Coordinated universal time

Universal time is measured by astrometry, and because of various factors, there are small errors relative to atomic time. In order to coordinate universal time and atomic time, scientists are dealing with coordinated universal time. Numbers below utc use atomic time data. When the difference between universal time and atomic time reaches one second, there is a second jump or negative second jump. The specific procedures are as follows:
When the world slows down, add a second to UTC. 23 hours, 59 minutes, 59 seconds --23 hours, 59 minutes, 60 seconds --0 hours, 0 minutes, 0 seconds
When the world is fast, cut UTC by a second. 23 hours, 59 minutes and 58 seconds --0 hours, 0 minutes and 0 seconds
Hop seconds or negative hop seconds are only available on December 31 or June 30. Hops are decided by the international bureau of time and notified to all timing units in advance. Due to the time difference, for different countries may not necessarily in the evening jump second and negative jump second.