UTC time — what is it and how is it used?

Universal Coordinated Time (or UTC) is an international standard by which the world regulates clocks and time. This standard was introduced in place of the outdated Greenwich Mean Time (GMT). Greenwich Mean Time is the mean solar time at the Royal Observatory in Greenwich, London, reckoned from midnight. At that time it was used as a reference point for other time zones.

The situation changed in 1972 when GMT replaced UTC time. A new timescale was introduced due to the fact that GMT is an uneven scale that is connected to the Earth daily rotation. The new UTC scale is based on a uniform atomic timescale. In simple terms, it is more friendly and convenient for the civil usage.

As far as the UTC time is concerned, this abbreviation does not have exact expansion. At first the abbreviation was CUT — Coordinated Universal Time (English acronym), and after that the abbreviation was changed into TUC - Temps Universel Coordonne (French acronym). The International Telecommunication Union decided that CUT and TUC brought a lot of confusion and adopted more neutral variant, that is UTC.

UTC Time

UTC time is used in various spheres of life:

  • In modern aviation and on the International Space Station (ISS).
  • In car and vehicles computers, which are responsible for crew condition monitoring.
  • World Wide Web and Internet Standards.
  • Weather forecast and satellite positioning.

The UTC scale is used for stable and convenient timekeeping. This time standard does not depend upon the rotation of the Earth or the Sun. UTC regulates 24 world time zones, and the Greenwich Meridian (UTC 0) is used as a reference point.

The UTC scale has both positive and negative values. The former are at right, the latter are at left. Thus, one can see the time zone offset from UTC. For instance, Moscow is in the UTC + 3 time zone, and New York is in UTC-5.

The particular characteristic of Coordinated Universal Time is that it does not change with a change of seasons. For this reason if the whole country change clocks at winter and summer, it does not change time zone offset from UTC.