Now, have you ever thought of how it may be daytime right now where you are while in the opposite part of the world it’s the middle of the night? You might have also noticed that many tv shows and movies when advertised on a channel are given two designated times. These times are different because they are for different time zones, which brings us to our topic of the day.
What is a Time Zone?
A time zone can be defined as a geographical area that observes a single standard time for legal, commercial and social purposes. Usually, countries follow a single time zone as it is much easier to follow a standard time for the entire country; the time zones are demarcated by the longitudes. But many countries are so large that they end up spanning more than one time zone. Read on to understand more about times zones!
Now, we all know that the Earth rotates on an axis and the completion of one single rotation around this takes 24 hours or one whole day. As the Earth rotates, the area of the Earth exposed to the Sun changes as well which means that the parts of the Earth receiving sunlight is changing as well. At any point, one half of the Earth is exposed to the Sun and experiences day while the other half remains in darkness and experiences nighttime. Due to this constant change, determining the time was a very complicated process.
In the olden days, a person in the village was responsible for determining noon when the Sun was at its highest point in the sky after which they were responsible for informing the rest of the people of the time as well as keeping track of the passing time. We have come a long way since then and time zones are now very well-defined and organized.
Concept of Time Zones
Scientists determined that the Earth rotates through 15 degrees every 60 minutes. This means that it takes 24 hours for the Earth to rotate through 360 degrees i.e., complete one full rotation and according to this data, the Earth can be divided into 24 time zones, each spanning 15 degrees wide across the longitudes. Now, because of the spherical shape of the Earth, the distance between the longitudes or time zones is the highest at the equator and is very little at the poles.
In order to settle the dispute over standard time once and for all, scientists came up with a brilliant solution. The longitude passing through Greenwich Village in London was assigned the Prime Meridian; every longitude 15 degrees to the west is considered to be 60 minutes behind on the clock while every longitude 15 degrees to the east is considered 60 minutes ahead. The time at Greenwich is considered a standard and is known as the Greenwich Mean Time.
This simplifies things greatly but not everywhere in the world is this system of the time zone considered standard.
Fun Fact: China, with an area of 3,705,407 square miles, assigns a single standard time for the entire country despite the fact that geographically it spans three separate time zones! Greenland, the world’s biggest island uses four time zones to administer its 836,109 square miles. The same is true for India, which uses a single time zone as well.
Wanna celebrate your birthday twice? Well, the International Date Line separates the Pacific in such a way that you can be in Somoa(GMT + 13), take a short flight across 30 miles to American Somoa (GMT – 11) and basically travel 25 minutes back in time.