What is the date line?

How to live twice the same day? How to jump from today to the day after tomorrow without a time machine? Where on the planet does New Year come first? The answers to these questions are connected with such a notion as the line for changing dates. This is a conventional boundary, drawn along the surface of the Earth and dividing the regions, the time in which is different for about a day.

The 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 the axis and in its circulation around the Sun. These patterns were observed and laid down in the basis of time dating back in antiquity. However, the need to take into account the motion of the planet and correct the definition of dates when moving to impressive distances appeared only in 1521, when Magellan made his round-the-world trip. The team, arriving at the point of departure, discovered that Europe already lives on September 7, while the on-board journal is dated September 6, - one day disappeared somewhere. Since the documentation on the ship was very carefully, the probability of error was extremely low. Soon, the inquisitive minds of Europe realized where Magellan's journey had gone one day.

Date change line: definition

The earth rotates around the axis from west to east. At the same time, navigators led by Magellan followed the opposite direction. They circled the planet from east to west, seeing one sunrise less than during the trip they met in Europe.

To ensure that such an annoying confusion does not arise every time someone decides to go around the world, a line has been made for the change of dates. It almost completely passes along the meridian of 180º 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 on May 18, then to the east - another 17th. In this case, both there and there the clock shows approximately the same time.

Placement on the geographical map

Unlike the zero meridian, the line for changing dates practically does not reach the territory of the land. Due 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 meridian of 180º. It connects two poles, getting to land only in Antarctica. For the first time, the time limit deviates from the meridian in the area of the eastern territory of our country. Then the line of change of dates passes through the Pacific Ocean, breaking the Bering Strait. To the south of it the border again deviates from the meridian of 180º: it circles the Aleutian Islands from the west . Further, the line of change of dates passes through the waters of the largest ocean of the Earth. The next significant deviation is in the area of the islands of Samoa, Fiji, Tongatapu, Chatham, Kermadec. The line in this area passes east of the meridian and then returns to it south of New Zealand.

In the Bering Strait area, the time boundary separates the islands of Diomida. The distance between them is only four kilometers. When on the island of Kruzenshtern, belonging to the territory of the United States, continues "yesterday", on the island of Ratmanov, which belongs to Russia, is already "today".

Rule

A change of dates must be made at the intersection of the line. If the ship is moving from east to west, then his team needs to increase the calendar number by one. In the case of moving in the opposite direction, it decreases. On the segment where the time limit deviates, skirting the islands of Oceania, the team has the right to change the date, only overcoming the meridian of 180º, if the vessel does not enter one of the ports, that is, there will not be a need for synchronization with local time.

It turns out that when crossing a line in a certain direction, you can twice live the same day. Some romantics make such a journey under significant dates: the anniversary of the wedding, the birthday.

Moving the Border

The date line on the map did not always look the same as today. In the Philippines, almost to the middle of the century before last, the calendar sheets were turned over in accordance with the "American" calculation. However, on the island of Celebes, which is located at the same geographical longitude, 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 US. Samoa changed its way of calculating twice according to the needs of trade. In 1892, when he was actively trading with the US, it was decided to move the time line to the west. Residents of the country that year twice met the dawn on 4 July. After a century with little, in 2011, trade relations with the countries of the Asia-Pacific region came to the forefront. The date line was moved to the east of the island. As a result, this year after December 29, the 31st immediately came.

Who in the world meets the New Year first?

A significant deviation of the line from the meridian in the equatorial region is connected with the decision of the Kiribati government in 1995 to allocate a new time zone for the Lain Islands. The reason for this was quite weighty. Kiribati was divided into two zones: while one was on the calendar, for example, on June 14, the other was already 15.

It is on the islands of Line that a new day begins earlier than anywhere else on Earth. The population of this territory first meets on January 1. It was the latter fact that aroused particular indignation 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 such an opportunity.

At its core, the line of change dates is only a conditional boundary. In its basis, there are no physical laws. The line was created for the convenience of international communication. The change of one date to another at the crossing of this border is similar to the translation of the clock in the transition to summer or winter time. These actions help a person to correlate his movement or activity with cosmic processes, but directly from them do not flow.