Product Item: KE-0139

National unity will slow the clocks one second
  People, Beijing, July 1 (Reporter JIANG Jian Branch) reporter learned from the China Institute of Metrology, July 1 in the morning, many computers will appear in the special phenomenon of 7:59:60. It turned out this year, January 5, the International Earth Rotation Service announced that the world will implement a positive leap second at June 30, 2015. Located in the East eight districts of China (Beijing) time by 1 second in July 1 as early as 8:00, when the country will be unified slow the wall clock for one second. What is a leap second? Why would leap seconds? Leap seconds will it affect our lives? China Institute of Metrology time frequency punctuality director Zhang Aimin explains that time is one of the earliest natural phenomena of human cognition. Earth's rotation based nominal "mean solar time", when belonging to astronomy. With an average cycle of astronomical observations of the Earth's rotation (length of day) astronomical, and then divided into 86400 parts (ie 24 hours a day, one hour 60 minutes, one minute 60 seconds) to obtain a second long. However, due to the Earth's rotation rate is not stable orbital motion, when slow fast. Mid-20th century, with the birth and development of the theory of quantum physics, the scientists found some stability with time quantum phenomena is far superior to astronomical phenomena, so there is a phenomenon of quantum measurement time recommendation that when atoms or seconds. In 1967, the General Conference on Weights and Measures decided to use the atomic seconds substituted astronomical seconds. International Atomic Time is based on the cesium atom oscillation period is determined, and therefore relatively constant, it depends on the rate of rotation of the earth astronomical, because of changes in the Earth's rotation speed varies. Over time, scientists have found that both the gradual emergence of a bias, and lopsided. So with a "compromise" Time - Coordinated Universal Time was born. 1971 General Conference on Weights and Measures adopted a resolution, the establishment of Coordinated Universal Time (UTC) as the world's standard time common. Zhang Aimin said, based in Paris, France, the International Earth Rotation Service (IERS) through the atomic and astronomical time monitoring data, and when the difference between 0.9 seconds and on to the world issued a notice on the next June or December the last day of the last minute of the coordinated Universal dial forward or backward by one second, this is the "leap second." Zhang Aimin said that since 1972 Coordinated Universal officially used since, the world has made 25 positive leap second adjustment, which means a total increase of 25 seconds Coordinated Universal Time. The last leap second in 2012, this year June 30 will be the 26th leap second, but also the positive leap seconds. Despite the leap second is in accordance with international IERS Bulletin worldwide unity of action, but in recent years about whether the presence of leap seconds value, whether to cancel the leap second controversy has been a concern. Zhang Aimin said, in people's daily life, if we use the time difference between sunrise and sunset, and a few minutes, or even two hours (such as Urumqi time), hardly bring any inconvenience. Leap seconds are therefore not affect their daily lives. But for aerospace and other sophisticated areas, a leap second is very important. "Leap seconds in many areas, especially in many of the recent development of modern science and technology but show a negative role. For example, the time-scale global satellite navigation system if the introduction of leap seconds, is bound to interrupt positioning, navigation and timing of continuity Again for example, the spacecraft can fly nearly 1 second and 8 km irregularly worse if one second off the mark may cause the spacecraft orbit, threaten its security "to this end, involving time-frequency two intergovernmental international organization internationally: General Conference on Weights and Measures (CGPM) and the international Telecommunication Union (ITU), respectively, in the framework of their respective feasibility study cancel leap seconds. Zhang Aimin said that if cancel leap seconds, in the time between atomic and astronomical "compromise" in Coordinated Universal Time (UTC) when the atoms return, contributed to the world to use a uniform time-scale system.
  • IPTV, Internet Protocol TV, Internet Protocol Television, IP set-top boxes, IP Cable Receivers, IPTV Receiver, IPTV Cable Receiver, IP TV Solutions