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Before high precision clocks and coordinated clock synchronization procedures, local times differed not just because of a different latitude, but also randomly, due to inaccuracy of clocks. But the same inaccuracy of clocks was mostly hiding the differences. Without a coordinated synchronization mechanism, each authoritative clock (without an even more ...


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I point out that the survivors of the Magellan expedition were startled by a date discrepancy. Twenty crewmen died of starvation by 9 July 1522, when Elcano put into Portuguese Cape Verde for provisions. The crew was surprised to learn that the date was actually 10 July 1522,[104] as they had recorded every day of the three-year journey without omission. ...


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At least over 4000 years ago probably much longer. The 3000-4000 year 'discovery' times given above was due to archeological and written proof, but as at that point it was already a well known and developed idea (just as spherical earth). An educated guess, would for the earliest date, would probably be at least 100,000 years ago. As the first person to ...


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The concept of longitude was first developed by ancient Greek astronomers. Hipparchus (2nd century BCE) used a coordinate system that assumed a spherical earth, and divided it into 360° as we still do today. His prime meridian passed through Alexandria. He also proposed a method of determining longitude by comparing the local time of a lunar eclipse at two ...


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There is no recorded moment, but the time difference in places with different longitude was discovered as soon as people realized that the Earth is round, and that Sun rotates about it (or vice versa, which does not matter for this question). We do not know when exactly did this happen, since almost all astronomic and geographic literature from the ancient ...


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Time zones were not discovered, they were defined. Without time zones, you have the concept of solar noon. A time zone is an area where the solar noon of a central place (like a royal observatory) is applied in a wider area. This became relevant with railway timetables. A train leaves at 12:00, travels for 60 minutes, and the clock at the destination should ...


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