[LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
This year's Y2K: 'Leap second' threatens to break the Internet http://money.cnn.com/2015/01/13/technology/leap-second/index.html -Brooks ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
Brooks Harris wrote: |This year's Y2K: 'Leap second' threatens to break the Internet |http://money.cnn.com/2015/01/13/technology/leap-second/index.html I liked very much that one of the first things Jobs' widow did was to spend money for high quality journalism. Oh man, *how* necessary that would be for a "free" world. --steffen ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
On Tue 2015-01-13T11:03:35 -0500, Brooks Harris hath writ: > This year's Y2K: 'Leap second' threatens to break the Internet > http://money.cnn.com/2015/01/13/technology/leap-second/index.html In that article is a link to a recent version of the Draft CPM document with the options that are being wordsmithed before the final tweak gets presented to the WRC in November http://acma.gov.au/Industry/Spectrum/Spectrum-planning/International-planning-ITU-and-other-international-planning-bodies/wrc-15-agenda-item-114 At the moment it still has options A, B, and C. There is also a similarly recent writeup from the ITU-R itself at https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-UTC.pdf which gives a deeper story about the lack of vote in 2012 to ensure that all the technical options have been fully addressed in further studies related to the issue. It was necessary because the decision was not only of a technical nature but had some regulatory and legal consequences. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165Lat +36.99855 1156 High StreetVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
The ITU link says there will be 2-3 minutes discrepancy by 2100. At the current rate of 1 every 3 years, we would expect 80/3, or 26.667 seconds discrepancy. I have found a reference which estimates the effect of the tidal slow-down and predicts that the discrepancy will still be less than a minute: http://www.gps.gov/cgsic/meetings/2014/matsakis.pdf. See the third backup viewgraph and the first six of the presentation. Steve Allen's web pages have values that are much larger. Who is right? From: Steve Allen To: Leap Second Discussion List Sent: Tuesday, January 13, 2015 10:28 PM Subject: Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks On Tue 2015-01-13T11:03:35 -0500, Brooks Harris hath writ: > This year's Y2K: 'Leap second' threatens to break the Internet > http://money.cnn.com/2015/01/13/technology/leap-second/index.html In that article is a link to a recent version of the Draft CPM document with the options that are being wordsmithed before the final tweak gets presented to the WRC in November http://acma.gov.au/Industry/Spectrum/Spectrum-planning/International-planning-ITU-and-other-international-planning-bodies/wrc-15-agenda-item-114 At the moment it still has options A, B, and C. There is also a similarly recent writeup from the ITU-R itself at https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-UTC.pdf which gives a deeper story about the lack of vote in 2012 to ensure that all the technical options have been fully addressed in further studies related to the issue. It was necessary because the decision was not only of a technical nature but had some regulatory and legal consequences. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://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
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
Le 14.01.2015 04:28, Steve Allen a écrit : On Tue 2015-01-13T11:03:35 -0500, Brooks Harris hath writ: This year's Y2K: 'Leap second' threatens to break the Internet http://money.cnn.com/2015/01/13/technology/leap-second/index.html [1] In that article is a link to a recent version of the Draft CPM document with the options that are being wordsmithed before the final tweak gets presented to the WRC in November http://acma.gov.au/Industry/Spectrum/Spectrum-planning/International-planning-ITU-and-other-international-planning-bodies/wrc-15-agenda-item-114 [2] At the moment it still has options A, B, and C. They don't appear to have been looking very hard at the issue. What happened to the option of going to UTC being defined as UT1 to some agreed precision. I wonder what WP7A have been doing for the last 2 years. They might have even concluded that messing with time was something that the worlds populations might be interested in and open up a public forum. It is not as though the current recommendation has run into a wall. There is also a similarly recent writeup from the ITU-R itself at https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-UTC.pdf [3] which gives a deeper story about the lack of vote in 2012 to ensure that all the technical options have been fully addressed in further studies related to the issue. It was necessary because the decision was not only of a technical nature but had some regulatory and legal consequences. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ [4] Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs [5] Links: -- [1] http://money.cnn.com/2015/01/13/technology/leap-second/index.html [2] http://acma.gov.au/Industry/Spectrum/Spectrum-planning/International-planning-ITU-and-other-international-planning-bodies/wrc-15-agenda-item-114 [3] https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-UTC.pdf [4] http://www.ucolick.org/~sla/ [5] https://pairlist6.pair.net/mailman/listinfo/leapsecs ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
In message <17038998.837509.1421292283082.javamail.ya...@jws100167.mail.ne1.yah oo.com>, Alex Currant via LEAPSECS writes: >Who is right? That reminds me, has anybody tried to do the math on climate change ? The main effect is (probably?) going to be the thermal expansion of the worlds oceans. I did a quick back of the envelope calculation modeling the earth as a sphere radius 6367 km, covered by a 4 km thick shell of water. Increasing the thickness of the water by one meter but retaining its mass, I get a realtive change in angular momentum of 6e-11 which is in the order of a millisecond per year. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@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. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] This year's Y2K: 'Leap second' threatens to break the Internet -Brooks
On Thu 2015-01-15T03:24:43 +, Alex Currant via LEAPSECS hath writ: > The ITU link says there will be 2-3 minutes discrepancy by 2100. > At the current rate of 1 every 3 years, we would expect 80/3, or > 26.667 seconds discrepancy. I have found a reference which > estimates the effect of the tidal slow-down and predicts that the > discrepancy will still be less than a minute: > http://www.gps.gov/cgsic/meetings/2014/matsakis.pdf > See the third backup viewgraph and the first six of the > presentation. > > Steve Allen's web pages have values that are much larger.� People have liked to suppose that the change of Length of Day is linear over time, a constant deceleration. See the first plot of Length of Day on http://www.ucolick.org/~sla/leapsecs/dutc.html The LOD change since Alexander the Great is not linear. It is only approximately matched by any of the three lines. Matsakis points out that looking only at the past two centuries the LOD is pretty much a random walk. This is clearly visible in the zoomed plots on that web page. A linear change in Length of Day results in a quadratic accumulation of Delta T. See the penultimate plot on http://www.ucolick.org/~sla/leapsecs/deltat.html The Delta T since Alexander the Great is not quadratic. It is only approximately matched by any of the three parabolae. > Who is right? The short term LOD variations (weeks or less) have been very well modelled by weather in the atmosphere since I was doing VLBI at JPL in the 1980s. Big snowstorms make visible changes. Richard Gross at JPL has a model of ocean currents which does pretty good at modelling the annual variations which are conventionally described in the equations for UT2-UT1. That's weather too. The decadal fluctuations have been huge and must be caused by changes in the body and or core of the earth. There's a quote (where academics argue about its attribution) "Prediction is hard, especially about the future." Being "right" means predicting the weather in the core of the earth for the next century. I make no such claim. I have merely plotted out the numbers in the literature. Pick your favaorite number. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB Natural Sciences II, Room 165Lat +36.99855 1156 High StreetVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com https://pairlist6.pair.net/mailman/listinfo/leapsecs
