4/10/2024 0 Comments Map of us time zonesIn 1764, John Harrison perfected the use of clocks to determine a ship’s east-west position at sea. The Royal Observatory in Greenwich, England, established Greenwich Mean Time (GMT) in 1675 as an aid to mariners in determining longitude. This inconsistency was the impetus for standardization, made possible by the telegraph.Īnother mode of transportation-the sailing ship-inspired the earliest efforts to standardize time. The railroads had been struggling with 100 different local time zones of their own devising. 18, 1883-the “day with two noons”-most places in the continental United States adopted the system of four time zones originally known as Standard Railway Time. When your clocks “spring forward” or “fall back” with Daylight Saving Time, take a moment to observe the birthday of America’s standard time zones. “Sun time” differs by four minutes for every degree of longitude, making New York and Boston eight minutes apart. Estimates of the number of these local “time zones” range from 300 to 8,000 across the United States alone. ( Wikimedia Commons)ĭoes anybody really know what time it is? For our ancestors, the answer depended on where they were, with each town’s official clock-typically on a church or city hall-set by the sun, which would be overhead at noon each day. This map shows the railroads’ time zones five years earlier, in 1913. The Standard Time Act in 1918 formally established four US time zones.
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