What is Universal Time (UT)?
UT refers to a time scale called “Coordinated Universal Time” (UTC) which is the basis for the worldwide system of civil time, and is therefore the international time standard. This time scale is determined using highly precise atomic clocks around the world. “Universal Time” is the current term for what was commonly referred to as Greenwich Mean Time (GMT). Zero (0) hours UTC is midnight in Greenwich England, which lies on the zero longitudinal meridian. (The standard of UT replaced GMT in 1926 because too many different definitions of GMT were in use.) Universal time is based on a 24 hour clock, therefore, afternoon hours such as 4 pm UTC are expressed as 16:00 UTC.
