenwich Mean Time (or geographic).

In 1964, the International Telecommunication Union adopted the uniformly variable universal time scale UTC as a standard. The UTC scale is based on the uniform atomic time scale (in French Temps Atomique International or TAI), which makes it more convenient for use in everyday life.

UTC was adopted as the standard in 1972 to replace the obsolete Greenwich Mean Time (GMT). The need for a new time base arose when it was found that the GMT scale is uneven, since it depends on the fluctuations in the daily rotation of the Earth. And since the Earth does not rotate evenly, the Greenwich meridian also rotates unevenly. The uneven rotation of our planet is expressed in the movement of the axis of rotation in the body of the Earth itself, as a result of which the North and South poles are displaced along the surface, which means that the planes of the true meridians also change their position.

Previously, GMT was considered the reference point for world time, that is, time in other time zones was counted from the Greenwich (zero) time zone. Now, the time zones of the world are expressed simply as a positive or negative offset from UTC. Do not forget that UTC time is not changed in summer or winter. Therefore, where there is a transition to daylight saving time, moving the arrows simply changes the offset relative to UTC.

Greenwich meridian (prime meridian) isthe geographical meridian passing through the axis of the Greenwich Observatory's transit instrument. The Greenwich meridian serves as the reference point for geographic longitudes; is the middle meridian of time zone zero. Local mean solar time on the Greenwich meridian is widely used in astronomy (to synchronize universal time).

Greenwich Mean Time

The modern time zone system is based on (universal time), on which the time of all time zones depends.

Local time in many countries of the Northern Hemisphere (but not in all) increases by 1 hour in summer (in the Southern Hemisphere it simultaneously decreases by 1 hour), and in winter it returns to normal, standard time, which often also changes. Due to these seasonal and non-seasonal changes in local time in broadcasting, international transport, radio communications, e-mail and other international communication, there is a huge confusion over time alignment between different countries.

Theoretically, 24 time zones of the globe should be limited by meridians running 7 ° 30 "east and west of the middle meridian of each zone, and universal time operates around the Greenwich meridian. However, in reality, in order to maintain a single time, within the same administrative or natural unit , the boundaries of the zones are displaced relative to the meridians; in some places, some time zones even "disappear", being lost between the neighboring ones.

At the North and South Poles, the meridians converge at one point, and therefore the concept of time zones, and at the same time local time, loses its meaning. It is believed that time at the poles corresponds to universal time, although at Amundsen-Scott station (South Pole), New Zealand time is in effect, and not universal time. World Time - UTC / GMT - Greenwich Mean Time (GMT) is equal to Coordinated Universal Time (UTC) to the nearest second - GMT \u003d UTC. The name UTC, over time, will completely replace the term "Greenich time".

GMT (Greenwich Mean Time) - "Greenwich time" - on the Greenwich meridian. Determined by astronomical observations of the diurnal movement of stars. It is unstable (within a second per year) and depends on a constant change in the speed of the Earth's rotation, the movement of geographic poles along its surface, and nutation of the planet's axis of rotation. Greenwich (astronomical) time is close in value to UTC (atomic time), and will still be used as its synonym. Another name - "Zulu Time"

Since 1900, the average solar day has increased by 0.002 atomic seconds, and, therefore, Greenwich mean time diverges from international atomic time by about 1 second every 500 days.

Taking into account this progressive phase shift between the two time scales, and without abandoning the high precision offered by the atomic clock, a compromise was found in 1972 that led to the definition of Coordinated Universal Time (UTC), which is now used as the official measure of time in the world. ... In fact, UTC time flows like international atomic time, and when the difference from Greenwich time reaches 1 second, 1 second is added to the UTC scale, which is called a leap second.

Thus, the difference is kept to less than 0.9 sec at all times. The addition of leaping seconds is reported by the International Earth Rotation Service (IERS), which continuously monitors the rotation rate. The best dates to add a leaping second are June 30 and December 31. By the way, the term UTC is also a compromise between the English CUT (Coordinated Universal Time) and the French TUC (Temps Universel Coordlnaire).

Exact time signals are transmitted by radio, television, Internet - in the UTC system. In Russian-language meteorology, GMT is referred to as GMT (Greenwich Mean Time or Geographic Time).

Daylight saving time (GMT)

Additional ambiguity is introduced by the use of "summer time" in many countries.

When switching to daylight saving time, its time is shifted relative to universal time. In addition, the transition to summer time and vice versa is not always carried out simultaneously. For example, when it is summer in the southern hemisphere, winter in the northern hemisphere, and vice versa.

The so-called summer time was the "brainchild" of William Willett, a London builder. In a brochure sent in 1907 to many members of parliament, city municipalities, businessmen and various organizations, he noted: “For almost half a year, the Sun illuminates the Earth every day when we are still sleeping, and quickly approaches the horizon, passing its the way to the west when we return home after a hard day ... ". Willett suggested "to improve well-being and cheerfulness" on each of the four Sundays in April, gradually move the clock forward by 20 minutes and return them back in September in the same way.

But, in addition to improving health and cheerfulness, this will lead, as Willett argued, to a decrease in energy consumption: at a cost of 0.1 pennies an hour, this would save £ 2.5 million. Art. Although Willett's scheme looked ridiculous and met with considerable resistance, especially from farmers, nevertheless, in 1909 a bill was drawn up to introduce daylight saving time, which was repeatedly considered in parliament, but was not passed before the war.

Daylight saving time, pros and cons

In April 1916, daylight saving time was introduced (in order to save energy) in Great Britain, and a week later - in almost all countries, both allied and enemy. Willett died a year earlier, never waiting for his ideas to come true. Many states immediately after the end of the war abandoned daylight saving time, others repeatedly introduced this time, then abandoned it, and some countries maintained this time shift throughout the year. During the Second World War, England also lived according to "summer time" in winter, and introduced "double summer time" in summer (DBST, two hours ahead of GMT)

Daylight saving time (one hour ahead) and winter time (one hour back) are switched on the last Sunday in March and October, respectively. This rule is valid in Russia (until March 2011), the European Union, the United States, etc. The dates and order of moving the clock hands in other countries may differ slightly in terms of time.

Daylight saving time, reduction of time zones

78 countries use daylight saving time in one form or another (of which 10 countries do not use it in all regions), and 161 countries do not use it. In the northern hemisphere, summer time is used almost everywhere in the United States, Canada, Mexico (except for a number of states and provinces), completely in all European countries, except Iceland, Russia and Belarus, as well as in Morocco, Turkey, Iran, Azerbaijan, Syria, Jordan, Lebanon, Israel, Palestine. In the southern hemisphere, summer time is used in Australia (in a number of states), New Zealand, Paraguay, Uruguay, Brazil (in a number of states), Chile, and Namibia.

Refused to introduce daylight saving time Japan, China, India, Singapore, as well as the republics of the former USSR: Uzbekistan, Tajikistan, Turkmenistan, Georgia, Kazakhstan, Kyrgyzstan. At the same time, Georgia, Turkmenistan, Kyrgyzstan and most of Kazakhstan and Uzbekistan retained "daylight saving time". Russia refused to translate the arrows in the fall of 2011, having adopted the law "On the calculation of time." Russia was soon followed by Belarus.

However, daylight saving time is not observed throughout America.

Daylight saving time is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, and the state of Arizona (except for the Navaja Indian Reservation, which does). Daylight Saving Time is underway on the Navaja Indian Reservation, due to its large size and location in three states.

In the period 1968-1971. England tried to experiment by keeping Daylight Saving Time (called British Standard Time - BST) all year round to align its time with other countries in the European Economic Community. This innovation caused general discontent in the country, especially the population of the westernmost regions of Great Britain objected to it. The experiment had to be abandoned, and since 1972 Britain has been using GMT in winter and BST in summer. Most other countries are now doing like France — keeping daylight saving time all year round.

UTC stands for Universal Coordinated Time, sometimes referred to as Zulu time, and is the basis of civil time based on atomic time. UTC is a legacy of Greenwich Mean Time (GMT), and is sometimes also erroneously referred to as GMT. Please note that UTC time is not translated in winter and summer. Therefore, for those places where there is a daylight saving time, the offset relative to UTC changes.

Daylight Saving Time in Russia

Until 1930, in our country, every year for the summer period, the clock hands were moved forward one hour, and in the fall they were again set in accordance with the standard time. By a government decree of June 16, 1930, daylight saving time was established throughout the country, which, in contrast to standard time, was called maternity time. On April 1, 1981, for economic reasons, the principle of shifting the time forward by an hour in summer was restored. Thus, in the summer, our country lived on a double summer time.

Cancellation of the transition to winter time in Russia

In 2015, there will be no daylight saving time in the Russian Federation. In October 2014, Russia set the clock back one hour and switched to constant winter time. More precisely, this time is called not winter, but zone time. Note that other countries switched their clocks to summer time already in March 2014 (on the night of the 30th).

Summer time - transition features

Disagreements between legal and geographic GMT time criteria

Since legal, political, socio-economic criteria in addition to physical or geographic criteria are used in drawing time zones, actual time zones do not exactly follow meridian lines.

The time zone "GMT" was, drawn in purely geographical terms, would consist of the area between the meridians 7 ° 30 "W and 7 ° 30" E. As a result, there are European locations that, despite being located in an area with "physical" UTC time, use a different time zone (UTC + 1 in particular); on the other hand, there are European areas that use UTC, even though their "physical" time zone is UTC − 1 (for example, most of Portugal), or UTC − 2 (the westernmost part of Iceland). Because the UTC time zone in Europe has been "moved" to the west, Lowestoft in Suffolk, East Anglia, England at only 1 ° 45 "E is the easternmost setting in Europe in which UTC is applied.

Countries (or parts of it) west of 22 ° 30 "W (" physical "UTC − 2) then use UTC

The westernmost part of Iceland, including the northwestern peninsula and its main town Isafjer Ur, which is west of 22 ° 30 "W, uses UTC. Bjargtangar, Iceland is the westernmost point at which UTC is applied.

Most of Portugal, including Lisbon, Porto, Braga, Aveiro and Coimbra. (Only the easternmost part, including cities such as Bragança and Guarda, lies east of 7 ° 30 "W.) Since the Treaty of Windsor in 1386 (the oldest diplomatic alliance in the world), Portugal has maintained a close relationship with Britain, which is possible explains her choice of UTC.Madeira, further west, also uses UTC.A more likely explanation is that during the mid 1970s, when Portugal was on CET all year, it did not start to get easy in Lisbon in winter until 08:30.

Western Ireland, including the cities of Cork, Limerick and Galway. The westernmost tip of Northern Ireland, including the main town of County Fermanagh, Enniskillen, Extreme Western Outer Hebrides, west of Scotland; for example, Vatersay, a populated island and westernmost settlement in Great Britain, is at 7 ° 54 "W. If uninhabited islands or rocks are considered St Kilda, west of the Outer Hebrides, at 8 ° 58" W, and Rockall, at 13 ° 41 "W, must be included.

Spain (excluding the Canary Islands, which use UTC). Parts of Galicia lie west of 7 ° 30 "W (physical UTC − 1), while there is no Spanish territory east of 7 ° 30" E (physical UTC + 1). The time of Spain is a direct result of Franco's Presidential Order (published in the Boletín Oficial del Estado of March 8, 1940) the abandonment of Greenwich Mean Time and advancing hours one hour effective 11:00 pm on March 16, 1940. This is an excellent example of political criteria used in the drawing time zones: the change in time was transmitted "in consideration of convenience from the national time, going in step according to that of other European countries".

How do I determine the GMT time?

The time of the time zone, in which the Royal Greenwich Observatory was once located near the British capital, was adopted as the zero point of reference for time zones. Greenwich Mean Time is abbreviated as GMT (Greenwich Mean Time). A revised standard is now in force, which is designated as UTC (Coordinated Universal Time). It differs from Greenwich by less than one second and is used more often in accurate calculations, and when determining the time of day in different parts of the planet, Greenwich time is still relevant.

You can find out the time according to Greenwich, for example, from the system time settings in the operating system of your computer. Click the clock in the notification area of \u200b\u200bthe taskbar with the left mouse button, and an additional panel with a calendar and an analog clock will pop up on the screen. In the lower part of it there is a link "Changing the date and time settings" - click on it. The system will open an additional settings window with three tabs, one of which is called "Date and Time" and has a section "Time Zone". In this section, you will see the shift of your local time relative to the Greenwich meridian - the corresponding inscription can be, for example, this: "UTC +04: 00 Volgograd, Moscow, St. Petersburg". This means that your operating system's system clock is four hours ahead of time zone zero.

Use online services to determine Greenwich Mean Time if you have Internet access. This is an even easier way.

In JavaScript, there is a whole group of functions (getUTCDate, getUTCDay, getUTCMilliseconds, and others), in MQL5 - TimeGMT, etc.

Why is the time zone called GMT?

How can I find out the time zone of my region?

GMT is an abbreviation of the English phrase Greenwich Mean Time, which translates to Greenwich Mean Time. Mean time is understood as the astronomical time of the meridian, on which the building of the Greenwich Observatory was previously located. This place is considered the "reference point" for all time zones.

Greenwich Mean Time

Time in other countries was determined by the distance from the Greenwich meridian, that is, from the time zone where Great Britain was located. In the seventies, the world time system was replaced by a more accurate one - to calculate according to universal time, which is slightly different from the time on the Greenwich meridian. Nevertheless, the abbreviation GMT is still often used as a tribute to tradition.

What do the numbers in front of the GMT abbreviation mean? This is the time difference between the Greenwich Observatory and another selected area. For example, if you are in the GMT + 3 time zone, for example, in Moscow, then the time difference with the reference meridian is three hours, while in Moscow the time is later.

Moscow time \u003d GMT 3

The minus sign in front of the number means that the time should be counted in the opposite direction: when it is 11 o'clock in London, then in the region with GMT-2 there is still 9 o'clock. time. In this case, the GMT will change depending on the season.

Several countries define their local time in relation to Greenwich Mean Time. Some examples:

United Kingdom - Interpretation Act 1978, Section 9 provides that whenever an expression of time occurs in an Act, the time referred to must be (unless otherwise specifically stated) deemed to be Greenwich Mean Time. In subsection 23 (3), the same rule applies to cases and other instruments;

Belgium - Decrees 1946 and 1947 set legal time as one hour ahead of GMT;

Republic of Ireland - Standard Time (Amendment) Act, 1971, Section 1, and Interpretation Act 2005, Section 18 (i);

Canada: Interpretation Act, R.S.C. 1985, c. I-21, section 35 (1).

Time zones of cities and countries of the world according to Greenwich Mean Time (UTC / GMT)

Time Zone or Time Zone is part of the surface of the earth (land and sea) on which the same time acts. Geographically, the land is divided into 24 equal zones, where the time differs by 1 hour in neighboring zones. However, real time zones differ from geographic boundaries because they are determined by the boundaries between states, state or administrative territories.

The time zone described in relation to the Global Time Coordinator (Greenwich Mean Time). Main time zone reference point - Main meridian (0 ° longitude), passing through the Greenwich Observatory in London. As a result, instead of the generally accepted designation UTC, it is still used in GMT (Greenwich Mean Time).

The international system UTC (World Time; it is denoted by UTC / GMT or, which is the same - UTC) is used, as well as the difference between local and Moscow time - MSK. The plus sign means - east, minus - west of the starting point.

For greater convenience (so as not to enter the local time for each degree of longitude), the Earth's surface was conditionally divided into 24 time zones. The boundaries of time zones are determined not by meridians, but by administrative units (states, cities, regions). This is also done for convenience. When moving from one time zone to another, the values \u200b\u200bof minutes and seconds (time) are usually saved, only in some countries, the local time differs from the universal time by 30 or 45 minutes. Greenwich Observatory in the suburbs of London is taken as the reference point (prime meridian or belt).

At the North and South Poles, the meridians converge at one point, so time zones are usually not adhered to there. Time at the poles is usually equated with universal time, although at polar stations it is sometimes led in its own way.

The boundaries of standard time are drawn taking into account the physical and geographical features - along large rivers, watersheds, as well as along interstate and administrative boundaries. States can change these boundaries within the country,

The formation of time zones is associated with the desire, on the one hand, to take into account the rotation of the Earth around its axis, and on the other hand, to define territories with approximately the same local time in such a way that the time differences between time zones are multiples of one hour. As a result, the decision was reached that there should be 24 time zones and each of them should cover an area of \u200b\u200bapproximately 15 ° in width (± 7.5 ° relative to the corresponding middle meridian). The reference point was taken to be the Greenwich meridian, the prime meridian, the middle meridian of the zero time zone.

The modern time zone system is based on Coordinated Universal Time (UTC), on which the time of all time zones depends. In order not to enter the local time for every degree (or every minute) of longitude, the Earth's surface is conventionally divided into 24 time zones. When moving from one time zone to another, the values \u200b\u200bof minutes and seconds (time) are saved, only the value of hours changes. There are some countries in which the local time differs from the world time not only by a whole number of hours, but also by an additional 30 or 45 minutes. True, these time zones are not standard time zones.

Theoretically, 24 time zones of the globe should be limited by meridians running 7 ° 30 "east and west of the middle meridian of each zone, and universal time operates around the Greenwich meridian. However, in reality, to maintain a single time within the same administrative or natural unit, the boundaries of the zones shifted relative to the meridians, in some places some time zones even "disappear", being lost between neighboring ones.

Time zones of the world and their numbers

At the North and South Poles, the meridians converge at one point, and therefore the concept of time zones, and at the same time local time, loses its meaning. It is believed that the time at the poles corresponds to universal time, although at Amundsen-Scott station (South Pole), New Zealand time is in effect, and not universal time. The territories of nine countries of the world are located in several time zones at once:

Russia has 11 time zones;

Canada 6 time zones;

USA also has 6 time zones (including Hawaii, excluding the island territories: American Samoa, Midway, Virgin Islands, etc.);

The autonomous territory of Denmark - Greenland has 4 time zones;

Australia and Mexico each have 3 time zones;

Brazil, Kazakhstan, Mongolia and the Democratic Republic of the Congo have 2 time zones.

The territories of each of the remaining countries of the world are located in only one any time zone.

Despite the fact that the territory of China is located in five theoretical time zones, there is a single Chinese standard time throughout its territory.

The only administrative-territorial unit in the world whose territory is divided into more than two time zones is the Republic of Sakha (Yakutia), which is a subject of the Russian Federation (3 time zones). In the USA and Canada, the boundaries of time zones are very tortuous: there are often cases when they go through a state, province or territory, since territorial affiliation to a particular zone is determined at the levels of administrative-territorial units of the second order.

Samoa time zone

Samoa time zone: UTC / GMT-11- SST stands for Samoa Standard Time.

Time zone in Hawaii

Hawaii has its own time zone, Hawaiian Standard Time. There is no Daylight Saving Time, which means Hawaii is two hours behind US West Coast in summer and three hours behind in winter. in Hawaii and the Aleutian Islands - the Hawaiian-Aleutian time zone (UTC-10, designation HAST).

Alaska time zone

Alaskan Time: 9 hours behind Greenwich Mean Time (GMT - 09:00), i.e. GMT -9

US Pacific Time

Pacific Standard Time is 1:00 PM or minus 8 hours from Greenwich Mean Time - GMT - 8. This zone includes the following states such as (California; Nevada, Oregon, Washington State);

Mountain time USA

Mountain Standard Time is 2:00 PM or minus 7 hours from Greenwich Mean Time - GMT - 7. This zone includes states such as (Arizona; Colorado; Idaho, Montana, Nebraska) (part of the state), New Mexico, Oregon (part of the state), South Dakota (western part), Texas (part of the state), Utah, Wyoming ));

United States Central Time

Central Time Zone (Central Standard Time) is 3:00 PM or minus 6 hours from Greenwich Mean Time - GMT - 6 This zone includes states such as (Alabama), Arkansas, Florida (Florida), Illinois (Illinois), Indiana (Indiana) ( part of the state), Iowa (Iowa), Kansas (Kansas), Kentucky (western part of the state), Louisiana (Louisiana), Michigan (part of the state), Minnesota, Mississippi (Mississippi), Missouri ( Missouri, Nebraska, North Dakota, Oklahoma, South Dakota (eastern part of the state), Tennessee (western part of the state), Texas (Texas (main part of the state) ), Wisconsin);

US Eastern Time

Eastern Standard Time - 4:00 PM or minus 5 hours from Greenwich Mean Time - GMT - 5. This zone includes states such as (Connecticut), Columbia (District of Columbia), Delaware (Delaware), Florida (mainland), Georgia (Georgia), Indiana (mainland), Kentucky (eastern part of state) Maine, Maryland, Massachusetts, Michigan (Michigan) (the main part of the state), New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania (Pennsylvania), Rhode Island ( Rhode Island, South Carolina, Tennessee (eastern part of the state), Vermont, Virginia, West Virginia);

South American Pacific Time

In South America, this time zone is called EST - South American Pacific Time (Eastern Standard Time), which is - GMT - 5 for Bogota, Lima, Quito;

Atlantic Standard Time

Atlantic Standard Time, in the summer - North American Eastern Time and all year round - Eastern Caribbean Time - GMT - 4;

South American Eastern Time

Most of Brazil is in the same time zone (South American Eastern Time) as the country's capital, Brasilia. In winter, time in Brasilia, the entire Federal District, all states of the Southeast, South and Northeast regions, as well as in the states of Goias, Tocantins, Para and Amapa, is GMT -3;

Time zone in Greenland

The territory of Greenland is divided into four time zones. The capital and most of the major cities on the southern coast lie in the time zone GMT / UTC -3, and the time here is 6 hours behind Moscow.

Mid atlantic time

Mid-Atlantic time, - UTC / GMT-2, on the map of time zones of the world:

Blue - Brazilian time (southern and metropolitan) in the UTC / GMT-2 zone in summer (November-March) in the Southern Hemisphere (in winter (April-October) - UTC / GMT-3);

Blue - UTC / GMT-2 zone in the oceans;

Bright yellow - Atlantic islands of Brazil and Antarctic islands of Great Britain - UTC / GMT-2 zone all year round;

Orange - UTC / GMT2 zone in summer (April-October) in the Northern Hemisphere;

Azores Standard Time

AZOST - Standard time of the Azores (Azores Standard Time) - corresponds to GMT -1;

Greenwich time is on the Greenwich meridian. Determined by astronomical observations of the diurnal movement of stars - GMT +00, it corresponds to Dublin, Edinburgh, Lisbon, London, Casablanca, Monrovia;

CET

Central European Time (CET) is one of the names of the UTC + 1 time zone. This time is used by some European and North African countries. Most of them also use Central European Summer Time (CEST) UTC + 2 for daylight saving time. In a narrower sense, the Central European time refers to the time reckoning system in those countries and territories of Europe (Amsterdam, Berlin, Bern, Brussels, Vienna, Copenhagen, Madrid, Paris, Rome, Stockholm), Belgrade, Bratislava, Budapest, Warsaw, Ljubljana, Prague , Sarajevo, Skopje, Zagreb),

EET

Eastern European Time (EET) is one of the names for the UTC + 2 time zone. This time is used by some European, North African and Middle Eastern countries. Most of them also use Eastern European Summer Time (EEST) as their daylight saving time. In a narrower sense, Eastern European time refers to the time reckoning system in those countries of Eastern Europe (Athens, Bucharest, Vilnius, Kiev, Chisinau, Minsk, Riga, Sofia, Tallinn, Helsinki, Kaliningrad), Egypt, Israel, Lebanon, Turkey, South Africa;

Moscow time

Moscow time (MSK) is the time of the time zone in which the capital of the Russian Federation is located - the city of Moscow (as defined in the Federal Law "On the Calculation of Time"). It operates in most regions of the European part of Russia. From October 26, 2014 it corresponds to UTC + 3, from March 27, 2011 to October 25, 2014 it corresponds to UTC + 4.

Samara time

Samara Time (SAMT) is the unofficial name of the local time of the time zone in which the city of Samara is located - the administrative center of the Samara region. Samara time differs by +4 hours from UTC (UTC + 4) and by +1 hour from Moscow time (MSK + 1). This is the official time in the Samara region and in Udmurtia.

GMT +4 - Samara time.

Also GMT +4 operates on the territory of the United Arab Emirates, Oman, Azerbaijan, Armenia, Georgia;

Yekaterinburg time

Yekaterinburg time (Russia Time Zone 4, RTZ 4, YEKT, sometimes Ural time) is the unofficial name of the local time of the time zone in which the city of Yekaterinburg is located - the administrative center of the Sverdlovsk region.

Time zone MSK + 2 (currently - GMT +5, until 2014 - GMT + 6, until 2011: in winter - GMT + 5, in summer - GMT + 6). This is the official time in Bashkortostan, Perm Territory, Kurgan, Orenburg, Sverdlovsk, Tyumen, Chelyabinsk regions, Khanty-Mansi and Yamalo-Nenets Autonomous Districts.

Also GMT +5 applies to regions with West Asian time (Islamabad, Karachi, Tashkent);

Omsk time

Omsk Time (OMST) is the unofficial name of the local time of the time zone in which the city of Omsk is located - the administrative center of the Omsk region. Omsk time is 6 hours ahead of UTC (UTC + 6) and 3 hours ahead of Moscow time (MSK + 3). This is the official time in the Omsk region and in most regions of Western Siberia (for 2014). Sometimes Omsk time is called "Novosibirsk".

Also GMT +6 applies to Bangladesh, Kazakhstan), Sri Lanka;

Krasnoyarsk time

Krasnoyarsk time (KRAT) is the unofficial name of the local time of the time zone in which the city of Krasnoyarsk is located - the administrative center of the Krasnoyarsk Territory. Krasnoyarsk time differs by +7 hours from UTC (UTC + 7) and by +4 hours from Moscow time (MSK + 4). This is the official time in four Siberian regions of Russia: in the Krasnoyarsk Territory, Kemerovo Region, Khakassia and Tuva.

GMT +7 is valid in Southeast Asia (Bangkok, Jakarta, Hanoi);

Irkutsk time

Irkutsk Time (IRKT) is the unofficial name of the local time of the time zone in which the city of Irkutsk is located - the administrative center of the Irkutsk region. Irkutsk time differs from Moscow time by +5 hours (MSK + 5). Currently it corresponds to the time zone GMT + 8, until October 26, 2014 it was GMT + 9, until March 27, 2011 it was GMT + 8 in winter, and GMT + 9 in summer. This is the official time in three East Siberian regions of Russia: Irkutsk Oblast, Buryatia and Trans-Baikal Territory. The Trans-Baikal Territory switched to Irkutsk time on October 26, 2014. Prior to this, the region lived according to the Yakut time.

In addition, a similar time (GMT + 8) is common in China, Xianggang (Hong Kong), Macau (Macau), central and eastern Mongolia, the Philippines, Malaysia, Western Australia (Perth), central Indonesia (eastern Kalimantan, Sulawesi and others), Singapore, Brunei;

Yakut time

Yakut time (YAKT) is the unofficial name of the local time of the time zone in which the city of Yakutsk is located - the capital of the Republic of Sakha (Yakutia). Yakut time differs by +9 hours from GMT (GMT +9) and by +6 hours from Moscow time (MSK + 6). This is the official time in the Amur Region and in the western and central parts of Yakutia, including Yakutsk.

In addition, the same time (GMT + 9) is used year-round in Korea (DPRK and the Republic of Korea), Japan, eastern Indonesia (West Papua), East Timor and Palau;

Vladivostok time

Vladivostok Time (VLAT) is the unofficial name of the local time of the time zone in which the city of Vladivostok is located - the administrative center of the Primorsky Territory.

Vladivostok time differs by +10 hours from GMT (GMT + 10) and by +7 hours from Moscow time (MSK + 7). This time in a number of East Siberian and Far Eastern regions of Russia: in the middle-northern and middle-eastern parts of Yakutia, in the Primorsky and Khabarovsk territories, in the Jewish Autonomous Region in the Magadan and Sakhalin regions (on Sakhalin Island and the southern part of the Kuril Islands [). There is no seasonal clock change.

In addition, the analogous time GMT +10 applies to Brisbane, Canberra, Melbourne, Sydney), Tasmania, Western Pacific Time (Guam, Port Moresby);

Middle Kolyma time

Srednekolymskoe time (SRET) is the unofficial name of the local time of the time zone in which the city of Srednekolymsk is located - the administrative center of the Srednekolymsky ulus of the Republic of Sakha. Srednekolymskoe time differs by +11 hours from GMT (GMT + 11) and by +8 hours from Moscow time (MSK + 8). This is the official time in the northeastern part of Yakutia and in the north of the Kuril Islands. Until October 26, 2014, the time GMT + 11 (during the period of summer time and "constant summer time" 2011-2014 - GMT + 12) was called Magadan time, as it operated on the territory of the Magadan region. In 2010-2014, it also operated on the territory of the Kamchatka Territory and the Chukotka Autonomous Okrug, it was the most eastern time zone of Russia.

Also, this time zone applies to the Solomon Islands, New Caledonia;

Wellington time zone

Wellington is the capital of New Zealand, the second most populous city in the country, the largest capital among the countries of Oceania and the southernmost capital in the world. The city is located in the Wellington region in the southern part of the North Island. Wellington's Maori name is Te Fanawi-a-Tara. City area: 290 km². Wellington population: 431,400 (2007). Coordinates: 41 ° 17'20 ″ S sh. 174 ° 46'38 "in. e. Time zone: GMT +12.

Time zones of Russia GMT

The territory of our country is very large and therefore there are as many as nine time zones in Russia. Each of us has heard the expression that when Muscovites wake up, they are already going to sleep in the Far East. This happens because these two cities are located in different parts of the country and live in different time zones with a maximum difference.

Time zones of Russia

The main time is considered to be Moscow time - in Moscow they announce the departure of trains from stations in all cities, according to Moscow time TV announcers inform us about the demonstration of films. All other regions must calculate the difference between Moscow and local time on their own.

There are a huge number of time zone maps, they are compiled for the convenience of people. Having looked at such a map, you can clearly see in which time zone you live and what is the difference between your local time and, for example, Moscow time. Therefore, there is no need to keep in mind information about the time zones of Russia or another country. You can open the desired page of the site at any time and find out all the information that interests us.

Russia was not among those states that adopted the division into time zones in 1884. The scientist-astronomer Otto Struve, who represented our country at the World Meridian Conference, reporting on the meeting, negatively assessed the project of division into belts. And in Russia everything remained the same, the solar time was decisive. The tsarist government did not dare to change anything in this matter. However, the 1917 revolution changed not only the state of Russian society, but also the current time. A few months after the October coup, the Council of People's Commissars issued a decree, which approved the zonal division - for monotonous counting of time with the entire civilized world, which should greatly simplify relations between peoples, registration of events and phenomena in time. The country was first divided into 11 time zones, their borders were drawn almost everywhere along the meridians.

Moscow time zone (in winter): +3 (GMT + 3:00).

Moscow time zone (summer time): +4 (GMT + 4:00)

On the territory of Russia, since March 28, 2010 - 9 time zones (before that there were 11 time zones). From March 21 to March 29, 2014, there were no longer 9 time zones on the territory of Russia, but 10. This was due to the inclusion of the Autonomous Republic of Crimea and the city of Sevastopol in the Russian Federation, in which the Eastern European time was in force before, which at that time coincided with the time UTC / GMT + 2. On March 17, 2014, the government of the Republic of Crimea adopted a resolution on the transition to Moscow time from March 30, 2014. On March 30, 2014, the Republic of Crimea and Sevastopol switched to Moscow time UTC / GMT + 4

On July 1, 2014, the State Duma adopted a law that introduces 11 time zones in Russia from 2:00 a.m. on October 26, 2014.

1st time zone of Russia (MSK-1, UTC + 2)

The 1st time zone (MSK-1, Moscow time minus 1 hour, UTC + 2) is the Kaliningrad region.

2nd time zone of Russia (MSK, UTC + 3)

2nd time zone (MSK, Moscow time, UTC + 3) is the Republic of Adygea, Republic of Dagestan, Republic of Ingushetia, Kabardino-Balkar Republic, Republic of Kalmykia, Republic of Crimea, Karachay-Cherkess Republic, Republic of Karelia, Republic of Komi, Republic of Mari El, Republic of Mordovia, Republic of North Ossetia - Alania, Republic of Tatarstan, Chechen Republic, Chuvash Republic, Krasnodar Territory, Stavropol Territory, Arkhangelsk Region, Astrakhan Region, Belgorod Region, Bryansk Region, Vladimir Region, Volgograd Region, Vologda Region, Voronezh Region, Ivanovo Region, Kaluga Region, Kirov Region, Kostroma Region, Kursk Region, Leningrad Region, Lipetsk Region, Moscow Region, Murmansk Region, Nizhny Novgorod Region, Novgorod Region, Oryol Region, Penza Region, Pskov Region, Rostov Region, Ryazan Region, Saratov Region , Smolensk region, Tambov region, Tvers kaya region, Tula region, Ulyanovsk region, Yaroslavl region, federal cities Moscow, St. Petersburg, Sevastopol and Nenets Autonomous Okrug.

3rd time zone of Russia (MSK + 1, UTC + 4)

The 3rd hour zone (MSK + 1, Moscow time plus 1 hour, UTC + 4) is the Udmurt Republic and the Samara region.

4th time zone of Russia (MSK + 2, UTC + 5)

4th hour zone (MSK + 2, Moscow time plus 2 hours, UTC + 5) is the Republic of Bashkortostan, Perm Territory, Kurgan Region, Orenburg Region, Sverdlovsk Region, Tyumen Region, Chelyabinsk Region, Khanty-Mansi Autonomous Okrug - Yugra and the Yamalo-Nenets Autonomous Okrug.

5th time zone of Russia (MSK + 3, UTC + 6)

The 5th hour zone (MSK + 3, Moscow time plus 3 hours, UTC + 6) is the Altai Republic, Altai Territory, Novosibirsk Region, Omsk Region and Tomsk Region.

6th time zone of Russia (MSK + 4, UTC + 7)

The 6th hour zone (MSK + 4, Moscow time plus 4 hours, UTC + 7) includes the Republic of Tyva, the Republic of Khakassia, the Krasnoyarsk Territory and the Kemerovo Region.

7th time zone of Russia (MSK + 5, UTC + 8)

7th hour zone (Moscow time + 5, Moscow time plus 5 hours, UTC + 8), it includes the Republic of Buryatia, the Trans-Baikal Territory and the Irkutsk Region.

8th time zone of Russia (MSK + 6, UTC + 9)

The 8th hour zone (MSK + 6, Moscow time plus 6 hours, UTC + 9) includes the Republic of Sakha (Yakutia) (in particular, uluts (districts): Aldansky (Aldan), Amginsky (Amga) , Anabarskiy (Saskylakh village), Bulunskiy ulus (Tiksi village), Verkhnevilyuisky (Verkhnevilyuisk village), Vilyuisky (Vilyuisk town), Gorny (Berdigestyakh village), Zhiganskiy national (Zhigansk village), Kobyaysky (Sangar village), Lensky (Lensk), Megino-Kangalassky (Nizhny Bestyakh town), Mirninsky (Mirny town), Namsky (Namtsy village), Neryungrinsky (Neryungri town), Nyurbinsky (Nyurba town), Olenek national (Olenek village ), Olekminsky (Olekminsk), Suntarsky (Suntar village), Tattinsky (Ytyk-Kyuyol village), Tomponsky (Khandyga village, Ust-Aldansky (Borogontsy village), Ust-Maisky (Ust-Maya village), Khangalassky (Pokrovsk), Churapchinsky (Churapcha village), Eveno-Bytantaysky national (Batagai-Alyta village), urban districts of Yakutsk and Zhatay) and Amursk region.

9th time zone of Russia (MSK + 7, UTC + 10)

The 9th hour zone (MSK + 7, Moscow time plus 7 hours, UTC + 10) is the Republic of Sakha (Yakutia) (Verkhoyansk, Oymyakonsky and Ust-Yansky uluses), Primorsky Territory, Khabarovsk Territory, Magadan Region, Sakhalin Region ( except for the North Kuril region) and the Jewish Autonomous Region.

10th time zone of Russia (MSK + 8, UTC + 11)

The 10th hour zone (MSK + 8, Moscow time plus 8 hours, UTC + 11) is the Republic of Sakha (Yakutia) (Abyisky, Allaikhovsky, Verkhnekolymsky, Momsky, Nizhnekolymsky and Srednekolymsky uluses), Sakhalin region (only North Kuril district ).

11th time zone of Russia (MSK + 9, UTC + 12)

The 11th hour zone (MSK + 9, Moscow time plus 9 hours, UTC + 12) includes the Kamchatka Territory and the Chukotka Autonomous Okrug.

International time format standard ISO 8601

ISO 8601 is an international standard issued by the International Organization for Standardization (ISO), which describes the date and time format and provides guidelines for its use in an international context. The name of the norm is Data elements and interchange formats - Information interchange - Representation of dates and times.

The first edition of ISO 8601 was published in 1988 and consolidated and replaced a number of older ISO standards for date and time representation: ISO 2014, 2015, 2711, 3307 and 4031. In 2000, the standard was superseded by the second edition and, later, in 2004 by the modern third edition of ISO 8601: 2004, published on December 3, 2004.

The standard uses the Gregorian calendar, which serves as the international standard for civilian use. Time zones in ISO 8601 are represented as local time (with unspecified location) as UTC, or as offset from UTC.

If no UTC relationship information is given with the time representation, the time is assumed to be in local time. While it may be safe to accept local time when communicating in the same time zone, it is ambiguous when used in a message across different time zones. It is usually preferable to point to the timezone (zone marker) using a standard notation.

If the time is in UTC, add Z immediately after the time without space. Z is the zone indicator for UTC zero offset. "09:30 UTC" is therefore represented as "09: 30Z" or "0930Z". "14:45:15 UTC" would be "14: 45: 15Z" or "144515Z". For a long time, periodically repeating processes of the same duration have been used to measure time. The easiest and most convenient way was to follow the astronomical phenomena. For example, solar time was determined from the change in the hour angle of the Sun, and stellar time was determined from the daily rotation of the Earth relative to the stars.

Other systems and time scales

It has long been used to measure time by observed periodically repeating processes of the same duration. The easiest and most convenient way was to follow the astronomical phenomena. For example, solar time was determined from the change in the hour angle of the Sun, and stellar time was determined from the daily rotation of the Earth relative to the stars.

However, scientific and technological progress demanded convenient and accurate time units based on a stable periodic natural process. In addition, a need arose for a time frame (time scale). Depending on the periodic process used, the scales of solar, stellar, dynamic and atomic time are currently defined and used.

Using the Timeline to Determine the Accuracy of the Length of a Second

Ephemeris time, ET

Uniformly current time is the ephemeris time ET (Ephemeris Time), the unit of which is the ephemeris second. The ephemeris time scale is set by the orbital motion of the bodies of the solar system, and the ephemeris time is determined from long-term astronomical observations of them. When calculating their positions, ephemeris time is used, and when observing - universal time, so you can calculate the difference between ephemeris and universal time. Unfortunately, the exact difference between ephemeris and universal time can be determined with a great delay, based on the phenomena that have occurred in the past.

Since 1986, the ET ephemeris time scale has been replaced by two DT dynamic time scales - TDT dynamic time and TDB barycentric dynamic time:

Terrestrial dynamic time TDT, equal in scale to ET, is referred to the center of mass of the Earth and serves as an independent argument for visible geocentric ephemeris, including when determining the ephemeris of a satellite;

Barycentric dynamic time TDB, which takes into account the motion of the center of mass of the Sun around the center of mass of the entire solar system (barycenter of the solar system). It is referred to the barycenter of the solar system and is an argument for the differential equations of all gravitational theories of the motion of bodies in the solar system. Ephemeris time is usually denoted by (ET). And it is defined using universal time (UT) as follows:

Atomic Time, TAI

The development of molecular and atomic frequency standards led to the emergence of a fundamentally new, independent of the rotation of the Earth and the movement of bodies of the solar system, the TAI (Time Atomic International) atomic time scale. At the XIII International Conference on Weights and Measures (1967), it was recommended for a unit time - a second - take "the duration of 9 192631 770 oscillations of radiation corresponding to the resonance frequency of the transition between two levels of the hyperfine structure of the ground state of the cesium-133 atom, in the absence of disturbances from external fields." The duration of the atomic second is as close as possible to the duration of the ephemeris.

The TAI scale is formed by the French Bureau International des Poids et Measures (BIPM) on the basis of averaging the readings of individual atomic clocks located in various institutes and laboratories around the world.To synchronize atomic clocks, special radio signals of precise time, the Internet and global navigation systems (GPS and GLONASS).

Universal Time or UT (English Universal Time) isa time scale based on the rotation of the earth. Coordinated Universal Time (UTC) is the modern replacement for Greenwich Mean Time (GMT), which is now sometimes incorrectly used as a synonym for Coordinated Universal Time (UTC). UTC was introduced on January 1, 1925. In fact, the term "universal time" is ambiguous, since there are several versions of universal time, the main ones being UT1 and UTC.

All versions of universal time are based on the rotation of the Earth relative to distant celestial objects (stars and quasars), using a scaling factor and other adjustments in order to be closer to solar time.

However, despite the high accuracy of such clocks, the need for universal time, determined from the results of astronomical observations, has not disappeared, and in solving certain problems, several systems of the universal time scale are used:

UT0 - universal time, obtained directly from astronomical observations and depending on the position of the observation point on the Earth's surface;

UT1 - universal time, obtained taking into account the calculated corrections for changes in the longitudes of observation points due to the movement of the Earth's poles;

UT2 is the universal quasi-uniform time (fairly uniform over several years), obtained taking into account the seasonal variations in the Earth's rotation speed calculated on the basis of studies of previous years.

Time of satellite navigation systems

GPS system time (TGPS) is Coordinated Universal Time (UTC), referenced to the beginning of 1980. TGPS corrections to UTC are recorded with high accuracy and are transmitted as a constant value in the navigation message, and are also published in special bulletins.

Highly stable frequency standards are installed on GPS satellites, on the basis of which their own atomic scale is formed, which is called TAI (GPS). GPS time differs from UTC by an integer number of leap seconds. This is due to the fact that the GPS time scale starts counting from January 6, 1980. At the end of 2004, the difference was 13 s. An integer number of seconds of the difference is included in the broadcast GPS signal, and then automatically processed in the GPS receiving equipment, so the time displayed by this equipment coincides with UTC. There is, however, a continuously varying small difference, which is almost always less than 25 ns.

Sources and links

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ru.wikipedia.org - resource with articles on many topics, free eccyclopedia Wikipedia

youtube.com - YouTube, the largest video hosting in the world

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infoknyga.lt - information book, what is time zone?

loco.ru - articles on the site, time zones, Greenwich Mean Time, UTC, CDT

subsidii.net - news site, watch translation in Russia

world-time-zones.ru - time zones, time zones of Russia

phcode.ru - telephone codes of Russia, time zones of Russia

liveinternet.ru - quotation book, time: time zones of the world - Greenwich Mean Time

pam65.ru - time portal, who needed time zones

travel-child.ru - Royal Observatory in Greenwich and Greenwich meridian

library.kiwix.org - articles on the site, Greenwich Observatory

tisamsebegid.ru - information portal about tourism and travel, Royal Observatory (Greenwich)

usaamerica.info - news site about America, time in the USA

gmt.su - GMT time, time in cities of the world

ru.thetimenow.com - Greenwich Mean Time (GMT)

bugaga.ru - articles on the site, 10 little-known facts about time zones

krasoteurop.ru - blog for tourists, Greenwich - the place where time begins

24timezones.com - directory of time zones, time zones of countries of the world

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bestreferat.ru - abstract bank, time zones of the Earth

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kakras.ru - directories, time zones UTC, GMT

ruqrz.com - articles on the site, exact time and frequency

planetolog.ru - maps of the world, time zones of Canada

ru.translate.net - time zones, Iceland time zone

kakprosto.ru - articles on the site, why the time zone is called GMT

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library.kiwix.org - material from Wikipedia, ephemeris time

studopedia.ru - studopedia, atomic time

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rasvetsiriusa.com - articles on the site, time zones

nteresnoe.info - a little about everything interesting, the current time in the cities of Russia

Links to Internet services

forexaw.com - information and analytical portal for financial markets

google.ru - the largest search engine in the world video.google.com - search for videos on the Internet via Google

translate.google.ru - translator from the search engine

Google yandex.ru - the largest search engine in Russia

video.yandex.ru - search for videos on the Internet via Yandex

images.yandex.ru - search for images through the Yandex service

Links to application programs

windows.microsoft.com - the site of the Microsoft corporation that created the Windows OS

office.microsoft.com - site of the corporation that created Microsoft Office

chrome.google.ru - a commonly used browser for working with sites

hyperionics.com - site for the creators of the screenshot program

HyperSnap getpaint.net - free imaging software

Article creator

vk.com/id238040329 - profile in VKontakte

odnoklassniki.ru/profile/236293636061 - profile in Odnoklassniki

facebook.com/profile.php?id\u003d100008317868136 - Facebook profile

twitter.com/goldcoin7777 - Twitter profile

plus.google.com/111295713717655619651/posts - profile on Google +

hellenker4rus.livejournal.com - blog in LiveJournal