GMT : A wonderful invention to remove the confusion of railways, a village with the time of which the world sets its clock!

History of Time Zone: The clock and our lives are completely intertwined. Ever wondered what would happen if all clocks in the world were set to the same time? So there will be a big mess right? Because the earth is so big that if there is morning in our country, then there will be night, somewhere evening, somewhere afternoon and somewhere different time on this earth. A single place was fixed for each day from which the whole world could set its clock time. Also know why the whole world time is set with GMT? What does GMT stand for Greenwich Mean Time? How was this time zone determined and how did the world determine its day before that?

When did the clock start?

Clocks were invented as early as the 16th century, and until the 18th century, time around the world was observed and measured based on the sun. But the world got time zones after the Industrial Revolution in Europe in the 18th century. In the early 19th century, local time in cities was determined by the sun. So, different time would be seen even between two cities which are at a distance of bus miles. So setting the train timetable according to this also became complicated. So efforts started to make this work easier.

How did time zone start?

This is very interesting. Yuval Noah Harari, anthropologist and author of the famous book Sapiens, explains the period, saying that with the advent of the Industrial Revolution in Britain in the year 1830, the first commercial rail service started between Liverpool and Manchester. Ten years later the first timetable was released. At that time the speed of trains was faster than the old horse carriages. So the difference between local time became a serious problem. This train went to many places but everywhere it worked like a time factory and dark and light. It was causing a lot of problems.

So in 1847, the British train companies met and agreed that henceforth all train timetables would be based on Greenwich Observatory time rather than Liverpool, Manchester or Glasgow time. So in 1980, the British government made a law that all timetables in Britain would follow the Greenwich Observatory clock. Later, the British also implemented it in the countries of their empire and that's how the world got the time of Greenwich Observatory i.e. Greenwich Mean Time (GMT).

What is Greenwich?

Greenwich is part of south-east London, once a village and famous for its observatory. Which is now known as 'Royal Observatory'. Astronomical phenomena were studied here since the Middle Ages. When Britain created this time zone, it considered it the center of the Earth map. Greenwich was made the time standard by placing it at 0 degrees on the map, with the argument that this would benefit the world's larger population. The Greenwich Observatory time was implemented throughout the country by making a law and eventually the world also adopted Greenwich Mean Time (GMT) as its time standard.

How is world time set from GMT?

At present time of every country is set with Greenwich time zone. When you look closely at a globe or world map, you will notice that there are two types of lines. One horizontal and another vertical line appears. This spherical part of the world is seen in 360 degrees and every degree of longitude is 4 minutes apart. That means if your location is 15 degrees away from GMT then the time zone difference will be 15X4 = 60 minutes. If we move eastward from GMT, the clock time will increase. India is located 82.5 degrees east of Greenwich and thus there is a difference of five and a half hours between our time zone and Greenwich. That means our time is five and a half hours ahead of British time.

How many time zones are there in the whole world?

Currently there are 24 time zones in the world. Each country determines its own time zone according to its political and geographical needs. In which the most time zones in the world are in France which is 12, Russia has 11, Antarctica has 10, America has 9, Britain has 9, Australia has 8, Denmark has 5 time zones.

How many time zones in India?

During the British rule, India was divided into two time zones. Till 1948, Kolkata time was set separately. But only one time zone was enforced during independence. Today there is a difference of 90 minutes in sunrise time between western and eastern parts of India, but clocks show the same time in both places. India's time zone is UTC/GMT (United Universal Time/Greenwich Mean Time) +5.5. It's the hour. There is only one time zone across India. In Shankargarh of Mirzapur (in Allahabad district of Uttar Pradesh) the time zone is calculated according to the longitude of 82.5° E.

Tea gardens in Assam do not follow Indian Standard Time (IST), they follow local time, known as "Tea Garden Time" or "Chah Bagan Time". It is one hour ahead of Indian Standard Time (IST). Because this system was introduced during the British period in view of early sunrise in this part of the country. The working hours for tea laborers in the gardens are usually between 9 A.M. (8 am IST) to 5 pm (4 pm IST). During winter the sun sets by 4 pm. Hence the tea growers thought of adopting local time for their labourers, as it was easier for them to work in sunlight.

In this part of the world, the sun does not set for 69 days

In the world there is no night for many months and no day for many months in Someroy Island. Tourists from all over the world come to see this scene on this island located in the western part of Norway. The life of the people here is totally different from ours. Due to the geographical location being different from us, there is no sunset here for the entire 69 days between 18th May to 26th July. Similarly, the people here also have to face the long polar night for 90 days between November and January. That means the sun does not rise during this time.

With only 24 hours of night between November and January, visitors also tie their watches to the bridge before entering the island and feel free from time-bound lives for a few days. How different time zones mean to people in different parts of the world. A country gets equal day and night, while another has to spend six months in daylight or darkness.