# Why large countries have many time zones?

• Last Updated : 24 May, 2022

As we all know, Earth rotates on its own axis, it takes about 24 hours for the earth to complete one rotation, which is the duration of one day. Earth revolves around the sun and it takes almost 365 days to complete one revolution which is the time duration of one year. Earth is a very vast planet and to identify various places on it we take the help of Latitude and Longitude. Time is measured keeping in mind the position of the sun so it is impossible for the whole world at the same time. When it is 10:00 AM in the United States; it is 03:30 PM in India. But how do we calculate the time?

### Definitions

• Longitude:  It measures distance east or west of the prime meridian. They are imaginary lines that run from north to south pole. It is measured in degrees, minutes, and seconds.
• Latitude: Distance is measured from north to south of the equator. Imaginary lines that run through the equator refer to Latitude.
• Time Zone: It refers to a space that observes uniform standard time for legal, commercial, and social purposes.

A time zone is a region or area on our earth that has the same time for all places in the region. It is impossible for every place around the earth to have the same time zones. Earth is divided into 24 regions according to time zones based on the 24 longitudes as one longitude is 15 degrees. To maintain a proper system of the time zones, one time zone is selected as the base or the standard time zone. GMT or Greenwich Mean Time is the standard time zone used for the purpose of measuring the time.

### Why do some countries have many time zones?

The answer to this question is very simple. As we now know that the time zone is calculated based on the longitudes, some countries have a very large area so it is evident that many longitudes pass through the countries. Earth is divided into 24 Time zones so a large country can be part of multiple time zones. That is the main reason why some countries have multiple time zones. For example, if a country passes through GMT, 15 degrees east, 30 degrees west then the time zones will be GMT, GMT + 1, GMT -2. So it is possible for large countries to have multiple time zones.

Small countries like Germany have no time discrepancy in time between Koln and berlin because they use one universal German time. On the other hand large countries like Australia, there is 3 hours difference between Perth and Sydney. So when even if they are in the same county sunrise for Sydney would be 3 hours before Perth, where it would be still dark. The reason for this is very simple all the time we measure is based on the relative position of the sun because the earth is constantly rotating on its own axis so when half of the earth has day the remaining half will have night but if we use a single standard time it would not be logical. So based on the same fact we have the longitude system in place to have a logical reason but it too has its own loopholes as a large country has multiple time zones so it would create confusion. But the reason for large countries have multiple time zones is straightforward their large area.

As each longitude is 15 degrees away from each other it can be used to calculate the time zone of one area. For example, if the longitude is 60 degrees east then the time zone is 60/15 =+4 so the time zone of that area will be GMT + 4:00 this means that the time of this area will be 4 hours ahead of the GMT, similarly, if the area is 15 degrees west then the time zone is 15/15 = -1 so the time zone of the area is GMT -1 hours, which means the time is 1 hour behind the GMT. This is the standard formula used for the calculation of the Time Zone.

### Sample Questions

Question 1:  How many time zones are earth divided into and why?

Earth is divided into 24 time zones as two longitudes are 15 degrees apart from each other so 360 / 15 =24. Each time zone is 1 hour apart from the other.

Question 2: Define a Time Zone?

A Time Zone is an area that observes a uniform standard time for legal, commercial, and social purposes. There are 24 Time zones in total.

Question 3: What is the Standard Time zone used?

Greenwich Mean Time is the standard Time Zone used for the calculation of other time Zones.

Question 4: Give an example of a country with multiple time zones.