On Thu, Nov 10, 2016, at 11:18, Clive D.W. Feather wrote:
Random832 said:
The Directive in question views UT, UTC, GMT, and various other terms as being equivalent, so doesn't tell us anything. Well, are they not?
UT and UTC definitely aren't the same.
To a layperson, "UTC" appears to be "UT" with an adjective attached. In technical terms, as far as I can tell, "UT" doesn't seem to exist, and it's not clear that UT1 has a better claim to it than UTC. But regardless, I meant this to set up my question on legal definitions as may be distinct from technical definitions.
What's the *legal* definition of UT and GMT?
To the best of my knowledge neither term is defined in either UK or EU law. Which means that - if it was relevant - a court would either look at the understanding of the person on the Clapham omnibus (possibly with a diversion via the OED) or would ask to be briefed by an accepted expert.
One has to wonder whether they would take into account whether there was really legislative intent to require continuous adjustment by fractional seconds. But it's hard for me to imagine what sort of case the difference might be relevant to in the first place. Incidentally, on the subject of time zone laws not specifying UTC, the US timezones were originally defined in 1918 as the mean time of some respective longitude each west of Greenwich, and wasn't amended to specify hours from UTC until 2007 [Pub. L. 110–69, title III, § 3013(c)(3), Aug. 9, 2007, 121 Stat. 598; this and the text of previous versions mentioning longitude (including an amendment as recent as 2000 defining Chamorro Standard Time as 150 degrees east) can be found at https://www.law.cornell.edu/uscode/text/15/261] The 2007 amendment also, amusingly, moved the southern part of Idaho to Mountain Time from Central Time.