# Greenwich Mean Time/Universal Time

Source: Internet
Author: User

It is also called "World Time ". The standard time of Greenwich Mean. Now, not only does astronomy use Greenwich mean time, but it is also frequently used in news and newspapers. We know that each region has its own time. If we use local time to record a major international event, we will feel complicated and inconvenient, and it will be easy to make mistakes in the future. Therefore, astronomers have proposed a method that everyone can accept and easily record, that is, the local time in Greenwich Mean as the standard. Greenwich Mean is the home of the original Greenwich Observatory in the southern suburbs of London, England. It is also the starting point of the world's geographic degree. Major events in the world are recorded at Greenwich Mean Time. Once Greenwich Mean Time is known, it is easy to calculate the equivalent local time. For example, an incident occurred at eight o'clock A.M. GMT, and our country was in the east of England. Beijing time was eight hours earlier than Greenwich Mean Time. We knew that this incident happened at 16 Beijing time, four o'clock P.M. Beijing time.

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GMT (Greenwich Mean Time) is Greenwich Mean Time:
Because the earth's orbit is not circular, its operation speed changes with the distance between the Earth and the Sun. Therefore, uniformity is lacking when the sun is regarded. The sun length is also affected by the tilt of the Earth's self-rotating shaft relative to the orbital plane. To correct the above non-uniformity, astronomers calculated the effect of the earth's non-circular trajectory and polar axis skew on the sun. Normal sun refers to the revised sun-watching time. The ordinary sun on the Greenwich meridian is called the Universal Time (UT0) and Greenwich Mean Time (GMT ).
GMT Standard Time
Greenwich Mean Time (GMT) refers to the standard time of the Royal Greenwich Observatory on the outskirts of London, because the meridian is defined as the meridian through which it passes.
Theoretically, midday Greenwich mean the time when the Sun crosses the Greenwich Meridian (the highest point over Greenwich. Because the earth's motion speed in its elliptical orbit is uneven, this time may be 16 minutes different from the actual sun time.
The daily rotation of the earth is somewhat irregular and is slowing down slowly. Therefore, Greenwich Mean Time is no longer used as the standard time. The current standard time-Coordinated Universal Time (UTC)-is provided by an atomic clock.
Since January 1, February 5, 1924, the Greenwich Mean observatory will distribute Time-of-adjustment information to the world every hour.
The record editing time of Chinese Wikipedia adopts the GMT Standard Time.

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