Anonymous
Anonymous asked in Science & MathematicsGeography · 1 decade ago

In the United States and around the world what causes different times zones?

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  • 1 decade ago
    Favorite Answer

    Time zones are an invention developed to orient people to comparative times around the world. The first time zone was set in the 1600s to aid British sailors to orient themselves to their latitude.

    The time base known to the military as Zulu time was called GMT for Greenwich Mean time. This is the time at the 0 degree prime meridian at the Royal observatory.

    We now use a more constant UTC (universal time constant) which has made the conversion from atomic clocks easier.

    Each country and state (in the US) determines the time zone.

    For example whether a state follows daylight savings time is determined by the state legislature. If the time zones were determined internationally they would follow the longitudes instead of state lines (as they do in the US)

  • Colin
    Lv 6
    1 decade ago

    The earth spinning moves the sun across the sky and below the horizon until it rises again the next day. Obviously in many of the inhabited parts of the world when the sun is at its highest the time is around midday and people have lunch soon after. Decisions are made by countries and states as to how closely they will adhere to what the time really is and what time they will use because of where their borders end and where most people live. The traditionally Greenwich Mean Time (GMT) or what I am told is now Universal Time (UT) is the reference point located close to 0(zero) longitude that time is measured from in conjunction with the International Date Line (IDL) that traverses the Pacific ocean longitudinally about 12hours away from Greenwich. The IDL avoids land as it meanders from the North Pole to the South Pole as on one side of the line it is one particular day of the week and on the other side it is the day before or the day after.

    Source(s): Surfin.
  • Anonymous
    1 decade ago

    The cause of creating different time zones is, obviously, the earth's rotation and the need for a uniform measure of a day in all parts of the world.

    The measurement which creates time zones is the Greenwich Meridian (Prime Meridian or Longitude Zero degrees), which marks the starting point of every time zone in the world. GMT or Greenwich Mean (Meridian) Time is the mean (average) time that the earth takes to rotate from noon-to-noon.

    Trivia: Newfoundland and part of Labrador (Canada) have a half-hour time zone.

  • 1 decade ago

    Because of how the different sections of the Earth are facing the sun at different times as it rotates around and round.

    If we all had the same time then it would not be dark from 8pm to 6am and light from 6am to 8pm all around the world.

    It is so that it will be noon lunchtime during daylight and dark night at midnight all over the Earth no matter where you live..with some exceptions for places coser too the poles where it can be day for months etc.....but that has nothing to do with your question,,,that is a different subject all together.dont let the fact that in Alaska and on the poles it can be daytime for months at a time..that is just because of the tilt of the Earth and the way the Earth rotates around the sun. During some months the top of the Earth is tilted away from the sun and during other months the top of the Earth is tilted towards the sun..but your question is answered more by simplifying the explanation to explain the way it is at the equator and near the middle sections of the planet where most of the people live and would want it to be dark at night and light during the day.

    If we didnt have different time zones, then only one spot on the Earth would have that type of daylight hours...everyone else would have light in the middle of their night and dark during their lunch hour, etc....

    The Earth rotates around it's axis about as fast as the time zones keep up with it....so that no matter where you are on the planet it is always sunrise at approximately 6am plus or minus...and always night at approximately 8pm plus or minus...I hope I have explained this the way I meant to.

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  • 1 decade ago

    Ha! Train wrecks!

    Before the invention of modern transportation, the time of day was determined locally. Noon was when the sun reached its highest point in the sky.

    Modern transportation put an end to simple convenience. They had trains before they had reliable telecommunications. Trains often had to use a single track in both directions. If they could not coordinante the time clearly, then trains often crashed together.

    From Enchanted Learning:

    "The idea to divide the Earth into time zones was proposed by the Canadian railway planner and engineer Sir Sandford Fleming (1827 - 1915) in the late 1870s.

    Time zones were first used in 1883 by railroads in order to standardize their schedules. World time zones were determined in 1884, at an international conference in Washington, D.C. Each of the 24 world time zones are about 15 degrees wide and differ by one hour. "

    ;-D Read more from their site. All of China uses the time of Beijing!

  • 1 decade ago

    Time zones were first proposed for the entire world by Canada's Sir Sandford Fleming in 1876 as an appendage to the single 24-hour clock he proposed for the entire world (located at the center of the Earth and not linked to any surface meridian).

  • 1 decade ago

    Generally the earth spinning on it's axis which relates to the measurement of time during the day when the sun is out. An area where the dividing lines are is where the sun is an hour difference in reference to the setting and rising on the horizon.

  • 1 decade ago

    It's just laws. time zoned date back to before the telegraph so people were comfortable with waking up around 5am and going to bed at 6pm and so they stuck with it. As the earth rotates through the 24 hour rotation different parts of the planet have a time that feels like 5am. Each country just sets it's own time zone by passing a law. It's one of those things like the metric system that would make things less complex if we just went to one time zone but people like to have a consistent experience no matter where on the planet they are. we are mentally lazy.

  • 1 decade ago

    Time is a conventional system, that means, we all got together and decided to measure time according to somebody's project. So the Greenwich Meridian in England is the point of departure of all time zones, so when astronomically it's 00:00 hours in Greenwich it will be 00:001 a little but further and 1:00 in the next time zone and so on.

  • 1 decade ago

    well its different times around the world because the earth is round and only one side faces the sun at any given time. the time zones however are manmade. i do not know who defined the timezones. but the majority was defined simply by which countries kept the same time, and which didnt.

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