Re: [LEAPSECS] podcast from Orolia
On Thu, 2022-05-05 at 20:05 +0100, Tony Finch wrote: > John Sauter via LEAPSECS wrote: > > > > One of the links on that page is to the draft of the resolutions > > for > > the 27th CGPM meeting, in November 2022. Resolution D notes that > > "recent observations on the rotation rate of the Earth indicate the > > possible need for the first negative leap second whose insertion > > has > > never been foreseen or tested". However, they are calling for an > > increase in the maximum value of UT1-UTC by 2035, which would be > > too > > late to avoid the negative leap second, if current predictions hold > > up. > > I have just got today's Bulletin A. The LoD term in the equation for > more > distant estimates of UT1-UTC is now 24h - 280 µs, down from -270 µs > last > week. It has been dropping rapidly again since March, after > increasing > slowly for half a year.. > > My guesstimate for the negative leap second is now end of 2027, and > likely > to get closer if things continue like this! > To illustrate Tony's point, here is a plot of the slope of the IERS's estimates of UT2-UTC since 2005. Values greater than zero predict a negative leap second. UT2 is UT1 with seasonal fluctuations removed. John Sauter (john_sau...@systemeyescomputerstore.com) -- get my PGP public key with gpg --locate-external-keys john_sau...@systemeyescomputerstore.com UT2_slope.pdf Description: Adobe PDF document signature.asc Description: This is a digitally signed message part ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] podcast from Orolia
John Sauter via LEAPSECS wrote: > > One of the links on that page is to the draft of the resolutions for > the 27th CGPM meeting, in November 2022. Resolution D notes that > "recent observations on the rotation rate of the Earth indicate the > possible need for the first negative leap second whose insertion has > never been foreseen or tested". However, they are calling for an > increase in the maximum value of UT1-UTC by 2035, which would be too > late to avoid the negative leap second, if current predictions hold up. I have just got today's Bulletin A. The LoD term in the equation for more distant estimates of UT1-UTC is now 24h - 280 µs, down from -270 µs last week. It has been dropping rapidly again since March, after increasing slowly for half a year.. My guesstimate for the negative leap second is now end of 2027, and likely to get closer if things continue like this! -- Tony Finchhttps://dotat.at/ Lands End to St Davids Head including the Bristol Channel: West or southwest 2 to 4. Slight, mainly smooth in the Bristol Channel, becoming moderate later in west. Occasional rain or showers later. Good, occasionally moderate.___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] podcast from Orolia
On Tue, 2022-05-03 at 14:20 -0700, Steve Allen wrote: > Orolia has a 17 minute podcast about leap seconds > > https://www.orolia.com/place-and-time-episode-3-the-leap-second-on-trial/ > One of the links on that page is to the draft of the resolutions for the 27th CGPM meeting, in November 2022. Resolution D notes that "recent observations on the rotation rate of the Earth indicate the possible need for the first negative leap second whose insertion has never been foreseen or tested". However, they are calling for an increase in the maximum value of UT1-UTC by 2035, which would be too late to avoid the negative leap second, if current predictions hold up. Also, of course, it isn't true that negative leap seconds have never been foreseen or tested. ITU-R TF.460-6 forsees negative leap seconds, and Microsoft made testing applications for the ability to handle leap seconds easier when they added support for leap seconds to Windows 10. Notice that they "propose a new maximum value for the difference (UT1- UTC) that will ensure the continuity of UTC for at least a century". To avoid leap seconds for a century would mean increasing the maximum allowed value of abs(UT1-UTC) to around 60 seconds, considering that there have been 27 leap seconds in the last half century. I expect that means that the leap second correction, when it comes, will be 60 seconds instead of 1. After a century of no leap seconds, having a leap minute will cause a lot of anguish. Thus, this proposal has the effect of wishing a big problem onto our descendents so we don't have a small problem today. John Sauter (john_sau...@systemeyescomputerstore.com) -- get my PGP public key with gpg --locate-external-keys john_sau...@systemeyescomputerstore.com signature.asc Description: This is a digitally signed message part ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] podcast from Orolia
"What is a leap second and why don't we want it?" I wonder where this is going and if I'll like it more than my leap second rants. Warner On Tue, May 3, 2022 at 3:20 PM Steve Allen wrote: > Orolia has a 17 minute podcast about leap seconds > > https://www.orolia.com/place-and-time-episode-3-the-leap-second-on-trial/ > > -- > Steve Allen 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 > ___ > LEAPSECS mailing list > LEAPSECS@leapsecond.com > https://pairlist6.pair.net/mailman/listinfo/leapsecs > ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
