is specified. Earth rotates in 24 hours, thus there are 24 hours in a day. The English alphabet has 26 letters; J is local time, and the other 25 letters are assigned to the 25 time zones. The International Date Line separates time zones M and Y. Zulu [Z] is a synonym for Coordinated Universal Time (UTC); and formerly a synonym for Greenwich Mean Time (GMT). Sources MIL-STD-2500A 12 October 1994 See also Calendar date ISO 8601 References TM 20-205, the Dictionary of United States Army Terms (1944) ACP 121(I) p 3–7 External links Calendars