Earth's Time Zones

The Earth always rotates from west to east, and the sun is always visible in the east before the west, and the time in the east is always earlier than that in the west. The difference between the time in the east and the time in the west is not only measured in hours, but also in minutes and seconds, which brings a lot of inconvenience to people's daily life and work.

In order to overcome the confusion of time, in 1884, held in Washington, an international j radius conference, the provisions of the global division into 24 time zones. They are the Central Time Zone (Zero Time Zone), East 1-12, and West 1-12. Each time zone spans 15 degrees of longitude and is exactly one hour long. The final zones, East and West 12, each span 7.5 degrees of longitude and are bounded by 180 degrees of East and West longitude. The time on the central meridian of each time zone is the time uniformly used within that time zone, called zone time. The time difference between two neighboring time zones is 1 hour. For example, the time in the East 8 zone of our country is always 1 hour earlier than the time in the East 7 zone of Thailand and 1 hour later than the time in the East 9 zone of Japan. Therefore, people traveling abroad must always adjust their watches to match the local time. Whenever you go west, you have to set your watch forward 1 hour (e.g. 2 o'clock to 1 o'clock) for every time zone you pass; whenever you go east, you have to set your watch back 1 hour (e.g. 1 o'clock to 2 o'clock) for every time zone you pass.

In fact, many countries and regions of the world do not strictly calculate time by time zones. In order to adopt a uniform time throughout the country, generally the time of a certain time zone as a unified national time. For example, China takes the time of the eastern 8 zones where the capital city of Beijing is located as the unified time for the whole country, which is called Beijing time. Another example, the United Kingdom, France, the Netherlands and Belgium and other countries, although located in the Central Time Zone, but in order to be consistent with the time of most countries in Europe, the use of East 1 time.

Thinking about time difference:

1.

The time of each country uses local time, and there is no uniform conversion method, which brings inconvenience to transportation and communication. (Awareness of the time difference existed before, just not a perfect system.) In order to unify, the world adopted the time difference system and followed it, and the time calendars of various countries are based on this system.

2. Why 24 time zones?

It corresponds to the 24 hours of the day. That is to say, to meet the 24 hours back to the origin, 24 time zones cover the world.

3. Why is there a zero time zone?

Explained by the principle of coordinate axes, which facilitates the calculation of time difference by the law of addition and subtraction.

4. Why are 12 East and 12 West half the size of other time zones?

To accommodate the existence of 24 time zones and zero time zones.

5. Calculation of time in different time zones?

Same minus different plus, east plus west minus

"Same" means the same in the east time zone or the same in the west time zone, then the two time zones are subtracted from each other, (e.g., if East 8 and East 5 are both in the east time zone, then 8 - 5 = 3.) "Different " is the opposite.

Follow a zero time zone centered world map, the requested time zone in the known time zone east then the same minus the result of the different plus the time of the known time zone. Otherwise it is minus.