Post #1576719
2026-04-20 20:34 UTC
Replies (1)
-
@s0@cathode.church 2026-04-20 21:30
@stibbons @cutesobri basically UTC is one compromise between the way time is experienced on earth (and the variations in gravity ie altitude, and the planet’s rotational speed in orbit). To distinguish from time zones, it’s called a time scale. TAI is another, that unlike UTC is by definition continuous. The main resulting difference is an offset from UTC caused by all the leap seconds that have occurred since their shared epoch. The history and academic side is a bizarre sprawl of different spinoff timescales that vary in parts per trillion retrospective corrections and and geoid compensations that drives one mad. It’s not even simple to name a date that TAI started, or the epoch of it. Having a vague understanding of this is necessary when dealing with GPS precision time and Precision Time Protocol (IP protocol for sub-microsecond synchronisation), as I do, as they use TAI because of its continuous nature. They then advise a UTC offset in seconds, which has become somewhat of a magic number, 37, since leap seconds in UTC are now officially deprecated and none have occurred since 2017.