Exploring Greenwich Mean Time (GMT) : The Story of Time Zones.

The Greenwich Mean Time (GMT) time zone is the time zone that is specifically referenced to the Prime Meridian, which runs at the Greenwich Observatory in London. Most locations within the scope of this research use GMT as the base time standard and do not adjust for daylight saving time.

History of GMT

The measurement of time was initiated in the early 17th century, when the concept of the Royal Observatory in Greenwich was developed in 1675. Its purpose was to observe the heavens and to come up with accurate data especially the longitude for aiding the British navy. There has been invention of marine chronometer by one John Harrison in 1735 to aid in longitude determinations.
By 1847 it was the electric telegraph that required the need for single standard time instead of the local times. The initial bulk distribution of standard time happened on 1st December 1847 when Coordinated Universal Time was transmitted to important cities in the country. In 1880 GMT reserved the same position as the universal time standard.
The use of the term Greenwich Mean Time cropped up during the early part of the 1900’s. Before this, there where several local times where in use, each major city had its own meridian. Such is seen to be the case when we consider the growth of the railways which resulted in the ultimate adoption of a standardized time as it became increasingly difficult to coordinate the trains over long distances if there was no single standard time.
Sometimes, this time is called the Zulu time, and the time is written as GMT, GMT+0000 or GMT-0000 in military and aviation. The last one is the most enigmatic, Z originally stands for Z time zone, Zulu in fact being a word attributed to the alphabet’s z.

Details of GMT

These countries have adopted GMT as their local time due to its position on the Prime Meridian: Western Sahara Burkina Faso Gambia Ghana Guinea Guinea-Bissau Ivory Coast Liberia Mali Mauritania Morocco Senegal Sierra Leone Togo United kingdom
Being on the Prime Meridian means it has an offset of UTC +00:00. As mentioned, UTC stands for Coordinated Universal Time which is basically the time standard, starting from which all the world time zones are determined. This implies that any given time as reflected in 12:00 pm time in London is also expressed as 12:00 pm UTC. Places like New York, five hours behind GMT, would show as 05:00 UTC.Most significantly, in the spectral lines that give this galaxy its red-shift there is a shift of 00 UTC.
GMT is not on daylight saving time and at the time of writing for this article, it is one hour behind BST, the daytime saving time employed in the United Kingdom. Specifically, there is no difference between GMT and BST during the time period that begins towards the end of October and ends in the middle of the following March since BST ceases during this period.
Being positioned roughly in the middle of the UTC+00:Due to this, most people make use of the Greenwich Mean Time, GMT, to estimate time disparities that exist in the time zones of 00 and UTC-12:00. For example, New York at UTC -05:Five hours behind GMT, 00 is the equivalent of 5 hours. Los Angeles at UTC-08:Hence 000 is eight hours behind. Wellington in New Zealand at +12:T of 00000 is in GMT zone which means it is 12 hours ahead of GMT.

Advantages of Using GMT

Using GMT has several advantages, for example.

  1. It is on the Prime Meridian and serves as the origin point for UTC, the universal time reference, and thus for every time zone in the world. This makes changing from one time zone to another easy to do.
  2. It is also a country that does not practice the system of daylight saving, so, there is no inconsistency of time differences throughout the year.
  3. As it is situated right in the middle of the world’s time zones, it is a convenient point of departure to determine differences, either positive or negative.
  4. For instance, historically Britain had colonies in many parts of the world and was involved in building trains and infrastructure for some of those colonies. They became engraved early on and used GMT as a time standard all over the world.

Whether it is an attempt to schedule a phone conference between New York and Sydney, or to determine arrival times of the transatlantic flights, GMT serves as a convenient zero starting point that allows to compare the times in different parts of the world. One of the advantages of GMT is the ability to perform cross-global time calculations as the timeline remains steady in spite of the changes in the daylight saving period.


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