The earth is divided into 24 equal parts every week, and each equal part is a time zone. Such a time zone is longitude 15 degrees. 24 hours a day, so a time zone is one hour apart. The time of longitude zero, that is, meridian, is the world standard time. Because the meridian passes through Greenwich City near London, it is called Greenwich Time, which is also the standard time in Britain. The longitude of Beijing is 1 16 degrees 2 1 minute, so it is in the eighth time zone east of the meridian. Which is the Dongba time zone. 8× 15 = 120, so the time zone of Dongba is east longitude 120 degrees, which is Beijing time.
So where is Beijing time calculated and published? It is the national time service center in pucheng county, Shaanxi Province. The reason for choosing this place is that Shaanxi is located in the hinterland of the mainland, only 100 km away from the origin of China, and the transmitted time signal is convenient to cover the whole country; The local geological structure is stable, and the coefficient of time service center being damaged by earthquakes and other disasters is very small; Because of its importance, it is safer to build in inland areas.
1 sec, which we are talking about now, is actually the time of 9 19263 1770 cycle of cesium atomic transition oscillation, which was officially defined by 1967 at the 13th international chronograph conference held in June. Internationally, the starting point of atomic time is 0: 00: 00 of 10 Universal Time 1958+ 1.
1968 10 In June, the National Time Service Center of Chinese Academy of Sciences was completed.
1970 12 15, Time City began to broadcast short waves to the whole country. Within 3,000 kilometers of Fiona Fang, people heard the familiar "... this national unified" Beijing Time "was broadcast from such a remote mountainous area and such a mysterious compound.