What is Greenwich Mean Time?
{{Time zones of Europe}} '''Greenwich Mean Time''' (GMT) is an [[international]]ly [[standard time|standardized time]] [[:wikt:format|format]]. It is the main [[time zone]] in several [[Country|countries]], including the [[United Kingdom]], the [[Republic of Ireland]] and [[Portugal]]. GMT has the same time as [[Coordinated Universal Time|UTC]], but there are differences between the two.<ref>{{Cite web|title=UTC & GMT – Same Difference?|url=https://www.timeanddate.com/time/gmt-utc-time.html|access-date=2021-03-11|website=www.timeanddate.com|language=en}}</ref> Technically, GMT is a time zone, while UTC is a time standard. GMT was established in 1884 at the International Meridian Conference,<ref>{{Cite web|title=GMT vs. UTC. What's the difference?|url=https://24timezones.com/gmt-vs-utc|access-date=2021-03-11|website=24timezones.com|language=en-us}}</ref> which met to establish a standardized system for measuring world longitude. They decided that the meridian passing through the Royal Observatory in Greenwich, England would be 0° longitude<ref>{{Cite web|title=What is the Prime Meridian and why is it in Greenwich?|url=https://www.rmg.co.uk/stories/topics/what-prime-meridian-why-it-greenwich|access-date=2021-03-11|website=www.rmg.co.uk|language=en}}</ref>.This conference also decided that the time zone around the meridian, GMT, would be the time zone used for reference around the world. Other countries would define their time based on GMT. UTC was defined in 1963 as the new world reference for time.<ref>{{Cite journal|date=2021-03-11|title=Coordinated Universal Time|url=https://en.wikipedia.org/w/index.php?title=Coordinated_Universal_Time&oldid=1011539476|journal=Wikipedia|language=en}}</ref> The major advantage of the new standard was that its time was determined by highly accurate atomic clocks, not the sun at Greenwich. Other advantages of UTC are that calling the new standard Coordinated Universal Time avoids giving more importance to any one country, and that UTC does not adjust for Daylight Saving Time, whi