1. The local time.
Time measured on a given geographic meridian is called local time this meridian. For all places on the same meridian, the hour angle of the vernal equinox (or the Sun, or the mean sun) at any given moment is the same. Therefore, on the entire geographic meridian, local time (stellar or solar) is the same at the same moment.
If the difference between the geographical longitudes of two places is D l, then in a more eastern place the hour angle of any star will be on D l greater than the hour angle of the same luminary in a more westerly location. Therefore, the difference of any local times on two meridians in the same physical moment is always equal to the difference between the longitudes of these meridians, expressed in hours (in units of time):
those. the local mean time of any point on earth is always equal to universal time at that moment plus the longitude of that point expressed in hours and considered positive east of Greenwich.
In astronomical calendars, the moments of most phenomena are indicated by universal time. T 0 . The moments of these events in local time T t. are easily determined by formula (1.28).
3. standard time. AT Everyday life using both local mean solar time and universal time is inconvenient. The first because there are, in principle, as many local time counting systems as there are geographic meridians, i.e. countless. Therefore, in order to establish the sequence of events or phenomena noted in local time, it is absolutely necessary to know, in addition to the moments, also the difference in longitudes of the meridians on which these events or phenomena took place.
The sequence of events marked according to universal time is easily established, but the large difference between universal time and the local time of meridians, which are far from Greenwich Mean Time, creates inconvenience when using universal time in everyday life.
In 1884, it was proposed belt counting system of average time, the essence of which is as follows. Time is only kept on 24 major geographic meridians located from each other in longitude exactly 15 ° (or 1 h), approximately in the middle of each time zone. Time zones are called plots earth's surface, into which it is conditionally divided by lines extending from its north pole to the south and separated by approximately 7°.5 from the main meridians. These lines, or boundaries of time zones, follow exactly the geographical meridians only in the open seas and oceans and in uninhabited places on land. For the rest of their length, they go along state, administrative and economic or geographical boundaries, retreating from the corresponding meridian in one direction or another. Time zones are numbered from 0 to 23. Greenwich is taken as the main meridian of the zero zone. The main meridian of the first time zone is located exactly 15 ° east of Greenwich, the second - 30 °, the third - 45 °, etc. until the 23 time zone, the main meridian of which has an east longitude from Greenwich 345 ° (or west longitude 15°).
Standard timeT p called the local average solar time, measured on the main meridian of the given time zone. It keeps track of time throughout the territory lying in a given time zone.
Standard time of this zone P is related to universal time by the obvious relationship
| T n = T 0 +n h . | (1.29) |
It is also quite obvious that the difference between standard times of two points is an integer number of hours, equal to the difference their time zone numbers.
4. Summer time. In order to more rationally distribute electricity used for lighting enterprises and residential premises, and to make the most complete use of daylight in the summer months of the year, in many countries (including our republic), the hour hands of clocks running in standard time are moved forward by 1 hour or half an hour. The so-called summer time . In the fall, the clock is again set to standard time.
DST connection T l any point with its standard time T p and with universal time T 0 is given by the following relations:
| (1.30) |
When traveling around the world, people inevitably find themselves at different times of the day - this is due to the movement of the planet around its axis. Russia is a very large country occupying an impressive territory. For greater convenience, its area was divided into a certain number of zones corresponding to the number of time zones in Russia.
What determines time on Earth
Our planet, as you know, has a spherical shape. In 24 hours, it manages to make a complete revolution around its axis, that is, 360 °. Accordingly, in one hour the Earth rotates around its axis by 15 °.
In different parts of the world, people meet sunrise or sunset at different times. In places located on different meridians, at the same moment, the hands of the clock will show different times of the day. For example, in Yakutsk it will be 21 hours, while in Yekaterinburg - only 17.
But at the same time, on the same meridian, throughout its entire length from the North to the South Pole, the time of day will be the same. Such time is called local or solar.
However, using local time is extremely inconvenient: it makes the development of relations between countries very difficult. To eliminate this discomfort, astronomers have proposed to introduce a standard time system around the world.
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As a result, the entire planet was divided along the meridians into 24 belts, each of which includes 15 ° longitude. Thus, the time in each time zone differs from the time in neighboring zones by 1 hour.
The zero time zone is considered to be the center of which runs the Greenwich meridian. He is also the 24th in a row. Time zones are counted from zero from west to east.
Rice. 1. Reference point - Greenwich meridian.
Time zones of Russia
The length of Russia from west to east is very large, and covers 11 time zones. Capital Russian Federation- Moscow - is in the second time zone, and, say, Chukotka autonomous region- in the twelfth.
Moscow time serves as a reference point for determining local time anywhere in Russia. The difference is calculated by the number full hours: The counting of minutes and seconds is the same in all time zones.
In order to avoid confusion on the territory of Russia, all work of river, sea, air and rail transport, as well as various kinds of communications, are carried out only in Moscow time.
Rice. 2. Time zones of Russia on the map.
For greater convenience in Russia, the second and eleventh time zones were combined into one. For this reason, within the Russian Federation, they meet not eleven, but ten times.
Independently calculate the standard time of each individual locality quite easy. It is enough to know the boundaries of its location and the number of the time zone in which it is located. For example, if in Moscow, located in the second zone, it is 8 am, then in Yekaterinburg, located in the fourth zone, it will be 10 am, since the difference with Moscow will be 2 hours.
Table by city (time difference)
Daylight Savings Time
In 1930, by decree of the Council of People's Commissars throughout Russia, the clock hands were moved one hour ahead of the relative standard time. The country lived in this regime for more than 50 years according to the so-called "maternity leave" time. It was believed that the change to a new time was installed in order to save electricity. The return to seasonal time only happened in 1981.
In the same year, summer time was introduced on the territory of the USSR. In the period from April 1 to October 1, clocks throughout the country were set one hour ahead. The official reason for this move is rational use daylight hours and energy savings.
Rice. 3. Physiologists are against the transition to a new time.
However, physiologists are sure that such jumps in time have a very negative effect on people's well-being. For any organism, the transition to a new time is stressful, and it takes some time to life cycles adapted to the new conditions.
The transition to daylight saving time in the Russian Federation was canceled in 2011.
What have we learned?
When studying one of the topics in the 8th grade geography program, we learned how many time zones there are in Russia. We found that their number of time zones corresponds to the number of meridians, and the difference in time in each neighboring zone is exactly one hour. Moscow time is considered the main time in Russia, according to which all types of transport operate, communications are established throughout the country.
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For almost the entire time of the existence of the Russian Federation, namely, from October 23, 1991, the resolution of the Council of the Republic of the Supreme Soviet of the RSFSR dated “On streamlining the calculation of time on the territory of the RSFSR” was in force on the territory of our country. This legal act established the annual introduction of summer time, the procedure and date of transition to it were to be determined in accordance with the requirements of the European Economic UN.
Cancellation of the annual switchover
In 2011, the then President of the Russian Federation Dmitry Medvedev signed, which abolished the practice of moving the hands on the clock. However, this regulatory legal act was signed in June, that is, after the inhabitants of the country switched their clocks to summer time on March 27, 2011.Thus, the Federal Law No. 107-FZ of June 3, 2011 “On the Calculation of Time” actually fixed permanent summer time in Russia. As the main factor that caused the refusal of the double annual change of the clock hands, the negative impact of the change of time on the human body, expressed in an increase in the incidence and population of the country, was called.
Discussion about temporary regime in Russia
At the same time, the decision made a few years ago cannot be called unequivocally popular: it found quite a few opponents. The main argument that is usually put forward to challenge the legitimacy of fixing summer time on the territory of the country is the continuing operation of the so-called daylight savings time.The fact is that back in 1930, by a special decree of the Council of People's Commissars of the USSR, a temporary regime was introduced on the territory of all republics, one hour ahead of standard time. And although in 1991 the effect of this decree was canceled, about a year later this temporary regime was restored on the territory of Russia.
The introduction of daylight saving time actually represents an increase of one more hour to the standard time: thus, the inhabitants of the Russian Federation are two hours ahead of standard time. In this regard, in last years periodically there are proposals to return to winter time.
At the moment, a draft law fixing the transition of the country to a constant winter time has been adopted. State Duma RF in the third reading. If it comes into effect, the actual time in Russia will be close to standard time.
On July 14 (July 1, according to the old style), 1917, the transition from "winter" to "summer" time was carried out for the first time in Russia.
The expression summer time (summer time or Daylight Saving Time) means an hour ahead of the time accepted in the given time zone. It is introduced for the summer period in order to save electricity by the governments of a number of countries approximately north of 30 ° north latitude and south of 30 ° south latitude.
Switching clock hands to "summer" time is not advisable everywhere. In tropical latitudes (less than 23.5°), daylight hours vary little throughout the year. In polar latitudes (more than 66.33°) there is a polar day and a polar night. The effect of shifting clock hands to "summer" and "winter" time can take place in the latitude range from 30 to 55 °.
Daylight Saving Time in different countries decrease from north to south, amounting to 20-30 weeks in April-May, summer months and September-October (in the northern hemisphere) and about 20 weeks in November-March (in southern hemisphere). With a significant decrease in the duration of daylight hours, the time is transferred back an hour. The mode of life according to the usual zone time in everyday life is called "winter" time.
For the first time, the idea of \u200b\u200btransferring clocks arose in the 18th century with the American public figure Benjamin Franklin (Benjamin Franklin) in order to save candles for lighting, but was blocked by candle manufacturers.
In 1895, New Zealand entomologist George Vernon Hudson submitted a paper to the Wellington Philosophical Society proposing a two-hour shift to preserve daylight.
The idea of introducing "summer" time found support in most economically developed countries at the beginning of the 20th century, during the period of mass electrification of industry and everyday life. More rational use of daylight hours was supposed to reduce the cost of electricity for lighting the premises.
In Great Britain, in 1909, a bill was drawn up on the introduction of "summer" time, which was repeatedly considered in Parliament, but was not adopted until the First World War.
Many states immediately after the end of the war abandoned "summer" time, others repeatedly introduced this time, then abandoned it, and some countries maintained such a time shift throughout the year.
Transfer to "summer" time was introduced in case of crisis situations, for example, during the Second World War (USA, Great Britain), during the oil crisis of 1973-1974 (USA, Germany and other countries).
In Russia, for the first time, this transition was carried out on July 1 (July 14, according to the new style), 1917, when, in accordance with the decree of the Provisional Government, the hands of all clocks in the country were moved one hour ahead.
They were transferred back on December 27, 1917 (January 9, 1918, according to the new style), already in accordance with the decree of the Council of People's Commissars of December 22, 1917 (January 4, 1918, according to the new style).
The practice of switching from "summer" to "winter" time continued until 1924.
Decree of the Council of People's Commissars of the USSR of June 16, 1930 introduced maternity time on the territory of the USSR. Then the hands of the clock were moved one hour ahead of standard time and after that they were not moved back, and the country began to live and work all year round, one hour ahead of the natural daily cycle. The transfer of clock hands to "summer" time was resumed from April 1, 1981, but already relative to the daylight savings time. Thus, in the country "summer" time was two hours ahead of standard time.
In the USSR, and since 1991 in Russia, the introduction of "summer" time was carried out on the night of the last Saturday on the last Sunday of March, and "winter" on the night of the last Saturday on the last Sunday of September.
In 1996, the period of validity of "summer" time in Russia was "in order to observe a single time regime with other countries. The transition to" winter "time began to be carried out on the last Sunday of October, as in all of Europe.
At the same time, the majority of the Russian population opposed summer time.
July 21, 2014 Russian President Vladimir Putin on Russia's transition from October 26, 2014 to "winter" time. In most constituent entities of the Russian Federation, the clocks were set back an hour, and in the future, the seasonal translation of the hands was not carried out. Five regions of Russia (Udmurtia, Samara Region, Kemerovo region, Kamchatka Krai and Chukotka Autonomous Okrug) did not switch to "winter" time.
After that, complaints began to come from a number of regions about the lack of sunlight in the evenings. In 2016, the Russian authorities approved laws that made it possible to move the clock forward: in the Republic of Altai, Altai and Trans-Baikal Territories, Sakhalin, Astrakhan, Magadan, Tomsk, Ulyanovsk, Novosibirsk and.
At present, there is no consensus among experts and the international community on the significant savings in energy resources during the transition to daylight saving time.
In 2017, more than 70 countries and territories implemented the transition to "summer" / "winter" time. From the former Soviet republics"summer" time was introduced only by Moldova, Ukraine and the three Baltic republics - Latvia, Lithuania and Estonia.
The material was prepared on the basis of information from RIA Novosti and open sources
Switching to winter time is carried out on the last Sunday of October
(in 2019 - 27th October- at 04:00 in Kyiv).
A person tends to get up at dawn in order to make the most of daylight hours. This is where the idea of summer and winter time originates, according to which people now live in many countries of the world. Combining waking hours with daylight hours allows you to save electricity consumption: in spring, the hands of clocks running in standard time are set one hour ahead, and in the fall they are set back to standard time.
Divide the whole earth into sentries belts 15 degrees in each, and for zero line to take the Greenwich meridian - the middle of the zero zone - was proposed by the Canadian communications engineer S. Fleming. Inside the belt, time is assumed to be the same everywhere, and at the border, the arrows are moved one hour forward or backward. In 1883, the US government accepted Fleming's idea. And in 1884, at an international conference in Washington, 26 countries signed an agreement on time zones and standard time. Representatives of Russia were also at the conference. They did not like the new account of time for the same reason that Russia stubbornly held on to a mile and a pood: any change seemed to be a “shaking of the foundations” and an impetus to “national ferment”.
After October revolution, February 8, 1918, zonal division was introduced by a decree of the Council of People's Commissars "in order to establish a uniform account of time with the whole civilized world during the day, which determines on everything the globe the same clock readings in minutes and seconds, and greatly simplifies the registration of the relationship of peoples, social events and most natural phenomena in time.
By a government decree of June 16, 1930, the hands of all clocks in the territory Soviet Union were moved forward by an hour. formed maternity leave time, the introduction of which allowed to save electricity. The period of validity of maternity time was set "until abolition" (lasted until 1981).
By a resolution of the Council of Ministers on April 1, 1981, the hands of the clock were moved forward another hour. Thus, summer time was already two hours ahead of standard time. Within ten years of winter period the hands of the clock were set back an hour compared to summer time, and in the summer they returned to their place again.
In March 1991, maternity time was abolished. The advance two hours ahead has been abolished. We switched to the summer-winter time reference system. Now the standard time is used in winter, and in summer the clock is moved forward 1 hour. This, in brief, is the history of the change in timing.
We measure time by the average solar day, divided into hours, minutes and seconds. Those. by the arithmetic mean of the duration of all true solar days per year (the difference between the duration of the true and average days reaches 15 minutes due to the non-circular orbit of our planet).
Rice. one. Changes in daylight and darkness throughout the year
On fig. 1 shows the change in daylight and darkness during the year for a latitude of 50° (the latitude of Kyiv). The border between light and dark time is considered to be the beginning or end of the so-called civil twilight, that is, the time when the Sun sank 6 ° below the horizon. In the evenings, by this time, lighting should be turned on on the streets of the city. The chart shows sunny true time(true solar time begins and ends at noon, i.e. when the luminary passes through the meridian and stands as high as possible).
The average person gets up at 7 am and goes to bed at 11 pm local time. On the graph, the time of wakefulness of such a person is marked by two horizontal dotted lines. Beginning with Martha he gets up after dawn. By moving the clock forward, he is forced to get up earlier (solid horizontal lines). This is justified by the fact that he will get up during daylight hours and consume less electricity for lighting.
Return to winter time in October does not result in energy savings. As it turned out, this is done solely so that in winter people do not get up much earlier than sunrise. Therefore, the transition to winter time is not justified.
From point of view common sense it is rational to return to standard time, abandon the annual clock change and live with an unchanged countdown, which will differ by one hour ahead in comparison with standard time. Such a rhythm of life, from a biological point of view, is the most favorable for a person.
Donetsk and Luhansk people's republics On October 26, 2014, they switched to a new time standard and moved the hands in accordance with the third time zone of the international system.
On October 24, 2014, the DPR Supreme Council adopted a resolution “On the transition to Donetsk time”, now Donetsk will have the same time with Moscow and an hour difference with Kyiv. A corresponding resolution was also adopted by the leadership of the LPR.