Number of posts : 339
Location : VN
Member of : VN
Registration date : 2010-10-01
|Subject: International Date Line Thu Dec 30, 2010 6:40 am|| |
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, where the date changes as a ship or airplane travels east or west across it. 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 traveler 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 resets. In practice, there are two such boundaries: one is the International Date Line, while the other moves around the globe as the midnight time line (2400 hours local time), marked by the moment at which the date changes to the next day at a given point on the globe. These two boundaries mark the transition from one day to the next.photo pursegowns