visor empowered
Member
Registered: Mar 2000
Location: McLean, VA USA
Posts: 216 |
James,
I went to "AskJeeves" and asked him. This is one of the responses I got:
"Introduction
The world is divided into 24 time zones. For easy reference in communications, a letter of the alphabet has been assigned to each time zone (less the letters "I" and "O"). The "clock" at Greenwich, England is used as the standard clock for international reference of time in communications, military, maritime and other activities that cross time zones. The letter designator for this clock is Z.
Times are usually written in military time or 24 hour format such as 1830Z. To pronounce this, the phonetic alphabet is used for the letter Z, or Zulu. This time is sometimes referred to as Zulu Time because of its assigned letter. It's official name is Universal Coordinated Time or UTC. Previously it had been known as Greenwich Mean Time or GMT but this has been replaced with UTC."
Here is the U.S. Navy explanation:
"What is "Zulu" time?
"Zulu" time is that which you might know as "GMT" (Greenwich Mean Time). Our natural concept of time is linked to the rotation of the earth and we define the length of the day as the 24 hours it takes the earth to spin once on its axis.
As time pieces became more accurate and communication became global, there needed to be a point from which all other world times were based. Since Great Britain was the world's foremost martime power when the concept of latitude and longitude came to be, the starting point for designating longitude was the "prime meridian" which is zero degrees and runs through the Royal Greenwich Observatory, in Greenwich, England, just outside London. As a result, when the concept of time zones was introduced, the "starting" point for calculating the different time zones was/is at the Royal Greenwich Observatory. When it is noon at the observatory, it is five hours earlier (under Standard Time) in Washington, D.C.; six hours earlier in Chicago; seven hours earlier in Denver; and, eight hours earlier in Los Angeles.
Unfortunately the Earth does not rotate at exactly a constant rate. Due to various scientific reasons and increased accuracy in measuring the earth's rotation, a new timescale, called Coordinated Universal Time (UTC), has been adopted and replaces the term GMT.
The Navy, as well as civil aviation, uses the letter "Z" (phonetically "Zulu") to refer to the time at the prime meridian. The U.S. time zones are Eastern ["R", "Romeo]; Central ["S", "Sierra"]; Mountain ["T", "Tango"]; Pacific ["U", "Uniform"]; Alaska ["V", "Victor"], and Hawaii ["W", "William"].
The Department of the Navy serves as the country's official timekeeper, with the Master Clock facility at the U.S. Naval Observatory, Washington, D.C."
Basically, this means that irregardless of where we might be in the world, if we agree to meet in a chat room or something at a specific time, we could use Zulu time and that way we could avoid the confusion of if it's 10PM here, then it's 7PM where he is and do I use my time or his time etc.
Does that make sense???
There were a couple of other time related resources as well.
www.askjeeves.com
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Have Visor Will Travel!
[This message has been edited by visor empowered (edited 04-13-2000).]
[This message has been edited by visor empowered (edited 04-13-2000).]
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04-13-2000 06:55 PM
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