Knowra International Date Line International Date Line The International Date Line is an imaginary boundary near 180° longitude where the calendar date changes by one day when crossed. Its course bends around national territories and island groups.
180th meridian : The meridian at 180° longitude, opposite the Greenwich meridian. The date line roughly follows this meridian, though political boundaries force it to bend.
International Meridian Conference : A 1884 conference in Washington, D.C., that selected Greenwich as the prime meridian. Its adoption of a global longitude reference made the opposite meridian a natural place for a date boundary.
Kiribati : An island country in the central Pacific Ocean, including islands on both sides of 180° longitude. Kiribati shifted its eastern islands’ time zones in 1995, creating a pronounced eastward bend in the date line.
Equator : The imaginary circle at zero degrees latitude, dividing Earth into Northern and Southern Hemispheres. Unlike the date line, the equator is a fixed geometric boundary rather than a calendar convention.
UTC+14 : A time offset fourteen hours ahead of Coordinated Universal Time. The Line Islands use this offset, placing them among the first inhabited places to begin a new date.
Prime meridian : The longitude line designated zero degrees, from which longitude is measured. The date line is conventionally positioned near the prime meridian’s antipode.
Samoa : An island country in the South Pacific Ocean, west of American Samoa. Samoa changed sides of the date line in 2011 to align its working week with Australia and New Zealand.
Tropic of Cancer : The northernmost latitude where the Sun can appear directly overhead at noon. It is a latitude defined by Earth’s axial tilt, unlike the date line’s timekeeping role.
Greenwich Mean Time : A time standard historically based on the mean solar time at Greenwich, England. Longitude-based timekeeping anchored at Greenwich helps explain why the date boundary lies near the opposite meridian.
Sandford Fleming : A Scottish-Canadian engineer who promoted worldwide standard time and time zones. Fleming’s proposals helped establish the standardized time system that gives the date line practical significance.
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