Taylor Swift From Japan to Las Vegas and added a few hours. The Hong Kong stock market closed and the London stock market opened. Clocks on the remote Pacific island are striking midnight 24 hours earlier on orders from politicians.
None of these times are empirical scientific facts. Humanity had just agreed to observe time zones, a concept introduced by railroad companies in the 19th century.
But time zones have physical dimensions. So, where exactly does the day begin and end? Simply put, Monday becomes Tuesday at the International Date Line (the border across the Pacific Ocean).
The longer answer is that there are no international rules governing the location of the Date Line, and its exact coordinates depend on the ever-changing whims of national governments. Maps that attempt to depict it are never quite correct, and technically the line itself doesn’t exist.
Confused? This is a primer.
People have been talking about this issue for centuries.
The idea of drawing a line between the beginning and end of the day has been floated since at least the 1300s. But while the equator is the logical dividing line between the Northern and Southern Hemispheres, there is no obvious place to divide the Eastern and Western Hemispheres.
Mapmakers have long chosen their own lines dividing east and west, called meridians, a word derived from the Latin for “noon.” In the absence of international standards for when daylight begins or ends, navigators on long-distance voyages must decide for themselves how to calculate the time they lose or gain.
An account of a voyage by the 16th-century English explorer and pirate Francis Drake describes the arrival of a ship on Sunday. But by “the normal calculation of those who stay at home in a place or country,” it’s already Monday.
The location of the date line has never been determined.
In 1884, 25 nations passed a resolution calling for the establishment of a “prime” meridian, setting Greenwich (a town outside London that houses the Royal Observatory) at 0 degrees longitude to provide mapmakers with , timekeepers and train dispatchers to establish an international reference point. They also decided to establish a “World Day”.
But according to Ian R. Bartky’s 2007 book “One Time Fits All,” it took decades for many countries to accept the Prime Meridian and officially establish a time zone associated with Greenwich. The actual location of this world anniversary – the International Date Line – has never been officially determined.
In 1921, the British Admiralty, which manages Britain’s naval affairs, stated that “no date limit has been clearly defined, either by any one country or by international agreement.” More than a century later, this remains the case.
“While the Prime Meridian feels sacrosanct, the International Date Line is not a meridian; it is a meridian,” said cartographer Tim Montenyohl, who created the date line: Written in 2018.
Some countries have moved the date line.
Since the concept of the International Date Line is not enforced by an international treaty, Pacific countries and territories are largely free to decide on which side of the date line they place themselves. Some people switch sides for political or business reasons.
Spain initially placed its 16th-century colony of the Philippines on the east side of the time change.This actually forces the dateline Dog-leg West Start at the 180th meridian. But in 1844, the Philippines moved the line back, declaring that December 31 of that year would be “removed as if it had really passed away.”
Some Pacific island countries have unilaterally moved the date line to simplify local timekeeping or promote trade relations in the Asia-Pacific region.
In the 1990s, Kiribati Move the line east across the 180 degree meridian to include its easternmost island. In 2011, Samoa – which celebrated the same Monday twice, thus crossing the same meridian in 1892, at the urging of American businessmen – Jump back Cut a Friday.
Emma Weave, an Asian Development Bank economist who has worked in the Pacific islands, said Samoa’s switch made business sense because it put the country on the same working day as New Zealand. Despite the fuss in the news media, people continued to live their lives, she said.
The date line still poses a challenge to mapmakers.
The International Date Line can be difficult for mapmakers and journalists to determine.
Cartographers often draw maps by consulting other maps, including time zone maps published by the CIA. But creating a more elaborate version is complicated, Montenior said. This is partly due to countries changing time zones; Digital maps often reflect flaws in the pre-digital maps they are based on; A country’s territory extends 200 nautical miles from its land border.
“If you get in too deep, your brain will collapse very quickly,” he said.
This is an interesting example.
In 2020, journalist Johnny Harris noticed some differences between the two renderings of the Dateline. Islandin the South Pacific.
“Google says the islands are on the Tuesday side, which is one day ahead, while PacIOOS says the islands are on the Monday side, which is one day behind,” Mr Harris YouTube video says,Refers Pacific Islands Ocean Observing Systema non-profit organization based in Hawaii.
So which version is correct? It’s not entirely clear yet.
A Cook Islands government spokesman did not respond to the question. A Google spokesperson said only that the company’s dateline map has been updated since 2020. A data systems engineer at PacIOOS said the organization’s version is not the gold standard.
“We’re certainly not experts or authorities on the date line,” said engineer John Maurer. He added that PacIOOS uses the same version as Wikipedia.
Wikipedia’s version includes the disclaimer that “additional citations are required for verification.”
