lobsters score: 16 · tags: science
I haven’t been paying close attention to this story in the last year or two, so it’s a surprise that the change is happening sooner than expected (tho it wouldn’t have been a surprise if I had looked at the meeting agenda):
- continuous UTC will become effective on 20 May 2027,
- the maximum value for the difference |UT1-UTC| will be 3 600 seconds (1 hour), ensuring the long term continuity for UTC for several centuries,
The provisional plan agreed at previous treaty conferences (GCPM and WRC) was to make the change in 2035, but the prospect of a negative leap second encouraged them to make the change sooner.
However it seems that the near-term likelihood of negative leap second has become much lower this year. If you look at the earth orientation parameters finals.data (IAU2000) plots observe:
- the slope of UT1-UTC seems to be returning to normal, and (equivalently) the length-of-day is roughly trending slightly over 24h instead of slightly under
- the mysterious change in behaviour of the dX and dY charts that matches the change in slope of UT1-UTC seems to have reverted as well
It’s hard to be sure if earth rotation is really back to its pre-2020 behaviour, because much of the change that I’m observing is in the blue prediction section of the charts.
score 1 · canonical
Sorry, about the title, but I couldn‘t resist.
Please, you should have. Titles like this are a pain.
I have suggested the subtitle: “On the technical actions needed to ensure the continuity of UTC”.
score 1 · canonical