The definition of GMT has always been an absolute, independent of the actual local clock time in Greenwich, England (which is currently British Summer Time, BST, one hour ahead of GMT/UTC).
You are correct that the acronym GMT is an anachronism, but it remains a very popular one. For all intents and purposes it is synonymous with UTC. My understanding is that the change from GMT to UTC was made to avoid historical confusion. Originally, 0 hours GMT was noon, matching the start of the Julian Day and convenient for astronomers who work through the night. Sometime in the 1920s it was moved to midnight, at which point GMT became possibly ambiguous for past dates. UTC is unambiguous: for any date in the past or future, 0 hours UTC refers to midnight. On Wed, May 29, 2002 at 03:33:14PM -0400, Rob Reid wrote: > At 9:51 AM EDT on May 28 David T-G sent off: > > GMT does not change in the summer. GMT is GMT all year round. That's > > why it's "Greenwich Mean Time" and not "Greenwich Most-of-the Time". UK > > Daylight time is BST , or GMT+1. > > I think you're behind the times, David ;-) > > I was taught that what you said above was true for a while until the town > (village?) of Greenwich got tired of not having daylight savings time (and > being an hour off from the rest of Britain for the summer) and relinquished > GMT. Thus was UT (Universal Time) born, which is the real, i.e. no Daylight > Savings, time at the longitude of Greenwich. In other words it's what used to > be called GMT, but Greenwich itself doesn't use it anymore, so GMT is an > anachronism. > > If anyone from the vicinity of Greenwich would like to correct me, please do. > Puns are optional. > > -- > I didn't attend the funeral, but I sent a nice letter saying that I > approved of it. - Mark Twain > Robert I. Reid <[EMAIL PROTECTED]> http://astro.utoronto.ca/~reid/ > PGP Key: http://astro.utoronto.ca/~reid/pgp.html -- Mark REED | CNN Internet Technology 1 CNN Center Rm SW0831G | [EMAIL PROTECTED] Atlanta, GA 30348 USA | +1 404 827 4754 -- Patch griefs with proverbs. -- William Shakespeare, "Much Ado About Nothing"
