How to live the same day twice? How to jump from today to the day after tomorrow without a time machine? Where on the planet does the New Year come first? The answers to these questions are related to such a concept as the date line. This is a conditional border drawn along the surface of the Earth and separating areas in which the time differs by about a day.
Lost day
As you know, counting time is not an abstract procedure. It is connected with the fundamental cosmic laws, expressed in the rotation of our planet around its axis and in its revolution around the Sun. These patterns were noticed and formed the basis of time reckoning in antiquity. However, the need to take into account the movement of the planet and adjust the determination of dates when moving over impressive distances arose only in 1521, when Magellan made his round-the-world trip.
The team, having arrived at their point of departure, found that Europe was already living on September 7, while inThe date in the log book is September 6, - one day has disappeared somewhere. Since the documentation on the ship was kept very carefully, the probability of error was extremely low. Soon the inquisitive minds of Europe realized where one day had gone during Magellan's journey.
Dateline definition
The earth rotates around its axis from west to east. At the same time, the sailors, led by Magellan, followed the opposite direction. They circled the planet from east to west, seeing one less sunrise than they had seen in Europe during their journey.
In order to prevent such annoying confusion every time someone decides to go around the world, a date line was drawn. It almost completely passes along the 180º meridian and is the boundary where the time of day remains the same, but the calendar date changes. For example, if to the west of the line on the calendar is May 18, then to the east is another 17th. At the same time, both there and there the clock shows approximately the same time.
Placement on the geographical map
Unlike the zero meridian, the international date line practically does not fall on land. Thanks to this, in most cases, when moving around the planet, you do not have to subtract or add one day. As already mentioned, the main part of the line coincides with the 180º meridian. It connects the two poles, falling on land only in Antarctica. For the first time, the time border deviates from the meridian in the region of the eastern territory of our country. Then the date linepasses through the Pacific Ocean, breaking the Bering Strait. To the south of it, the boundary again deviates from the 180º meridian: it goes around the Aleutian Islands from the west. Further, the date line passes through the waters of the largest ocean on Earth. The next significant deviation is located in the area of the islands of Samoa, Fiji, Tongatapu, Chatam, Kermadec. The line in this area passes east of the meridian and then returns to it south of New Zealand.
In the Bering Strait region, a temporary boundary separates the Diomede Islands. The distance between them is only four kilometers. While "yesterday" is still going on on Kruzenshtern Island, which belongs to the United States, on Ratmanov Island, which belongs to Russia, it is already "today".
Rule
Change of dates must be carried out when crossing the line. If the ship is moving from east to west, then its crew needs to increase the calendar date by one. In the case of movement in the opposite direction, it decreases. On the segment where the time border deviates, going around the islands of Oceania, the team has the right to change the date only after overcoming the 180º meridian, if the ship does not call at one of the ports, that is, there is no need to synchronize with local time.
It turns out that when crossing the line in a certain direction, you can live the same day twice. Some romantics plan such a trip for significant dates: wedding anniversary, birthday.
Moving the border
The International Date Line on the map didn't always look like it does today. In the Philippines, almost until the middle of the century before last, the calendar sheets were turned over in accordance with the "American" calculus. At the same time, on the island of Celebes, which is located on the same geographical longitude, they adhered to the so-called Asian date.
In Alaska, the calendar synchronized with the time in the country to which it belonged: until 1867 with Russia, and then with the United States. The island of Samoa changed its method of calculation twice in accordance with the needs of trade. In 1892, when he was actively trading with the United States, it was decided to move the temporary border to the west. Residents of the country that year met the dawn twice on July 4th. A little over a century later, in 2011, trade relations with the countries of the Asia-Pacific region came to the fore. The date line has been moved to the east of the island. As a result, this year after December 29th immediately came the 31st.
Who in the world is the first to celebrate the New Year?
Significant deviation of the line from the meridian near the equator is associated with the decision of the government of Kiribati in 1995 to allocate a new time zone for the Line Islands. The reason for this was quite weighty. Kiribati was divided into two zones: while in one the calendar indicated, for example, June 14, in the other it was already 15.
It is on the Line Islands that a new day begins earlier than anywhere else on Earth. The population of this territory is the first to meet January 1. It was the latter fact that caused a specialoutrage among the population of Tonga and the New Zealand Islands. They were going to be the first to meet the Millennium, but the formation of a new time zone deprived them of this opportunity.
At its core, the international date line is just a conditional border. It is not based on any physical laws. The line was created for the convenience of international communication. The change from one date to another when crossing this border is similar to the change of clocks during the transition to summer or winter time. These actions help a person correlate his movement or activity with cosmic processes, but do not follow directly from them.
