Back to the Future - the Magic of Time-Zone Time Travel
One of the most exhausting travel challenges (literally) is, dealing with time changes. They're confusing to calculate, (they've caused me to miss a connection on at least one occasion), you can loose precious exploration time from your schedule, and worse, you can loose a day or more to the time it takes for your body to reset and recover from the time change.
Sadly, the world stands still for no man, so jet lag is a necessary travel evil to keep in line with the sun. But what's the story behind the seemingly haphazard ways time zones are laid out? How did we get to a time map with approximately 200 time-zones that we have today.
Discussed In This Blog:
The world is a globe. It spins in space around a North/ South axis, changing the position of specific locations relative to the the sun, which creates periods that are hotter/ brighter in that location than others: 'high noon' being the time of day when the area is angled so as to have the shortest distance between itself and the sun. TIME (for the purposes of day to day life) is the expression of were in the rotation cycle we are at any particular moment. This is called the Apparent or Natural Solar Time.
Solar Time | Latin solaris, sol=sun - relating to the sun - Time measured by the actual relationship of an area with the sun - solar noon being when the sun crosses the Meridian line of any particular location.
Meridian: Me·rid·i·an - /məˈridēən/ | Latin meridianum = noon (medius = middle’ + dies= day) - A circle of constant longitude passing through a given place on the earth's surface and the terrestrial poles.
Longitude: Lon·gi·tude - /ˈlônjəˌto͞od/ | Latin longitudo - longus =long - An imaginary line perpendicular to the equator & part of a circle passing through the North & South Pole. Also the angular distance east or west of the standard meridian of a celestial object, expressed in degrees & minutes. eg: longitude 2° W
Depending were you're situated on said globe at this moment, when you personally are closest to the sun is different from place to place. Since we base our entire system of labeled time on this relative position to the sun throughout these cycles that means TIME, in the measured, tangible sense, is different from one location to the next.
Creation of the Time Zones
Why does it matter? Well for a long time it didn't. People simply knew and lived within their local solar times and that was that. (Even that local time was a more generalized before or after noon system for most of history with precise time keeping not even possible until the 1300's and personal watches not really a thing until the 19th century.)
Some more commercially connected area's would coordinated their local times with the nearest important city, rather than the local solar time. Much of France, for example, would use the solar time of Paris. So you had areas using the Paris Meridian or the Copenhagen Meridian as the time standard. And that meant there were as many 'standards' as there where influential cities. But everything was forced to change with the industrial revolution and the spread of the railroads in the 1800's.
Sure, people traveled before railways, even long distances, but the infrequency and low number of people traveling, and more importantly the speed at which they traveled, meant the shift from one geographical solar time to another was so gradual that the alteration in solar times of day wasn't noticeable. Trains, however, jumped time altering distances very quickly, and the speed of change, compared to the earths rotation before the sun, became very noticeable, especially while trying to keep accurate train schedules.
If a train left station A at noon (when then sun's directly overhead in Town A) but arrived in station B, to the West, also at noon (when the sun's directly overhead in Town B) how do you accurately record the length journey? (For the purposes of calculating things like wages and fuel needed per hour) And how do you tell passengers when trains will arrive or depart? If a ticket lists a 3pm arrival time does it mean 3pm by the departure Town A time or by arrival Town B time?
So for the sake of train timetables, train stations started created their own Standard Time Systems,* similar to those based on major cities, only now spread wider across the railways whole length of service. They worked well, as far as they went, until you had to make a connection with a different company on a different time table! In England, the birth place of the train companies, it soon became clear that national standards were needed.
In 1852 the Royal Observatory in England, (their largest astrological observatory) began broadcasting by telegraph standard times for the whole country to set local clocks and train tables to - and the concept of an official standardize Time-Zone was born. (Though they didn't make it legally official until 1880.)
The adjustment to a standard time was fairly simple in England because the solar shifts were minor (it's a small, skinny country.) It was far more complicated in places like the North America though, where (in today zone system) there's a full 3 hour difference between coasts. When you start adding international travel into the mix it got even more complex. It became obvious that a universal standard would be needed, so an international council was formed in 1884 to sort out the mess.
The Prime Meridian
First things literally first, the Meridian Conference of 1884 had to define a standard zone of time to measure all other times against. A universal Town A - to compare the other time-zones with. Like a time ruler, they needed to set a specific point to be time-zero. A first, or Prime Meridian to count off from [from Latin prima= first.]
Truthfully there is nothing special about the Prime Meridian we chose, any meridian line would do so long as it was internationally agreed on. Though putting the meridian in line with an already extant astrological observatory, with a pendulum clock, would make time calculations as accurate as possible (for the time.)
In the 19th century Great Britain was at the forefront of the sciences (and the world, politically.) Their Royal Observatory, already setting the time for the country, was located in Greenwich, England [literally green harbor or trading place.] So it's no surprise** the Prime Meridian was set as the longitudinal line that intersects Greenwich, making Greenwich point zero, (longitude line 0°.) Thus Greenwich Time & it's time-zone, GMT (Greenwich Mean Time)^ became the standard for time-zone comparisons.
All time zones today are still measured by how much ahead or behind they are in comparison to the time at 0° longitude. For example, the sun crosses the New York City meridian approximately 5 hours behind the time it crosses at longitude 0° meaning EST (US Eastern Standard Time) is expressed as UTC-5.
Wait what is this UTC? What happened to Greenwich Time, GMT?
Coordinated Universal Time
For practical, lay purposes UTC & GMT are essentially the same most of the year. UTC or Coordinated Universal Time was substituted for GMT as the standard denomination in 1963 because it's a more precise unit of measure based on the newer technology of atomic clocks. UTC also isn't subject to a Daylight Savings Time, like GMT, which simplifies the comparative times of other zones. It also replaced the 12 hour clock with the clearer 24 hour military time keeping method.
The next step after setting the Prime Meridian was to expand out, delineating the new relative zones of time. Our day was already segmented into 24 hour long periods so it made sense to segment the globe into 24 zones, and have the time changes be calculated in easy 1 hour increments.
So far so good; in our train example if we make Town A Greenwich then it's time-zone now needs to be 1 hour ahead of Town B in zone B, and Town C would be 1 hour further away in a third zone C and so on until... well until when? What happens when you get all the way back around to Town A?
The spinning world doesn't stop and rewind to reset at the end of the day, it continues to rotate, so where does one day actually end so the next can begin?
Enter the artificially arbitrated International Date Line (IDL). For the sake of human records we needed an end mark, where the +1hour system stops and the count reset as the next calendar day. But how to determine where it would be?
The International Date Line
While designating zones, had they moved in a single direction away from the Prime Meridian, adding an hour every 15° of longitude (1/24th of the 360° globe) we would have 24 zones ranging from +1 to +23 hours and the resulting IDL would've been the same longitudinal line as the Prime Meridian. But that isn't how the zones were created.
Instead they choose to move both East and West simultaneously, adding hours in one direction and subtracting in the other, thus delineating the Eastern and Western hemispheres and the time ranges of UTC +1 on going East & UTC -1 onward going West.
Hemisphere: Hem·i·sphere - /ˈheməˌsfir/ | Greek hēmi= half - Half of a sphere. In the case of the earth, either divided into Northern and Southern halves by the equator, or Western and Eastern by a meridian passing through the poles.
The benefit of this system was the resultant location of the IDL. If the last zone ended back at the starting point of Greenwich the calendar day would 'switch over' at Greenwich. Which would be extremely confusing; if you lived on the West of the IDL but worked outside of town to the East of the IDL, for example, you would have to leave your house on Tuesday to get to work on Monday!
By moving forward in time going East and backwards in time going West the two time sides meet, and create this inevitable, very confusing, equational time jump, in the middle of the empty Pacific Ocean where it doesn't affect people's daily schedules. (Only messing with people and their sense of reality, when they fly or sail internationally across it; like going from Honolulu to Japan in the morning, when Tuesday suddenly becomes Wednesday, or flying from Tokyo to Hawaii on Wednesday and having it jump back to Tuesday.)
This meridian line, exactly half way around the world from Greenwich, at the now labeled 180° longitude, thus became the theoretical International Date Line.
(Even this IDL still wasn't perfectly out of the way though - most of Alaska, for instance, is in the Western hemisphere but a few of the far islands of the Alaskan Aleutian chain are in the Eastern Hemisphere so Alaska exists in two different days at once.)
Todays Multiplicity of Zones
Such was the simple original theory behind 24 neatly segmented time zones. But it didn't stay simple for long!
For one thing the same issue of jumping days over the IDL also occurs on a smaller scale between zones, because the time changes can't match the reality of gradual Solar Time change, they jump a full hour instantly.
(Just imagine how many zones there'd have to be, if we attempted gradual changes! Your work might be three minutes ahead of your home in Civil Time and the specialty grocery store all they way across town that you like could be five minutes behind... It would be madness to try and keep track of and no one would ever be on time!)
Civil Time (Latin civilis, civis = citizen - relating to ordinary citizens and their concerns) - The time designation we actually assign to hours of our day. The goal is for Civil Time to be close to Solar Time, but for practicality sake they're never an exact match.
So what do you do if your town happens to be bisected by a zone line and half the town is an hour ahead of the other half? This is why, in reality, time-zones start to get very complicated in an attempt to avoid this kind of confusion.^^
What's more, the body of scientist that met at the Meridian Conference had no authority to enforce any kind of standards going forward. So when issues of implementation like the above came up every country went their own way trying to solve them, so no solutions were applied consistently.
To start with the delineation of the zones doesn't actually match up with the global longitudinal lines they theoretically should. They're greatly influenced by geopolitical landscapes, shifting, bending and altering along borders to avoid having the jumps occur in inconvenient places like through the centers of towns. In addition, not all countries use hour offsets, many zones offset by 30 minute jumps and some zones extend over more than the mean 15°s.
China, for instance, covers a global land mass that should encompass 5 time zones^^ but it insists on the unity of only one consistent time ( & zone) which means in Beijing the Solar noon occurs at 2:56 PM Civil time, and in the most Western city of Kashi the sun may not rise until after 10am. As a result when you cross from China to Afghanistan you'll make the largest time jump in the world, a whopping 3 and half hours!
In India, Sri Lanka, Iran & Afghanistan they went to the other extreme, offsetting zones in 30 minute increments, (to have their Civil time stay as close to Solar time as possible, I suppose?) Except for, inexplicably Nepal, who decided to have its own special 45 minutes offset (UTC+5h & 45min)
And in Russia they have an impressive 11 time zones across their great expanse.
As if all that wasn't complicated enough, some countries don't use the time zone associated with their geographical location at all. Sometimes, as a hold over from colonial times, a country has maintained the zone of its original parent nation (that it was once forced to be on) despite being no where near them on the map.
Other countries reject what should be their geographical time zone for financial or political purposes.
Tonga is actually East of 180° but has placed itself (via time) in the Western Hemisphere so as to be on the same day as their nearest trading partners, New Zealand and Australia. It makes total sense from a business, and even common sense standpoint, they're much closer physically and trade relationally to these Oceania countries than any countries in the Eastern hemisphere, and it would be very inconvenient to be on the opposite side of the IDL day jump from your closest business partners. The resulting time calculation however means they are UTC+13 (when theoretically the max in either direction should +/-12 before it switches to the other time side.)
Then there are the really odd situations like Spain which is actually on the Prime Meridian but follows a UTC+1 time schedule purely for the outdated political reason that in the 1940s Generalissimo Franco officially changed the zone so that Spain would be on the same time as it's ally, Germany.
Even the IDL itself, despite being in the middle of nowhere, is not a able to stay consistent on the 180° longitude - it too alters course to avoid populated islands and this creates some very odd time anomalies.
Kiribati is made up of several long island chains spread out it across the hemispheres, and in 1994 Kiribati opted to shift it's whole country into the Eastern Hemisphere, meaning the IDL now makes a giant detour to get around the Western islands. It's time zones thus now include a UTC+13 & a UTC+14! The easternmost part of their country, in it's own private time zone, is therefor the very first part of the world to officially welcome every new day, and it has a zone that is the exact same time as nearby Hawaii (in the Western Hemisphere) only an entire day ahead. Strangely that means there is one hour everyday now when there are three concurrent calendar days on earth that can all be called 'the present day'... Eg. - When it's 11:01pm on August 6th in Western Kiribati (my birthday!) it's 12:01am on the 7th in Eastern Kiribati (the day after my birthday) AND 11:01pm on the 5th in Hawaii (very nearly my birthday...)
In 2011 Samoa also decided to switch sides over the international dateline and in doing so they skipped December 30, jumping from the 29th to the 31st with the change. Like Tonga, they had more connections with New Zealand than countries on their own side of the IDL so it made sense for business, but it does mean they are now on a totally different from their very close neighbor American Samoa.
Many of the world's militaries also use there own universal time-zone system so that there is no confusion between international bases. There are 25 Military Time Zones. They are based on a clean UTC hour offset time division and designated by letters of the NATO phonetic alphabet, with zone "Z" being GMT or UTC time. (The letter J was initially not used because it's too close looking to I, but it is now used to designate ones local, non military time.) The zones are referred to by their military code words - eg 1800G would be called "eighteen hundred Golf"
All of these individual variations, combined with the insane complications of Day Light Savings Zones^^^ are how we ended up with around 200 inconsistent, seemly random global time zones.
Daylight Savings: A time shift of 1 hour forward in summer months. First implemented in Germany in WWI, the Daylight Savings shift allowed for longer daytime light, it was a way to reduce electricity usage and therefor costs, and increase productive hours in each day. It essentially creates a summer version of any time zone that uses it, adding +1 hour offset to the zone's UTC comparison. The concept was not new in WWI, Benjamin Franklin, among others had suggested it's use as early as 18th century. In Franklin's case, while he was in Paris, because he thought it ridiculous that the indulgent French slept through 'the majority of the day light hours.' The practice soon spread and is now used by most countries, (though its continued use is always hotly debated.) There are some holdouts though, Iceland, Russia, Turkey, China, Japan and India do not utilize a Daylight Savings.
So what's a traveler to do with such inconsistent fluctuations to not get lost in time?
Time Zones By Region
If you are traveling internationally it's always a good idea to familiarize yourself with local time standards. You can check out the time zones of your particular destination with the links below:
Europe: Four main zones; Greenwich Mean, Western European Time, Central European Time
& Eastern European Time (+ their Daylight Savings Alternates.)
Asia: Five - thirteen zones, (depending on how you divide Asia) Mostly designated by country.
Australia & the South Pacific: Three main zones in Australia; Eastern, Central & Western
plus one main New Zealand zone and multiple throughout the Pacific Islands.
The United States & North America: Eight geographical zones in total,
Plus few small specialized zones US zones located in other geographical regions
Central & South America: Six geographical zones total.
Three zones in Central America and five in South America, (with two zones in common.)
Antarctica: multiple zones radiated out from the South Pole
For a full list of Time-Zones, including minor & unofficial zones & their abbreviations & UTC offsets check out the 24timezones website.
*The Great Western Railway in England was the first in 1840.
**Two French representatives at the conference did object, staying the 0 meridian shouldn’t be in any one country but be in a neutral place, that wasn't very practical though considering it needed to be inline with an observatory.
^The mean in Greenwich Mean Time indicates the average time the clocks need to pass through the solar day. (The time from one solar noon to the next is not consistent through the year, days being shorter and longer throughout the seasons based on the elliptical orbit of the earth changing the relative distance between the earth and the sun, not to mention the imperfect axis of rotation.)
To account for the inconsistencies we don't use the actual solar time of any particular day for our time calculations but the averaging)of the solar times in a year. This takes these changes into account while producing a consistent, usable result.
^^China did i fact start with 5 zones but the PRC changed them to one zone when they took power.
^^^Despite our best efforts we do still encounter this kind of an issue with Day Light Savings Times not being observed in any uniform way. Up until 2005 some parts of Indiana were on DST time and other weren't so you could have an hour time jump county to county. Arizona doesn’t observe daylight savings, but the Navajo Nation, which occupies a quarter of the state does, and the then Hopi Nation, whose territory is totally inside the Navajo territory, doesn't so if you travel in a straight line from Hopi land to Navajo to Arizona proper and then to New Mexico during Day light savings the time will change 3 times!
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