http://www.nytimes.com/2012/01/20/sc...ml?ref=science

"Opponents of leap seconds, led by the United States,
say the sporadic addition of these timekeeping hiccups
is a potential nightmare for computer networks that
depend on precise time to coordinate communications."

Which is a pretty silly statement as leap seconds have been inserted
regularly in the past without causing problems to networks or cell phone
comms. Next L.S. is in June 2012.

--
"We demand rigidly defined areas of doubt and uncertainty."
Douglas Adams - (Could have been a GPS engineer).

On Fri, 20 Jan 2012 14:50:35 -0500, Alan Browne
<(E-Mail Removed)> wrote:

>
>http://www.nytimes.com/2012/01/20/sc...ml?ref=science
>
> "Opponents of leap seconds, led by the United States,
> say the sporadic addition of these timekeeping hiccups
> is a potential nightmare for computer networks that
> depend on precise time to coordinate communications."
>
>Which is a pretty silly statement as leap seconds have been inserted
>regularly in the past without causing problems to networks or cell phone
>comms. Next L.S. is in June 2012.

The networks and things like CDMA networks and GPS are very sensitive
to time keeping, but they could care less about the external world's
time of day. All that matters to them is the Internal device and
network clocks, and whether they are off by a nano-second, or an hour
from real time of day, as long as all of the internal clocks are
synched up. While these devices require very accurate time keeping,
there is not requirement that it be anywhere near in synch with real
world time.

Actually, GPS runs GPS time, which does not have leap seconds, but
broadcasts the current correction to UCT, which does change each time
a leap second is added.

Alan Browne wrote on Jan 20, 2012:

>
>
http://www.nytimes.com/2012/01/20/sc...-leap-seconds-
reprieve.html?ref=s
> cience
>
> "Opponents of leap seconds, led by the United States,
> say the sporadic addition of these timekeeping hiccups
> is a potential nightmare for computer networks that
> depend on precise time to coordinate communications."
>
> Which is a pretty silly statement as leap seconds have been inserted
> regularly in the past without causing problems to networks or cell phone
> comms. Next L.S. is in June 2012.
>
>

Abandoning leap seconds would simply postpone problems into the future as UTC
and solar time drifted further apart.

"In 2004, the idea of swapping leap seconds for a leap hour in a few hundred
years' time was proposed"
<http://www.bbc.co.uk/news/science-environment-15546124>

--
Mike Lane
UK North Yorkshire
mike_lane at mac dot com

On 2012-01-20 17:42 , Mike Lane wrote:
> Alan Browne wrote on Jan 20, 2012:
>
>>
>>
> http://www.nytimes.com/2012/01/20/sc...-leap-seconds-
> reprieve.html?ref=s
>> cience
>>
>> "Opponents of leap seconds, led by the United States,
>> say the sporadic addition of these timekeeping hiccups
>> is a potential nightmare for computer networks that
>> depend on precise time to coordinate communications."
>>
>> Which is a pretty silly statement as leap seconds have been inserted
>> regularly in the past without causing problems to networks or cell phone
>> comms. Next L.S. is in June 2012.
>>
>>
>
> Abandoning leap seconds would simply postpone problems into the future as UTC
> and solar time drifted further apart.
>
> "In 2004, the idea of swapping leap seconds for a leap hour in a few hundred
> years' time was proposed"
> <http://www.bbc.co.uk/news/science-environment-15546124>

Seems off.

It could be done at the minute level, then it would be about every 100
years per this chart (about +30s in 47 years).
http://upload.wikimedia.org/wikipedi...om_SI_day_.svg

--
"We demand rigidly defined areas of doubt and uncertainty."
Douglas Adams - (Could have been a GPS engineer).

matt weber wrote:
> ... All that matters to them is the Internal device and
> network clocks, and whether they are off by a nano-second, or an hour
> from real time of day, as long as all of the internal clocks are
> synched up.

Hmm, the speed of light is about a foot per nanosecond, so I wonder what is
the definition of synchronisation across the whole world...

Mike.
--
If reply address is Mike@@mjcoon.+.com (invalid), remove spurious "@"
and substitute "plus" for +.

Alan Browne wrote on Jan 20, 2012:

> On 2012-01-20 17:42 , Mike Lane wrote:
>> Alan Browne wrote on Jan 20, 2012:
>>
>>>
>>>
>> http://www.nytimes.com/2012/01/20/sc...-leap-seconds-
>> reprieve.html?ref=s
>>> cience
>>>
>>> "Opponents of leap seconds, led by the United States,
>>> say the sporadic addition of these timekeeping hiccups
>>> is a potential nightmare for computer networks that
>>> depend on precise time to coordinate communications."
>>>
>>> Which is a pretty silly statement as leap seconds have been inserted
>>> regularly in the past without causing problems to networks or cell phone
>>> comms. Next L.S. is in June 2012.
>>>
>>>
>>
>> Abandoning leap seconds would simply postpone problems into the future as
>> UTC
>> and solar time drifted further apart.
>>
>> "In 2004, the idea of swapping leap seconds for a leap hour in a few hundred
>> years' time was proposed"
>> <http://www.bbc.co.uk/news/science-environment-15546124>
>
> Seems off.
>
> It could be done at the minute level, then it would be about every 100
> years per this chart (about +30s in 47 years).
>
http://upload.wikimedia.org/wikipedi...day_length_fro

> m_SI_day_.svg
>
>

OK - whatever...
The fact remains that abandoning leap seconds means you have an even bigger
correction to make in the future - with even more disruption presumably.

--
Mike Lane
UK North Yorkshire
mike_lane at mac dot com

In article <(E-Mail Removed) >,
"Mike Coon" <Mike@@mjcoon.+.com> wrote:

> matt weber wrote:
> > ... All that matters to them is the Internal device and
> > network clocks, and whether they are off by a nano-second, or an hour
> > from real time of day, as long as all of the internal clocks are
> > synched up.
>
> Hmm, the speed of light is about a foot per nanosecond, so I wonder what is
> the definition of synchronisation across the whole world...

It's their *rates* that need to be the same, not their epochs.

Isaac

On Jan 20, 10:42*pm, Mike Lane <mike.lane.use...@ntlworld.co.uk>
wrote:
> Alan Browne wrote on Jan 20, 2012:
>
>
>
> http://www.nytimes.com/2012/01/20/sc...-leap-seconds-
> reprieve.html?ref=s
>
> > cience
>
> > * * * * *"Opponents of leap seconds, led by the United States,
> > * * * * * say the sporadic addition of these timekeeping hiccups
> > * * * * * is a potential nightmare for computer networks that
> > * * * * * depend on precise time to coordinate communications.."
>
> > Which is a pretty silly statement as leap seconds have been inserted
> > regularly in the past without causing problems to networks or cell phone
> > comms. *Next L.S. is in June 2012.
>
> Abandoning leap seconds would simply postpone problems into the future asUTC
> and solar time drifted further apart.
>
> "In 2004, the idea of swapping leap seconds for a leap hour in a few hundred
> years' time was proposed"
> <http://www.bbc.co.uk/news/science-environment-15546124>
>
> --
> Mike Lane
> UK North Yorkshire
> mike_lane at mac dot com

"... our clocks kept so good a correspondence with the Heavens that I
doubt it not but they would prove the revolutions of the Earth to be
isochronical (equable/constant)" John Flamsteed ,1677

They not only decoupled timekeeping from the Earth's dynamics
centuries ago but in doing so introduced 4 extra rotations that the
Earth does not have ,that late 17th century error is framed concisely
in this NASA statement -

"The Earth spins on its axis about 366 and 1/4 times each year, but
there are only 365 and 1/4 days per year." Goddard Space Flight
Center

So there is this rolling 4 extra rotations in 1461 days/4 years while
everyone fusses in the direction of atomic clocks and the ridiculous
'leap second'.

To explain how 1461 days in 4 years converts into 1461 rotations in 4
orbital circuits is the equivalent of trying to explain the workings
of a Saturn V rocket,computer programming or any other process that
requires intricate details to an audience unfamiliar with the
components however the fact is the dominant ideology on which a 'leap
second' is based is a mindnumbing 1465 rotations in 1461 days.

So,the issue is that the 'leap second' exposes an underlying problem
rather than guys congratulating themselves on how accurate their
atomic clocks are or more importantly,the false conclusion that the
Earth's rotation as an independent motion can be extracted directly
from stellar circumpolar motion whether by ancient pendulum clocks
(Flamsteed) or contemporary VLBI.

oriel36 wrote:
> "... our clocks kept so good a correspondence with the Heavens that I
> doubt it not but they would prove the revolutions of the Earth to be
> isochronical (equable/constant)" John Flamsteed ,1677
>
> They not only decoupled timekeeping from the Earth's dynamics
> centuries ago but in doing so introduced 4 extra rotations that the
> Earth does not have ,that late 17th century error is framed concisely
> in this NASA statement -
>
> "The Earth spins on its axis about 366 and 1/4 times each year, but
> there are only 365 and 1/4 days per year." Goddard Space Flight
> Center
>
> So there is this rolling 4 extra rotations in 1461 days/4 years while
> everyone fusses in the direction of atomic clocks and the ridiculous
> 'leap second'.
>
> To explain how 1461 days in 4 years converts into 1461 rotations in 4

1465 rotations presumably

> orbital circuits is the equivalent of trying to explain the workings
> of a Saturn V rocket,computer programming or any other process that
> requires intricate details to an audience unfamiliar with the
> components however the fact is the dominant ideology on which a 'leap
> second' is based is a mindnumbing 1465 rotations in 1461 days.

You have most of your facts right, and still totally misunderstands the
issues! :-(

Yes, the Earth takes less than 24 hours to make a full rotation, this
has nothing at all to do with leap seconds: This is simply because we
defined a "day" (i.e. 24 hours) to be the average time interval between
high noon, and since the Earth uses a year to make one full circuit of
the Sun, it has to rotate a little bit more than 360 degrees to get back
to facing the Sun.

In fact, the ratio between a full rotation and a day has to be about
365.2422/366.2422 or (days_in_a_year)/(days_in_a_year+1)

If you do this calculation you'll also find the same ratio between the
GPS orbit time (~11:58) and 12 hours, since the GPS sats work in an ECEF
coordinate system, disregarding the movement around the Sun.
>
> So,the issue is that the 'leap second' exposes an underlying problem
> rather than guys congratulating themselves on how accurate their
> atomic clocks are or more importantly,the false conclusion that the
> Earth's rotation as an independent motion can be extracted directly
> from stellar circumpolar motion whether by ancient pendulum clocks
> (Flamsteed) or contemporary VLBI.

Huh?

VLBI is in fact how IERS measure the current speed of the Earth's rotation:

http://www.iers.org/nn_10406/IERS/EN...tml?__nnn=true

Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"