![]() ġ913 time zone map of the United States, showing boundaries very different from todayĬharles F. Some junctions served by several railroads had a clock for each railroad, each showing a different time. Each railroad used its own standard time, usually based on the local time of its headquarters or most important terminus, and the railroad's train schedules were published using its own time. Timekeeping on North American railroads in the 19th century was complex. This standard was known as New Zealand Mean Time. It was based on longitude 172☃0′ east of Greenwich, that is 11 hours 30 minutes ahead of GMT. ![]() ![]() On November 2, 1868, the then British Colony of New Zealand officially adopted a standard time to be observed throughout the colony. Some British clocks from this period have two minute hands, one for the local time and one for GMT. By 1855, 98% of Great Britain's public clocks were using GMT, but it was not made the island's legal time until August 2, 1880. This practice was soon followed by other railway companies in Great Britain and became known as Railway Time.Īround August 23, 1852, time signals were first transmitted by telegraph from the Royal Observatory. In November 1840, the Great Western Railway started using GMT kept by portable chronometers. In the 19th century, as transportation and telecommunications improved, it became increasingly inconvenient for each location to observe its own solar time. Watch: Earth spins through a full year in this time-lapse video.The control panel of the Time Zone Clock in front of Coventry Transport Museum.Find out what the time difference is between UTC and your time zone, using this chart from the National Hurricane Center.Army, which divides up the Earth into time zones named after letters of the alphabet, refers to UTC as Zulu time, since it falls in the Z time zone, and Zulu is the code word for that letter in the International Radiotelephony Spelling Alphabet. The acronym came about as a compromise between English and French speakers: Coordinated Universal Time would normally be abbreviated as CUT, and the French name, Temps Universel Coordonné, would be TUC. You might be wondering why UTC is the abbreviation for Coordinated Universal Time. UTC incorporates measurements of the Earth's rotation as well as averaged readings from around 400 atomic clocks around the world, according to the website. In 1967, a committee at the United Nations officially adopted UTC as a standard that's more accurate than GMT for setting clocks. Earthquakes, melting ice sheets and natural oscillations in our planet's motion can cause changes of a few fractions of a second in the amount of time it takes the Earth to spin on its axis, according to NASA. The time standard against which clocks were set then became known as Greenwich Mean Time (GMT).īut by the middle of the 20th century, the new technology of the atomic clock, which can measure time with incredible accuracy, was showing that the Earth's rotation actually varied slightly from day to day. ![]() At the conference, 41 delegates from 25 countries chose to set the prime meridian - the zero point for longitude lines - as passing through Greenwich, England, according to. But there was no universally agreed-upon equivalent for lines of longitude, which run north to south. Lines of latitude, which run east to west around our planet, had always been measured from the equator. In 1884, members met at the International Meridian Conference in Washington, D.C., to discuss a way to synchronize clocks around the globe. ![]()
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