Comment by anonymous_user9
3 days ago
UTC is still fixed to the sun. Without leap seconds, it will be hundreds of years before the divergence between UTC and the sun is perceptible in daily life. Even then, I can't think of anything where that would matter.
I think there is a good alternative available, UT1. UTC was always divergent from UT1 anyway, so this change shouldn't affect anyone who actually needs precise solar timekeeping.
More importantly, there are many good reasons to drop leap seconds, such as the massive increase in complexity they impose on all time-related code.
Standards should serve people, which is why leap seconds should never have existed. Imagine: "Sure some airliners crashed, and half the internet went offline for a couple days, but if you drive to the right longitude line, the sun will be exactly overhead at 12:00:00, and here in town it's overhead at 12:23:48. That's worth anything. I'd hate to live in a world where it was overhead at 12:23:49, or that'd be over my great-great-great grandchildren at 12:23:47."
The promise of UTC is bounded deviation from solar time while keeping the intervals of ISO seconds. I think this is a valuable trade-off that should continue to exist.
> I think this is a valuable trade-off that should continue to exist.
And it has, the bound on the deviation was increased slightly to 3600 seconds
I'd prefer if dUT1 was restored to ±.9s after NTP rollover in 2036, Y2K38, and GPS week rollover in 2038. This way we now know precisely what the UTC times will be for those events and dUT1 probably will be <10s at that point. Software will need to deal with times like 23:59:63 properly by then (too much still can't handle 23:59:60 leap seconds yet). Maybe we could have dUT1 < ±9.9s going forward.
The problems with letting dUT1 > 1800 and above is that well before that it starts mattering for almost everything and then you have to consult the solution (here's just 2025's):
That's generated by the US Navy for all intents and is way more data than used now for leap seconds which are fine enough of a granularity for most things. Future timestamps in UT1 will get difficult to handle as well. Previously software could assume it knew to the closest second which was often good enough.
I'm not sure if I completely follow you, but I'd like to ask: Why is it a problem if there's a divergence between UT1 and UTC? Besides astronomers, who cares if the sun is directly overhead a few minutes later than it "should" be?
Everyone who paid for expensive equipment that gets UT1 time to a tenth of a second in a year or two.
https://www.nist.gov/pml/time-and-frequency-division/time-di...
Nope, the whole point of this is to remove the coupling for UTC. You can either have monotonic time (or at least per-observer monotonic time), or you can follow earth's rotation. Choosing monotonic time is perfectly fine (and feel free to pick your epoch and time unit), but like we have timezones such that 12:00 means something (mostly), having the human conception of what time means does imply that we do kinda need to look at what's happening outside.