Once, I was working on a few geospatial APIs handling many time zones. While writing tests, I realized I did not know much about timezones. A lame excuse might be, my subpar schooling as a village kid. Nevertheless, I decided to turn the pages on timezones, what I found was more politics than science.
Before diving into anomalies, let’s talk about history then we will go to science followed by politics.
History
The world without time zones
By 300 BCE, the western world agreed that the earth is round. Each developed civilization devised its unique distinct system to measure distances, times & absolute locations, but relative to prime locations within their civilizations.
It all worked in ancient times because long-distance travel was not prevalent among common people. Only merchants or armies traveled long distances. And they already developed systems that worked on their predetermined routes, irrespective of the time differences between locations.
Colonialism Needs & Funding
Little past medieval ages, Imperial powers looked towards the maritime for empire expansions. They started venturing into unknown places to find better trade routes & new conquerable territories.
As the insatiable western greed increased, so did the requirement for a better navigation system. Kings, rich merchants, and wealthy investors started showing interest in improving navigation methods because it could increase the scope for expansion and reliability of profits.
This western imperialism and commercial expansion led to the foundation of observatories, committees, and science schools, which among many other goals had a goal to successfully identify longitudes.
Prominent Early Institutions
After Columbus discovered the new world, the Spanish empire set up Casa de la Contractación at Seville in 1503. It was the very first databank of all information collected from earlier navigators/travelers. This information was used to develop charts as well as navigation instruments.
Century later, the other two colonial superpowers France & England set up observatories in Paris in 1667 and Greenwich in 1675 respectively.
All of these agencies marked the earth for navigation. Principles for markings were the same but the end products were not.
International Meridian Conference (IMC)
By the late 1800s, another colonial superpower was rising in the far west. The 13 colonies on the east coast of this newly discovered continent, which started as a free country called America, now owned vast lands, stretching from the Atlantic to the Pacific and far beyond.
This new country was so vast that the sunrise in one corner is the deep dark on the other side. With the invention of the Railways, the problems of the time differences compounded.
In 1884 America invited all great minds from the world to establish a universal prime meridian & uniform standard times, These bunch of old white men in the below picture, formulated the rules that govern how the whole world sees the time to this day.
The Science (sort of)
These wise men passed a few resolutions in International Meridian Conference which directly or indirectly decide how we observe the time.
A simple interpretation of IMC resolutions
- A universal solar day begins at midnight in Greenwich and is counted on a 24-hour clock
- All nautical and astronomical days begin everywhere at 12:00 a.m.
- Meridians are imaginary circles passing through the geographic poles. The Meridian passing through Greenwich Observatory England is considered the prime meridian.
- Longitudes are the angular distance measured west or east of the prime meridian.
- The timezone at the prime meridian is called Greenwich Mean Time (GMT). Time here is known as Coordinated Universal Time (UTC).
Time Rule by mixing IMC Resolutions with Sun/Earth movement
- Earth rotates anticlockwise, causing the sun to appear traveling east to west. Therefore, sunlight reaches later on the west of the Prime meridian and earlier on the east. This makes the time towards
* East of the Prime meridian more (earlier) than GMT
* West of the Prime meridian less (later) than GMT - Earth is a sphere, so moving 360 ° brings us back to the same meridian. In 1884, wise men added an east-west concept to avoid the sudden time change confusion at the prime meridian. instead of 360° longitudes, we have longitudes 0°-180° towards each side of the prime meridian.
- The line at 180° EAST/WEST longitude is known as Antimeridian. In 1884 by opting for 180° east/west instead of 360°, the wise men moved that date changing confusion at this location because only Europe & Americas mattered. There is another phenomenon near Antimeridian called as International Date Line. It deserves a post of its own, I’ve covered it here.
- This brought us to the picture below, which shows the circle in red as the prime meridian, and in blue are other Meridians with longitudes denoted at the center
- As the earth is round, these longitudes have more gaps near the equator almost 70 miles, and theoretically zero mile gaps near the poles.
- As one earth day is 24 hours and the earth moved 360° in one earth day, a 360 ÷ 24 = 15° change in longitude should change the time to 1 hour. So if the time at Greenwich observatory is 2 PM the time at 10° longitude should be 1 PM. But the science ends here.
The Politics (Adjustments )
Scientifically a 15° change in longitude should change the time by one hour. But country borders in the world, are not parallel to longitudes. Usually, one or many 15° longitudes pass through a country. And, no one wants to keep changing clocks when moving within the country.
So politicians have decided the timezones according to business suitability instead of core science. In the majority, Countries have adopted the nearest possible timezone used by the influential country in their vicinity.
However, the countries on earth come in different shapes and sizes. Some countries are simply too big to have a single time zone. So there are 23 countrieswith at least two time zones. for example,
- America has longitudes ranging from 66.5°W in Maine to 172.2°W In Alaska, covering a whopping 110° in Longitude, Scientifically, it should have 7 or more timezones but politics prevailed over science and it's decided to have 6 timezones. America also invented a weird time-related phenomenon called Daylight Savings, It deserves its post, we will discuss it later.
- Russia at the time of this writing has 11 time zones. that means you need to change your watch 10 times if you drive from one end to another.
- China has a different approach. If you think changing the watch 10 times in Russia is weird, China also thought the same, so it decided to keep only one timezone.
Until mid 20th century, china did follow 5 time zones, but after the civil war, with the rise of the Communist Party and the creation of the People’s Republic of China, Mao Zedong decided that all of China was to use Beijing Time UTC+8. - In Samoa, Fiji, Tonga, and a few more pacific island nations, there is a lot of politics here to discuss, with weird life losing or gaining phenomenon. Will cover it under the international Date Time Line post.
I maintained only a few countries but many have adjusted the timezone as per political needs.
Below is a colored map of the timezone. you can see, that there are only a few places where it follows meridians (straight lines, usually at the ocean). Wherever humans live, rules are bent and timezones are adjusted to meet the political and financial alliances.
Conclusion
Before I conclude the topic, one last location I want to talk about is North-South Poles. As we saw, all longitudes converge at the north and the South poles. So in theory, all timezones are valid on the poles. In other words, poles lie in all time zones. :-)
So, at the same instant, two people can refer to the time as, 1 PM Sunday or as 3 PM Saturday, both will be right. Makes me wonder if any time reference even matters in this world? What am I doing here?
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