What is UTC?
UTC literally stands for “Universal Time Coordinated”. It is more commonly known as “Coordinated Universal Time” and is based on the time at the zero or Greenwich meridian. The use of UTC as a standard time used by the world is derived from the International Atomic Time, which involves a time-tracking system based on the rotating surface of the Earth. The town of Greenwich in England is designated as the “Z” zone for ‘Zulu’ or “zero” hours in which the standard world time will start. It is for this reason that “UTC” was actually referred to as GMT or Greenwich Mean Time in the past. Based on the IAT standard, the calculation of UTC time is allowed to add additional few leap seconds to adjust to the irregularities of the rotation of our planet.
When interpreting time from different locations on the Earth, it may be expressed as “positive” or “negative” offset values from standard UTC time. With the world map projected on a flat image with Greenwich representing the center and the zero-hour zone, all time zones of countries to the East of Greenwich will have positive values from UTC time, while countries on the West of Greenwich will have negative values. This means that the Eastern half of the map will be part of starting a particular day and the end will be on the Western part.
UTC is the most commonly used time standard and reference by countries all over the world. The internet and the World Wide Web also use UTC as the basis for standard time. Many television and radio stations all across the globe also based their times on the UTC standard. The same goes for the aviation industry including the systems used by air traffic controllers, the computers used in making flight plans, and even weather forecasting instruments.