Several imaginary lines bisect our planet. One twists through the middle of the Pacific Ocean, swerving around islands and atolls. It is the International Date Line.
The Date Line was first proposed in 1884, at the International Meridian Conference held in Washington, D.C., where the most urgent item of business was to choose “a meridian to be employed as a common zero of longitude and standard of time reckoning throughout the world.” The common zero chosen was Greenwich Mean Time, established in Britain in the 17th century in part to aid naval navigation. But it wasn’t until 1929 that most major countries had adopted time zones and they still did so at their own discretion. Today’s Coordinated Universal Time (UTC) is universal only in the sense that it is an internationally agreed upon reference point. Otherwise, local time zones are still decided upon by individual nations.
The International Date Line is an imaginary north-south line drawn through the middle of the Pacific Ocean about half way around the world, at a point close to 180 degrees of longitude away from the Prime Meridian, which cuts through Greenwich, England. The Date Line on all but the most recent maps is the one drawn by the British Admiralty in 1921.
On Thursday 29 December 2011, citizens of the Pacific island of Samoa went home as usual to sleep. When they woke up, instead of Friday it was Saturday 31 December. A whole day has vanished. Friday 30 December 30 had been erased from their lives. Those with anniversaries and people who thought they still had two days before the New Year were out of luck. No one in Samoa was born on 30 December 2011 – and no one died.
Earlier that year the government of Samoa had decided to move the island westward across the International Date Line, because it wanted to align Samoa with neighbouring trading partners: Australia, New Zealand, China, and the rest of Asia in general. Samoa is not the first country – and may not be the last – to tinker with time.
China’s citizens speak 292 dialects and the country’s land mass that has almost as many climates as exist on Earth. Geographically it spans five times zones but observes just one — stretching from the rapidly expanding eastern city of Shanghai to the rural far west. From 1912 until 1949, China had five time zones, but after the Chinese Civil War, the Communist Party used a unified time zone as a way to consolidate its power over all the territories it claimed and to create a unified Chinese nation.
The current International Date Line zigzags quite a bit. Countries nearby have moved it over the years to take account of their own needs. One of the biggest zigs occurs around Kiribati, an island nation of 32 atolls straddling the equator. In 1995, Kiribati moved a chunk of the line to the east so that instead of being divided, the entire country was on the same side.
Virgil had it right all those centuries ago: “Stat sua cuique dies, breve et inreparabile tempus omnibus est vitae” (Everybody has their appointed day; life is brief and irrevocable) The Aeneid (X, 467). But he reckoned without the Date Line.