The International Date Line!
The International Date Line! The International Date Line (IDL) is a generally north-south imaginary line on the surface of the Earth, passing through the middle of the Pacific Ocean, that designates the place where each calendar day begins. It is roughly along 180° longitude, opposite the Prime Meridian, but it is drawn with diversions to pass around some territories and island groups. Crossing the IDL travelling east results in a day or 24 hours being subtracted, so that the traveller repeats the date to the west of the line. Crossing west results in a day being added, that is, the date is the eastern side date plus one calendar day. The line is necessary in order to have a fixed, albeit arbitrary, boundary on the globe where the calendar date advances. Geography For part of its length, the International Date Line follows the meridian of 180° longitude, roughly down the middle of the Pacific Ocean. To avoid crossing nations internally, however, the line deviates to pass around the far east of Russia and various island groups in the Pacific. In the north, the date line swings to the east of Wrangel island and the Chukchi Peninsula and through the Bering Strait passing between the Diomede Islands at a distance of 1.5 km (1 mi) from each island. It then goes southwest, passing west of St. Lawrence Island and St. Matthew Island, until it passes midway between the United States' Aleutian Islands and Russia's Commander Islands before returning southeast to 180°. This keeps Russia which is north and west of the Bering Sea and the United States' Alaska which is east and south of the Bering Sea, on opposite sides of the line in agreement with the date in the rest of those countries.
[Show full text]