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OT - Why Do We Have Time Zones?


Anderton

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Seriously...why does it matter? If we all went with GMT and a 24-hour clock, wouldn't it make life easier? Hours are just arbitrary numbers. When people say they work "9 to 5," would it really make any difference if in Nashville, people worked from 3 to 11?

 

Think about when you do a conference call, and people are trying to figure out what time the call is based on their time zone and the origination of the call. If the conference call was set for 22 hours, then anyone anywhere in the world would know what time to dial in.

 

Or plane schedules. How many hours does it take to get from point A to point B? You have to figure out how many time zones you cross and take that into account.

 

There's gotta be a reason why people feel the need to correlate an arbitrary series of numbers to sunrise and sunset, but I'll be darned if I can figure it out. Hopefully the smart people here can enlighten me!

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IIRC, it came from the railroads. So to make sure the trains would run 'on time' and be where they are supposed to be, you need to have a consistent time. If my 4:30 is 17 minutes different from yours (as we travel from east to west) based on the sun, well it can cause issues. Time zones solve that problem.

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Oh, and this whole "global economy" thing is a very recent development. How long has it been that we have been able to make affordable calls around the world? 20 years? Local time has always been more practical. MP is right about navigation too.

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The one thing that's not arbitrary about our time system is that noon is when the sun is directly overhead (as pointed out above). Of course, most places undermine that understanding by going on Daylight Savings Time. I had to remind a dermatologist—who stressed not to go out between the hours of 10-2 without sunblock—that those hours are actually 11-3 while on DST, so it's problematic to even to diverge from the norm a little.

 

I agree that the need for a global time is becoming ever greater as we increasingly interact with, and travel to, other time zones; but I also think there are good reasons to keep local times in place as they relate to circadian rhythms and position of the sun. My guess is that we'll eventually adopt a dual system of time—local and global—and refer the one that's appropriate to the conversation at hand.

 

Best,

 

Geoff

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Before time zones, noon in one city might be a half hour or more different from the next because they set their clocks to noon 'straight up' and it takes the sun an hour to "cross" a time zone.

 

And if we went on universal time, and for the purposes of this conversation we set universal time as New York -- when a New Yorker flew to Los Angeles, he'd have to say, "We take lunch break at Noon in New York, what time to you eat lunch here?" and the answer would be "9 AM."

 

So with universal time, you would be trading one person's confusion for another person's problem.

 

Insights and incites by Notes

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I'm sure we could adapt to using a universal time scheme. We do already have words that are diurnal references - "morning", "noon", "evening", "midnight", and so on.

 

It's not all that long ago that there were no mechanical clocks - so a sundial would have a starting place at the top of the circle that had to correspond to consistent sun position. There was no such concept as "universal time" except as a philosophical notion. Day to day people were only concerned with sunrise, sunset, and where the day was in reference to the diurnal round. So the practice of keeping time had to begin historically as a diurnal reference - there was nothing else to refer to. So it wasn't arbitrary at all - the first second of the day was counted from the physical position on the dial.

 

Now why the dial got divided into twelve basic slices instead of 8 or 16 or some other number, I can't even guess.

 

That's my guess as to the "why" we have time zones. It's another question, asking why don't we change. That's easy - we can't even get consensus on daylight savings much less throwing it all over for GST.

 

For a true geek high on this sort of thing, the history of clock making is pretty fascinating as is the related history of the search for a way for ships to keep track of longitude while out of sight of land.

 

nat

 

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The one thing that's not arbitrary about our time system is that noon is when the sun is directly overhead (as pointed out above). Of course, most places undermine that understanding by going on Daylight Savings Time. I had to remind a dermatologist—who stressed not to go out between the hours of 10-2 without sunblock—that those hours are actually 11-3 while on DST, so it's problematic to even to diverge from the norm a little.

 

I agree that the need for a global time is becoming ever greater as we increasingly interact with, and travel to, other time zones; but I also think there are good reasons to keep local times in place as they relate to circadian rhythms and position of the sun.

 

But aren't the local times just an arbitrary construct? The sun is going to be in the same position whether we call it noon, 12, 3, or even Blurf. In other words, our circadian rhythms are dictated by the sun, not the arbitrary number we ascribe to the sun's position at any given time. Nor is even that particularly accurate...when a time zone crossing exists, you can move six inches and change the time by an hour. So if you're on one side of the line at the sun is at high noon, it will be at high eleven or high one on the other side of the line.

 

It's not like I'm on a crusade about this or anything, I'm just not wrapping my head around why what we use as a label for the position of the sun matters.

 

As just one more example, suppose I have to cross a time zone on a road trip and it's an 8 hour trip. Okay, so if I leave at 12, I'll get there by 8, right? No, if I'm going east I'm going to get there by 9. And when I return, it will be a 7 hour trip by the arbitrary clock, even though it's an 8-hour trip. I guess I'm just easily confused :)

 

 

 

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IIRC' date=' it came from the railroads. So to make sure the trains would run 'on time' and be where they are supposed to be, you need to have a consistent time. If my 4:30 is 17 minutes different from yours (as we travel from east to west) based on the sun, well it can cause issues. Time zones solve that problem.[/quote']

 

 

The time ZONES came from that. But it originated in the fact that people were already calling when the sun is straight up in the air "noon" regardless of where they lived. The time zones themselves just sort of organized the whole mess.

 

 

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Should we insist people in the southern hemisphere call the period from Dec to March "winter" as we do up here?

 

Actually an equivalent is kind of already in place...people refer to something coming out in the "second quarter" instead of spring.

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Time zones were for railroads, and weren't standardized nationally until the early 20th century. The meridian system, and GMT, was for navigation. With an accurate clock (which really didn't exist) one could know how far one was from Greenwich, even on open water.

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From Wikipedia (https://en.wikipedia.org/wiki/Time_in_the_United_States)

 

Prior to the adoption of four standard time zones for the continental United States, many towns and cities set clocks based on sunsets and sunrises at their locations and by observing the Sun's zenith at noon (mean solar time). Dawn and dusk occur at different times but time differences between distant locations were barely noticeable prior to the 19th century because of long travel times and the lack of long-distance instant communications prior to the development of the telegraph.

 

The use of local solar time became increasingly awkward as railways and telecommunications improved.[1] American railroads maintained many different time zones during the late 1800s. Each train station set its own clock making it difficult to coordinate train schedules and confusing passengers. Time calculation became a serious problem for people travelling by train (sometimes hundreds of miles in a day), according to the Library of Congress. Every city in the United States used a different time standard so there were more than 300 local sun times to choose from. Time zones were therefore a compromise, relaxing the complex geographic dependence while still allowing local time to be approximate with mean solar time. Railroad managers tried to address the problem by establishing 100 railroad time zones, but this was only a partial solution to the problem.[1]

 

Operators of the new railroad lines needed a new time plan that would offer a uniform train schedule for departures and arrivals. Four standard time zones for the continental United States were introduced at noon on November 18, 1883, when the telegraph lines transmitted time signals to all major cities.[2]

 

In October 1884, the International Meridian Conference at Washington DC adopted a proposal which stated that the prime meridian for longitude and timekeeping should be one that passes through the centre of the transit instrument at the Greenwich Observatory in the United Kingdom (UK). The conference therefore established the Greenwich Meridian as the prime meridian and Greenwich Mean Time (GMT) as the world's time standard. The US time-zone system grew from this, in which all zones referred back to GMT on the prime meridian.[1]

From GMT to UTC

 

GMT was superseded as the international civil time standard by Coordinated Universal Time (UTC) in 1960, when the International Radio Consultative Committee formalized the concept of Coordinated Universal Time, abbreviated as UTC. It is, within about 1 second, mean solar time at 0°.[3] It does not observe daylight saving time. It is one of several closely related successors to Greenwich Mean Time (GMT). For most purposes, UTC is considered interchangeable with GMT, but GMT is no longer precisely defined by the scientific community.

 

US Naval Observatory (http://www.usno.navy.mil/USNO/time)

As one who used to work in DC, one should also remember that the US Naval Observatory has a part in all of this today. The U. S. Naval Observatory is charged with maintaining the DoD reference for Precise Time and Time Interval (PTTI). That reference is UTC(USNO).

  • The USNO Master Clock is the underlying product for all of our precise time and time interval products. The timing reference produced by this timing ensemble is called UTC(USNO). This timing reference is mandated to be the precise time reference for all of the DoD.
  • USNO monitors the GPS constellation and provides system timing offsets to 2SOPS, timing data for individual GPS satellites, and time transfer services using GPS.
  • USNO servers provide a wide variety of web-based time synchronization products including embedded web clocks to display UTC(USNO) on other web pages.
  • The highest precision and accuracy in time dissemination is provided through Two-Way Satellite Time Transfer (TWSTT). USNO provides operational time transfer and calibration services for TWSTT.
  • USNO provides both voice announcements of the time, and services to synchronize systems over telephone modems.
  • Network Time Protocol (NTP) is an Internet standard that enables client computers to synchronize to USNO. NTP runs as a client program on a computer.

Of course, what exactly is time? (http://www.exactlywhatistime.com/definition-of-time/)

Physics is the only science that explicitly studies time, but even physicists agree that time is one of the most difficult properties of our universe to understand. ... In the sciences generally, time is usually defined by its measurement: it is simply what a clock reads. Time is something we deal with every day, and something that everyone thinks they understand. However, a compact and robust definition of time has proved to be remarkably tricky and elusive.

 

And of course, some would say I have spent way too much time on this topic! :cool03::cool03::cool03::cool03::cool03::cool03::cool03::cool03::cool03::cool03::cool03:

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Before mechanical clocks they had primitive methods of telling time like Hour glasses, sun dials water clocks and even how long a candle would burn.

 

The first decent mechanical clocks came about in the 13th century. Pendulum clocks in the 15th and 16th centuries. The first electric clock in the late 1800's

 

A sun dial may have been OK back in the day because people really didn't travel very far. If someone said meet me at 2pm their sun dial wouldn't have been off by much from the next door neighbor.

 

Travel is where clocks became most important and it really began with the Chronometer. It was a matter of navigating accurately. Without it you could be off by thousands of miles and countries like Britain needed accurate navigation for war and commerce.

 

A major stimulus to improving clocks was the importance of precise time-keeping for navigating aboard ship. The position of a ship at sea could be determined with reasonable accuracy if a navigator could refer to a clock that lost or gained less than about 10 seconds per day. This clock could not contain a pendulum, which would be virtually useless on a rocking ship. In 1714, the British government offered large financial rewards to the value of 20,000 pounds for anyone who could determine longitude accurately. John Harrison, who dedicated his life to improving the accuracy of his clocks, later received considerable sums under the Longitude Act.

 

In 1735, Harrison built his first chronometer, which he steadily improved on over the next thirty years before submitting it for examination. The clock had many innovations, including the use of bearings to reduce friction, weighted balances to compensate for the ship's pitch and roll in the sea and the use of two different metals to reduce the problem of expansion from heat. The chronometer was tested in 1761 by Harrison's son and by the end of 10 weeks the clock was in error by less than 5 seconds

 

They had an excellent movie on Harrison a few years ago. Definitely worth watching.

 

What occurred on sea simply migrated to land once high speed travel was possible with the rail roads.

The time zones are NOT scientific however. They usually follow geographic or country boundaries, not the longitudinal meridians used in navigating the sea.

 

The railroads in Britain adopted rail time first, In the us it was a total cluster. Each railroad used its own standard time usually based on where its headquarters was located. Stations often had to have multiple clocks to track train movements.

 

It was this confusion that brought about the standard time zones. It was simply too difficult for shippers or travelers to do all this mental juggling between one companies clock and another.

 

When you ask what good are clocks good for its not just a matter of knowing the time of day.

All your digital devices from computers to cell phones and even our recording interfaces run on clocks. Whenever you have times events there is some kind of clock dictating when things occur. Even something as simple as an can be considered a clock because it produces are timed pulse, a frequency. Everything from radio, TV electronic keyboards, Even your DAW programs run on a clock. so do any effects units involving an LFO.

 

We'd be pretty much SOL as musicians if we didn't have clocks. They just become annoying when your world revolves around them.

 

In the end we trade time and labor for money. you work a day and get paid for that time and labor, but money can buy you time once it runs out so be wise and not waste it. You'll fly through life thinking there will always be more time. Then when you get to be my age, you realize just how much is really left and how much was used wisely. We all wait for that last alarm to ring and do what we can to push it back but no one is immune to when that last chime rings.

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Should we insist people in the southern hemisphere call the period from Dec to March "winter" as we do up here?

 

Here, the four seasons are Chain Saw, Lawn Mower, Leaf Blower, and Snow Blower. Fortunately there's some daylight (as in sunlight during a period we call "day") during each of them.

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All your digital devices from computers to cell phones and even our recording interfaces run on clocks. Whenever you have times events there is some kind of clock dictating when things occur. Even something as simple as an can be considered a clock because it produces are timed pulse, a frequency. Everything from radio, TV electronic keyboards, Even your DAW programs run on a clock. so do any effects units involving an LFO.

 

Time interval is what's counted by a computer clock. The absolute time is the number of seconds, or milliseconds, or microseconds, from some reference time, usually some landmark time in the computer's history, like what was called midnight, January 1 1980 in Greenwich. When you "set the clock" on your computer, you set the local starting point for counting those time intervals.

 

The computer doesn't care whether it's light or dark, but humans do. We can sort of train ourselves to live our lives in "musician time," but it really does screw up the body's internal clock, which seems to care about light and dark. I had a neighbor who was a warehouse manager for the local Safeway grocery stores. He went to work at 9 PM and got off at 5:30 AM, just about 12 hours offset from my work time. When I was getting into my car to go to work, he'd be out in the yard tending his garden. But he'd go to bed around 10 AM and would sleep at least 10 hours. Most night people that I've known sleep more than the "normal" 8 hours because that's what their body tells them to do.

 

 

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There's no reason we can't have more than one convention of time-telling going at once. No one system really satisfies the numerous ways in which we care about "what time it is."

 

I can imagine a convention that has clocks routinely reporting a global time, plus some sort of diurnal-relative time. The diurnal data could easily be reduced to a symbolic convention. Like a circle that is either AM or PM, divided into the number of hours of daylight or dark, depending. So at a glance you could see global time, plus an absolute reference to where you are in relation to the diurnal cycle for your own locale.

 

So mom says "what time is it?" and pop says "16 30, A 6" or something.

 

Here's a link to a Smithsonian article on why not one time zone - some more juicy bits of info....

 

https://www.smithsonianmag.com/science-nature/one-time-zone-for-the-world-127795315/

 

nat

 

 

 

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