On Wed 2024-04-03T13:41:16-0700 Paul Eggert via tz hath writ:
The "U" in "UTC" is completely inflated of course. It's no more "Universal" than the World Series is a world-wide contest.
Universal Time derives from the 1884 International Meridian Conference where the delegates agreed on a Universal Day. In the late 19th century the meaning of universal was everyone in the world, not more than that. Universal Time is the subdivision of the Universal Day which was resolved to be a mean solar day. (It could have been worse, they could have adopted a different trendy word for everyone in the world like "Catholic Time". The IMC did discuss using Rome or Jerusalem as the prime meridian.) Simon Newcomb attended the IMC until US Department of State kicked him out for comments on the practical issues of defining a prime meridian. A decade later astronomers from countries producing almanacs for navigation all agreed to use Newcomb's expressions for the motion of the earth and sun. The result was every nation agreeing to Universal Time for almanacs. Ironically, as soon as that agreement went into effect the place over which the mean sun stands at 12:00 Universal Time began an increasing deviation eastward from Greenwich. Now the value of UT1 continues to increase its difference from the value of the mean solar time at Greenwich Observatory, but this becomes irrelevant as UTC without leap seconds will abandon close connection with the sun and deviate 365.25 times faster from Greenwich. -- Steve Allen <sla@ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m