World Time Zone Map
No wonder there are vast differences
in what time it is, often depending on where you are on the earth.
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
maritime 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, southeast of central 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",
"Whiskey"].
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.
No comments:
Post a Comment