Back to the top of the page. What does UTC mean and how does it relate to local time?
Actually UTC stands for Universal Coordinated Time (the acronym coming from the French “Universel Temps Coordonne”). It is ALMOST exactly the same as GMT, they only differ by a fraction of a second. UTC counts the number of SI unit (atomic clock) seconds so it is synchronized with International Atomic Time (TAI or atomic time). TAI is simply a count of atomic seconds that have occurred since the instant of midnight January 1, 1958 at the Royal Observatory in Greenwich, England. GMT is tied to the true rotation of the Earth and is related to the prime meridian angle. It is derived from the mean sidereal time at the Greenwich Observatory and determined by astronomical observations of stars and radio sources. Although it is angular in nature, it can be expressed using a calendar system having the familiar six components of year, month, day, hours, minutes, and seconds that specify an instant of time. Midnight is defined as 0 hours, minutes, and seconds, or 00:00:00. However since the rota
