international date line

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Related to International Dateline: GMT, Time zones

international date line,

imaginary line on the earth's surface, generally following the 180° meridian of longitudelongitude
, angular distance on the earth's surface measured along any latitude line such as the equator east or west of the prime meridian. A meridian of longitude is an imaginary line on the earth's surface from pole to pole; two opposite meridians form a great circle dividing
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, where, by international agreement, travelers change dates. Traveling eastward across the line, one subtracts one calendar day; traveling westward, one adds a day. The date line is necessary to avoid a confusion that would otherwise result. For example, if an airplane were to travel westward with the sun, 24 hr would elapse as it circled the globe, but it would still be the same day for those in the airplane while it would be one day later for those on the ground below them. The same problem would arise if two travelers journeyed in opposite directions to a point on the opposite side of the earth, 180° of longitude distant. The eastward traveler would set his clock ahead 1 hr for each 15° of longitude (see standard timestandard time,
civil time used within a given time zone. The earth is divided into 24 time zones, each of which is about 15° of longitude wide and corresponds to one hour of time. Within a zone all civil clocks are set to the same local solar time.
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), so that his clock would gain a total of 12 hr; the westward traveler would set his clock back 1 hr for each 15°, resulting in a total loss of 12 hr. The two clocks would therefore differ by 24 hr, or one calendar day. The apparent paradox is resolved by requiring that the traveler crossing the date line change his date, thus bringing the travelers into agreement when they meet. The international date line does not follow the 180° meridian along its entire course but bends eastward around the eastern tip of Siberia, westward around the Aleutian Islands, and eastward again around various island groups in the South Pacific (mostly extremely around Kiribati) to avoid a date change within island nations and territories or between important trade partners.

date line, international:

see international date lineinternational date line,
imaginary line on the earth's surface, generally following the 180° meridian of longitude, where, by international agreement, travelers change dates.
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international date line

[¦in·tər¦nash·ən·əl ′dāt ‚līn]
A jagged arbitrary line, roughly equal to the 180° meridian, where a date change occurs: if the line is crossed from east to west a day is skipped, if from west to east the same day is repeated.

international date line

international date line
The Greenwich antimeridian, or 180° longitude. The international date line, however, does not follow the Greenwich antimeridian exactly but is distorted to place inhabited areas definitely on one side or the other of the line to avoid a difference in date in an inhabited area. Also called a calendar line or a date line.

International Date Line

the line approximately following the 180? meridian from Greenwich on the east side of which the date is one day earlier than on the west
References in periodicals archive ?
SQUABBLES over time arise because there is no authority governing the international dateline.
Lacy piloted his Boeing 727 from Southern California by way of Hawaii and Midway Island to the International Dateline.
For example, travelers wishing to be "the first" to experience the millennium can reserve an oceanfront house in Taveuni, Fiji, the only island in which the International Dateline officially crosses.
crosses the international dateline and arrives the next day in Yuzhno-Sakhalinsk at 5:10 p.
crosses the international dateline, and arrives atSapporo's New Chitose Airport at 7:00 p.
Bobby Frankel and David Flores weren't close in their bids for major wins on both sides of the international dateline Sunday.
The "Millennial Midnight" project will feature a Russian greeting an American on the International Dateline in the frozen Bering Strait between Siberia and Alaska.
on Mondays, Wednesdays and Fridays, crosses the international dateline, and arrives in Honolulu at 1:10 p.
00PM on Mondays, Thursdays, and Saturdays, and reach Honolulu on the same day, crossing international dateline.
A single land mass in the center of a triangle of Polynesian islands, made up of Tonga, Western Samoa and the Cook Islands, Niue is located 2400 km north-east of New Zealand, on the eastern side of the International dateline, and is 11 hours behind Greenwich meantime.
cross the international dateline, and arrive at Narita International Airport at 7 p.
And in 2011, Samoa moved across the international dateline, losing one day, to ease links with neighbours Australia and New Zealand.

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