The Roger thread reminded me of something I’ve been wondering about. What is the origin of using Z (or its radio code word Zulu) for Greenwich Time in the military? Why not A or Alpha? Is the designation “Zulu” ever used other than by the military? I think most people call it Greenwich Mean time or Universal Coordinated time.
I’ll admit this is idle speculation, but I’d guess that the “Z” in Zulu time comes from “zero” as in the zeroth meridian (the Greenwich meridian)
You hear Zulu time mentioned a bit if you float around the shortwave band although from my experience it’s called Greenwich or GMT the most there.
Update–The Telecommunications Glossary ( http://physics.hallym.ac.kr/resource/glossary/glossary.html )confirms my conjecture that zulu comes from zero.
Also, I plucked the following from the Navy
[QUOTE}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”].
[/quote]
GMT no longer exists having been replaced by UTC (compare with UT0, UT1 etc)
William??? I thought W was whisky!
And here I thought this was going to be about how I came to be…
W is indeed currently Whiskey for Canada, NATO, and commercial Aviation, but has been William in the past, and still is in some places.
Jenn
It’s “whiskey” for general (civilian) aviation too.