[LEAPSECS] LEAPSECS Digest, Vol 153, Issue 3

Wed Jul 15 10:45:21 EDT 2020

Here is a prediction I made in 2014 as well: https://www.gps.gov/cgsic/meetings/2014/matsakis.pdf <https://www.gps.gov/cgsic/meetings/2014/matsakis.pdf>

Slide 6 is an Allan-deviation analysis of UT1-UTC, and from that I concluded that on a decadal scale it looked like a random run.  That means the change in Length of Day is a random walk, and therefore best prediction on a decadal scale is that the LOD would average out at the current average value.   That didn’t work out too well - although back then the predictions being quoted at the ITU meetings just assumed some variation of a long-term slow-down.  

I haven’t re-run the statistics.  I’d still bet that the average LOD stays constant at its latest several-year average value for the next ten years, meaning no negative leap second.   But I’d lower the ante :)

> On Jul 12, 2020, at 4:39 PM, leapsecs-request at leapsecond.com wrote:
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> Today's Topics:
> 
>   1. Re: Bulletin C number 60 (Poul-Henning Kamp)
>   2. Re: Bulletin C number 60 (Warner Losh)
>   3. Re: Bulletin C number 60 (Tom Van Baak)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sun, 12 Jul 2020 15:07:19 +0000
> From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
> To: Leap Second Discussion List <leapsecs at leapsecond.com>, Tony Finch
> 	<dot at dotat.at>
> Subject: Re: [LEAPSECS] Bulletin C number 60
> Message-ID: <78681.1594566439 at critter.freebsd.dk>
> Content-Type: text/plain; charset="us-ascii"
> 
> --------
> Tony Finch writes:
> 
>> The LOD is hovering around 0 and the UT1-UTC chart is looking remarkably flat.
>> 
>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-UT1-UTC-BULA&id=9
>> 
>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-LOD-BULA&id=9
> 
> Is it time for a LEAPSECS betting pool on when the first negative leap second is deleted ?
> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by incompetence.
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Sun, 12 Jul 2020 11:47:07 -0600
> From: Warner Losh <imp at bsdimp.com>
> To: Leap Second Discussion List <leapsecs at leapsecond.com>
> Subject: Re: [LEAPSECS] Bulletin C number 60
> Message-ID:
> 	<CANCZdfoHJdrg50CXyO4LPCTf-5B_SWmqEPOphz6t5H=eV6oTWA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> On Sun, Jul 12, 2020, 9:07 AM Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
> 
>> --------
>> Tony Finch writes:
>> 
>>> The LOD is hovering around 0 and the UT1-UTC chart is looking remarkably
>> flat.
>>> 
>>> 
>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-UT1-UTC-BULA&id=9
>>> 
>>> 
>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-LOD-BULA&id=9
>> 
>> Is it time for a LEAPSECS betting pool on when the first negative leap
>> second is deleted ?
>> 
> 
> I'll have to stock up on the popcorn for the broken things that will find...
> 
> Warner
> 
> -- 
>> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
>> phk at FreeBSD.ORG         | TCP/IP since RFC 956
>> FreeBSD committer       | BSD since 4.3-tahoe
>> Never attribute to malice what can adequately be explained by incompetence.
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> ------------------------------
> 
> Message: 3
> Date: Sun, 12 Jul 2020 13:39:06 -0700
> From: Tom Van Baak <tvb at LeapSecond.com>
> To: leapsecs at leapsecond.com
> Subject: Re: [LEAPSECS] Bulletin C number 60
> Message-ID: <a9f6eb24-a79f-f997-5827-0c50a9508cfb at LeapSecond.com>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
> 
>> Is it time for a LEAPSECS betting pool on when the first negative 
> leap second is deleted?
> 
> Yes. Or when UTC will stop having leap seconds, yes.
> 
> Here's betting on leap seconds; in a long thread from 2012:
> 
> [LEAPSECS] Straw men
> https://pairlist6.pair.net/pipermail/leapsecs/2012-January/003762.html
> 
> Here's a prediction about 2020; from 2014:
> 
>> Any betting person would say the plot shows an upward trend over the
>> past 40 years. A simple linear fit suggests the earth will be back to an
>> honest 86400 second day within a few years, around MJD ~59000 (year 
> ~2020).
> 
> [LEAPSECS] earth speeding up
> https://pairlist6.pair.net/pipermail/leapsecs/2014-April/005102.html
> 
> Attached are the plots from the above posting.
> 
> /tvb
> 
> On 7/12/2020 8:07 AM, Poul-Henning Kamp wrote:
>> --------
>> Tony Finch writes:
>> 
>>> The LOD is hovering around 0 and the UT1-UTC chart is looking remarkably flat.
>>> 
>>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-UT1-UTC-BULA&id=9
>>> 
>>> https://datacenter.iers.org/singlePlot.php?plotname=FinalsAllIAU2000A-LOD-BULA&id=9
>> Is it time for a LEAPSECS betting pool on when the first negative leap second is deleted ?
>> 
> 
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> End of LEAPSECS Digest, Vol 153, Issue 3
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